Behavioural and biochemical stress responses of Palinurus elephas after exposure to boat noise pollution in tank

Investigating the impact of anthropogenic noise on the decision-making of dwarf mongoose offspring

Anthropogenic (man-made) noise constitutes a novel and widespread pollutant which is increasing in prevalence in terrestrial and aquatic ecosystems, resulting in alterations of natural soundscapes. There is proliferating evidence that noise leads to maladaptive behaviour in wildlife, yet few studies have addressed the effect on mammalian parent-offspring interactions. We investigated the impact of road noise on dwarf mongoose (Helogale parvula) offspring nearest-neighbour decision-making while foraging, using a field-based playback experiment. We predicted that offspring would forage closer to groupmates, especially adult and dominant individuals, when experiencing road noise compared with ambient sound to reduce communication masking and alleviate stress. We also predicted that noise would have a reduced effect with increasing offspring age owing to reduced reliance on adult groupmates for provisioning and predator defence. However, we found that mean nearest-neighbour distance and nearest-neighbour intrinsic characteristics (age, sex and dominance status) did not differ significantly between sound treatments, and these responses did not vary significantly with focal individual age. Noise may not impact nearest-neighbour decision-making owing to habituation from chronic natural exposure; alternatively, noise could induce stress and distraction, resulting in maladaptive decision-making. Future work should aim to detangle the underlying mechanisms mediating parent-offspring interactions in conditions of anthropogenic noise.

Anthropogenic noise limits resource distribution without changing social hierarchies

Increasing evidence demonstrates that anthropogenic noise is a global pollutant that threatens marine ecosystems. Mounting numbers of studies show its diverse effects on individuals and their behaviour. However, little is known about how individual changes in response to anthropogenic noise could cascade through groups and populations affecting resource distribution vital for survival and fitness. Here we test the hypotheses that anthropogenic noise could alter resource distribution, associated hierarchies and consequently individual benefits. We used groups of hermit crabs, a globally distributed model system for assessing impacts of environmental change on wildlife and measured in controlled laboratory conditions the resource distribution of their reusable shelters (gastropod shells) under ship noise and ambient control playbacks. We applied vacancy chain theory to test three predictions about how new resource units create benefits for a population. A new resource unit leads to (i) a cascade of resource abandonments and acquisitions (= chain of vacancy moves) based on an internal (ii) hierarchy (here size-based) which allows (iii) more than one individual to benefit. All three predictions were supported under control sound. Under anthropogenic noise however, fewer individuals benefitted from the arrival of a new, empty shell, while the size-based hierarchy was maintained. The latter was apparent in chain structures, which were concordant between sound treatments. This experiment shows that anthropogenic noise can affect individual behaviours that cascade through groups. This has the potential to disrupt wider resource distribution in populations.

The effect of anthropogenic substrate-borne vibrations on locomotion of the fiddler crab Austruca lactea

The anthropogenic construction activities on the coasts, such as pile-driving, generate vibrations that propagate through the substrate. Such substrate-borne vibrations could potentially affect marine organisms inhabiting the benthic environments. However, there is a lack of documented studies on the effects of vibrations on benthic animals. To investigate whether anthropogenic substrate-borne vibrations such as pile-driving operation influence the fiddler crab, Austruca lactea, we measured their locomotion response under vibrations of 35, 120, 250, 500, and 750 Hz generated by a vibrator. We compared the locomotion of crabs between control and vibration-treatment groups using videography. The duration of movements was significantly lower under 120 Hz vibrations compared to the control. Moreover, crab velocity was significantly higher under vibrations of 120 Hz and 250 Hz compared to the control group. Our result suggests that A. lactea can detect low-frequency substrate-borne vibrations and experience stress, leading to increased energy consumption.

Soundscape of a Mediterranean seashore during loggerhead sea turtle (Caretta caretta) spawning season

The soundscape is an intrinsic property of an ecosystem and influences the species that live in it. Here, we examined for the first time the soundscape of a beach, one of the most dynamic ecosystems on Earth, where every year the loggerhead sea turtle Caretta caretta lays eggs. The aim of this work was to analyze the acoustic components (biophony, anthropophony and geophony) to which turtles embryos were exposed throughout the development and the post-hatching period. The acoustic monitoring was carried out on the volcanic island of Linosa (central Mediterranean Sea, Strait of Sicily), during the months of July and August 2022, close to two turtle nests. Results revealed that all the acoustic levels (octave bands from 4 Hz to 16 kHz, and total 1-24,000 Hz band) showed lower values in July, and during the night. Furthermore, above 1 kHz the levels decreased and had very little variability. Anthropogenic noise was the main component of the soundscape and consisted of marine and land traffic, that affected sound levels directly or via seismic tremors. When the beach was exposed to the breaking waves, the latters were the first contributor to the noise up to 1 kHz. The only recognized biophony was represented by the shearwater choruses in July (at the frequency band 700-1500 Hz), but they had a negligible weight on the soundscape. Finally, human speech contributed to the soundscape at higher frequencies (1-8 kHz). These outcomes show that the embryos and the post-hatching turtles are exposed to a high anthropogenic noise level, which the effects of are still unknown.

The impact of chasing stress on the metabolism of the Atlantic Ghost Crab Ocypode quadrata (Fabricius, 1787)

Ocypode quadrata, a Ghost crab species found along the western Atlantic coast, is considered a bioindicator of anthropogenic impact on sandy beaches. Ghost Crabbing, a touristic activity in which ghost crabs are chased just for fun, is a potentially threatening activity for this crab. In crustaceans, metabolites such as glucose and lactate, and the gene expression of crustacean hyperglycemic hormone (CHH) and heat shock proteins (HSPs) increase when the animals are exposed to several types of stress, including alterations in temperature, salinity, or exposure to xenobiotics. This work was developed to identify if being chased by humans would affect these markers of stress in this species of crab. The effects of chasing stress on hemolymph and tissue metabolites and the gene expression levels of CHH and HSP70 were investigated. The levels of lactate in the hemolymph of stressed crabs were six times higher than those of control crabs immediately after chasing and decreased progressively during recovery, indicating an active anaerobic metabolism during the stress. On the contrary, glucose levels in the hemolymph of the stressed crabs increased progressively from 30 to 60 min after chasing, indicating an inverse correlation between glucose and lactate and the conversion of lactate to glucose by gluconeogenesis. In stressed crabs, the levels of triglycerides in the hemolymph decreased 30 min after chasing, while the opposite tended to occur in the hepatopancreas, indicating that during recovery, the crabs use triglycerides as energy source to sustain aerobic metabolism. Finally, this study demonstrates that ghost crabs are stressed by minimum human contact and that "ghost crabbing" must not be encouraged as a tourist activity.

Pile driving and drilling underwater sounds impact the metamorphosis dynamics of Pecten maximus (L., 1758) larvae

One of the biggest challenges of the 21st century is to reduce carbon emissions and offshore wind turbines seem to be an efficient solution. However, during the installation phase, high levels of noise are emitted whose impacts remain not well known, particularly on benthic marine invertebrates displaying a bentho-planktonic life-cycle. For one century, larval settlement and subsequent recruitment has been considered as a key topic in ecology as it determines largely population renewal. Whereas several recent studies have shown that trophic pelagic but also natural soundscape cues could trigger bivalve settlement, the role of anthropogenic noise remains poorly documented. Therefore, we conducted experiments to assess potential interacting effects of diet and pile driving or drilling sounds on the great scallop (Pecten maximus) larval settlement. We demonstrate here that pile driving noise stimulates both growth and metamorphosis as well as it increases the total lipid content of competent larvae. Conversely, drilling noise reduces both survival and metamorphosis rates. For the first time, we provide evidence of noise impacts associated to MREs installation on P. maximus larvae and discuss about potential consequences on their recruitment.

Separate and combined effects of boat noise and a live crab predator on mussel valve gape behavior

Noisy human activities at sea are changing the acoustic environment, which has been shown to affect marine mammals and fishes. Invertebrates, such as bivalves, have so far received limited attention despite their important role in the marine ecosystem. Several studies have examined the impact of sound on anti-predator behavior using simulated predators, but studies using live predators are scarce. In the current study, we examined the separate and combined effects of boat sound playback and predator cues of shore crabs (Carcinus maenas) on the behavior of mussels (Mytilus spp.). We examined the behavior of the mussels using a valve gape monitor and scored the behavior from the crabs in one of two types of predator test conditions from video footage to control for effects from potential, sound-induced variation in crab behavior. We found that mussels closed their valve gape during boat noise and with a crab in their tank, but also that the stimulus combination did not add up to an even smaller valve gape. The sound treatment did not affect the stimulus crabs, but the behavior of the crabs did affect the valve gape of the mussels. Future research is needed to examine whether these results stand in situ and whether valve closure due to sound has fitness consequences for mussels. The effects on the well-being of individual mussels from anthropogenic noise may be relevant for population dynamics in the context of pressure from other stressors, their role as an ecosystem engineer, and in the context of aquaculture.

Types, sources, socioeconomic impacts, and control strategies of environmental noise: a review

Noise exposure has reached an alarming degree over the years because of rapid growth in the industry, transportation, and urbanization. Therefore, it is a dire need to provide awareness of the sources and mitigation strategies of noise, and to highlight the health, and socio-economic impacts of noise. A few research studies have documented this emerging issue; however, there is no comprehensive document describing all types of noise, their impacts on living organisms, and control strategies. This review article summarizes the sources of noise; their effects on industrial workers, citizens, and animals; and the value of property in noisy areas. The plethora of literature is showing an increased level of noise in various cities of the world, which have various health consequences such as high blood pressure, insomnia, nausea, heart attack, exhaustion, dizziness, headache, and triggered hearing loss. Apart from humans, noise also affects animal habitat, preying, and reproduction ability; increases heart rate and hearing loss to even death and loss in property value; and impairs the hospital environment. Finally, we have discussed the possible strategies to mitigate the noise problem, policy statements, and regulations to be followed, with future research directions based on the identified research gaps.

The impact of seismic survey exposure on the righting reflex and moult cycle of Southern Rock Lobster (Jasus edwardsii) puerulus larvae and juveniles

Anthropogenic aquatic noise is recognised as an environmental pollutant with the potential to negatively affect marine organisms. Seismic surveys, used to explore subseafloor oil reserves, are a common source of aquatic noise that have garnered attention due to their intense low frequency inputs and their frequent spatial overlap with coastal fisheries. Commercially important Southern Rock Lobster (Jasus edwardsii) adults have previously shown sensitivity to signals from a single seismic air gun. Here, the sensitivity of J. edwardsii juveniles and puerulus to the signals of a full-scale seismic survey were evaluated to determine if early developmental stages were affected similarly to adults, and the range of impact. To quantify impact, lobster mortality rates, dorsoventral righting reflex and progression through moult cycle were evaluated following exposure. Exposure did not result in mortality in either developmental stage, however, air gun signals caused righting impairment to at least 500 m in lobsters sampled immediately following exposure, as had previously been reported in adults with corresponding sensory system damage following exposure. Impairment resulting from close range (0 m) exposure appeared to be persistent, as previously reported in adults, whereas juveniles exposed at a more distant range (500 m) showed recovery, indicating that exposure at a range of 500 m may not cause lasting impairment to righting. Intermoult duration was (time between moults) significantly increased in juveniles exposed at 0 m from the source, indicating the potential for slowed development, growth, and physiological stress. These results demonstrate that exposure to seismic air gun signals have the potential to negatively impact early life history stages of Southern Rock Lobsters. The similarity of both the impacts and the sound exposure levels observed here compared to previous exposure using a single air gun offer validation for the approach, which opens the potential for accessible field-based experimental work into the impact of seismic surveys on marine invertebrates.

Traffic noise and adiposity: a systematic review and meta-analysis of epidemiological studies

Traffic noise has attracted much attention as a significant and intractable public health threat. This study was designed as a systematical review to explore the association of traffic noise with different indicators of obesity, thus providing updated quantitative estimates for the pooled effect estimates of the existing literature. We conducted an extensive search for epidemiological studies that investigated the association of traffic noise with obesity in three electronic databases till February 23, 2021. We used random-effects meta-analysis to calculate the summary effect estimates for each 10-dB(A) increase in noise and compared the highest with the lowest category of noise in relation to seven obesity indicators. Meanwhile, we assessed the risk of bias and the overall quality of the evidence of each study as well as the level of evidence for each exposure-outcome pair. The initial search identified 30 studies, 13 of which were ultimately included. The meta-analysis for the highest versus the lowest category of noise exposure was generally associated with higher waist circumfluence (WC) ranging from 0.326 cm (95% confidence interval (CI) = 0.078, 0.574) to 0.705 cm (95% CI = 0.071, 1.340) and higher odds of central obesity ranging from 1.055 (95% CI = 1.000, 1.109) to 1.167 (95% CI = 1.037, 1.298). When the continuous exposure (each 10 dB(A) increase in noise) was introduced, similar results were found. This study indicated positive associations of traffic noise with WC and central obesity. However, in consideration of some limitations, there is an urgent need for future studies to increase the sample size, discriminate the etiological differences in different noise and obesity indicators, and thoroughly consider socioeconomic status.

Effect of low-frequency noise on the survival rate and immunity of infected Vibrio parahaemolyticus sea slug (Onchidium reevesii)

Anthropogenic noise in the marine environment has become a global environmental pollutant that affects the behavior, physiology and immunity of marine animals. However, the resistance of marine animals to pathogens while under the influence of noise is a topic that has received little attention. To assess the immune defense response of sea slugs against pathogens when exposed to low frequency noise, we performed 120 h exposure experiments on sea slugs after a Vibrio parahaemolyticus application in low frequency noise at 500 Hz and 1000 Hz. We found that after the infection with V. parahaemolyticus, the survival rate of the sea slugs decreased, the apoptosis rate and reactive oxygen species (ROS) production of hemocytes increased significantly (P < 0.05), the proliferation of hemocytes accelerated, the activities of enzymes such as superoxide dismutase (SOD), catalase (CAT), alkaline phosphatase (AKP), alanine transaminase (ALT) and lysozyme (LZM) in the hepatopancreas increased significantly, and the expression of TNF signaling pathway-related genes (TNF-α, FADD, Caspase 8, Caspase 3) and Hsp70 genes were generally upregulated. In addition, exposure of sea slug after infected with V. parahaemolyticus to low frequency noise resulted in a significant increase in both antioxidant and immune parameters, which were positively correlated with frequency. The results showed that noise frequency and exposure time had an interactive effect on the above indicators. In summary, low-frequency noise exposure increases the risk of pathogenic infections in sea slugs and exacerbates the negative effects on the antioxidant capacity and immune metabolism of the organism.

Effect of biological and anthropogenic habitat sounds on oxidative stress biomarkers and behavior in a key crab species

Soundscapes are characterized by a combination of natural and anthropogenic sounds. This study evaluated the stress effect of biological and anthropogenic sounds characterizing a Man and Biosphere UNESCO wetland, by assessing the protein content, oxidative biomarkers, and behavior of a key crab species (Neohelice granulata), through a tank-laboratory experiment. Biological sounds corresponded to predators of N. granulata (fish and crustacean stimuli), while anthropogenic ones belonged to motorboat passages (boat stimulus). Biochemical results showed differences depending on the sound stimuli used and the crab tissue analyzed. Protein content was higher in hemolymph when crabs were exposed to fish and boat stimuli, and in gills when exposed to boat stimulus. The enzymatic activity in hemolymph showed a decreased GST (fish stimulus) and CAT (fish and boat stimuli) activity, in hepatopancreas a higher GST (crustacean stimulus) and CAT (crustacean and boat stimuli) activity was found, and in gills a higher CAT activity was also observed (crustacean and boat stimuli). Lipid peroxidation was higher only in hemolymph (fish and crustacean stimuli). Protein oxidation was higher in gills (fish stimulus) and hepatopancreas (crustacean stimulus). Behavioral analysis demonstrated that the crab locomotion activity diminished when exposed to diverse sound stimuli. Thus, both sound sources caused physiological and behavioral stress in this species. The results contribute important data to be used in the development of management plans considering the habitat importance in terms of biodiversity, the ecosystem services provided and the role of the studied species.

Recent progress in marine noise pollution: A thorough review

The increase in urbanization and the progressive development of marine industries have led to the appearance of a new kind of pollution called "noise pollution". This pollution exerts an increasing pressure on marine mammals, fish species, and invertebrates, which constitutes a new debate that must be controlled in a sustainable way by environmental and noise approaches with the objective of preserving marine and human life. Despite, noise pollution can travel long distances underwater, cover large areas, and have secondary effects on marine animals; by masking their ability to hear their prey or predators, finding their way, or connecting group members. During the COVID-19 pandemic, except for the transportation of essential goods and emergency services, all the public transport services were suspended including aircraft and ships. This lockdown has impacted positively on the marine environment through reduction of the noise sources. In this article, we are interested in noise pollution in general, its sources, impacts, and the management and future actions to follow. And since this pollution is not studied in Morocco, we focused on the different sources that can generate it on the Moroccan coasts. This is the first review article, which focuses on the impact of the COVID 19 pandemic on this type of pollution in the marine environment; which we aim to identify the impact of this pandemic on underwater noise and marine species. Finally, and given the increase in noise levels, preventive management, both at the national and international level, is required before irreversible damage is caused to biodiversity and the marine ecosystem.

Haemolymphatic Parameters in Two Aquaculture Crustacean Species Cherax destructor (Clark, 1836) and Cherax quadricarinatus (Von Martens, 1868)

Simple Summary

The spread of freshwater crustacean farms, in particular of the Australian species Cherax, has been widespread in recent years and has aroused particular interest at an economic level. Knowledge of the basic levels of some biochemical parameters becomes particularly important to understanding the health status of the animals and, therefore, for the maintenance of aquaculture facilities. In this study, the values of some biochemical parameters of two species of Cherax, Cherax destructor and Cherax quadricarinatus, reared in an Italian aquaculture plant, were evaluated for the first time. These parameters should contribute to assessing the health status of these animals on a farm and to understanding if they will be affected by stressful conditions or not.

Abstract

In the last few years, there has been a notable development in the breeding of freshwater shrimp (astaciculture), which involved various species and in particular, the two Australian Parastacidae species, Cherax destructor and Cherax quadricarinatus. Information about the haemolymphatic parameters of these two species is fragmentary, and filling these gaps becomes important given their importance in aquaculture. Cellular and biochemical parameters were analyzed in both species to create a reference baseline for these parameters to identify the state of welfare or suffering of these animals. The results showed that the total haemocyte count, haemocyte subpopulations, enzymatic activities and pH are similar between the two species, while total protein and osmolality are higher in C. destructor than C. quadricarinatus. Knowledge of these parameters could assist in evaluating the good health status of these species kept in aquaculture facilities.

Potential impacts from simulated vessel noise and sonar on commercially important invertebrates

Human usage of coastal water bodies continues to increase and many invertebrates face a broad suite of anthropogenic stressors (e.g., warming, pollution, acidification, fishing pressure). Underwater sound is a stressor that continues to increase in coastal areas, but the potential impact on invertebrates is not well understood. In addition to masking natural sound cues which may be important for behavioral interactions, there is a small but increasing body of scientific literature indicating sublethal physiological stress may occur in invertebrates exposed to high levels of underwater sound, particularly low frequency sounds such as vessel traffic, construction noise, and some types of sonar. Juvenile and sub-adult blue crabs (Callinectes sapidus) and American lobsters (Homarus americanus) were exposed to simulated low-frequency vessel noise (a signal was low-pass filtered below 1 kHz to ensure low-frequency content only) and mid-frequency sonar (a 1-s 1.67 kHz continuous wave pulse followed by a 2.5 to 4.0 kHz 1-s linear frequency modulated chirp) and behavioral response (the animal's activity level) was quantified during and after exposure using EthoVision XT™ from overhead video recordings. Source noise was quantified by particle acceleration and pressure. Physiological response to the insults (stress and recovery) were also quantified by measuring changes in hemolymph heat shock protein (HSP27) and glucose over 7 days post-exposure. In general, physiological indicators returned to baseline levels within approximately 48 h, and no observable difference in mortality between treatment and control animals was detected. However, there was a consistent amplified hemolymph glucose signal present 7 days after exposure for those animals exposed to mid-frequency sound and there were changes to C. sapidus competitive behavior within 24 h of exposure to sound. These results stress the importance of considering the impacts of underwater sound among the suite of stressors facing marine and estuarine invertebrates, and in the discussion of management actions such as protected areas, impact assessments, and marine spatial planning efforts.

Noisy waters can influence young-of-year lobsters' substrate choice and their antipredatory responses

Offshore human activities lead to increasing amounts of underwater noise in coastal and shelf environments, which may affect commercially-important benthic invertebrate groups like the re-stocked Helgoland European lobster (Homarus gammarus) in the German Bight (North Sea). It is crucial to understand the impact tonal low-frequency noises, like maritime transport and offshore energy operations, may have on substrate choice and lobsters' behavior to assess potential benefits or bottlenecks of new hard-substrate artificial offshore environments that become available. In this study, we investigated the full factorial effect of a tonal low-frequency noise and predator presence on young-of-year (YOY) European lobsters' in a diurnal and nocturnal experiment. Rocks and European oyster shells (Ostrea edulis) were offered as substrate to YOY lobsters for 3 h. Video recordings (n = 134) allowed the identification of lobsters' initial substrate choice, diel activity and key behaviors (peeking, shelter construction, exploration and hiding). To ensure independence, YOY lobsters in the intermolt stage were randomly selected and assigned to the experimental tanks and used only once. We provide the first evidence that stressors alone, and in combination, constrain YOY lobsters' initial substrate choice towards rocks. During nighttime, the joint effect of exposure to a constant low-frequency noise and predator presence decreased antipredator behavior (i.e., hiding) and increased exploration behavior. Noise may thus interfere with YOY lobsters' attention and decision-making processes. This outcome pinpoints that added tonal low-frequency noise in the environment have the potential to influence the behavior of early-life stages of European lobsters under predator pressure and highlights the importance of including key benthic invertebrates' community relationships in anthropogenic noise risk assessments. Among others, effects of noise must be taken into consideration in plans involving the multi-use of any offshore area for decapods' stock enhancement, aquaculture, and temporary no-take zones.

Marine invertebrate anthropogenic noise research - Trends in methods and future directions

Selecting the correct methods to answer one's chosen question is key to conducting rigorous, evidence-based science. A disciplines' chosen methods are constantly evolving to encompass new insights and developments. Analysing these changes can be a useful tool for identifying knowledge gaps and guiding future studies. Research on the impact of anthropogenic noise on marine invertebrates, a topic with specific methodological challenges, has undergone substantial changes since its beginning in 1982. Using this field as an example, we demonstrate the benefits of such method analysis and resulting framework which has the potential to increase conclusive power and comparability of future studies. We list taxa studied to date, use a range of descriptors to analyse the methods applied, and map changes in experimental design through time. Based upon our analysis, three research strategies are proposed as a best practice framework for investigating effects of noise on marine invertebrates and delivering policy-relevant information.

No negative effects of boat sound playbacks on olfactory-mediated food finding behaviour of shore crabs in a T-maze

Anthropogenic noise underwater is increasingly recognized as a pollutant for marine ecology, as marine life often relies on sound for orientation and communication. However, noise may not only interfere with processes mediated through sound, but also have effects across sensory modalities. To understand the mechanisms of the impact of anthropogenic sound to its full extent, we also need to study cross-sensory interference. To study this, we examined the effect of boat sound playbacks on olfactory-mediated food finding behaviour of shore crabs. We utilized opaque T-mazes with a consistent water flow from both ends towards the starting zone, while one end contained a dead food item. In this way, there were no visual or auditory cues and crabs could only find the food based on olfaction. We did not find an overall effect of boat sound on food finding success, foraging duration or walking distance. However, after excluding deviant data from one out of the six different boat stimuli, we found that crabs were faster to reach the food during boat sound playbacks. These results, with and without the deviant data, seem to contradict an earlier field study in which fewer crabs aggregated around a food source during elevated noise levels. We hypothesise that this difference could be explained by a difference in hunger level, with the current T-maze crabs being hungrier than the free-ranging crabs. Hunger level may affect the motivation to find food and the decision to avoid or take risks, but further research is needed to test this. In conclusion, we did not find unequivocal evidence for a negative impact of boat sound on the processing or use of olfactory cues. Nevertheless, the distinct pattern warrants follow up and calls for even larger replicate samples of acoustic stimuli for noise exposure experiments.

Biological Sound vs. Anthropogenic Noise: Assessment of Behavioural Changes in Scyliorhinus canicula Exposed to Boats Noise

Despite the growing interest in human-made noise effects on marine wildlife, few studies have investigated the potential role of underwater noise on elasmobranch species. In this study, twelve specimens of small-spotted catshark (Scyliorhinus canicula) were exposed to biological and anthropogenic sounds in order to assess their behavioural changes in response to prey acoustic stimuli and to different amplitude levels of shipping noise. The sharks, individually held in aquariums, were exposed to four experimental acoustic conditions characterized by different spectral (Hz) components and amplitude (dB re 1 µPa) levels. The swimming behaviour and spatial distribution of sharks were observed. The results highlighted significant differences in swimming time and in the spatial use of the aquarium among the experimental conditions. When the amplitude levels of biological sources were higher than those of anthropogenic sources, the sharks' swimming behaviour was concentrated in the bottom sections of the aquarium; when the amplitude levels of anthropogenic sources were higher than biological ones, the specimens increased the time spent swimming. Moreover, their spatial distribution highlighted a tendency to occupy the least noisy sections of the aquarium. In conclusion, this study highlighted that anthropogenic noise is able to affect behaviour of catshark specimens and the impact depends on acoustic amplitude levels.

Boat Noise and Black Drum Vocalizations in Mar Chiquita Coastal Lagoon (Argentina)

Human-generated underwater noise and its effect on marine biota is recognized as an important issue. Boat noise can affect the communication success of fish species that use sounds for spawning purposes. During the reproductive period, males of the black drum Pogonias spp. produce calls ranging from 90 Hz to 300 Hz. In the Mar Chiquita coastal lagoon (Buenos Aires, Argentina), Pogonias courbina is one of the primary fishing species. Although no regulation is directly applied to protect it, a ban protects the reproductive period of other fish species during weekdays. Here, we investigated the potential effect of boat noise on P. courbina vocalizations through a passive acoustic method. Acoustic data were collected, and P. courbina calls were identified and counted. The files with boat noise passages were categorized into classes according to their noise frequency range (A = below 700 Hz, B = over 700 Hz, and C = below and above 700 Hz). The fish call rate was lower in files where boat noise overlapped the fish call frequency (Classes A and C). Only boat noise from Class C was significantly reduced during days with the active fishing ban. These results suggest that anthropogenic noise may affect the P. courbina call rate and underline the importance of including the evaluation of anthropogenic noise in the current management of the area.

Accumulation of paralytic shellfish toxins by Southern Rock lobster Jasus edwardsii causes minimal impact on lobster health

Recurrent dinoflagellate blooms of Alexandrium catenella expose the economically and ecologically important Southern Rock Lobster in Tasmania to paralytic shellfish toxins (PST), and it is unknown if PST accumulation adversely affects lobster performance, health and catchability. In a controlled aquaculture setting, lobsters were fed highly contaminated mussels to accumulate toxin levels in the hepatopancreas (mean of 6.65 mg STX.2HCl equiv. kg^-1), comparable to those observed in nature. Physiological impact of PST accumulation was comprehensively assessed by a range of behavioural (vitality score, righting ability and reflex impairment score), health (haemocyte count, bacteriology, gill necrosis and parasite load), nutritional (hepatopancreas index and haemolymph refractive index) and haemolymph biochemical (21 parameters including electrolytes, metabolites, and enzymes) parameters during a 63 day period of uptake and depuration of toxins. Exposure to PST did not result in mortality nor significant changes in the behavioural, health, or nutritional measures suggesting limited gross impact on lobster performance. Furthermore, most haemolymph biochemical parameters measured exhibited no significant difference between control and exposed animals. However, the concentration of potassium in the haemolymph increased with PST, whilst the concentration of lactate and the sodium:potassium ratio decreased with PST. In addition, exposed lobsters showed a hyperglycaemic response to PST exposure, indicative of stress. These findings suggest that PST accumulation results in some measurable indicators of stress for lobsters. However, these changes are likely within the adaptive range for Jasus edwardsii and do not result in a significant impairment of gross performance. Our findings support previous conclusions that crustaceans are relatively tolerant to PST and the implications for the lobster fishery are discussed.

Lobsters with pre-existing damage to their mechanosensory statocyst organs do not incur further damage from exposure to seismic air gun signals

Staotcysts, the mechanosensory organs common to many marine invertebrates, have shown sensitivity to aquatic noise. Previously, rock lobsters (Jasus edwardsii) from a remote site with little exposure to anthropogenic noise incurred persistent damage to the statocyst and righting reflex following exposure to seismic air gun signals. Here, J. edwardsii collected from a site subject to high levels of anthropogenic noise were exposed to an equivalent seismic air gun signal regime as the previous study of noise-naïve lobsters. Following exposure, both control and exposed treatments were found to have damage to the statocyst equivalent to that of noise-naïve lobsters following seismic exposure, which led to the conclusion that the damage was pre-existing and not exacerbated by seismic exposure. The source of the damage in the lobsters in this study could not be ascertained, but the soundscape comparisons of the collection sites showed that the noisy site had a 5-10 dB greater level of noise, equivalent to a 3-10 times greater intensity, in the 10-700 Hz range than was found at the remote collection site. In addition to the lack of further damage following seismic exposure, no disruption to the righting reflex was observed. Indeed, compared to the noise naïve lobsters, the lobsters here demonstrated an ability to cope with or adapt to the mechanosensory damage, indicating a need for better understanding of the ecological impacts of the damage caused by low frequency noise on marine organisms. More broadly, this study raises historical exposure to noise as a previously unrecognised but vitally important consideration for studies of aquatic noise.

Social context and noise affect within and between male song adjustments in a common passerine

Across populations, animals that inhabit areas with high anthropogenic noise produce vocalizations that differ from those inhabiting less noisy environments. Such patterns may be due to individuals rapidly adjusting their songs in response to changing noise, but individual variation is seldom explored. Therefore, we tested the hypothesis that male house wrens (Troglodytes aedon) immediately adjust their songs according to changing noise and that social context further modifies responses. We recorded songs, quantified noise, and defined social context within pairs as female fertile status and between males as number of conspecific neighbors. We used a reaction-norm approach to compare song trait intercepts (between-male effects) and slopes (within-male effects) as a function of noise. Individuals immediately adjusted song duration in response to changing noise. How they achieved adjustments varied: some sang shorter and others longer songs with greater noise, and individuals varied in the extent to which they adjusted song duration. Variation in song duration could be affected by competition as between-male noise levels interacted with number of neighbors to affect syllable duration. Neither within- nor between-male noise effects were detected for frequency traits. Rather, males with fertile mates sang lower-frequency songs and increased peak frequency with more neighbors. Among males, social context but not noise affected song frequency, whereas temporal structure varied between and within individuals depending on noise and social factors. Not all males adjusted signals the same way in response to noise, and selection could favor different levels of variation according to noise.

Effects of marine noise pollution on Mediterranean fishes and invertebrates: A review

Marine noise pollution (MNP) can cause a multitude of impacts on many organisms, but information is often scattered and general outcomes difficult to assess. We have reviewed the literature on MNP impacts on Mediterranean fish and invertebrates. Both chronic and acute MNP produced by various human activities - e.g. maritime traffic, pile driving, air guns - were found to cause detectable effects on intra-specific communication, vital processes, physiology, behavioral patterns, health status and survival. These effects on individuals can extend to inducing population- and ecosystem-wide alterations, especially when MNP impacts functionally important species, such as keystone predators and habitat forming species. Curbing the threats of MNP in the Mediterranean Sea is a challenging task, but a variety of measures could be adopted to mitigate MNP impacts. Successful measures will require more accurate information on impacts and that effective management of MNP really becomes a priority in the policy makers' agenda.

The effect of low frequency noise on the behaviour of juvenile Sparus aurata

Anthropogenic activities are causing increased noise levels in the marine environment. To date, few studies have been undertaken to investigate the effects of different noise frequencies on the behaviour of juvenile fish. In this study, the behavioural changes of juvenile gilthead seabream (Sparus aurata) are evaluated when exposed to white noise filtered in third-octave bands centred at 63, 125, 500, and 1000 Hz (sound pressure level, 140-150 dB re 1 μΡa) for 7 h. The group dispersion, motility, and swimming height of the fish were analysed before and during the acoustic emission. Dispersion of the fish was found to reduce immediately upon application of low frequency sound (63 and 125 Hz) with a return to control condition after 2 h (indicative of habituation), whereas at 1 kHz, dispersion increased after 2 h without any habituation. The motility decreased significantly at 63 Hz throughout the 7 h of sound exposure. The swimming height decreased significantly for all frequencies other than 125 Hz. The results of this study highlight significant variations in the behavioural responses of juvenile fish that could have consequences on their fitness and survival.

Effects of acoustic stimulation on biochemical parameters in the digestive gland of Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819)

Underwater sounds generated by anthropogenic activity can cause behavior changes, temporary loss of hearing, damage to parts of the body, or death in a number of marine organisms and can also affect healing and survival. In this study, the authors examined the effects of high-frequency acoustic stimulations on a number of biochemical parameters in the Mediterranean mussel, Mytilus galloprovincialis. During the experiment, animals were placed in a test tank and exposed to acoustic signals [a linear sweep ranging from 100 to 200 kHz and lasting 1 s, with a sound pressure level range of between 145 and 160 dBrms (re 1μParms)] for 3 h. Total haemocyte count was assessed and glucose levels, cytotoxic activity and enzyme activity (alkaline phosphatase, esterase and peroxidase) in the digestive gland were measured. For the first time, this study suggests that high-frequency noise pollution has a negative impact on biochemical parameters in the digestive gland.

Underwater high frequency noise: Biological responses in sea urchin Arbacia lixula (Linnaeus, 1758)

Marine life is extremely sensitive to the effects of environmental noise due to its reliance on underwater sounds for basic life functions, such as searching for food and mating. However, the effects on invertebrate species are not yet fully understood. The aim of this study was to determine the biochemical responses of Arbacia lixula exposed to high-frequency noise. Protein concentration, enzyme activity (esterase, phosphatase and peroxidase) and cytotoxicity in coelomic fluid were compared in individuals exposed for three hours to consecutive linear sweeps of 100 to 200 kHz lasting 1 s, and control specimens. Sound pressure levels ranged between 145 and 160 dB re 1μPa. Coelomic fluid was extracted and the gene and protein expression of HSP70 with RT-PCR was evaluated on coelomocytes. A significant change was found in enzyme activity and in the expression of the HSP70 gene and protein compared to the control. These results suggested that high-frequency stimuli elicit a noise-induced physiological stress response in A. lixula, confirming the vulnerability of this species to acoustic exposure. Furthermore, these findings provide the first evidence that cell-free coelomic fluid can be used as a signal to evaluate noise exposure in marine invertebrates.

Effects of chronic hypercapnia and elevated temperature on the immune response of the spiny lobster, Jasus lalandii

The West Coast rock lobster (WCRL), Jasus lalandii, inhabits highly variable environments frequented by upwelling events, episodes of hypercapnia and large temperature variations. Coupled with the predicted threat of ocean acidification and temperature change for the coming centuries, the immune response in this crustacean will most likely be affected. We therefore tested the hypothesis that chronic exposure to hypercapnia and elevated seawater temperature will alter immune function of the WCRL. The chronic effects of four combinations of two stressors (seawater pCO₂ and temperature) on the total number of circulating haemocytes (THC) as well as on the lobsters' ability to clear (inactivate) an injected dose of Vibrio anguillarum from haemolymph circulation were assessed. Juvenile lobsters were held in normocapnic (pH 8.01) or hypercapnic (pH 7.34) conditions at two temperatures (15.6 and 18.9 °C) for 48 weeks (n = 30 lobster per treatment), after which a subsample of lobsters (n = 8/treatment), all at a similar moult stage, were selected from each treatment for the immune challenge. Baseline levels of haemocytes (THC ml^-1) and bacteria (CFU ml^-1) in their haemolymph were quantified 24 h prior to bacterial challenge. Lobsters were then challenged by injecting 4 × 10⁴V. anguillarum per g body weight directly into the cardiac region of each lobster and circulating haemocyte and culturable bacteria were measured at 20 min post challenge. No significant differences in THC ml^-1 (p < 0.05) were observed between any of the treatment groups prior to the bacterial challenge. However lobsters chronically exposed to a combination of hypercapnia and low temperature had significantly higher (p < 0.05) THCs post-challenge in comparison with lobsters chronically exposed to hypercapnia and high temperature. A significant interactive effect was recorded between temperature and pH for the post-challenge THC data (two-way ANOVA, p = 0.0025). Lobster were very efficient at rendering an injected dose of bacteria non-culturable, with more than 83% of the theoretical challenge dose (∼1.7 × 10⁵Vibrio ml^-1 haemolymph) inactivated within the first 10 min following injection. Although differences in the inactivation of V. anguillarum were observed between treatment groups, none of these differences were significant. Clearance efficiency was in the following order: Hypercapnia/low temperature > normocapnia/high temperature > normocapnia/low temperature > hypercapnia/high temperature. This study demonstrated that despite chronic exposure to combinations of reduced seawater pH and high temperature, the WCRL was still capable of rapidly rendering an injected dose of bacteria non-culturable.

Seismic air guns damage rock lobster mechanosensory organs and impair righting reflex

The effects of anthropogenic aquatic noise on marine invertebrates are poorly understood. We investigated the impact of seismic surveys on the righting reflex and statocyst morphology of the palinurid rock lobster, Jasus edwardsii, using field-based exposure to air gun signals. Following exposure equivalent to a full-scale commercial assay passing within 100-500 m, lobsters showed impaired righting and significant damage to the sensory hairs of the statocyst. Reflex impairment and statocyst damage persisted over the course of the experiments-up to 365 days post-exposure and did not improved following moulting. These results indicate that exposure to air gun signals caused morphological damage to the statocyst of rock lobsters, which can in turn impair complex reflexes. This damage and impairment adds further evidence that anthropogenic aquatic noise has the potential to harm invertebrates, necessitating a better understanding of possible ecological and economic impacts.

Acoustic impact of a wave energy converter in Mediterranean shallow waters

In this study, underwater noise from a full-scale wave energy converter system (ISWEC), installed on the coast of Pantelleria Island (central Mediterranean Sea), was characterized. The noise was measured using an autonomous acoustic recorder anchored to the sea bottom 40 m from the ISWEC hull. Acoustic monitoring continued for 15 months, starting 7 months before (PRE), 2 months during (INST) and 6 months after the ISWEC installation (POST). The levels of noise, assessed with power spectrum density and octave and third-octave band sound pressure levels (BSPLs), were higher during the POST period than during the PRE period at lower frequencies up to 4 kHz and increased with wave height. During the ISWEC activation for energy production (POST_ON) in the wave height range 1–2.9 m, the BSPLs increased much more at lower frequencies up to 4 kHz (the median BSPLs at 63 Hz for the PRE, POST, and POST_ON conditions were 73, 106, and 126 dB re 1μPa, respectively). Considering the biophonies that make up the soundscape of the area, we examined the possible masking of fish choruses due to ISWEC noise and highlighted that at a distance of 1000 m, the 800 Hz peak frequency was 10 dB above the ISWEC signal. Within this distance from ISWEC, a possible masking effect is supposed.

The impact of holding stressors on the immune function and haemolymph biochemistry of Southern Rock Lobsters (Jasus edwardsii)

Lobsters are fished world-wide due to their status as a high value, luxury seafood. A large proportion of the product is sold via live export, with lobsters subject to a range of stressors during holding post-capture. Improving the current understanding of the immune response to these stressors assists in improving efficiency and reducing loss in the chain between capture and consumption. In this study, the immune status of four treatment groups of Southern Rock Lobster (Jasus edwardsii) were studied: controls recently landed from a fishing boat, lobsters displaying advanced shell necrosis, lobsters in an unexplained moribund state and lobsters held in a processing facility for 10 weeks in standard conditions (i.e. high density, fasted). A total of 15 immune parameters and 19 haemolymph biochemical parameters were assayed. Phenoloxidase activity was only sporadically observed in haemocyte lysate and was consistently observed at a low level in the plasma with no difference between treatments for either. Haemocyte lysate prophenoloxidase activity was detected in most individuals, with no differences found between treatments. Prophenoloxidase in the plasma showed the highest level of activity, with the shell necrosis treatment demonstrating an elevated activity level relative to the other three treatments. Cell viability was not affected in any treatment. Lobsters with shell necrosis had a reduced capacity for phagocytosis, a significantly higher total haemocyte count, fewer hyalinocytes and more granulocytes and semigranulocytes. Fasted lobsters showed an opposite shift, with significantly more hyalinocytes compared to the other treatments and very few granulocytes and semigranulocytes. The balance of a range electrolytes, minerals metabolites and enzymes were affected in shell necrosis and fasted treatments, raising them as potential markers for immunocompromised lobsters. Multivariate analysis of all assayed parameters showed that all individuals in the necrosis treatment showed a similar, distinct immune response and that the fasted treatment, along with one control and one moribund individual, showed a separate intermediate response. The remainder of the control and moribund lobsters demonstrated a distinct "non-response" in comparison. These results offer a characterisation of the physiological response to common challenges during post-capture holding of rock lobsters, demonstrating the differential response to pathogenic bacterial infection, long term fasting, non-specific moribundity and the stress of capture and transport.

School is out on noisy reefs: the effect of boat noise on predator learning and survival of juvenile coral reef fishes

Noise produced by anthropogenic activities is increasing in many marine ecosystems. We investigated the effect of playback of boat noise on fish cognition. We focused on noise from small motorboats, since its occurrence can dominate soundscapes in coastal communities, the number of noise-producing vessels is increasing rapidly and their proximity to marine life has the potential to cause deleterious effects. Cognition-or the ability of individuals to learn and remember information-is crucial, given that most species rely on learning to achieve fitness-promoting tasks, such as finding food, choosing mates and recognizing predators. The caveat with cognition is its latent effect: the individual that fails to learn an important piece of information will live normally until the moment where it needs the information to make a fitness-related decision. Such latent effects can easily be overlooked by traditional risk assessment methods. Here, we conducted three experiments to assess the effect of boat noise playbacks on the ability of fish to learn to recognize predation threats, using a common, conserved learning paradigm. We found that fish that were trained to recognize a novel predator while being exposed to 'reef + boat noise' playbacks failed to subsequently respond to the predator, while their 'reef noise' counterparts responded appropriately. We repeated the training, giving the fish three opportunities to learn three common reef predators, and released the fish in the wild. Those trained in the presence of 'reef + boat noise' playbacks survived 40% less than the 'reef noise' controls over our 72 h monitoring period, a performance equal to that of predator-naive fish. Our last experiment indicated that these results were likely due to failed learning, as opposed to stress effects from the sound exposure. Neither playbacks nor real boat noise affected survival in the absence of predator training. Our results indicate that boat noise has the potential to cause latent effects on learning long after the stressor has gone.

Effects of broadband sound exposure on the interaction between foraging crab and shrimp - A field study

Aquatic animals live in an acoustic world in which they often rely on sound detection and recognition for various aspects of life that may affect survival and reproduction. Human exploitation of marine resources leads to increasing amounts of anthropogenic sound underwater, which may affect marine life negatively. Marine mammals and fishes are known to use sounds and to be affected by anthropogenic noise, but relatively little is known about invertebrates such as decapod crustaceans. We conducted experimental trials in the natural conditions of a quiet cove. We attracted shore crabs (Carcinus maenas) and common shrimps (Crangon crangon) with an experimentally fixed food item and compared trials in which we started playback of a broadband artificial sound to trials without exposure. During trials with sound exposure, the cumulative count of crabs that aggregated at the food item was lower, while variation in cumulative shrimp count could be explained by a negative correlation with crabs. These results suggest that crabs may be negatively affected by artificially elevated noise levels, but that shrimps may indirectly benefit by competitive release. Eating activity for the animals present was not affected by the sound treatment in either species. Our results show that moderate changes in acoustic conditions due to human activities can affect foraging interactions at the base of the marine food chain.

Are semi-terrestrial crabs threatened by human noise? Assessment of behavioural and biochemical responses of Neohelice granulata (Brachyura, Varunidae) in tank

This study examined the effects of human lab-generated noise (sweep tone) on the behaviour and biochemistry of a semi-terrestrial crab (Neohelice granulata). The experiment was carried out in tanks equipped with video- and audio-recording systems on a total of seventy-eight specimens. In total, 42 experimental trials with sweep-tone exposure and control conditions were performed using crabs in single and group layouts. After a habituation period of 30 min, the locomotor and acoustic (sound signals emitted by the crabs) behaviours were monitored for 30 min. During this time, the animals in sweep-tone conditions were exposed to ascending sweeps in a bandwidth range of 2.5-25 kHz. Exposure to sweep-tone noise produced significant changes in the number of signals emitted, locomotor behaviours and plasma parameters, such as haemolymph total haemocyte count and glucose, lactate and total protein concentrations, revealing that human noise could represent a disturbance for this crustacean species.

Redox and metabolic strategies developed by anterior and posterior gills of the crab Neohelice granulata after short periods of hypo- or hyper-osmotic stress

The aim of this study was to identify the response pattern of redox balance, Na⁺/K⁺ATPase activity and HSP70 expression in the posterior and anterior gills of the crab Neohelice granulata submitted to hypo- or hyper-osmotic stress for 1 h and 6 h. After 1 h of either type of osmotic stress, there was an increase in catalase activity, but a decrease in GSSG/GSH ratio (oxidized to reduced glutathione ratio) and Na⁺/K⁺ATPase activity in both gill sets. H₂O₂ levels decreased only in the posterior gills. H₂O₂ levels and Na⁺/K⁺ATPase activity remained reduced after 6 h of exposure to either type of osmotic stress in both gill sets. The GSSG/GSH ratio returned to initial levels after 6 h of hyper-osmotic stress, whereas it increased 10 times in both gill sets after hypo-osmotic stress. Furthermore, HSP70 protein expression increased in posterior gills after 6 h of hypo-osmotic stress. H₂O₂ levels in tank water decreased after hypo-osmotic challenge and increased after 6 h of hyper-osmotic stress, indicating increased H₂O₂ excretion. Therefore, N. granulata gills have redox, metabolic and molecular strategies to deal with rapid osmotic challenges, an important environmental parameter that influences juvenile and adult crab distribution and abundance within different populations.

The effects of auditory enrichment on zebrafish behavior and physiology

Environmental enrichment is widely used to improve welfare and behavioral performance of animal species. It ensures housing of laboratory animals in environments with space and complexity that enable the expression of their normal behavioral repertoire. Auditory enrichment by exposure to classical music decreases abnormal behaviors and endocrine stress responses in humans, non-humans primates, and rodents. However, little is known about the role of auditory enrichment in laboratory zebrafish. Given the growing importance of zebrafish for neuroscience research, such studies become critical. To examine whether auditory enrichment by classical music can affect fish behavior and physiology, we exposed adult zebrafish to 2 h of Vivaldi’s music (65–75 dB) twice daily, for 15 days. Overall, zebrafish exposed to such auditory stimuli were less anxious in the novel tank test and less active, calmer in the light-dark test, also affecting zebrafish physiological (immune) biomarkers, decreasing peripheral levels of pro-inflammatory cytokines and increasing the activity of some CNS genes, without overt effects on whole-body cortisol levels. In summary, we report that twice-daily exposure to continuous musical sounds may provide benefits over the ongoing 50–55 dB background noise of equipment in the laboratory setting. Overall, our results support utilizing auditory enrichment in laboratory zebrafish to reduce stress and improve welfare in this experimental aquatic organism.

Underwater operational noise level emitted by a tidal current turbine and its potential impact on marine fauna

Marine renewable energy development raised concerns over the impact of underwater noise. Here we assess the acoustic impacts of an operating tidal current turbine (Paimpol-Bréhat site, France) on marine fauna. Its source level (SL) has been measured in situ using 19 drifting transects at distances between 100 m to 2400 m from the turbine. SL ranged from 118 to 152 dB re1 μPa@1 m in third-octave bands at frequencies between 40 and 8192 Hz. It is comparable to the SL of a 19 m boat travelling at 10kt speed. This SL was used to estimate the impact of this noise type based on acoustic propagation simulations. The acoustic footprint of the device corresponds to a 1.5 km radius disk. Our results show that within this area of greatest potential impact, physiological injury of the hearing apparatus of invertebrates, fishes and marine mammals is improbable. Behavioral disturbance may occur up to 1 km around the device for harbor porpoises only. This is of little concern for a single turbine. However, greater concern on turbine noise impact, particularly on behavioral reactions has to be granted for a farm with up to 100 turbine. The lack of consolidated knowledge on behavioral disturbances identifies the needs for specific research programs.

Effects of Organotins on Crustaceans: Update and Perspectives

Organotins (OTs) are considered some of the most toxic chemicals introduced into aquatic environments by anthropogenic activities. They are widely used for agricultural and industrial purposes and as antifouling additives on boat hull's paints. Even though the use of OTs was banned in 2008, elevated levels of OTs can still be detected in aquatic environments. OTs' deleterious effects upon wildlife and experimental animals are well documented and include endocrine disruption, immunotoxicity, neurotoxicity, genotoxicity, and metabolic dysfunction. Crustaceans are key members of zooplankton and benthic communities and have vital roles in food chains, so the endocrine-disrupting effects of tributyltin (TBT) on crustaceans can affect other organisms. TBT can disrupt carbohydrate and lipid homeostasis of crustaceans by interacting with retinoid X receptor (RXR) and crustacean hyperglycemic hormone (CHH) signaling. Moreover, it can also interact with other nuclear receptors, disrupting methyl farnesoate and ecdysteroid signaling, thereby altering growth and sexual maturity, respectively. This compound also interferes in cytochrome P450 system disrupting steroid synthesis and reproduction. Crustaceans are also important fisheries worldwide, and its consumption can pose risks to human health. However, some questions remain unanswered. This mini review aims to update information about the effects of OTs on the metabolism, growth, and reproduction of crustaceans; to compare with known effects in mammals; and to point aspects that still needs to be addressed in future studies. Since both macrocrustaceans and microcrustaceans are good models to study the effects of sublethal TBT contamination, novel studies should be developed using multibiomarkers and omics technology.

Implementation of Fractal Dimension and Self-Organizing Map to Detect Toxic Effects of Toluene on Movement Tracks of Daphnia magna

Movement behaviors of an indicator species, Daphnia magna, in response to contaminants have been implemented to monitor environmental disturbances. Complexity in movement tracks of Daphnia magna was characterized by use of fractal dimension and self-organizing map. The individual movement tracks of D. magna were continuously recorded for 24 hours before and after treatments with toluene at the concentration of 10 mg/L, respectively. The general complexity in movement tracks (10 minutes) was characterized by fractal dimension. Results showed that average fractal dimension of movement tracks was decreased from 1.62 to 1.22 after treatments. The instantaneous movement parameters of movement segments in 5 s were input into the self-organizing map to investigate the swimming pattern changes under stresses of toluene. Abnormal behaviors of D. magna are more frequently observed after treatments than before treatments. Computational methods in ecological informatics could be utilized to obtain the useful information in behavioral data of D. magna and would be further applied as an in situ monitoring tool in water environment.

The impact of seismic air gun exposure on the haemolymph physiology and nutritional condition of spiny lobster, Jasus edwardsii

There is a critical knowledge gap regarding the impacts of seismic air gun signals on the physiology of adult crustaceans. We conducted four controlled field experiments to examine the impact of seismic acoustic signals on spiny lobster, Jasus edwardsii. Seismic air gun exposure suppressed total haemocyte count (THC) for up to 120days post-exposure, suggesting a chronic negative impact of immune competency. THC levels after 365days post-exposure, were elevated two fold, potentially indicating an immune response to infection. Haemolymph refractive index was reduced after 120days post exposure in one experiment, suggesting a chronic impairment of nutritional condition. There was no effect of air gun exposure on 24 haemolymph biochemical parameters, hepatopancreas index or survival. Collectively these results indicate that the biochemical haematological homeostasis of J. edwardsii is reasonably resilient to seismic acoustic signals, however, air gun exposure may negatively influence the lobster's nutritional condition and immunological capacity.

Noise elicits hematological stress parameters in Mediterranean damselfish (Chromis chromis, perciformes): A mesocosm study

In the last few decades, technological developments and the widespread rise of anthropic activities have increased the exposure of organisms to noise pollution, thus evoking great interest in its biological effects, particularly on the immune system. The aim of the present work was to investigate some of the biochemical parameters in the blood of Chromis chromis (Linnaeus, 1758) following in vivo exposure to noise levels of 200 and 300 Hz. Our results revealed that, compared to the control specimens, the fish exposed to noise had significantly increased levels of stress biomarkers such as glucose, lactate and total proteins in plasma, as well as a rise in the expression of heat shock protein 70 (HSP70).

A critical review of the potential impacts of marine seismic surveys on fish & invertebrates

Marine seismic surveys produce high intensity, low-frequency impulsive sounds at regular intervals, with most sound produced between 10 and 300Hz. Offshore seismic surveys have long been considered to be disruptive to fisheries, but there are few ecological studies that target commercially important species, particularly invertebrates. This review aims to summarise scientific studies investigating the impacts of low-frequency sound on marine fish and invertebrates, as well as to critically evaluate how such studies may apply to field populations exposed to seismic operations. We focus on marine seismic surveys due to their associated unique sound properties (i.e. acute, low-frequency, mobile source locations), as well as fish and invertebrates due to the commercial value of many species in these groups. The main challenges of seismic impact research are the translation of laboratory results to field populations over a range of sound exposure scenarios and the lack of sound exposure standardisation which hinders the identification of response thresholds. An integrated multidisciplinary approach to manipulative and in situ studies is the most effective way to establish impact thresholds in the context of realistic exposure levels, but if that is not practical the limitations of each approach must be carefully considered.

Vessel noise pollution as a human threat to fish: assessment of the stress response in gilthead sea bream (Sparus aurata, Linnaeus 1758)

This study examined the effects of boat noise pollution on the stress indices of gilthead sea bream (Sparus aurata, Linnaeus 1758). To assess the stress response in these fish, biometric values and plasma parameters such as ACTH, cortisol, glucose, lactate, haematocrit, Hsp70, total protein, cholesterol, triglycerides and osmolarity were analysed. After acclimatization of the animals, the experiment was carried out in a tank fitted with underwater speakers where the fish were exposed to sound treatments (in duplicate) consisting of: 10 days of no sound (control treatment; the animals were only exposed to the experimental tank's background noise) and 10 days of noise derived from original recordings of motor boats, including recreational boats, hydrofoil, fishing boat and ferry boat (vessel noise treatment). The exposure to noise produced significant variations in almost all the plasma parameters assessed, but no differences were observed in weights and fork lengths. A PERMANOVA analysis highlighted significantly increased values (p < 0.05) of ACTH, cortisol, glucose, lactate, haematocrit, Hsp70, cholesterol, triglycerides and osmolarity in the fish exposed to vessel noise for 10 days. This study clearly highlights that anthropogenic noise negatively affects fish, and they are valuable targets for detailed investigations into the effects of this global pollutant. Finally, these experimental studies could represent part of the science that is able to improve the quality of the policies related to management plans for maritime spaces (Marine Strategy Framework Directive 56/2008 CE) that are aimed at stemming this pollutant phenomenon.

Anthropogenic sources of underwater sound can modify how sediment-dwelling invertebrates mediate ecosystem properties

Coastal and shelf environments support high levels of biodiversity that are vital in mediating ecosystem processes, but they are also subject to noise associated with mounting levels of offshore human activity. This has the potential to alter the way in which species interact with their environment, compromising the mediation of important ecosystem properties. Here, we show that exposure to underwater broadband sound fields that resemble offshore shipping and construction activity can alter sediment-dwelling invertebrate contributions to fluid and particle transport--key processes in mediating benthic nutrient cycling. Despite high levels of intra-specific variability in physiological response, we find that changes in the behaviour of some functionally important species can be dependent on the class of broadband sound (continuous or impulsive). Our study provides evidence that exposing coastal environments to anthropogenic sound fields is likely to have much wider ecosystem consequences than are presently acknowledged.

Rearing Tenebrio molitor L. (Coleptera: Tenebrionidae) in the "Lunar Palace 1" during a 105-day multi-crew closed integrative BLSS experiment

Yellow mealworm (Tenebrio molitor L.) is one of the animal candidates for space bioregenerative life support systems. In this study, T. molitor was involved in a 105-day multi-crew closed integrative BLSS experiment for a tentative rearing study. The results showed that the overall bioconversion rate (ratio of T. molitor gained to the total feed consumed) of T. molitor reared in the closed system was 8.13%, while 78.43% of the feed was excreted as frass. T. molitor reared in the closed system had a good nutritional composition. The eight essential amino acids (EAAs) in T. molitor larvae accounted for 41.30% of its total amino acids, and most EAA contents were higher than the suggested amino acid pattern recommended by the FAO/WHO. T. molitor sample obtained in this work was high in polyunsaturated fatty acids, and low in saturated fatty acids, indicating that the composition of fatty acids was beneficial to human health. In the open environment outside the experimental system, we simultaneously reared three parallel groups of larval T. molitor using the same feeding regime and temperature condition. Compared with T. molitor reared in the open environment, larvae reared in the closed system grew slower. With the course of time t, the growth rate of T. molitor in the open environment was 0.839e(0.017t) times that of larvae in the closed system. This paper can provide data for future design and improvement of BLSS containing a T. molitor rearing unit.

Shipping noise affecting immune responses of European spiny lobster (Palinurus elephas)

Marine crustaceans are influenced by numerous environmental factors. Environmental stress from pollutants seems to affect their metabolism, growth, moulting, survival, and immune defence. Recently, it has become clear that there is an impact of the global increase in sea noise levels due to shipping traffic on crustacean welfare. Considering the ecological and commercial importance of the European spiny lobster (Palinurus elephas (Fabricius, 1787)) in most parts of the Mediterranean coastal area, in the present study we investigated whether shipping noise pollution contribute to changing the immune parameters of stress in the European spiny lobster. The animals were exposed to a mix of noises produced by different typologies of the boat played back in a tank, and the values of cellular and humeral parameters were evaluated. Total haemocyte count (THC), haemolymphatic protein concentration, phenoloxidase (PO) activity in cell-free haemolymph, and heat shock protein 27 (Hsp27) expression in haemocyte lysate were considered potential biomarkers of stress. THC and PO activity decreased significantly, whereas total protein and Hsp27 expression increased significantly. Overall, the results demonstrate that the stressful conditions investigated in this study affect both cellular and biochemical parameters in the European spiny lobster.