Knowledge Shared by Alaska Native Commercial Salmon Set Gillnetters in Norton Sound to Reduce Marine Fatalities

OBJECTIVES

The goal of this exploratory pilot study was to reduce marine fatalities in Norton Sound using knowledge shared from Alaska Native salmon set gillnetters in Unalakleet, AK. The following objectives to address this goal were: 1) identify factors that influence safety for Alaska Native commercial set gillnetters in Norton Sound; 2) use findings from objective 1 to improve commercial fishing training, education, and resources; and 3) disseminate and communicate results from objective 1 to commercial fishers in the Norton Sound fleet, commercial fishing safety partners, and the Alaska Native injury prevention community.

METHODS

Ten semi-structured interviews were conducted with Alaska Native commercial set gillnetters in Unalakleet, AK. We utilized knowledge shared to identify factors that influence safety for their fleet. Using an Interpretative Phenomenological Analysis Methodology, 10 interviews were recommended for a homogenous sample.

RESULTS

Most participants learned to fish at a young age from the family, with safety lessons passed on by family members. Fishing is a lifestyle and interconnected with harvesting and a way of living. Set gillnetters in Norton Sound use open skiffs and have limited access to workable Personal Flotation Devices (PFDs) and safety training. Participants reported health benefits but also negative long term physical effects, financial stress, and difficulty fishing with age. Respect and awareness of the ocean was reported as the most important strategy to reduce risk. Stories were shared of falls overboard, capsizing, and local fatalities and hazards, such as being overloaded with fish, entanglement, and maneuvering a small boat in large waves. Stronger winds and shifting weather patterns were experienced from climate change.

CONCLUSION

This exploratory pilot study identified factors that influence safety for Alaska Native commercial set gillnetters. Findings should be used to 1) determine best methods to influence behaviors to reduce risks in this hazardous fishery; 2) increase awareness and promote expanded application of best practices, equipment, and resources; 3) encourage and promote outreach initiatives targeted for this unique population; and 4) develop tailored training programs for commercial fishing in an open skiff. Research with Alaska Native fishing communities will require value and respect of indigenous knowledge, collaboration with local people, and follow-up to bring findings back to the community.

Naloxone training and availability in the US commercial fishing industry

INTRODUCTION

Workers in physically demanding jobs with high injury rates, long hours, productivity pressures, and lack of job security, such as commercial fishing, are at higher risk for substance use and misuse. In the United States, the federal government is urging employers to consider having naloxone available to reverse the effects of an opioid overdose, especially in workplaces. This study examined naloxone training, naloxone availability, and level of concern over substance use in commercial fishing.

METHODS

As part of a larger study of commercial fishing vessel captains, we asked participants how worried they are about various potential problems, including substance use by crew members, using a five-point scale. We also asked whether they had completed naloxone training and whether their vessel was equipped with naloxone.

RESULTS

Of the 61 vessel captains who participated, 10 had naloxone training. Most were "not at all worried" about a crew member misusing alcohol (n = 52; 85.2%), a crew member using marijuana (n = 50; 82.0%), a crew member using other drugs (n = 49; 80.3%), or a crew member having a drug overdose (n = 52; 86.7%). Only five fishing vessels were equipped with naloxone.

CONCLUSION

Our results indicate that few fishing vessels are equipped with naloxone or have captains trained in its use. Fishing captains tend not to be worried about substance use in their crew. Given the higher rate of overdose deaths in the fishing industry compared to other industries, having more vessels equipped with naloxone and captains trained to administer it could save lives.

Dissemination and Implementation of a Text Messaging Campaign to Improve Health Disparities among Im/Migrant Workers

The use of short message service (SMS) text messaging technology has grown in popularity over the last twenty years, but there is limited data on the design and feasibility of campaigns to reduce work-related injury, particularly among rural workers, non-native English speakers, and illiterate or low-literacy populations. Although there is a critical need for tech equity or 'TechQuity' interventions that reduce injury and enhance the wellbeing of under-reached communities, the barriers and benefits to implementation must be empirically and systematically examined. Thus, our team used D&I science to design and implement an 18-week texting campaign for under-reached workers with a higher-than-average risk of fatal and non-fatal injury. The experimental project was conducted with English-, Spanish-, and Vietnamese-speaking commercial fishermen in the Gulf of Mexico to test the design and feasibility, and messaging focused on preventing injury from slips, trips, and falls, as well as hurricane preparedness. The ubiquity of mobile devices and the previous success of texting campaigns made this a promising approach for enhancing health and preventing injury among an under-reached population. However, the perceived benefits were not without their barriers. The lessons learned included the difficulty of navigating federal regulations regarding limits for special characters, enrolling migratory participants, and navigating areas with limited cellular service or populations with limited accessibility to technology. We conclude with short- and long-term suggestions for future technology interventions for under-reached worker populations, including ethical and policy regulations.

The Receptivity to Safety-Related Mobile Apps Among Commercial Fishing Captains: Descriptive Exploratory Study

BACKGROUND

Mobile apps addressing a variety of workplace safety issues have proliferated over the last decade as mobile technology has advanced and smartphone ownership has increased. Workplace safety interventions are often designed for a specific work site. However, some of the most dangerous jobs are ones in which workers frequently change field locations, such as commercial fishing. Mobile apps may be particularly suitable for delivering safety interventions to these workers.

OBJECTIVE

We sought to gauge the potential for using mobile apps to deliver safety interventions to commercial fishing workers. The purpose of this paper is to describe how fishermen use their mobile devices during fishing operations and identify any mobile apps they already use for safety.

METHODS

Participants comprised commercial fishing captains who already owned an iOS or Android smartphone or tablet. They completed a questionnaire that asked about their current mobile device use and their use of safety-related mobile apps, in addition to questions about their fishing operations. We performed descriptive analyses of the data.

RESULTS

A total of 61 participants completed the questionnaire. The most common types of mobile devices participants reported owning were iPhones (n=36, 59%) and Android phones (n=24, 39%). Most participants (n=53, 87%) reported using their mobile device for both work and personal purposes, including while out at sea (n=52, 85%). Over half of the participants reported that they had either safety-related apps (n=17, 28%) or apps that help them with their work (n=35, 57%). The types of apps most frequently mentioned were apps for weather, wind, tides, and navigation.

CONCLUSIONS

The results of this study indicate that some commercial fishing captains who own a mobile device are receptive to using safety-related apps for work. Apps that help avoid hazards by monitoring environmental conditions and apps optimized for use on smartphones may be most likely to be adopted and used. Overall, these results suggest that mobile apps are a promising avenue for improving safety among workers in commercial fishing and similar occupations.

Working hours, sleep, and fatigue in the agriculture, forestry, and fishing sector: A scoping review

INTRODUCTION

Agriculture, forestry, and fishing industry (AgFF) workers often work extremely long hours during peak production seasons, resulting in sleep deprivation and fatigue. The National Occupational Research Agenda has classified fatigue as a "significant safety issue" and area of concern for many industry sectors, including AgFF. This review explores current research and practice in AgFF and proposes next steps.

METHODS

We conducted a scoping literature review to examine the extent and nature of research in this area. Article inclusion criteria included peer-reviewed journal articles written in English; published after 1989; covering AgFF workers in high-income countries; with data on working hours/schedules and sleep related to safety and health.

RESULTS

Limited research has addressed long hours and sleep deprivation among AgFF workers. We identified 8350 articles for title and abstract review. Among those, 407 underwent full-text review and 96 met all inclusion criteria (67% agriculture, 25% fishing/seafood processing, 8% forestry). The literature provided some evidence fatigue contributes to fatalities, injuries, and illnesses in AgFF. Older, new, young, foreign-born, and female workers, as well as those who work in small organizations or longer hours (40+) may be at higher risk for fatigue-related injury and illness. Few studies have developed or evaluated interventions to control risks.

DISCUSSION

Given that fatigue is a factor in injury and illness for this sector, future AgFF surveillance and research should increase efforts to capture fatigue and sleep data, directly investigate the role of long hours and nonstandard work schedules in the sector, and most importantly, create practical interventions to manage fatigue.

Using Participatory Ergonomics to Improve Health and Safety in Commercial Lobstering in the United States: 2 Case Studies

The lobster-harvesting industry has a high occupational injury incidence compared to land-based industries. Participatory ergonomics methods were used to partner with lobstermen to develop and implement ergonomic improvements. The model included training in ergonomics principles, a forum for ergonomics discussions, and a sequence of meetings planned to focus on problem identification, intervention, evaluation, and dissemination of findings. One crew initiated 3 specific actions: the introduction of a conveyor belt to assist material handling at a local lobstering pier, the installation of a star block at the space for hauling traps onto the boat, and the initiation of a design process for improved mechanical assistance for hauling traps onto the boat. The other crew took action to reduce force and postural exposures by creating a short video intended to disseminate ergonomic ideas to other lobstermen. The influence of important cultural norms was observed for future research and development in the community.

Commercial Fishing as an Occupational Determinant of Opioid Overdoses and Deaths of Despair in Two Massachusetts Fishing Ports, 2000-2014

The opioid epidemic has had disproportionate effects across various sectors of the population, differentially impacting various occupations. Commercial fishing has among the highest rates of occupational fatalities in the United States. This study used death certificate data from two Massachusetts fishing ports to calculate proportionate mortality ratios of fatal opioid overdose as a cause of death in commercial fishing. Statistically significant proportionate mortality ratios revealed that commercial fishermen were greater than four times more likely to die from opioid poisoning than nonfishermen living in the same fishing ports. These important quantitative findings suggest opioid overdoses, and deaths to diseases of despair in general, deserve further study in prevention, particularly among those employed in commercial fishing.

Characterizing Industrial and Artisanal Fishing Vessel Catch Composition Using Environmental DNA and Satellite-Based Tracking Data

The decline in wild-caught fisheries paired with increasing global seafood demand is pushing the need for seafood sustainability to the forefront of national and regional priorities. Validation of species identity is a crucial early step, yet conventional monitoring and surveillance tools are limited in their effectiveness because they are extremely time-consuming and require expertise in fish identification. DNA barcoding methods are a versatile tool for the genetic monitoring of wildlife products; however, they are also limited by requiring individual tissue samples from target specimens which may not always be possible given the speed and scale of seafood operations. To circumvent the need to individually sample organisms, we pilot an approach that uses forensic environmental DNA (eDNA) metabarcoding to profile fish species composition from the meltwater in fish holds on industrial and artisanal fishing vessels in Ecuador. Fish identified genetically as present were compared to target species reported by each vessel’s crew. Additionally, we contrasted the geographic range of identified species against the satellite-based fishing route data of industrial vessels to determine if identified species could be reasonably expected in the catch.

Injuries and illnesses to children in commercial fishing in Alaska: A brief report

BACKGROUND

Commercial fishing is the most hazardous occupation in the United States. While the epidemiology of adult injuries and fatalities are well documented, injuries to children (<18 years old) are not described. The purpose of this report was to describe the characteristics of nonfatal injuries to children involved in commercial fishing.

METHODS

Nonfatal commercial fishing injuries to children were identified in the Alaska Fishermen's Fund. The Alaska Fishermen's Fund is an emergency fund payor of last resort. Data on nonfatal injuries to victims aged 17 or younger were analyzed. Descriptive statistics were used to characterize demographics and injury characteristics.

RESULTS

Forty-four nonfatal child injury claims were made between 2012 and 2016. The mean age at the time of claim was 15.6 years (SD = 1.8) and 84% were male. The most common types of injuries among children were sprains and strains and the most commonly injured body parts were upper extremities and the trunk. Most injuries occurred in salmon fisheries.

CONCLUSIONS

Children are participating in commercial fishing. Based on the results of this analysis, children are also experiencing occupational injuries. The results of this analysis underscore the need for additional safety and health information, guidance for supervisors, and intervention to prevent injuries to children participating in commercial fishing.

Tracking the response of industrial fishing fleets to large marine protected areas in the Pacific Ocean

Large marine protected areas (MPAs) of unprecedented size have recently been established across the global oceans, yet their ability to meet conservation objectives is debated. Key areas of debate include uncertainty over nations' abilities to enforce fishing bans across vast, remote regions and the intensity of human impacts before and after MPA implementation. We used a recently developed vessel tracking data set (produced using Automatic Identification System detections) to quantify the response of industrial fishing fleets to 5 of the largest MPAs established in the Pacific Ocean since 2013. After their implementation, all 5 MPAs successfully kept industrial fishing effort exceptionally low. Detected fishing effort was already low in 4 of the 5 large MPAs prior to MPA implementation, particularly relative to nearby regions that did not receive formal protection. Our results suggest that these large MPAs may present major conservation opportunities in relatively intact ecosystems with low immediate impact to industrial fisheries, but the large MPAs we considered often did not significantly reduce fishing effort because baseline fishing was typically low. It is yet to be determined how large MPAs may shape global ocean conservation in the future if the footprint of human influence continues to expand. Continued improvement in understanding of how large MPAs interact with industrial fisheries is a crucial step toward defining their role in global ocean management.

From Bad to Worse: The Impact of COVID-19 on Commercial Fisheries Workers

This commentary provides an overview of the impact of COVID-19 on the commercial fishing industry. The information highlighted in the article was gathered from fishermen, fishing industry experts, health and safety advisors, and advocates. From these first-hand accounts, we provide the immediate and expansive impacts of COVID-19 on fishermen's health and wellbeing. In particular, we discuss the economic impact of COVID-19 market disruptions, as well as the very real, logistical challenges of protecting workers on fishing vessels. We also provide examples of how these combined issues have led to increased occupational risk in one of the nation's most deadly industries. Lastly, we identify a number of recommendations for providing much-needed support for commercial fishermen in light of the COVID-19 pandemic.

Accelerometers: Assessing their potential for measuring personal flotation device use on commercial fishing vessels

BACKGROUND

Falls overboard are the most common cause of fatalities in commercial fishing. As a result, interventions aimed at increasing and measuring the use of personal flotation devices (PFDs) are a high priority. The focus of this study was to explore the use of accelerometers as a means for objectively measuring PFD use on lobster fishing vessels.

METHODS

For participating vessels, researchers attached an accelerometer to a PFD worn by a crewmember and another to the vessel's wheelhouse. GoPro videos were also employed to record crewmember activities so these could be synchronized with accelerometer outputs. Accelerometer outputs included two distinct measures, the proportional integration mode (PIM) and zero crossing mode (ZCM). Data were fitted to various equations to identify the best method for predicting PFD use.

RESULTS

Seven lobster fishing vessels participated in the trial. Data indicated that accelerometers could predict PFD use with a fairly high degree of accuracy. In particular, a logistic equation incorporating PIM values from the PFD and the absolute value of the difference between the PFD PIM readings and the PIM readings from the stationary accelerometer demonstrated the highest degree of accuracy, with correct classifications for 73.3% to 77.6% of the 10-second data intervals. Accuracy was highest when crew members were moving versus stationary. The predictive value of ZCM was comparatively limited.

CONCLUSIONS

PIM accelerometer readings can be used to measure PFD use with a considerably high degree of accuracy, especially for sternmen who are moving regularly and have the highest risk for falling overboard.

Fatigue and workload among Danish fishermen

BACKGROUND

Fishery is a hazardous occupation and fatigue may contribute to the observed risks. This study aims to investigate the association between workload and fatigue among Danish fishermen.

MATERIALS AND METHODS

The cross-sectional survey of demographic characteristics and self-reported exposure and health data was performed on a random sample of 270 active fishermen. We applied the validated Multidimensional Fatigue Inventory (MFI-20) to assess the degrees of the different dimensions of perceived fatigue. We estimated physical workload using questions regarding the frequency of seven physical work activities and analysed the association between fatigue and workload using multiple linear regressions.

RESULTS

The mean fatigue scores were 9.18 (SD 3.58) for general fatigue, 9.05 (SD 3.36) for physical fatigue, 7.57 (SD 3.03) for reduced activity and 7.16 (SD 3.07) for mental fatigue. Highest levels of fatigue were observed among fishermen at Danish seiners (mean 10.21), and fatigue scores decreased with more days at sea. However, none of these results were significant. Adjusted analyses showed that physical workload was significantly related to general fatigue (b = 0.20, 95% CI: 0.12-0.28), physical fatigue (b = 0.10, 95% CI: 0.04-0.16) and mental fatigue (b = 0.09, 95% CI: 0.01-0.16). Reduced activity was unrelated to work exposures.

CONCLUSIONS

General fatigue was the dominant fatigue dimension among Danish fishermen and it is mostly associated with physical workload. Physical workload was additionally significantly associated to the levels of physical and mental fatigue. Fishermen had a lower average score for all fatigue dimensions compared to those seen in general Danish working population. Prospective studies are required to assess whether the identified associations are causal.

Predictors for occupational injuries and diseases among commercial fishers in Finland 1996-2015

Fishing is a hazardous occupation worldwide. Commercial fishers in Finland are an aging and diminishing population with a high injury rate. Insurance claims data for self-employed Finnish commercial fishers during the years 1996 through 2015 (n = 1951) were analysed to assess predictors for occupational injuries and diseases. Out of the available variables, fishery location, career length, and participation in the voluntary occupational health service programme were not significant predictors. Male gender (OR 2.02; 95% CI 1.37-2.99), Finnish mother tongue vs. Swedish (OR 1.98, 95% CI 1.53-2.55), and higher income levels from fishing (four income categories, OR range: 1.71-3.53) were associated with higher odds for a compensated occupational injury or disease claim among commercial fishers in the final multivariate model. The identified risk groups could be targeted for interventions, and the content of the occupational health service programme should be developed to gain protective effect.

Historical spatial reconstruction of a spawning-aggregation fishery

Aggregations of individual animals that form for breeding purposes are a critical ecological process for many species, yet these aggregations are inherently vulnerable to exploitation. Studies of the decline of exploited populations that form breeding aggregations tend to focus on catch rate and thus often overlook reductions in geographic range. We tested the hypothesis that catch rate and site occupancy of exploited fish-spawning aggregations (FSAs) decline in synchrony over time. We used the Spanish mackerel (Scomberomorus commerson) spawning-aggregation fishery in the Great Barrier Reef as a case study. Data were compiled from historical newspaper archives, fisher knowledge, and contemporary fishery logbooks to reconstruct catch rates and exploitation trends from the inception of the fishery. Our fine-scale analysis of catch and effort data spanned 103 years (1911-2013) and revealed a spatial expansion of fishing effort. Effort shifted offshore at a rate of 9.4 nm/decade, and 2.9 newly targeted FSAs were reported/decade. Spatial expansion of effort masked the sequential exploitation, commercial extinction, and loss of 70% of exploited FSAs. After standardizing for improvements in technological innovations, average catch rates declined by 90.5% from 1934 to 2011 (from 119.4 to 11.41 fish/vessel/trip). Mean catch rate of Spanish mackerel and occupancy of exploited mackerel FSAs were not significantly related. Our study revealed a special kind of shifting spatial baseline in which a contraction in exploited FSAs occurred undetected. Knowledge of temporally and spatially explicit information on FSAs can be relevant for the conservation and management of FSA species.

Musculoskeletal Disorders in Northeast Lobstermen

BACKGROUND

The objective of this study was to report on the prevalence of musculoskeletal pain in lobstermen in the northeast USA.

METHODS

Crews were randomly selected from those licensed to fish in Maine and Massachusetts and followed prospectively. The survey used a Nordic Musculoskeletal Questionnaire format to characterize musculoskeletal disorders.

RESULTS

A total of 395 individuals participated. One half of the respondents reported low back pain. Back pain was attributed to or exacerbated by lobstering. Low back pain was prevalent among both captains and sternmen, while sternmen reported more hand/wrist pain than captains. Multiple locations for pain were common in individual participants.

CONCLUSION

Equipment or technology to assist material handling should be a priority, as the body segments with high prevalence of pain (back, hand/wrists, shoulders, knees) are all affected by the repetitive and forceful handling of the lobster traps.

Reported traumatic injuries among West Coast Dungeness crab fishermen, 2002-2014

BACKGROUND

Commercial fishing is a high-risk occupation. The West Coast Dungeness crab fishery has a high fatality rate; however, nonfatal injuries have not been previously studied. The purpose of this report was to describe the characteristics of fatal and nonfatal traumatic occupational injuries and associated hazards in this fleet during 2002-2014.

MATERIALS AND METHODS

Data on fatal injuries were obtained from a surveillance system managed by the National Institute for Occupational Safety and Health. Data on nonfatal injuries were manually abstracted from Coast Guard investigation reports and entered into a study database. Descriptive statistics were used to characterise demographics, injury characteristics, and work processes performed.

RESULTS

Twenty-eight fatal and 45 nonfatal injuries were reported between 2002 and 2014 in the Dungeness crab fleet. Most fatalities were due to vessel disasters, and many nonfatal injuries occurred on-deck when fishermen were working with gear, particularly when hauling the gear (47%). The most frequently reported injuries affected the upper extremities (48%), and fractures were the most commonly reported injury type (40%). The overall fatality rate during this time period was 209 per 100,000 full-time equivalent workers and the rate of nonfatal injury was 3.4 per 1,000 full-time equivalent workers.

CONCLUSIONS

Dungeness crab fishermen are at relatively high risk for fatal injuries. Nonfatal injuries were limited to reported information, which hampers efforts to accurately estimate nonfatal injury risk and understand fishing hazards. Further research is needed to identify work tasks and other hazards that cause nonfatal injuries in this fleet. Engaging fishermen directly may help develop approaches for injury prevention.

Occupational injuries and diseases among commercial fishers in Finland 1996-2015

BACKGROUND

Commercial fishing is recognised as one of the most hazardous professions worldwide. In Finland, commercial fishing has some special characteristics, including fishing on ice during frozen waters, and pluriactivity of the fisher family to gain additional income. The goal of this study was to describe injury characteristics among commercial fishers in Finland during the years 1996-2015. With this information, we wish to promote creation of effective safety campaigns and interventions.

MATERIALS AND METHODS

The data for this study was acquired from The Farmers' Social Insurance Institution, who handles the mandatory pension and occupational injury insurance of Finnish commercial fishers. Descriptive statistics was used to categorise and analyse the data that comprised the anonymized insurance history of 1954 insured fishers and reports on 1135 compensated injuries, 11 fatalities, and 53 occupational disease cases.

RESULTS

The results show, that the injury rate of Finnish commercial fishers is high. Forty per cent of the fishing-related injuries occur aboard or when entering or leaving the vessel, while 37% happened ashore, and 11% on sea or lake ice. The most common type of incident is preceded by a slip, trip, or sway followed by a fall to lower level. The injuries result in a median disability length of 21 days. An elevated risk for Finnish (vs. Swedish) speaking, as well as for male fishers was found. The occupational diseases of the studied population were for the most part results of manual, repetitive and/or physically straining work due to e.g. hauling in fishing equipment. Due to small numbers and lack of case data, it is not possible to make any further analysis of the 11 fatalities, which were all drownings.

CONCLUSIONS

Based on our findings, injury prevention should be targeted, besides preventing fatalities because of drowning, at mitigating the risks for slips, trips, and falls both aboard and ashore.

Utility of a Work Process Classification System for characterizing non-fatal injuries in the Alaskan commercial fishing industry

BACKGROUND

The US commercial fishing industry is hazardous, as measured by mortality data. However, research on non-fatal injuries is limited. Non-fatal injuries constitute the majority of occupational injuries and can result in workers' lowered productivity and wages, lost quality of life, and disability. In the United States, a Work Process Classification System (WPCS) has previously been applied in Alaskan freezer-trawl and freezer-longline fleets to identify causes of injuries and specific hazards, but not to other fishing fleets.

OBJECTIVES

This descriptive epidemiologic study aimed to explore the application and modification of the WPCS in multiple Alaskan fleets, characterize non-fatal occupational injuries in these fleets, and identify work processes that could be targeted for further investigation and future injury prevention efforts.

DESIGN

Traumatic, non-fatal injuries on-board Alaskan commercial fishing vessels were identified through United States Coast Guard investigative reports. Characteristics of injuries, as well as worker characteristics, were analysed. Injuries were coded using the WPCS.

RESULTS

We successfully utilized the WPCS to code non-fatal injury cases (n = 136). The most frequent main work processes associated with non-fatal injuries included: on-board trawlers, handling frozen fish and processing the catch; on-board vessels using pot/trap gear, handling the gear and shooting/setting the gear; on-board longliners, traffic on board and hauling the gear; and on-board processor vessels, processing the catch, other work with the catch, and handling frozen fish.

CONCLUSIONS

The study confirmed that a WPCS can be applied to multiple Alaskan fleets to identify hazardous tasks. Hazards were unique for each vessel gear type. Future injury prevention efforts should target work processes associated with the most frequent and most severe injuries. Future studies should establish time estimates for work processes in order to determine risk estimates. Efforts to improve non-fatal injury reporting, especially on smaller commercial fishing vessels, should be undertaken.

Pikeperch (Sander lucioperca (L.)) in decline: high mortality of three populations in the northern Baltic Sea

The development of three pikeperch (Sander lucioperca (L.)) populations in the northern Baltic Sea was monitored using standardized multimesh gillnets in 1995-2009. Declining trends in the abundances of pikeperch over 40 cm total length, low numbers of individuals older than 6 years, and high mortality rates were observed in all three populations. In the site with the largest commercial catches per unit area and a rapidly increased colony of great cormorants (Phalacrocorax carbo sinensis Blumenbach 1798), also the abundance of pikeperch below 40 cm total length and year-class strength showed declining trends. The adverse population level changes did not correlate with changes in water quality or eutrophication status. Together, the results suggest that in all study sites fisheries are harvesting a large proportion of the pikeperch soon after or even before reaching the maturity, and that predation from great cormorants may increase mortality of juveniles. Pikeperch is important not only for fisheries but also for ecosystem functioning, and our results point at the need for further management measures to ensure viable populations in the areas studied.