Drivers of ecological effectiveness of marine protected areas: A meta-analytic approach from the Southwestern Atlantic Ocean (Brazil)

Evaluating the influence of marine protected areas on surf zone fish

Marine protected areas (MPAs) globally serve conservation and fisheries management goals, generating positive effects in some marine ecosystems. Surf zones and sandy beaches, critical ecotones bridging land and sea, play a pivotal role in the life cycles of numerous fish species and serve as prime areas for subsistence and recreational fishing. Despite their significance, these areas remain understudied when evaluating the effects of MPAs. We compared surf zone fish assemblages inside and outside MPAs across 3 bioregions in California (USA). Using seines and baited remote underwater videos (BRUVs), we found differences in surf zone fish inside and outside MPAs in one region. Inside south region MPAs, we observed higher abundance (Tukey's honest significant difference [HSD] = 0.83, p = 0.0001) and richness (HSD = 0.22, p = 0.0001) in BRUVs and greater biomass (HSD = 0.32, p = 0.0002) in seine surveys compared with reference sites. Selected live-bearing, fished taxa were positively affected by MPAs. Elasmobranchs displayed greater abundance in BRUV surveys and higher biomass in seine surveys inside south region MPAs (HSD = 0.35, p = 0.0003 and HSD = 0.23, p = 0.008, respectively). Although we observed no overall MPA signal for Embiotocidae, abundances of juvenile and large adult barred surfperch (Amphistichus argenteus), the most abundant fished species, were higher inside MPAs (K-S test D = 0.19, p < 0.0001). Influence of habitat characteristics on MPA performance indicated surf zone width was positively associated with fish abundance and biomass but negatively associated with richness. The south region had the largest positive effect size on all MPA performance metrics. Our findings underscored the variability in species richness and composition across regions and survey methods that significantly affected differences observed inside and outside MPAs. A comprehensive assessment of MPA performance should consider specific taxa, their distribution, and the effects of habitat factors and geography.

Organohalogen compounds in a hotspot for chemical pollution: Assessment in free-ranging Atlantic spotted dolphins (Stenella frontalis)

The assessment of chemical pollution in free-ranging living mammals is viable using remote biopsies and portrays a comprehensive scenario of environmental health. The Southwestern Atlantic Ocean holds incredible biodiversity, but it is under the constant and invisible threat of persistent organic pollutants (POPs) of anthropogenic origin, such as pesticides, brominated flame retardants, and industrial-use compounds (e.g., PCBs). Thus, this study aimed to assess the bioaccumulation of POPs (PCBs, DDTs, HCB, mirex and PBDEs) and natural organobromine compounds (MeO-BDEs) using gas-chromatography coupled to mass spectrometry in biopsy samples of Atlantic spotted dolphins (Stenella frontalis, n = 20) that inhabit and forage both inside and in adjacent areas to degraded (Guanabara Bay) and conserved (Ilha Grande Bay) coastal bays in the Southeastern Brazil. Among the studied compounds, PCBs were predominant in the contamination profile with median concentration of 97.0 μg.g-1 lipid weight (lw), followed by the sum of the p,p' isomers of DDT, DDD, and DDE of 11.0 μg.g-1 lw, the brominated flame retardants PBDEs of 1.6 μg.g-1 lw, and the other organochlorine pesticides mirex of 0.78 μg.g-1 lw, and HCB of 0.049 μg.g-1 lw. The MeO-BDEs were detected with a median concentration of 22.8 μg.g-1 lw. 85 % of the Atlantic spotted dolphins analyzed in this study presented PCB concentration that exceeded even the less conservative threshold limits for adverse health effects (41 μg.g-1 lw). This study shows that despite the conservation status of preserved bays, cetacean species foraging in these locations are still under increased threat. Hence chemical pollution demands local and global efforts to be mitigated.

Feeding behavior of yellowfin tuna around two insular regions of the western Atlantic Ocean

The yellowfin tuna is a very abundant tropical tuna species in the western equatorial Atlantic Ocean and an important fishery resource for the Brazilian tuna fleet. In this study we performed stable isotope analysis to better understand the spatial trophodynamics and dietary changes in yellowfin tuna around two insular marine protected areas in Brazil. A total of 65 yellowfin tuna specimens measuring between 47 and 138 cm LT (total length) were sampled around the archipelagos of Fernando de Noronha (FNA; n = 34) and Saint Peter and Saint Paul (SPSPA; n = 31) between July 2018 and September 2019. Bayesian mixing models and generalized additive models were used to investigate the contributions of four different prey items (zooplankton, cephalopods, fish larvae, and flying fish) to yellowfin tuna diet in each area and their potential changes in relation to predator growth. The four prey items were found to have different overall contributions between the two studied areas, with zooplankton being the most important prey in FNA, whereas flying fish was the most relevant prey to the species' diet in SPSPA. Significant changes in the species diet by size were also found, with fish smaller than 90 cm (TL) having a more generalist diet and larger animals relying more on consuming larger and more nutritious prey (i.e., flying fish). Our results suggest that these two marine protected areas play an important role in ocean dynamics, providing important and different foraging grounds for the development of this predator species.

Effects of Madagascar marine reserves on juvenile and adult coral abundance, and the implication for population regulation

Recruitment is a critical component in the dynamics of coral assemblages, and a key question is to determine the degree to which spatial heterogeneity of adults is influenced by pre-vs. post-settlement processes. We analyzed the density of juvenile and adult corals among 18 stations located at three regions around Madagascar, and examined the effects of Marine Protected Areas (MPAs). Our survey did not detect a positive effect of MPAs on juveniles, except for Porites at the study scale. The MPA effect was more pronounced for adults, notably for Acropora, Montipora, Seriatopora, and Porites at the regional scale. For most dominant genera, densities of juveniles and adults were positively correlated at the study scale, and at least at one of the three regions. These outcomes suggest recruitment-limitation relationships for several coral taxa, although differences in post-settlement events may be sufficiently strong to distort the pattern established at settlement for other populations. The modest benefits of MPAs on the density of juvenile corals demonstrated here argue in favor of strengthening conservation measures more specifically focused to protect recruitment processes.

Comparative study of pristine and polluted estuaries in Souss Massa National Park (Morocco): Implications for conservation strategies

Estuaries are among the ecosystems most affected by human actions worldwide. Economic development in Morocco puts pressure on these aquatic systems, making them vulnerable. This study compares the state of benthic communities between a pristine estuary (Massa estuary) and a polluted one (Souss estuary). Both ecosystems belong to the Souss Massa National Park (SMNP), registered in the Ramsar list for its ecological importance as a Marine Protected Area (MPA). Twenty-one benthic species were identified in the pristine estuary, but only six species in the polluted one. Similar differences were detected for the species abundance and biomass. The total organic matter and the water-dissolved oxygen also revealed a notable negative effect of the sewage discharge. The results confirmed human disturbances on faunal communities related to direct wastewater inputs and indirect anthropogenic activities such as the urbanization and the litter generation. A combination of ending wastewater discharge and adding tertiary-level water treatment plants is recommended. The findings highlight the importance of MPAs in conservation strategies if coupled with continuous surveillance of pollution.

Assessing the Effect of Full Protection on the Biomass of Ericaria amentacea and Understory Assemblages: Evidence from Two Mediterranean Marine Protected Areas

Cystoseira sensu lato marine forests, which are among the most productive and diverse systems in rocky intertidal and subtidal habitats of the Mediterranean Sea, are experiencing a widespread decline throughout the basin due to increasing human pressures. Yet it is still unclear whether Marine Protected Areas (MPAs) may represent effective tools for conservation of these important habitat formers and their associated assemblages. Here, we compared the biomass of intertidal stands of Ericaria amentacea (C. Agardh) Molinari and Guiry and their understory assemblages between the no-take zone and control sites in two Mediterranean MPAs. We did not find evidence supporting a significant effect of full protection in increasing the biomass of E. amentacea stands and associated assemblages, except for macroalgae of the understory in one of the investigated MPAs, raising concerns on the potential effectiveness of MPAs in mitigating human impacts on these marine forests. Such findings call for major efforts to implement long-term monitoring programs of protected Cystoseira s.l. forests in order to inform an adaptive management of conservation measures within MPAs and eventually to set active interventions of restoration.

A contemporary baseline of Madagascar's coral assemblages: Reefs with high coral diversity, abundance, and function associated with marine protected areas

Madagascar is a major hotspot of biodiversity in the Western Indian Ocean, but, as in many other regions, coral reefs surrounding the island confront large-scale disturbances and human-induced local stressors. Conservation actions have been implemented with encouraging results for fisheries, though their benefit on coral assemblages has never been rigorously addressed. In this context, we analyzed the multiscale spatial variation of the composition, generic richness, abundance, life history strategies, and cover of coral assemblages among 18 stations placed at three regions around the island. The potential influences of marine protected areas (MPAs), algal cover, substrate rugosity, herbivorous fish biomass, and geographic location were also analyzed. Our results highlight the marked spatial variability, with variation at either or both regional and local scales for all coral descriptors. The northeast coastal region of Masoala was characterized by the high abundance of coral colonies, most notably of the competitive Acropora and Pocillopora genera and stress-tolerant taxa at several stations. The southwest station of Salary Nord was distinguished by lower abundances, with depauperate populations of competitive taxa. On the northwest coast, Nosy-Be was characterized by higher diversity and abundance as well as by high coral cover (~42-70%) recorded at unfished stations. Results clearly underline the positive effects of MPAs on all but one of the coral descriptors, particularly at Nosy-Be where the highest contrast between fished and unfished stations was observed. Biomass of herbivorous fishes, crustose coralline algae cover, and substrate rugosity were also positively related to several coral descriptors. The occurrence of reefs with high diversity, abundance, and cover of corals, including the competitive Acropora, is a major finding of this study. Our results strongly support the implementation of locally managed marine areas with strong involvement by primary users, particularly to assist in management in countries with reduced logistic and human resources such as Madagascar.

Ecological effectiveness of marine protected areas across the globe in the scientific literature

A systematic literature review (SLR) of scientific articles on the effectiveness of marine protected areas (MPAs) to conserve biodiversity in the 2010-2019 decade using Scopus was done. Only studies that used Before-After-Control-Impact (BACI-type) research designs and at least one marine biodiversity indicator were included. The 23 studies included in the review were published in 19 journals and comprised 66 MPAs from 18 countries from the five continents. Fifty-seven percent of the studies used species-specific indicators of MPA effectiveness, chiefly density/abundance and size of organisms. Over 90% of the studies used incomplete research designs, with just 9% using BACI-type designs or over. Just over half of the studies reported positive or slightly positive ecological outcomes from MPAs, with 17.4% of them reporting negative or slightly negative outcomes, and 30.4% reporting mixed or inconclusive outcomes. Legally stringent reserves clearly outperformed multiple-use MPAs ecologically. The major stated pressures to both types of MPAs related to fishing, whereas the main mentioned MPA effectiveness factors included managerial and regulatory issues. Our results add to the existing evidence that the global ocean coverage by legally stringent reserves should be expanded if effective marine biodiversity conservation is to be achieved.

Effectiveness of management zones for recovering parrotfish species within the largest coastal marine protected area in Brazil

The establishment of multiple zones offering different protection levels within a Marine Protected Area (MPA) can minimize social conflicts while maintaining associated biodiversity benefits such as fish population replenishment. Parrotfishes are among one of the most ecologically important reef fishes; yet extremely overexploited worldwide. In this context, well-designed priority management areas allowing no fishing activity (no-take zones) could help recover fish species, such as parrotfishes, through a MPA zoning process. Here, we tested this hypothesis by identifying the spatial configuration of zones that maximize the recovery of endangered parrotfish species (Scarus trispinosus; Scarus zelindae; Sparisoma amplum; Sparisoma axillare; Sparisoma frondosum) at the largest MPA in Brazil protecting nearshore coral reefs (MPA Costa dos Corais). We used parrotfish distribution data to produce species distribution models (SDMs) and combined them with conservation planning tools to delineate priority zones following a systematic approach. Then, we contrasted priority zones against non-systematic, newly designed no-take zones based on managers' and stakeholders' perspectives. After mapping the predicted abundance of each species within both zones based upon field surveys, we found that priority zones were more effective than non-systematic ones for the protection of two out of the five species: Scarus trispinosus and Sparisoma amplum. Thus, we considered that designing systematic zones was particularly relevant for increased protection of the two parrotfish species facing the largest decline. The prioritization analyses also showed that priority areas for parrotfish conservation following a systematic approach were mostly located surrounding and within no-take zones delineated by local stakeholders. The spatial overlap between systematic and non-systematic zones was of 38%. Hence, our study reinforces the importance of considering scientific information and methods (e.g., spatial distribution data and prioritization analyses) as a complementary strategy along with local stakeholders' knowledge, for delineating and refining management zones within MPAs.

Protected Area Effectiveness in the Scientific Literature: A Decade-Long Bibliometric Analysis

Protected areas (PAs) aim to safeguard biodiversity and ecosystem services in the long term. Despite remarkable growth in the area covered by PAs in recent years, biodiversity trends still show worrisome outcomes. Here, we conducted a systematic literature review (SLR) of scientific articles focusing on the ecological effectiveness of PAs that were published in the 2010–2019 decade using Scopus in order to show the latest publication trends in that research field. After three consecutive screenings, we analyzed a final census sample of 76 articles that used semiexperimental research designs. We assessed 3 thematic variables (i.e., related to ecological effectiveness) and 13 bibliometric variables through descriptive statistics, Spearman correlation tests, and Kruskal–Wallis difference tests. Our results demonstrate the growing size of research teams working on this topic, broader international collaboration, and greater length of the articles published on this subject. During that decade, the number of normalized citations (+28%) and the mean field-weighted citation impact (FWCI) of the set of reviewed articles (33% higher than expected) increased. We also observed an increase in open access publications (+13%). However, this mode of publication did not ensure more citations. Finally, we observed a positive correlation between the number of normalized citations and the inclusion of Supplementary Data in the articles.

Evaluating effects of partial fishing closures on the composition and structure of estuarine fish assemblages

Partial fishing closures are an integral component of contemporary aquatic resource conservation and fisheries management. This study examined whether assemblages of fishes differed between partially closed (PC) estuaries that permit recreational fishing compared to fully fished (FF) estuaries that permit commercial and recreational fisheries. Fish assemblages were quantitatively sampled in a standard and stratified manner using a multimesh gillnet and beam trawl that sampled different ichthyofaunal components in two PC and two FF estuaries across three years, ∼ six to eight years post commercial fishing closure and PC implementation. There was no global support for the hypothesis that assemblages, diversity and numbers of fishes would differ between PC and FF estuaries. Assemblages significantly and consistently differed among individual estuaries regardless of estuary management category. Differences between PC and FF estuaries in terms of numbers of species and individuals were inconsistent across years, with more species (gillnet) and individuals (trawl) occurring in PC estuaries in only one of three years. Only one species (Gerres subfasciatus) was more abundant (gillnet) in the PC category, most likely due to reduced fishery harvests. In contrast, juveniles of three harvested species (G. subfasciatus, Rhabdosargus sarba and Acanthopagrus spp.) occurred in greater numbers (trawl) in FF estuaries, potentially a result of strong recruitment and estuary-specific environmental conditions. This study demonstrated the complexity, and potential scale-dependent ecological and fishery-related constraints, in comparatively examining the effects of different fishery management arrangements on fish assemblages across estuary systems.