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The fishing gear deployed by fishermen in seas and oceans throughout the world not only captures target species but also unintentionally ensnares non‐target species, a phenomenon known as ‘by‐catch’. This unintended capture of marine life can represent significant challenges for the fishing industry, with adverse impacts on both the environment and species such as sea turtles, marine mammals, seabirds and elasmobranchs, which may be injured or even killed. To address this problem, the fishing industry has implemented regulations and mitigation measures. In this literature review, we have examined 389 papers published between 2010 and 2022 that assess the effectiveness of these measures. Taking into account the fishing gear with which each group interacts the most, trawls for sea turtles, gillnets for marine mammals and longlines for seabirds and elasmobranchs, it has been demonstrated that ‘TEDs’ (Turtle Excluder Devices) are an effective measure for sea turtles, ‘pingers’ for marine mammals and ‘BSLs’ (Bird Scaring Lines), more commonly known as ‘tori lines’, for seabirds. The most complex case is that of elasmobranchs, and the most effective measure has yet to be discovered. This complexity arises from the ongoing targeted fishing of these species, resulting in less monitoring of their catches and, therefore, fewer surveys. Overall, we encourage the global implementation of these measures by the fishing industry in order to reduce by‐catch in an attempt to ensure the future of many endangered species. [ABSTRACT FROM AUTHOR]

Strandings have been extensively documented for large mammals, however, a comprehensive survey focusing on batoids is currently lacking. To address this knowledge gap, we conducted a review of available stranding data sourced from iNaturalist, news websites, and published papers. A total of 3.148 reports encompassing 189 batoid species were recovered, revealing the vulnerability of both oceanic and coastal species to strandings. Nevertheless, limited data on life stage, sex, animal condition, and fate hinder a comprehensive understanding of this phenomenon. Putative causes were identified only for a small percentage (6%) of the reports, namely pollution, abrupt environmental alterations, predation, pathologies, and fishing activities. The earliest reported stranding dates back to 1989, with an increase in reports observed since 2019. iNaturalist accounted for the majority (75%) of records, emphasizing its significance as a platform for reporting and monitoring batoid strandings. These strandings were reported in 51 countries, with the coastal areas of California, United States, particularly notable. Among the identified species, Rhinoptera bonasus exhibited the highest number of strandings, with 392 recorded individuals. Alarmingly, more than half of the reports involved threatened species, underscoring the need for increased attention to batoid strandings. To address these issues, we propose the establishment of stranding monitoring networks and the development of a freely accessible global database. In addition, the training of volunteer citizen scientists, the development of rescue and rehabilitation protocols, and manuals of good fishing practices aimed at commercial and recreational fisheries are also recommended. [ABSTRACT FROM AUTHOR]

Bycatch in fisheries is a key threat to non-target marine species, particularly for those species that have life histories with low productivity or poor conservation status. In this paper, the requirements of the new Marine Stewardship Council (MSC) Fisheries Standard (hereafter "the Standard") are summarised relevant to Endangered, Threatened and Protected (ETP) species. This covers both how species are designated as ETP, and how performance of management is assessed with respect to ETP species, when scoring fisheries against the Standard. The process used to select these requirements is described, including a review of the requirements for earlier versions of the Standard and the scoring of these requirements in assessment reports for a selection of fisheries that have achieved MSC certification. The review identified a lack of consistency in the implementation of scoring guidelines, which was in part due to a lack of clarity in the requirements of the Standard. The revised Standard has been designed to achieve more consistent implementation of the requirements with respect to management of impacts on ETP species, and to align the requirements more closely with global best practice. The requirements may be used as a template for fisheries managers seeking to prioritise bycatch species for improved management and setting more specific and measurable objectives in relation to population status and minimising mortalities. [ABSTRACT FROM AUTHOR]

The fisheries sector, exemplified here by Malawi's Karonga District, illustrates the global consequences of insufficient ethical considerations, leading to the depletion of fisheries resources. Using data spanning from 2012 to 2021, including frame surveys and catch assessment surveys, this study employs ethical theories and the ethical matrix to identify and analyse ethical issues. The observed concerns include illegal fishing, heightened investment in a limited resource fishery, consumption of the critically endangered Chambo species, the environmental impact of trawl surveys, technological overreliance, and inadequate resource support from local politicians. Recommendations encompass ending open-access fisheries, revising biomass assessment methods, promoting mindset change, implementing poverty alleviation programmes, promoting aquaculture development, and enhancing the establishment of freshwater protected areas as sites for biodiversity conservation. Ending open-access to fisheries as stipulated in the international frameworks Diversified strategies to reduce poverty incidence, especially for the lakeshore communities Promotion of aquaculture development Environmental DNA to replace trawl surveys in biomass surveys Mindset change to embrace ethical fishery. [ABSTRACT FROM AUTHOR]

Introduction: Monitoring bycatch of protected species is a fisheries management priority. In practice, protected species bycatch is difficult to precisely or accurately estimate with commonly used ratio estimators or parametric, linear model-based methods. Machine-learning algorithms have been proposed as means of overcoming some of the analytical hurdles in estimating protected species bycatch. Methods: Using 17 years of set-specific bycatch data derived from 100% observer coverage of the Hawaii shallow-set longline fishery and 25 aligned environmental predictors, we evaluated a new approach for protected species bycatch estimation using Ensemble Random Forests (ERFs). We tested the ability of ERFs to predict interactions with five protected species with varying levels of bycatch in the fishery and methods for correcting these predictions using Type I and Type II error rates from the training data. We also assessed the amount of training data needed to inform a ERF approach by mimicking the sequential addition of new data in each subsequent fishing year. Results: We showed that ERF bycatch estimation was most effective for species with greater than 2% interaction rates and error correction improved bycatch estimates for all species but introduced a tendency to regress estimates towards mean rates in the training data. Training data needs differed among species but those above 2% interaction rates required 7-12 years of bycatch data. Discussion: Our machine learning approach can improve bycatch estimates for rare species but comparisons are needed to other approaches to assess which methods perform best for hyperrare species. [ABSTRACT FROM AUTHOR]

The study calculated the Length-Based Spawning Potential Ratio (LB-SPR) for several species, including red grouper (Epinephelus morio), black grouper (Mycteroperca bonaci), gag grouper (M. microlepis), yellowtail snapper (Ocyurus chrysurus), lane snapper (Lutjanus synagris), hogfish (Lachnolaimus maximus), and white grunt (Haemulon plumierii). Data were obtained from the small-scale commercial fleet operating in the red grouper fishery on the Campeche Bank within the Yucatan Peninsula. Monthly records of total length (cm) from April 2017 to May 2018, totaling 10,182 fish, were collected from five fishing ports along the Yucatan Peninsula coast. Biological data, such as growth and reproductive patterns and exploitation parameters were gathered from scientific literature. The LB-SPR package on the R Core Team platform was utilized for analysis. Despite being the largest, groupers exhibited immaturity ( SL 50 < L 50 ) and low Spawning Potential Ratio (SPR). Red and black groupers showed particularly low SPR values (0.10 and 0.05, respectively), indicating a looming risk of local extinction. The gag grouper achieved the highest SPR value (0.26) among groupers, although it was very close to the minimum critical value (i.e., 0.20). Snappers, hogfish, and white grunt were generally captured in the adult state ( SL 50 > L 50 ). Yellowtail, hogfish, and white grunt displayed high SPR values (0.44, 0.72, and 0.98, respectively). Lane snapper had a low SPR (0.28) but fell within the range for maintaining satisfactory stock productivity, albeit with reduced yields. The findings emphasize the urgent need to adjust the current management framework for the red grouper fishery, focusing on improving fishing gear selectivity to address heightened pressure on both juvenile groupers and adult lane snapper. Implementing these measures is crucial to mitigate the risks of local extinction and population decline for each species. [ABSTRACT FROM AUTHOR]

Increasing the population density of target species is a major goal of ecosystem and agricultural management. This task is especially challenging in hazardous environments with a high abundance of natural enemies such as parasites and predators. Safe locations with lower mortality have been long considered a beneficial factor in enhancing population survival, being a promising tool in commercial fish farming and restoration of threatened species. Here we challenge this opinion and revisit the role of behavior structuring in a hostile environment in shaping the population density. We build a mathematical model, where individuals are structured according to their defensive tactics against natural enemies. The model predicts that although each safe zone enhances the survival of an individual, for an insufficient number of such zones, the entire population experiences a greater overall mortality. This is a result of the interplay of emergent dynamical behavioral structuring and strong intraspecific competition for safe zones. Non-plastic structuring in individuals' boldness reduces the mentioned negative effects. We demonstrate emergence of non-plastic behavioral structuring: the evolutionary branching of a monomorphic population into a dimorphic one with bold/shy strains. We apply our modelling approach to explore fish farming of salmonids in an environment infected by trematode parasites. A theoretical model, based on empirical data, predicts that population structuring according to defensive tactics used against natural enemies enhances the population mortality, whereas nonplastic (permanent) structuring reduces this negative effect. [ABSTRACT FROM AUTHOR]

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Over one third of shark and ray (henceforth elasmobranch) species are threatened by global extinction. Overfishing, driven largely by human consumption of various products is a key threat to >95% of threatened elasmobranch species. The local consumption of elasmobranch meat is an emerging driver of these fisheries particularly in the Global South. Very little data exists on local elasmobranch meat consumption and restaurants offer a useful insight into patterns of consumption. We examined local elasmobranch consumption in India, which has the world's third highest elasmobranch catches. We surveyed 2649 seafood restaurants across 10 coastal states and found that two states alone accounted for 70% of all restaurants serving shark meat. Nine percent of all seafood restaurants advertised elasmobranch meat. 251.6 tonnes, equivalent to 9.8% of India's annual landings, is sold every year in India's restaurants. The drivers of these sales are local cultural affinities and regional cuisines, with evidence of new and evolving consumption pathways, in states like Goa. In Goa, the state with the highest prevalence of elasmobranch meat on restaurant menus, consumption by locals, as well as consumption of "baby sharks" by tourists was driving the demand for elasmobranch meat. Small‐bodied and juvenile sharks of threatened species are at risk from local meat consumption. Elasmobranch meat consumption can be reduced by targeting interventions in the regional hotspots of maximum consumption, substituting other types of seafood as alternatives in regional cuisines, bycatch reduction, increased price and seafood consumer awareness campaigns. Preliminary findings suggest that focusing on the health implications of eating species that concentrate heavy metals will produce the greatest decreases in elasmobranch meat sales at India's restaurants. [ABSTRACT FROM AUTHOR]

Research on mesophotic reefs has increased thanks to technological advances such as remotely operated vehicles (ROV). The aim of this study was to evaluate differences in ichthyofaunal assemblages between shallow (<30 m) and mesophotic (>30 m) reef zones in three sites of the Parque Nacional zona marina del Archipiélago de Espíritu Santo (PNZMAES), a Marine protected area from the Gulf of California. To accomplish this objective, we used 14 video transects recorded with an ROV in October 2019 between 13 and 72 m depth. From these recordings, we determined species richness and abundance to analyze community structure and estimate biomass. A permutational multivariate analysis of variance was used to analyze differences between zones, sites, and their interaction. The abundance and estimated biomass of trophic groups were plotted to describe the trophic structure of the depth zones at PNZMAES. We also analyzed functional structure, functional richness (FRic), functional evenness (FEve), functional divergence (FDiv), functional specialization (FSpe), and functional originality (FOri) by depth zone and video transect based on six biological traits and estimated biomass. The taxonomic and functional indices were the response variables of linear models, while the explanatory variables were in situ temperature, light, and dissolved oxygen. At PNZMAES, 61 species were registered: 42 species in the shallow zone (high abundance and estimated biomass of planktivorous) and 40 species in the mesophotic zone (high abundance of planktivorous and high estimated biomass of piscivores). When comparing the ichthyofaunal community structure, differences were observed in richness, abundance, and estimated biomass associated with the depth zone, site, and the interaction of these variables. An overlap of more than 60% in the functional volume between zones was observed. Higher values of FRic, FDiv, and FSpe in the deep zone indicated that ecological functions were equivalent to those in the shallow zone. Finally, the linear models indicated an effect of environmental variables on the ecological indicators. The mesophotic reefs of PNZMAES are potential refuges for certain species (some of them endangered) and should be considered in the proposal of management strategies to protect them from future anthropogenic threats. • Fish richness and abundance declined due to temperature/light reduction with depth. • Functional diversity increased at deep reefs where commercial species were present. • Complex habitat and low fishing pressure at deep reefs could favor distinct functions. • Mesophotic reefs of PNZMAES potentially represent a refuge for different fish species. • Endangered species in mesophotic depths make conservation there a priority. [ABSTRACT FROM AUTHOR]