Using fisher-contributed secondary fins to fill critical shark-fisheries data gaps.

Developing-world shark fisheries are typically not assessed or actively managed for sustainability; one fundamental obstacle is the lack of species and size-composition catch data. We tested and implemented a new and potentially widely applicable approach for collecting these data: mandatory submission of low-value secondary fins (anal fins) from landed sharks by fishers and use of the fins to reconstruct catch species and size. Visual and low-cost genetic identification were used to determine species composition, and linear regression was applied to total length and anal fin base length for catch-size reconstruction. We tested the feasibility of this approach in Belize, first in a local proof-of-concept study and then scaling it up to the national level for the 2017-2018 shark-fishing season (1,786 fins analyzed). Sixteen species occurred in this fishery. The most common were the Caribbean reef (Carcharhinus perezi), blacktip (C. limbatus), sharpnose (Atlantic [Rhizoprionodon terraenovae] and Caribbean [R. porosus] considered as a group), and bonnethead (Sphyrna cf. tiburo). Sharpnose and bonnethead sharks were landed primarily above size at maturity, whereas Caribbean reef and blacktip sharks were primarily landed below size at maturity. Our approach proved effective in obtaining critical data for managing the shark fishery, and we suggest the tools developed as part of this program could be exported to other nations in this region and applied almost immediately if there were means to communicate with fishers and incentivize them to provide anal fins. Outside the tropical Western Atlantic, we recommend further investigation of the feasibility of sampling of secondary fins, including considerations of time, effort, and cost of species identification from these fins, what secondary fin type to use, and the means with which to communicate with fishers and incentivize participation. This program could be a model for collecting urgently needed data for developing-world shark fisheries globally. Article impact statement: Shark fins collected from fishers yield data critical to shark fisheries management in developing nations.

Uso de Aletas Secundarias Proporcionadas por Pescadores para Llenar Vacíos Importantes de Información sobre las Pesquerías de Tiburones Resumen Con frecuencia no se evalúan las pesquerías de tiburones del mundo en desarrollo ni cuentan con un manejo activo de sustentabilidad. Uno de los principales obstáculos para esto es la falta de información sobre las especies y la composición de los tamaños en las capturas. Probamos e implementamos una estrategia nueva y potencialmente aplicable en todas partes para la recolección de estos datos: la entrega obligatoria de las aletas secundarias de bajo valor económico (aletas anales) obtenidas de los tiburones desembarcados por parte de los pescadores y el uso de estas aletas para reconstruir las especies y tamaños en la captura. Usamos identificaciones genéticas de bajo costo e identificaciones visuales para determinar la composición de las especies y aplicamos una regresión lineal a la longitud total y a la de la base de la aleta anal para la reconstrucción del tamaño en captura. Probamos la viabilidad de esta estrategia en Belice, primero en un estudio de prueba de concepto y después subiendo al nivel nacional para la temporada de pesca de tiburón 2017-2018 (1,786 aletas analizadas). Se registraron 16 especies en esta pesquería. Las más comunes fueron Carcharhinus perezi, C. limbatus, Rhizoprionodon terraenovae y R. porosus (consideradas como un grupo) y Sphyrna cf. tiburo. Las últimas tres especies fueron desembarcadas principalmente por encima del tamaño maduro, mientras que con las dos primeras especies lo hacían por debajo del tamaño maduro. Nuestra estrategia demostró ser efectiva en la obtención de información crítica para el manejo de la pesquería de tiburones y sugerimos que las herramientas desarrolladas como parte de este programa puedan ser exportadas a otras naciones en esta región y aplicadas casi de manera inmediata si existen los medios para comunicarse con los pescadores e incentivarlos a proporcionar las aletas anales. Fuera del Atlántico Occidental tropical, recomendamos una mayor investigación de la viabilidad del muestreo de aletas secundarias, incluyendo la consideración del tiempo, esfuerzo y costo de la identificación de especies a partir de estas aletas; cuál tipo de aleta secundaria utilizar; y los medios mediante los cuales comunicarse con los pescadores e incentivarlos a participar. Este programa podría ser un modelo para la recolección de información de necesidad urgente para las pesquerías del mundo en desarrollo.

The use of machine learning to detect foraging behaviour in whale sharks: a new tool in conservation.

In this study we present the first attempt at modelling the feeding behaviour of whale sharks using a machine learning analytical method. A total of eight sharks were monitored with tri-axial accelerometers and their foraging behaviours were visually observed. Our results highlight that the random forest model is a valid and robust approach to predict the feeding behaviour of the whale shark. In conclusion this novel approach exposes the practicality of this method to serve as a conservation tool and the capability it offers in monitoring potential disturbances of the species.

The Economy of Shark Conservation in the Northeast Pacific: The Role of Ecotourism and Citizen Science.

Historically sharks have been seen either as a source of income through harvesting, or as a nuisance and danger. The economic value of sharks has traditionally been measured as the total value of sharks caught for liver oil, fins, or meat for consumption. Sharks have also been killed to near extinction in cases where they were seen as a threat to fisheries on other species. This is illustrated by the mass extermination of Basking Sharks (Cetorhinus maximus) in British Columbia. They were seen as a nuisance to fishermen as they got entangled in gill nets during the salmon fishing season. However with the development of the SCUBA diving industry, and ecotourism in general, increased awareness of the role sharks play in marine ecosystems has resulted in changes in how they are perceived and utilized. Despite an ongoing harvest of sharks such as the North Pacific Spiny Dogfish (Squalus suckleyi), sharks now generate economic value through SCUBA diving enthusiasts who travel the globe to see, swim with, and photograph them. The use of digital cameras and other digital media has brought sharks into households around the world and increased awareness of the conservation issues facing many species. This renewed appreciation has led to a better understanding of sharks by the public, resulting in advocates calling for better protections and conservation. In particular, a growing part of the SCUBA diving community wants to contribute to conservation and research projects, which has led to participation in citizen science projects. These projects provide scientific data but also gain ground as ecotourism activities, thus adding to both economic value of tourism and conservation efforts.

Sharks in Captivity: The Role of Husbandry, Breeding, Education, and Citizen Science in Shark Conservation.

The role of public aquariums in promoting conservation has changed substantially over the decades, evolving from entertainment attractions to educational and research centres. In many facilities, larger sharks are an essential part of the collection and represent one of the biggest draws for the public. Displaying healthy elasmobranchs comes with many challenges, but improvements in husbandry techniques have enabled aquariums to have success with a variety of species. The establishment of organisations such as the Association of Zoos and Aquariums, and the completion of texts like the Elasmobranch Husbandry Manual, has helped set high standards of care for sharks in captivity and promoted international conservation efforts. Aquariums keeping sharks are in a unique position to influence local, regional, and international attitudes and policies by acting as both educational and research facilities. Interactions with multiple stakeholders of diverse educational and demographic backgrounds through the use of in-house advocacy, public outreach, media interviews, and partnerships with academic and government institutions enable these facilities to engage and share information with a broad audience. Although the data collected on sharks in captivity often cannot be directly translated to animals in the wild, it offers better insight into a number of life history traits and poorly understood behaviours, and has been the foundation for many captive breeding programs. Several Northeast Pacific (NEP) shark species are commonly displayed for long durations or bred in aquariums, while other less studied species have been held for short periods to collect valuable data that can be applied towards ongoing studies and conservation measures. Here, we discuss past and current tangible benefits of holding NEP sharks in captivity, as well as noting several ways in which future research and education activities will continue to inform and shape public opinions on shark management and conservation.

Long-term sperm storage in the brownbanded bamboo shark Chiloscyllium punctatum.

This study investigated the birth of a brownbanded bamboo shark Chiloscyllium punctatum at the Steinhart Aquarium. Genetic analyses suggest this is the longest documented case of sperm storage for any species of shark (45 months).

Two decades of genetic profiling yields first evidence of natal philopatry and long-term fidelity to parturition sites in sharks.

Sharks are a globally threatened group of marine fishes that often breed in their natal region of origin. There has even been speculation that female sharks return to their exact birthplace to breed ('natal philopatry'), which would have important conservation implications. Genetic profiling of lemon sharks (Negaprion brevirostris) from 20 consecutive cohorts (1993-2012) at Bimini, Bahamas, showed that certain females faithfully gave birth at this site for nearly two decades. At least six females born in the 1993-1997 cohorts returned to give birth 14-17 years later, providing the first direct evidence of natal philopatry in the chondrichthyans. Long-term fidelity to specific nursery sites coupled with natal philopatry highlights the merits of emerging spatial and local conservation efforts for these threatened predators.

Poaching of endangered species in Mediterranean Sea: Alopias vulpinus.

A thresher shark poached by fishermen in the stretch of sea between the island of Ponza and the coast of Terracina (Lazio, Central Italy, Mediterranean Sea) and confiscated by the Italian health authorities was evaluated for the presence of chemical contaminants. Hg mean concentration of 2.1 mg kg-1 was found in muscle; speciation analysis confirmed it was almost in the toxic organic form of MeHg (2.0 mg kg-1). The Se:Hg molar ratio was <1 not protective against the toxic effect of Hg. 137Cs was detected at a mean concentration of 0.53 Bq kg-1, and 40K, radioisotope of natural origin was found at 91 Bq kg-1. Dioxins and PCBs were found in the common thresher shark at mean concentrations of 0.012 and 0.088 pg TEQ-WHO g-1 w.w. while NDL PCBs at 4.5 ng g-1 w.w., lower than limits set by European Regulation. The major concern is constituted by the presence of Hg twice the maximum limit set by EU Regulation, then the consumption of thresher shark flesh should be strongly discouraged.

Understanding non-compliance in small-scale fisheries: Shark fishing in Myanmar's Myeik Archipelago.

Achieving fisheries compliance is challenging in contexts where enforcement capacity is limited and the incentives for rule-breaking are strong. This challenge is exemplified in Myanmar, where an active shark fishery exists despite a nationwide ban on targeted shark fishing. We used the Kipling method (5W1H) to gather a complete story of non-compliance in five small-scale fishing communities in the Myeik Archipelago. Among 144 fishers surveyed, 49% were aware of the nationwide ban. Shark fishers (24%) tended to be younger individuals who did not own a boat and perceived shark fishing to be prevalent. Compliant fishers were motivated by a fear of sharks and lack of capacity (equipment, knowledge), whereas food and income were cited as key motivations for non-compliance. The results of our study emphasize that in resource-dependent communities, improving compliance for effective shark conservation may require addressing broader issues of poverty, food security and the lack of alternatives.

Shark ecotourism in Mexico: Scientific research, conservation, and contribution to a Blue Economy.

Shark ecotourism has the potential to contribute significantly to local and national economies and conservation, though this depends on a concerted effort to implement evidence-based management. Sharks are key attractions at some of the most important marine ecotourism sites throughout Mexico, focusing particularly on whale sharks, white sharks, hammerhead sharks, and several other reef-associated and pelagic species. This generates important employment opportunities and millions of USD in revenue, but truly implementing ecotourism requires that education and conservation be a part of activities and that these benefit local communities, so that the industry can be socially, economically and ecologically sustainable. In Mexico, this includes addressing potential negative impacts from vessel overcrowding, provisioning, inequitable distribution of ecotourism and conservation benefits and costs, and a broader lack of governance capacity to ensure that coastal development is environmentally sustainable and socially equitable. In the context of a Blue Economy centred on sustainability and local benefits, ecotourism provides a key incentive and opportunity to improve ocean management.

Fisheries interactions and the challenges for target and nontargeted take on shark conservation in the Mexican Pacific.

Sharks have been of great cultural and socioeconomic importance in Mexico since the late 19th century, when the first fisheries were prosecuted in the Gulf of California to export fins to China. Mexican shark and ray fisheries are classified mainly by the size of the fishing vessel and include small- (7.5-10m), medium- (10-27m), and large-sized (>27m) fisheries. All are multispecies fisheries that use longline or gillnet gear, with their relative productivity varying over time. Off the Pacific coast, early shark small size vessel fisheries in the Gulf of California were driven by the need for vitamin A from livers, especially during World War II. As this fishery declined, new shark fishing opportunities arose because of government support and the development of the medium-sized fishery, which was capable of farther offshore excursions. Shark meat became an important part of the diets of poor and impoverished citizens during the 1950s and 1960s. The establishment of a Mexican Exclusive Economic Zone in 1976 pushed foreign vessels from Asia out of Mexican waters and led to the development of the large-sized vessel fishery to exploit pelagic sharks in offshore waters. By the early 1980s, Mexico shark fisheries were among the most productive in the world; however, a national economic crisis reduced effort and landings until the late 1980s, when several new fisheries emerged. Landings from Pacific states fluctuated between ~13,000 and 24,000t (dressed weight) during 1987-2012 but expanded steadily thereafter because of government support and offshore fleet expansion. Shark fisheries landings from the Mexican Pacific are currently at their highest recorded levels, exceeding 31,000t; however, a lack of species-specific landings and life history information has precluded population assessments of targeted stocks. In addition, though several recent management measures have been enacted to protect Mexican shark and ray fishery resources, the enforcement of these regulations is severely lacking. Therefore, the long-term sustainability of current fishing levels is unknown but should engender concern based on anecdotal evidence of serial depletion among historical elasmobranch targets in the Mexican Pacific.

Introduction: The sharks of Pacific Mexico and their conservation: Why should we care?

Sharks exhibit a broad range of body forms, occupy diverse ecological niches, and are found in every ocean on earth. They have roles as both predator and prey and have an evolutionary history far longer than that of human beings. As long as humans have interacted with the ocean they have interacted with sharks and, as a result, sharks have featured in the mythology, history, and fisheries of diverse cultures around the world. Only in the last 100 years or less, however, have humans begun to study and fully realize the susceptibility of these animals to intensive fishing pressure, ecological degradation, and other anthropogenic factors. This volume highlights the biodiversity and biological attributes of, and conservation efforts targeted at, populations of sharks that reside in the Northeast Pacific Ocean (NEP) bordering the west coast of Mexico. Together with a pair of companion volumes published in 2017 that focused on the NEP adjacent to the United States and Canada, this volume provide readers a detailed backdrop of shark biology and conservation in the Mexican waters of the Northeast Pacific against which to consider their own actions, and those of resource managers, academics, and educators, as they relate to the long-term conservation of sharks and their relatives.

Global pattern of phylogenetic species composition of shark and its conservation priority.

The diversity of marine communities is in striking contrast with the diversity of terrestrial communities. In all oceans, species richness is low in tropical areas and high at latitudes between 20 and 40°. While species richness is a primary metric used in conservation and management strategies, it is important to take into account the complex phylogenetic patterns of species compositions within communities. We measured the phylogenetic skew and diversity of shark communities throughout the world. We found that shark communities in tropical seas were highly phylogenetically skewed, whereas temperate sea communities had phylogenetically diversified species compositions. Interestingly, although geographically distant from one another, tropical sea communities were all highly skewed toward requiem sharks (Carcharhinidae), hammerhead sharks (Sphyrnidae), and whale sharks (Rhincodon typus). Worldwide, the greatest phylogenetic evenness in terms of clades was found in the North Sea and coastal regions of countries in temperate zones, such as the United Kingdom, Ireland, southern Australia, and Chile. This study is the first to examine patterns of phylogenetic diversity of shark communities on a global scale. Our findings suggest that when establishing conservation activities, it is important to take full account of phylogenetic patterns of species composition and not solely use species richness as a target. Protecting areas of high phylogenetic diversity in sharks, which were identified in this study, could form a broader strategy for protecting other threatened marine species.

Populations analysis of the Brazilian Sharpnose Shark Rhizoprionodon lalandii (Chondrichthyes: Carcharhinidae) on the São Paulo coast, Southern Brazil: inferences from mt DNA sequences

Sharks of the genus Rhizoprionodon can be considered some of the most important predators along the trophic coastal marine ecosystems and represent an important economic resource for the small-scale fisheries, especially on the Brazilian coastline. In order to analyze the population structure of the shark Rhizoprionodon lalandii of São Paulo, Southeastern coast of Brazil, levels of genetic diversity were identified by nucleotide sequence analyses of the mitochondrial DNA control region. The results obtained from this study present moderate values of haplotype diversity and low nucleotide diversity. Although the AMOVA tests (ΦST = 0.08394, P < 0.01) had shown slightly differences among the studied samples, evidence for the occurrence of population structuring was not found, which may be a general feature of sharks living in coastal areas.

Tubarões do gênero Rhizoprionodon são considerados predadores de grande importância ao longo da cadeia trófica nos ecossistemas costeiros e marinhos, também representando um importante recurso econômico para a pesca, especialmente no litoral brasileiro. A fim de analisar a estrutura populacional do tubarão Rhizoprionodon lalandii no litoral de São Paulo, sudeste do Brasil, foram identificados os níveis de diversidade genética a partir da análise de sequências nucleotídicas da região controladora do DNA mitocondrial. Os dados obtidos neste estudo apresentam valores moderados de diversidade haplotípica e baixos índices de diversidade nucleotídica. Embora os testes de AMOVA (ΦST = 0,08394, P < 0,01) tenham revelado uma pequena diferença entre as amostras estudadas, evidências sobre a ocorrência de estruturação populacional não foram encontradas o que pode representar uma característica geral para tubarões vivendo em áreas costeiras.