Rediscovery of bonnethead shark Sphyrna tiburo after more than two decades of non-record on central coast of Brazil

Reis‐Filho, José Amorim; Sampaio, Cláudio L. S.; Leite, Luciana; Oliveira, Gabriel S.A.; Loiola, Miguel; Nunes, José de Anchieta C. C.

doi:10.1017/s1755267214000487

Cited by 9 publications

(9 citation statements)

References 21 publications

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“…Previous studies from Brazil and the Mexican Pacific indicate that this species is susceptible to overfishing. In northern Brazil, the bonnethead was the second most frequently captured small shark species during the 1970s and 1980s (Lessa, 1986;Reis-Filho et al, 2014). However, it is now rarely captured (Reis-Filho et al, 2014), and has been reported as regionally collapsed or extinct (Bornatowski et al, 2009;Bressan et al, 2009).…”

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Temporal and latitudinal comparisons of reproductive parameters in a heavily exploited shark, the bonnethead, Sphyrna tiburo (L. 1758), in the southern Gulf of Mexico

Palacios‐Hernández

Castillo‐Géniz

Méndez‐Loeza

et al. 2020

Journal of Fish Biology

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In the southern Gulf of Mexico, the bonnethead shark, Sphyrna tiburo, is one of the most frequently captured species in landings of small-scale fisheries. Based on the analysis of two fishery-dependent sampling periods (1993-1994 and 2007-2014), this study aimed to determine reproductive parameters and identify temporal differences between the two time periods. In the first sampling period, 776 males and 352 females with a size range of 28.0-120.0 cm total stretched length (L T) were analysed, and in the second sampling period, 387 males and 432 females with a size range of 28.0-122.0 cm L T were analysed. The size at 50% maturity in the second sampling period was significantly different between sexes, 82.6 cm L T for females and 73.8 cm L T for males (no estimation was possible for the first sampling period). The size at 50% maternity was not different between sampling periods, 97.3 cm L T for the first sampling period and 99.0 cm L T for the second sampling period. Litter size varied from 3 to 19 embryos and the average was not statistically different in both periods, 10.1 (S.D. = 3.8) for the first sampling period and 11.3 (S.D. = 3.5) for the second sampling period. The female reproductive cycle is asynchronous, and it seems to be annual, with a gestation period of 5-6 months, and a consecutive ovarian cycle and gestation period. Temporal (between sampling periods) and latitudinal (southern Gulf versus northern regions) variations occur in the synchronicity of the reproductive cycle, temporal variation in the relationship between maternal length and litter size, and latitudinal variation in average size of mature sharks.

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Temporal and latitudinal comparisons of reproductive parameters in a heavily exploited shark, the bonnethead, Sphyrna tiburo (L. 1758), in the southern Gulf of Mexico

Palacios‐Hernández

Castillo‐Géniz

Méndez‐Loeza

et al. 2020

Journal of Fish Biology

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“…Examples include the extirpation of scoophead, S. media, and the bonnethead, S. tiburo, in Central and Southern Mexican Pacific (Pérez-Jiménez, 2014), the collapse of S. tiburo (Reis-Filho et al, 2014) and S. tudes populations in Brazil (Brasil, 2014). These species are susceptible to overfishing because of their life-history traits and the growing use of gill nets and trawls along the coastal zones (Castro, 1989;Lessa et al, 1998;Brasil, 2014).…”

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confidence: 99%

Fishers' ecological knowledge of smalleye hammerhead, Sphyrna tudes , in a tropical estuary

Giglio

Bornatowski

2016

Neotrop. ichthyol.

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Coastal hammerheads have suffered from overexploitation and environmental degradation. We interviewed 79 artisanal fishers to verify fishery aspects, temporal changes in catches and biological aspects of the smalleye hammerhead, Sphyrna tudes, in a marine protected area on Abrolhos Bank, Brazil. Data were compared between three generations of fishers: young, middle-aged and old. Fishers´ age varied between 17 and 88 years. We verified significant reductions in the weight of individuals caught by younger fishers. The main types of fishing gear used to catch S. tudes were gill nets and longlines. Overfishing through gill nets and trawl fisheries were mentioned as the cause of S. tudes population collapse in the region. The shark's diet as reported by fishers consisted of fish, crab and shrimp; austral summer was the reproductive season. A strong similarity was verified between fishers' knowledge and biological data. We suggest as plausible strategies to conserve the local population of S. tudes the reduction of net fisheries impact through zoning and establishment of no take areas. These steps can help to initiate the recovery of this depleted species.Tubarões martelo costeiros têm sofrido com a sobrepesca e degradação ambiental. Foram entrevistados 79 pescadores artesanais para verificar aspectos da pesca, mudanças temporais nas capturas e aspectos biológicos de Sphyrna tudes em uma área marinha protegida no Banco dos Abrolhos, Brasil. Os dados foram comparados entre três gerações de pescadores: novos, meia idade e mais velhos. A idade dos pescadores variou entre 17 e 88 anos. Verificaram-se reduções significativas no peso dos indivíduos capturados pelos pescadores mais jovens. Os principais petrechos usados para captura de S. tudes foram redes de emalhe e espinhel. Pescadores mencionaram que o colapso da população local de S. tudes foi decorrente do excessivo uso de redes de emalhe e pelas pescarias de arrasto. A dieta reportada foi peixes, caranguejos e camarões e a época de reprodução foi o verão. Uma forte similaridade foi verificada entre o conhecimento dos pescadores e dados biológicos. São sugeridas como estratégias plausíveis para conservar a população local de S. tudes a redução do esforço das pescas com rede através de zoneamento e estabelecimento de áreas de exclusão de pesca. Esses passos podem ajudar a iniciar a recuperação de espécies depletadas.

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“…Likewise, the Brazilian coastal fisheries mostly use synthetic encircling nets and gillnets (Freire et al, 2015). Brazilian landings data are incomplete and the statistical catch collection system has recently collapsed (Reis-Filho & Leduc, 2017;Reis-Filho et al, 2014) making historical reconstructions of fishing practices and catches data essential for the understanding and management of contemporary fisheries systems (Murray, Neis, & Schneider, 2007;Ommer, 2007). This work captures the complexities characterising the interactions occurring among fish, fishers and their social-ecological context.…”

Section: Con Clus Ionsmentioning

confidence: 99%

“…However, this knowledge mostly reflects actual and near-recent conditions and suffers from poor historical contextualisation resulting from the paucity of past data. Landings data, which are often the primary source for historical reconstruction of fisheries (Garcia & Leiva-Moreno, 2003;Pauly, Christensen, Dalsgaard, Froese, & Torres, 1998;Reis-Filho, Harvey, & Giarrizzo, 2018;Reis-Filho et al, 2014), are rarely available for the medium or distant past (i.e. 20 years before present and older).…”

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confidence: 99%

“…In these regions, small-scale and artisanal fisheries include the use of traditional vessels (small, wooden or fibreglass, motor-powered or sail-propelled), seine nets (ranging from 10 to 100 m length), gillnets and purse seines ranging from 100 to 1,000 m length and stretched mesh sizes varying from 10 to 150 mm. Hooks, harpoons and blue crab traps are the main fishing gears (Cetra & Petrere, 2014;Reis-Filho et al, 2014;Reis-Filho, Sampaio, Oliveira, Nunes, & Barros, 2018;Reis-Filho & Specht, 2015;Soares, Lopez, Muto, & Giannini, 2011). Local livelihoods involve combinations of smallscale agriculture and extractive activities related to fishing, mostly fish, shellfish and plant products, which are a source of income traded to purchase consumer goods (Caroso, Tavares, & Pereira, 2011;Reis-Filho, 2016).…”

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confidence: 99%

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Historical perspective of artisanal encircling gillnet use at the Brazilian coast: Changes in fishing behaviour is mirrored by dwindling stocks

Reis‐Filho

2019

Fisheries Management Eco

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Managing coastal resources sometimes requires looking into the past, as this provides a baseline against which present conditions may be gauged. The present study evaluated the circumstances that led Brazilian coastal fishers to modify their use of encircling gillnets. Other stressors (i.e. water pollution and habitat degradation) acted synergistically on the fisheries dynamic between 1950 and 2016. Declining catches of several species were observed through fishers' historical perception and through fisheries landing records. Three notable trends in net handling were associated with distinct historical periods. Specifically, pressures from modern fishery practices and gear (e.g. monofilament nets), the adoption of spiral setting arrangements and the increasing use of trammel nets appear responsible for the decline of many stocks. Mullet, seabass, jack and pilchard stocks decreased over time and were associated the changes witnessed in the encircling net operations. These changes occurred in response to overexploitation of fish stocks, to exploit the dwindling fisheries resources. The study also discusses the reasons leading fishers to accept how encircling gillnets ought to be used, their interpretation of such changes and the implications these changes have for fisheries management.

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Rediscovery of bonnethead shark Sphyrna tiburo after more than two decades of non-record on central coast of Brazil

Cited by 9 publications

References 21 publications

Temporal and latitudinal comparisons of reproductive parameters in a heavily exploited shark, the bonnethead, Sphyrna tiburo (L. 1758), in the southern Gulf of Mexico

Temporal and latitudinal comparisons of reproductive parameters in a heavily exploited shark, the bonnethead, Sphyrna tiburo (L. 1758), in the southern Gulf of Mexico

Fishers' ecological knowledge of smalleye hammerhead, Sphyrna tudes , in a tropical estuary

Historical perspective of artisanal encircling gillnet use at the Brazilian coast: Changes in fishing behaviour is mirrored by dwindling stocks

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