Sphyrna tudes, Smalleye Hammerhead

The Smalleye Hammerhead (Sphyrna tudes) is a medium-sized (to 150 cm total length) shark that occurs in the Western Central and Southwest Atlantic from Colombia to the Rio de La Plata, Argentina. It inhabits inshore waters over the continental shelf at depths of 5–80 m. It is captured in intense and largely unmanaged commercial and artisanal beach seines, gillnets, longlines, and trawls throughout its geographic range. This shark is targeted or retained as bycatch for its meat, which is consumed or sold locally. There are few data on population reduction but these intensive unmanaged fisheries are suspected to have caused reductions and possibly local extinctions throughout this species' range. For example, in Brazil, this hammerhead has not been recorded in 35 years from Ceará state and it is considered by local fishers to be depleted in Bahia state. This shark is supposed to be strictly protected in Brazil, but it is clear that it is still landed and traded in various states. Overall, due to intense and largely unmanaged fisheries across its range, lack of refuge at depth, suspected declines in many areas and local extinctions suspected from an absence of records (despite continued sampling and observation), and its relatively unproductive life history, it is suspected that the Smalleye Hammerhead has undergone a population reduction of >80% over the past three generations (37 years), and it is assessed as Critically Endangered A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Barreto, R.. Instituto Chico Mendes de Conservacao Da Biodiversidade; BrasilFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Faria, V.. Universidade Federal Do Ceara; BrasilFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Lasso Alcala, O.. Fundación la Salle de Ciencias Naturales; VenezuelaFil: Marcante, F.. Universidade Federal Do Rio Grande.; BrasilFil: Mejía Falla, P.A.. Wildlife Conservation Society; Estados UnidosFil: Montealegre Quijano, S.. Universidade Federal de Sao Paulo; BrasilFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Navia, A. F.. Fundación Squalus; ColombiaFil: Nunes, J.. Universidade Federal Do Maranhao.; BrasilFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Myliobatis freminvillii, bullnose eagle ray

The Bullnose Eagle Ray (Myliobatis freminvillii) is a medium-sized (to 106 cm disc width) demersal coastal eagle ray that occurs in the Northwest, Western Central, and Southwest Atlantic Oceans from Massachussetts, USA to the Texas coast of the Gulf of Mexico and from Venezuela to Buenos Aires, Argentina and inhabits continental shelves from the surface to a depth of 122 m. Its is captured by artisanal longlines, gillnets, beach seines and also in industrial shrimp trawls. In the Northwest Atlantic, population trend data are available from a deep-water trawl survey in the northern Gulf of Mexico that reveal steep increases in abundance over 2002-2013. There are no known threats in the Northwest and Western Central Atlantic, but in the Southwest Atlantic artisanal fisheries are intense. Further, there are largely unmanaged commercial trawl and longline fisheries in this area. This inshore eagle ray is exposed to intense and often unmanaged fishing pressure throughout the Southwest Atlantic portion of its range, and it has no refuge at depth. Due to the level of exploitation by widespread artisanal fisheries which lack adequate management, it is suspected that this species has undergone a population reduction of >80% over the past three generation lengths (44 years) in the Atlantic South American part of its range, but is stable in the Northwest and Western Central Atlantic. Overall, based on its range, with almost all threats found in the Southwest Atlantic, and the suspected low productivity of the species, the Bullnose Eagle Ray is suspected to have undergone a population reduction of 30-49% in the past three generation lengths (44 years) due to levels of exploitation, and it is assessed as Vulnerable A2bd.Fil: Carlson, J.. National Marine Fisheries Service; Estados UnidosFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Avalos, C.. Fundacion Mundo Azul; GuatemalaFil: Blanco Parra, M. P.. Universidad de Quintana Roo; MéxicoFil: Briones Bell lloch, A.. Direccion de Regulaciones Pesqueras y Ciencias; CubaFil: Cardeñosa, D.. Florida International University; Estados UnidosFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Derrick, D.. University Fraser Simon; CanadáFil: Espinoza, E.. Direccion Parque Nacional Galapagos; EcuadorFil: Mejía Falla, P. A.. Wildlife Conservation Society; Estados UnidosFil: Morales Saldaña, J. M.. Smithsonian Tropical Research Institute; PanamáFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Naranjo Elizondo, B.. Universidad de Costa Rica; Costa RicaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Perez Jiménez, J. C.. El Colegio de la Frontera del Sur; MéxicoFil: Rincon, G.. Universidade Federal Do Maranhao.; BrasilFil: Schneider, E. V. C.. Cape Eleuthera Institute; BahamasFil: Simpson, N. J.. Salvageblue; San Vicente y las GranadinasFil: Talwar, B. S.. Florida International University; Estados UnidosFil: Pollom, R.. University Fraser Simon; Canad

Myliobatis goodei, southern eagle ray

The Southern Eagle Ray (Myliobatis goodei) is a medium-sized (to at least 115 cm DW) coastal eagle ray that occurs in the Western Central and Southwest Atlantic Oceans from South Carolina and Florida, USA and Quintana Roo, Mexico to San Jorge Gulf, Santa Cruz, Argentina. It inhabits continental shelves from inshore to depths of 181 m. It is captured using artisanal longlines, gillnets, beach seines, and in industrial shrimp trawls. This species is inferred to be stable or increasing in the Western Central Atlantic, based on its similarity to the Bullnose Eagle Ray (Myliobatis freminvillei). In the Southwest Atlantic artisanal fisheries are intense, further there are largely unmanaged commercial trawl and longline fisheries in many areas. In Brazil, landings of eagle rays have been reduced by 60% over 2000?2012 in Santa Catarina State, and a reduction of 91% in Rio Grande do Sul since the 1980s. This inshore eagle ray has no refuge at depth and is exposed to intense and often unmanaged fishing pressure throughout the Atlantic South American portion of its range and there it is suspected that this species has undergone a population reduction of >80% over the past three generation lengths (44 years), but is stable in the Western Central Atlantic. Overall, based its range with the almost all threats found in the Southwest Atlantic, the suspected low productivity of the species, this species is suspected to have undergone a population reduction of 30 49% in three generation lengths (44 years) due to levels of exploitation, and it is assessed as Vulnerable A2d.Fil: Carlson, J.. National Marine Fisheries Service; Estados UnidosFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Avalos Castillo, C.. Fundación Mundo Azul; GuatemalaFil: Blanco Parra, M. P.. Universidad de Quintana Roo; MéxicoFil: Briones Bell lloch, A.. Dirección de Regulaciones Pesqueras y Ciencias; CubaFil: Cardeñosa, D.. Florida International University; Estados UnidosFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Derrick, D.. University Fraser Simon; CanadáFil: Espinoza, E.. Galapagos National Park Directorate; EcuadorFil: Mejía Falla, P. A.. Wildlife Conservation Society; Estados UnidosFil: Morales Saldaña, J. M.. Smithsonian Tropical Research Institute; PanamáFil: Motta, F.. Universidade Federal Do Sao Paulo; BrasilFil: Naranjo Elizondo, B.. Universidad de Costa Rica; Costa RicaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Paesch, L.. Direccion Nacional de Recursos Acuaticos ; UruguayFil: Pérez Jiménez, J. C.. El Colegio de la Frontera del Sur; MéxicoFil: Rincon, G.. Universidade Federal Do Maranhao.; BrasilFil: Schneider, E. V. C.. Cape Eleuthera Institute; BahamasFil: Simpson, N. J.. Salvageblue; San Vicente y las GranadinasFil: Talwar, B. S.. Florida International University; Estados UnidosFil: Pollom, R.. University Fraser Simon; Canad

Reproductive Strategy of the Giant Electric Ray in the Southern Gulf of California

The objective of the present study was to describe and characterize macroscopic and microscopic aspects of the reproductive biology of the Giant Electric Ray Narcine entemedor, a viviparous elasmobranch targeted by commercial fishers in Mexico. A total of 305 individual rays were captured (260 females, 45 males); all males were sexually mature. The median size at maturity for females was estimated to be 58.5 cm TL, the median size at pregnancy was 63.7 cm TL, and the median size at maternity was 66.2 cm TL. The range of ovarian follicles recorded per female was 1–69; the maximum ovarian fecundity of fully grown vitellogenic oocytes was 17, and uterine fecundity ranged from 1 to 24 embryos per female. The lengths of the oblong ovarian follicles varied significantly among months, and the largest ovarian follicles were found in July, August, and September. Median embryo size was largest in August, and the size at birth was between 12.4 and 14.5 cm TL. Histological evidence of secretions from the glandular tissue of the uterine villi indicate that this species probably has limited histotrophy as a reproductive mode. Vitellogenesis in the ovary occurred synchronously with gestation in the uterus. The Giant Electric Ray has a continuous annual reproductive cycle; a period of ovulation occurs between May and September and two peaks of parturition, one in January and one in August, occur, suggesting that embryonic diapause occurs in some individuals. These results provide useful information for the management of this important commercial species in Bahía de La Paz, Mexico, and will allow possible modification of the current Mexican regulations to enable better protection of this species

Tropical Eastern Pacific Records of the Prickly Shark, Echinorhinus cookei (Chondrichthyes: Echinorhinidae)

v. ill. 23 cm.Also available through BioOne: http://www.bioone.org/doi/abs/10.2984/65.4.433QuarterlyMost records of the prickly shark, Echinorhinus cookei Pietschmann, 1928, are from temperate and subtropical areas of the Pacific rim, with few records from the tropics. This seemingly disjunct distribution led some authors to consider E. cookei to have an antitropical distribution. Unreported museum specimens and underwater observations of E. cookei from Cocos Island, Costa Rica; the Galápagos Islands; and northern Peru confirm its occurrence in the tropical eastern Pacific and, combined with other published records from the eastern Pacific, establish a continuous, panhemispheric eastern Pacific distribution