Sawfishes are among the most endangered of all elasmobranch species, a factor fostering considerable worldwide interest in the conservation of these animals. However, conservation efforts have been hampered by the confusing taxonomy of the group and the poor state of knowledge about the family's geographical population structure. Based on historical taxonomy, external morphology, and mitochondrial DNA sequences (NADH-2), we show here that, globally, the sawfish comprise five species in two genera: Pristis pristis (circumtropical), Pristis clavata (east Indo-West Pacific), Pristis pectinata (Atlantic), Pristis zijsron (Indo-West Pacific), and Anoxypristis cuspidata (Indo-West Pacific, except for East Africa and the Red Sea). This improved understanding will have implications for the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), International Union for Conservation of Nature (IUCN) Red List assessments, and endangered species laws and regulations in several countries. Furthermore, based on both or either of NADH-2 and the number of rostral teeth per side, we show that populations of P. pristis, P. pectinata, P. zijsron, and A. cuspidata exhibit significant geographic structuring across their respective ranges, meaning that regional-level conservation will be required. Finally, the NADH-2 gene may serve as a marker for the identification of rostra and fins involved in illegal trade.

Sawfishes currently are among the most threatened elasmobranchs in the world. Only two species inhabit Atlantic waters: the largetooth sawfish (Pristis pristis) and the smalltooth sawfish (Pristis pectinata), both having suffered dramatic declines in their ranges. The goal of this study was to evaluate the status of P. pristis in the Atlantic, and estimate local extinction risk based on historical and recent occurrence records. In order to accomplish these goals, a thorough search for historical and recent records of P. pristis in the Atlantic was conducted, by reviewing scientific and popular literature, museum specimens, and contacting regional scientists from the species’ historical range. In total, 801 P. pristis records (1830–2009) document its occurrence in four major regions in the Atlantic: USA (n = 41), Mexico and Central America (n = 535), South America (n = 162), and West Africa (n = 48). Locality data were not available for 15 records. Historical abundance centres were the Colorado‐San Juan River system in Nicaragua and Costa Rica (and secondarily Lake Izabal of Guatemala), the Amazon estuary, and coastal Guinea‐Bissau. Currently, the species faces drastic depletion throughout its entire former range and centres of abundance. It appears to have been extirpated from several areas. The probability of extinction was highest in the USA, northern South America (Colombia to Guyane), and southern West Africa (Cameroon to Namibia). Currently, the Amazon estuary appears to have the highest remaining abundance of P. pristis in the Atlantic, followed by the Colorado–San Juan River system in Nicaragua and Costa Rica and the Bissagos Archipelago in Guinea Bissau. Therefore the protection of these populations is crucial for the preservation and recovery of the species. Copyright © 2013 John Wiley & Sons, Ltd.

The nurse shark, Ginglymostoma cirratum, is considered an endangered species in Brazil and its capture by fisheries forbidden. Despite such legislation, nurse sharks continue to be caught as these laws are unenforced and fisheries are not monitored. The goal of the present study was to describe the population structure of nurse sharks caught off Ceará State, north-eastern Brazil, based on the following aspects: abundance and size, sex-ratio, fisheries incidence and seasonality of captures. Landings were monitored weekly during a two-year period. A total of 189 specimens were recorded. Total length (TL) varied between 73 and 274 cm. The male-female ratio did not differ significantly (1.19C:1F). TL of individuals landed as carcasses was estimated based on interdorsal length. The following equation was obtained for males and females: TL ¼ 12.606ID + 14.24 (R 2 ¼ 0.9505). Most of the landed sharks were juveniles (86.2%). No seasonal pattern of abundance and TL variation was observed. Management of this fishery is required in order to prevent localized over-fishing of nurse sharks.

Large gaps in reef distribution may hinder the dispersal of marine organisms, interrupting processes vital to the maintenance of biodiversity. Here we show the presence and location of extensive reef habitats on the continental shelf between the Amazon Reef System (ARS) and the Eastern Brazilian Reef System (ERS), two reef complexes off eastern South America. Formations located 20–50 m deep include both biogenic and geogenic structures. The presence of diverse reef assemblages suggests the widespread occurrence of rocky substrates below 50 m. These habitats represent an expansion of both the ARS and ERS and the closure of the only remaining large-scale gap (~ 1000 km) among West Atlantic reef environments. This indicates that the SW Atlantic harbors a single, yet heterogeneous, reef system that stretches for about 4000 km, and thus, represents one of the largest semi-continuous tropical marine ecosystems in the world.