RESUMO
The deep ocean is the last natural biodiversity refuge from the reach of human activities. Deepwater sharks and rays are among the most sensitive marine vertebrates to overexploitation. One-third of threatened deepwater sharks are targeted, and half the species targeted for the international liver-oil trade are threatened with extinction. Steep population declines cannot be easily reversed owing to long generation lengths, low recovery potentials, and the near absence of management. Depth and spatial limits to fishing activity could improve conservation when implemented alongside catch regulations, bycatch mitigation, and international trade regulation. Deepwater sharks and rays require immediate trade and fishing regulations to prevent irreversible defaunation and promote recovery of this threatened megafauna group.
Assuntos
Conservação dos Recursos Naturais , Extinção Biológica , Caça , Tubarões , Rajidae , Animais , Humanos , Internacionalidade , Carne , Óleos de Peixe , Biodiversidade , Oceanos e Mares , RiscoRESUMO
A combination of morphological and molecular techniques was used to confirm the existence of a second species of the monotypic centrolophid genus Tubbia. Adults of the seamount rudderfish, T. stewarti sp. nov., which reaches about 56 cm SL, is mesopelagic at depths of 525-1438 m in the temperate waters of the Southern Hemisphere. It has a confirmed distribution off Australia and New Zealand where it occurs sympatrically with the wider ranging T. tasmanica Whitley. Like most other members of the group, juveniles live in the epipelagic zone where they have been taken at 30-50 m depth. The new species has a more robust head, more slender body, more flattened interorbit, longer jaws, denser head pores, relatively larger eyes and nostrils, narrower caudal peduncle and more vertebral centra than T. tasmanica, and also differs subtly in some morphometric ratios. A rediagnosis of T. tasmanica is also provided.