ABSTRACT

Chondrichthyans are one of the most successful groups of fishes and have penetrated most marine ecosystems, including high latitude seas. Worldwide, most chondrichthyans (~55%) occur on continental shelves from the intertidal zone down to 200 m depth and to a lesser extent on insular shelves (Compagno 1990). The diversity of shelf species is greatest in the tropics and lower in high latitude seas. However, studies on the biodiversity and life history of high latitude seas chondrichthyans, those occurring in cold-temperate latitudes and higher, are relatively few compared to those in lower latitude seas. The paucity of data from these habitats may be due to the inaccessibility of the environment and a general lack of directed chondrichthyan fisheries in lieu of more economically important bony fish species. Several major teleost fisheries (e.g., groundfish and Patagonian toothfish) in high latitude seas take chondrichthyans as bycatch, but they are discarded, and little information is gathered regarding species complexes or abundance. One exception is for larger pelagic shark species (e.g., Lamna spp.) that have been intensely targeted by directed fisheries in some regions.