by
It has long been recognized that the longevity and low fecundity of sharks makes them particularly vulnerable to over-exploitation. Previous studies have emphasized the range of natural productivities observed across elasmobranch species and have used this to explain the sustainability of some elasm...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2002
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.604.4904 http://archive.nafo.int/open/sc/2002/scr02-139.pdf |
| Summary: | It has long been recognized that the longevity and low fecundity of sharks makes them particularly vulnerable to over-exploitation. Previous studies have emphasized the range of natural productivities observed across elasmobranch species and have used this to explain the sustainability of some elasmobranch fisheries and the depletion of others. This paper discusses the assessment of the two principle species fished by the Southern Shark Fishery of Australia, school shark (Galeorhinus galeus) and gummy shark (Mustelus antarcticus). It presents modeling results which illustrate that other patterns of behaviour and interactions with fisheries may be equally or more important in determining the relative robustness of different species under exploitation. Counter-intuitively concentrating a fishery on a few year-classes of pups, juveniles or sub-adults proves to be a robust management strategy for elasmobranch fisheries as long as the means exist for protecting adults from fishing mortality. Furthermore this management strategy proves to be most effective with the least productive species with the greatest longevity. The obverse of this finding is to highlight the damaging impact on elasmobranch fisheries of human activities such as by-catch, finning, sport fishing and beach protection that cause even low levels of adult mortality. |
|---|