Skate post haulage survival experiments were conducted by one Chilean fishing vessel throughout the months of May and June, during 2003 toothfish fishing season in Subarea 48.3. From these results we can conclude that depth has a significant influence on the mortality of skate, with a predicted mortality of 0% for skate caught in waters of less than 1100m. A predicted mortality of 65% for skate caught in waters between, 1400 to 1600m and a mortality of 100% for skate caught at 2000m. We recommend from these findings that further survival experiment be conducted, particularly in more shallow waters where our sampling was restricted. Our findings support the suggestion of cutting ray from the line before landing (FSA-02 Para 5.78), as this will help ensure survival chances of skate are maximised. Results from this experiment can also be used to calculate the expected skate mortality within the fishery, based on depth of capture.
The survivorship of rays discarded from the South Georgia
longline fishery
Document Number:
WG-FSA-03/57
Agenda Item(s)
Abstract