Members of the Epinephelinae subfamily of serranids (‘grouper’) are heavily
exploited by bottom longline in the Gulf of Gabès located in the south of
Tunisia. In addition to direct mortality, hook and release mortalities
likely occur when fish are caught and released, due to injuries sustained
from hooking as well as those associated with retrieval. During five
experimental trips (29 fishing sets) conducted in August 2011 from the port
of Djerba (south of the Gulf of Gabès), we evaluated the effect of hook
styles (9/0 ‘J’ and 12/0 circle hook) on groupers and non-target species. A
total of 340 specimens representing 10 species were captured. The higher
catch rate was registered for Epinephelus aeneus. The
majority of groupers captured were female mature. The circle hook increased
the capture of the most common grouper E. aeneus and did
not affect the catch of Epinephelus marginatus and
Epinepheleus costae. The effect of the type of hook on
hooking location was inconclusive. Managing of the grouper fishery using
some management actions such as size limits, bag limits, and closed seasons
may prevent more unnecessary losses of grouper species. From this
preliminary study, a definite conclusion for or against the use of circle
hook cannot be drawn. Further research on the role of gear modification and
hook designs in reducing by-catch, hooking-related injury and mortality
should be encouraged.