Effects of different harvesting strategies on the stock of Antarctic icefish Champsocephalus gunnari around South Georgia

The effects of a number of harvesting strategies on the Antarctic icefish Champsocephalus gunnari have been simulated for a period of 30 years.
These were
- diffierent levels of constant fishing mortality (F0.1, Fmax, 2xFmax),
- harvesting contantly at 50%F0.1 with an increase of F 3 or 6 years after a good recruitment,
- pulse fishing at an interval of 3 years with no fishing in between;
- a shift in partial recruitment values due to changes in net selectivity.
For the projections recruitment was assumed to fo11wed the historical pattern.
Pulse fishing prove to be the least preferable harvesting alternative. In the absence of regular recruit surveys constant fishing at F0.1 is most likely to be the most profitable and least risky harvesting strategy at present. The establishment of regular recruit survey would offer the possibility to adjust constant levels of fishing mortality to the strength of the incoming year class. An increaseof F, however, should not occur before 4 years after a good recruitment. A forward shift in partial recruitment values would not alter yield significantly when fishing at F0.1 and Fmax but would lead to a higher spawning biomass.