2 research outputs found
Bycatch: complementary information for understanding fish behaviour. Namibian Cape hake (M. capensis and M. paradoxus) as a case study
7 páginas, 4 figuras, 1 tablaTo identify spatio-temporal distribution in Namibian Cape hake (M. paradoxus and
M. capensis), incidental hake catch by the horse mackerel fleet and targeted catch by the
hake fleet were analysed for the period 1999e2004. The targeted catch, 45 955 fishing
days, came from hake fishery logbooks and the incidental catch, 24 689 trawls, from observers’
sample data collected aboard vessels of the horse mackerel fleet. A strong negative relationship
between monthly catch rates (cpue) and bycatch was observed, confirming that the seasonal
change in catchability is caused by differences in hake vertical dispersion. The
October trends were an exception: both cpue and bycatch were negative. A drop in catchability
at different depths of the fishing grounds indicates that M. capensis migrates to shallower
water (<200 m) at the peak of spawning. Although there was no significant
relationship between annual catch rates and bycatch, probably because of the short length
of the time-series, annual bycatch should not be discarded as an indicator of hake recruitment.
The results highlight the potential informative component of bycatch in identifying
population patterns that cannot be extracted from the targeted catch.Peer reviewe