Collecting size-selectivity data for Antarctic krill (Euphausia superba) with a trawl independent towing rig

For the development of efficient trawls to minimize catch loss, escape mortality and potential
negative ecosystem impacts from the fishery, the understanding about trawl selectivity processes
are crucial. Small crustaceans are regarded as being less motile than most fish species.
Crustaceans also display low levels of active avoidance from trawl netting, which in
turn may cause direct contact with netting on multiple occasions on their passage towards
the codend increasing the probability for escapement. Full-scaled experiments to estimate
gear selectivity are highly resource demanding and are highly technically challenging for
several types of fisheries. In this study, we developed and tested a trawl-independent
towed-rig construction designed to investigate size selectivity of Antarctic krill (Euphausia
superba). The results indicate that valid selectivity estimates can be obtained using this
method, but due to the small sample size, results are inconclusive. However, the findings of
the current study show a potential for developing easier and more cost-effective ways of
investigating and estimating size selectivity of Antarctic krill and other small crustacean species
in trawls.