A trap with a twist: evaluating a bycatch reduction device to prevent rockfish capture in crustacean traps

Abstract

Favaro, B., Duff, S. D., and Côté, I. M. 2013. A trap with a twist: evaluating a bycatch reduction device to prevent rockfish capture in crustacean traps. – ICES Journal of Marine Science, 70:114–122. Bycatch, or the incidental capture of non-target species, occurs in fisheries around the world, with often detrimental ecological consequences. Bycatch reduction devices (BRDs) that increase catch specificity have been used successfully in some fisheries, and the development of such devices remains an important component of the global effort to reduce bycatch rates. We tested novel devices designed to exclude juvenile rockfish (Sebastes spp.) from traps used to catch spot prawns (Pandalus platyceros), a commercially important species in British Columbia, Canada. The devices included reductions in trap opening sizes and novel bent-tunnel openings. Reducing trap opening size did not affect bycatch rates of rockfish or other non-target fish species. In contrast, bent-tunnel BRDs eliminated rockfish bycatch, and two of the bent-tunnel variants also excluded other fish species. However, prawn catch rates were reduced in all modified gear, and large prawns were often excluded more than small prawns. Videos recorded in situ revealed that prawn attempts to enter traps took longer and were more likely to fail in BRD-equipped than in unmodified traps. We conclude that bent-tunnel BRDs have the potential to be useful, but improvements are needed to increase prawn catch to levels similar to that of unmodified traps.

Increasing the Selectivity of the Stone Crab Menippe mercenaria Trap by the Addition of a Cull Ring

“…; Favaro et al. ). The 16 unmodified plastic stone crab traps used in our study during the 2016–2017 fishing season caught 569 nontarget individuals of other species and 616 prerecruit stone crabs.…”

Mitigating unaccounted fishing mortality from gillnets and traps

“…; Favaro et al . ). In many cases, escape gaps can be cheaply purchased and simply installed in a range of existing traps (Adey et al .…”

“…Escape gaps for traps are very common and range from simple openings designed to match the size and shape of unwanted organisms (Tallack 2007;Adey et al 2008) to more novel designs that function by exploiting differences in behaviour (Brock et al 2006a,b;Gilman et al 2010;Favaro et al 2013). In many cases, escape gaps can be cheaply purchased and simply installed in a range of existing traps (Adey et al 2008).…”

How to build a low-cost underwater camera housing for aquatic research

“…There are many uses for camera systems in underwater environments and their flexibility is only limited by the creativity of the researcher. To list a few applications, underwater cameras can be used to study fish behaviour (Hammar et al 2013;Binder et al 2014;Domenici et al 2014), monitor interactions with fishing gear (Jury et al 2001;Bacheler et al 2013;Robbins et al 2013), evaluate bycatch reduction devices (Favaro et al 2013;Cairns et al 2014;Lomeli and Wakefield, 2014), assess abundance and community structure (Clarke et al 2012;Harasti et al 2014), or map habitat and bathymetry (Schmidt and Rzhanov 2012). However, many studies involving action cameras are still limited by the duration and quality of video they are able to record.…”