Use a different method to sort or bring catch onboard
Overall effectiveness category Awaiting assessment
Number of studies: 0
Background information and definitions
The process of fish being lifted out of the water in fishing nets and on to a vessel for sorting can create extreme stress (Ashley 2006). In trawl nets there is also an increased likelihood of crush or puncture injuries under the weight of the catch. In addition, depending on the duration of time exposed during the catch sorting process , fish survival is decreased, not only due to factors such as oxygen deprivation, but also to the drying out of the fishes’ protective layer. Using different methods to move and sort fish (e.g. using water) may help improve the survival of discarded fish that after sorting are returned to the sea, by minimising air exposure and overall damage, including disruption to their mucus layer and scales (Hürlimann et al. 2014). One potential sorting method to reduce discard mortality, using a water-filled sorting tray instead of a conventional dry tray, led to fewer deaths of discarded fish during longer sorting times (Broadhurst et al. 2008).
For related interventions, see ‘Handling of catch’.
Ashley P.J. (2007) Fish welfare: current issues in aquaculture. Applied Animal Behaviour Science, 104, 199–235.
Broadhurst M.K., Uhlmann S.S. & Millar R.B. (2008) Reducing discard mortality in an estuarine trawl fishery. Journal of Experimental Marine Biology & Ecology, 364, 54–61.
Hürlimann R., Laan R., Vissia S., Willemsma A. & Zagenia F. (2014) Welfare of wild caught plaice (Pleuronectes platessa) An inventory how current practices in fisheries may affect welfare of plaice and possible indicators thereof. MSc thesis. Wageningen University, Netherlands.