Gillnets are used world-wide for harvesting groundfish and pelagic species at sea and in freshwater. Little consideration has been given to how fish are caught in gillnets, even though the capture mode provides valuable information for understanding gear catchability. This paper describes a new method of estimating the length-dependent fish capture modes in gillnets. Using this method, we investigated the length-dependent capture modes for cod (Gadus morhua) in commercial monofilament nylon gillnets. Cod is a target species for several fisheries in the Northern Atlantic. This is the first time the capture mode was formally related to fish size with a direct representation of the experimental observations. The results demonstrated that gillnets are clearly designed for gilling. However, capture modes were size dependent, with small fish being caught by the mouth and larger fish by the maxillary. The application of the method is relevant when used by gear technologists to evaluate different gear characteristics to improve size or species selectivity. Changing the hanging ratio, for instance, or replacing nylon twine by thicker biodegradable material may considerably change the capture modes and their effect on gear efficiency.

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N. (2016). Testing the effect of soak time on catch damage in a coastal gillnetter and the consequences on processed fish quality. Food Control, 70, 310-317. DOI: 10.1016/j.foodcont.2016 ABSTRACTThis study aims at testing how to improve catch quality aboard a coastal gillnetter by looking at an easily controllable parameter known to have an effect on the degree of fish damage, soak time, and investigating if the registered damages on whole fish have an effect on processed products such as fillets. Plaice (Pleuronectes platessa) was captured with commercial gillnets soaked for 12 and 24 hours. Damages were assessed using semiquantitative indices of individual fish condition gathered in a Catch-damage-index for onboard fish and a Processed fish-damage-index for whole, skinned and filleted plaice processed at a land-based factory. Cumulative link mixed modelling allowed the estimation of the size of effects. Damage in fish was significantly more likely for longer soak times but effects were comparable to those of fish length and between-sets, making a change in soak time not so substantial for improving plaice quality in coastal gillnetting. Damage in fish was significantly more likely for whole than filleted fish, but there was substantial heterogeneity among fish. Severe damage in whole fish may not matter in filleted fish whereas some damage may only be visible at the fillet level.

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