Injury, reflex impairment, and survival of beam-trawled flatfish
| Autor: | Jochen Depestele, Ruben Theunynck, Bart Ampe, Maarten Soetaert, Marieke Desender, Sven Sebastian Uhlmann |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
Ecology 010604 marine biology & hydrobiology Anatomy Aquatic Science Biology Animal behaviour Oceanography biology.organism_classification 010603 evolutionary biology 01 natural sciences Pleuronectes platessa [Plaice] Flatfish Solea solea [Sole] Reflex Ecology Evolution Behavior and Systematics Beam (structure) |
| Popis: | Under the “high survival” exemption of the European landing obligation or discard ban, monitoring vitality and survival of European flatfish becomes relevant to a discard-intensive beam trawl fishery. The reflex action mortality predictor (RAMP) method may be useful in this context. It involves scoring for the presence or absence of natural animal reflexes to generate an impairment score which is then correlated with post-release or discard mortality. In our first experiment, we determined suitable candidate reflexes for acclimated, laboratory-held European plaice (Pleuronectes platessa) and common sole (Solea solea). In a second experiment, we quantified reflex impairment of commercially trawled-and-handled plaice and sole in response to commercial fishing stressors. In a third experiment, we tested whether a combined reflex impairment and injury (vitality) score of plaice was correlated with delayed post-release mortality to establish RAMP. Five-hundred fourteen trawled-and-discarded plaice and 176 sole were assessed for experimentally confirmed reflexes such as righting, evasion, stabilise, and tail grab, among others. Of these fish, 316 plaice were monitored for at least 14 d in captivity, alongside 60 control plaice. All control fish survived, together with an average of 50% (±29 SD) plaice after being trawled from conventional, 60 min trawls and sorted on-board a coastal beam trawler. Stressors such as trawl duration, wave height, air, and seawater temperature were not as relevant as a vitality score and total length in predicting post-release survival probability. In the second experiment where survival was not assessed, reflex impairment of plaice became more frequent with prolonged air exposure. For sole, a researcher handling-and-reflex scoring bias rather than a fishing stressor may have confounded results. Scoring a larger number of individuals for injuries and reflexes from a representative selection of trawls and trips may allow for a fleet-scale discard survival estimate to facilitate implementation of the discard ban. |
| Databáze: | OpenAIRE |
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