Plaice (Pleuronectes platessa) survivability in a Celtic Sea bottom-seine fishery: A phased approach

Fish survival studies in Europe have been common practice by member states since the introduction of the Landing Obligation (LO) in 2013. “High survivability” exemptions to the LO may be granted for species that demonstrate high post catch and release survival. Implementing full-scale captive monitoring or tagging survival studies are costly and logistically complex. Preliminary assessment of fish condition can provide useful information on the feasibility of such experiments. We assessed the post capture condition and survival of plaice ( Pleuronectes platessa ) caught in an Irish bottom-seine fishery using a phased approach. Phase 1 assessed the condition of plaice from the Irish fishery and inferred potential survival from a Danish bottom-seine fishery that assessed plaice condition and related survival. Positive results supported implementation of phase 2, a full-scale assessment of plaice survival in the Irish fishery. Plaice were caught during commercial fishing operations and held in captivity in a bespoke holding facility. A Kaplan-Meier estimator model was used to approximate survival over time while in captivity. Plaice survival after 15 days in captivity was 71%. Predictive modeling forecasted a similar survival estimate over a 25-day period. The benefits and limitations of this approach are discussed. The developed approach has potential to be used as a decision support tool on the feasibility of full-scale survival experiments in other fisheries. • Inferred survival estimates helped determine the feasibility for full scale survival assessment. • A bespoke mobile holding facility provided opportunity for a captive survival experiment. • A Kaplan-Meier estimator and predictive modeling was used to estimate plaice survival. • The study findings resulted in implementation of a high-survival exemption in the Celtic Sea bottom-seine fishery.