To estimate the proportion of plaice that might survive being returned to the sea when they are caught accidentally whilst fishing for other species.
This is so that CEFAS can provide scientific evidence to guide DEFRA’s decision making about the implementation of the EU Common Fisheries Policy. Specifically, about whether unwanted plaice can be released back to the sea rather than being brought to shore and deducted from a fishing vessel’s annual plaice quota.
Data were available from studies run by CEFAS on different fishing vessels. The vitality of plaice caught under commercial conditions had been assessed and their survival monitored in tanks on land. For each separate vessel, CEFAS estimated the probability of fish surviving, given their vitality, using cure models. The methodology and results were described in this report.
Survival rates varied between vessels and fish were monitored for different periods of time from each vessel. The challenge for this project was to use the available data to predict the probability of survival for plaice caught on any vessel, not just those vessels in the existing studies.
This project develops new models that combine information from across the different studies. The variability in survival between studies can then be estimated. This makes it possible to estimate survival for plaice caught on a different vessel.