DCF (Data Collection Framework): Mortality of eel released by anglers
Project code: TI-OF-08-PID1611
Contract period: 01.06.2013 - 30.06.2016
Purpose of research: Inventory & Assessment
European eel (Anguilla anguilla) is an important target species for european anglers. Catch restictions and minimum landing sizes lead to high releases of recreational caught eel. The European eel stock has experienced dramatic declines, and is currently considered to be outside safe biological limits and listed as critically endangered by the IUCN. In spite of high release rates, up to now there is no information about the survival rates of released eel caught by anglers. Therefore, a combined field and laboratory study was conducted to 1. estimate post-release survival of eel for different treatments, 2. examine factors affecting survival, 3. investigate the effects of catch-and-release on physical condition, and 4. study the potential hook shedding mechanism of deeply hooked eels. For the field study, a pond was stocked with tagged, wild-caught eels. After four weeks of acclimatization these were captured with rod and line. After release back into the pond eels were held together with control fish for 4 weeks. A comprehensive examination was performed for all eels that had died and survived to determine probable causes of death, progress of wound healing, physical condition, and occurrence of wound infections, haemorrhages and hook shedding. During the supplementary laboratory study, a subsample of deeply hooked eels were held in tanks and frequently radiographed to qualitatively evaluate potential hook shedding.