T1 - Does tagging transparent fish increase predation risk? A laboratory study with glass eel (Anguilla anguilla) and sea bass (Dicentrarchus labrax) It also shows that the proportion of predation in relation to local glass eel abundance can be estimated if stomach content analysis is conducted within 4–6 h after predation.",
This study showed that tagging does not increase predation in mark-recapture studies using VIE-tags in transparent glass eel.
Stomach content analysis showed intact glass eel bodies 4–6 h after ending the 2 h trial and parts of glass eel bodies up to 16–18 h. Large sea bass predated more, but all sizes consumed glass eel under laboratory conditions. No significant difference was found in predation rate between tagged and untagged glass eels and between red and blue tagged glass eels. In 48% of the trials, successful predation was present and 13% showed clear predation attempts in which bass did not capture glass eels. Tagged (visible implanted elastomer, VIE) and untagged glass eels were exposed to small (19.1–24.4 cm) and large (31.9–43.5 cm) sea bass (Dicentrarchus labrax) during a 2 h trial. A laboratory experiment with 48 trials was conducted. This study aimed to determine whether there is an increased predation risk for tagged glass eel it also studies glass eel digestion status in piscivorous fish after appointed time frames. Nonetheless, whether tagging transparent glass eels increases predation risk and what the digestion rate of glass eel is in piscivorous fish are unknown. The proportion of predation losses can be estimated using mark-recapture techniques and abundance estimates in combination with stomach content analysis of piscivorous fish. This leads to an unnatural accumulation of migrating glass eels below the barriers, and this may lead to additional losses in glass eels by piscivorous fish. It also shows that the proportion of predation in relation to local glass eel abundance can be estimated if stomach content analysis is conducted within 4–6 h after predation.Ībstract = "Barriers in the estuaries of the rivers prevent the immigration of glass eels (Anguilla anguilla) arriving on the European coast every spring.
Barriers in the estuaries of the rivers prevent the immigration of glass eels (Anguilla anguilla) arriving on the European coast every spring.