Homing Ability of Goldsinny Wrasse (Ctenolabrus rupestris)
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OriginalversjonStarbatty, Ö.I. (2021) Homing Ability of Goldsinny Wrasse (Ctenolabrus rupestris) (Master's thesis). University of Agder, Kristiansand.
After the discovery of delousing abilities of temperate wrasses, several wrasse species are increasingly harvested in Norway and supplied to salmonid aquafarms to combat sea lice infestations. An increased harvesting intensity has raised concerns regarding the sustainability of this comparatively new fishery. Therefore, more research is needed about the targeted wrasses species. Goldsinny wrasses (Ctenolabrus rupestris)are known for having small home ranges and being highly territorial. Minimum size restrictions oblige fishermen to release goldsinnies smaller than 11 cm back to the sea, but this is often done far from the capture site. It is very important to know the fate of discarded fishes because fishing mortality might be higher than anticipated if those individuals cannot manage to survive. Animals derive benefits from being familiar with their environment. Therefore, homing is regarded to contribute to overall fitness of individuals. In this mark-recapture study,I examined the homing ability and site fidelity of goldsinny wrasses by experimentally translocating 104 PIT-tagged goldsinnies at 100m and 300m, while 53 individuals were released to the capture site as a control group. The impact of length, sex, and behavioral traits (catchability and mobility) on homing success of goldsinny wrasses were also tested. Logistic regression analysis revealed 92% of translocated goldsinny wrasses having homed from up to 300m. The translocation distances tested in this study did not affect the homing success of goldsinny wrasses. 54% of homed individuals were still found to be present at the capture area 30-62 days post-release.
Master's thesis in Coastal ecology (BIO501)