Assessing change in temperate fish species: Using stereo baited camera systems in a marine reserve

Stereo baited underwater video systems (SBUVs) are a promising alternative to traditional tools for marine reserve effectiveness assessments. Early detection measures based on species traits have shown to detect protection effects in reserves as young as 4 years. Opposed to this, traditional measures (e.g. average body length or species richness) may take decades to manifest. Here we demonstrate that boat-deployed SBUVs can be utilized to assess temperate reserve effectiveness. We utilized a conservative, relative abundance measure (MaxN) and obtained biomasses from precise stereogrammetric length measurements of fishes. Regardless of test used, groups of species compared or indicator used, we found no significant differences between protected and unprotected sites. One prior study of the area has shown larger sizes and biomasses of Diplodus spp. inside as compared to outside while we could not detect any size differences for any fish species. The reserve did not show differences in diversity indices from this study or other studies before. Both traditional indicators and early detection indicators of reserve effectiveness strongly suggest that the studied 5-year old reserve is non-functional. Despite the young nature of the reserve, we conclude that it urgently needs revision and enforcement in order to match its protection goals.

Promotor(s) & Supervisor: Barbara Horta e Costa, Karim Erzini
Thesis Institute: Center of Marine Science (CCMAR)

ISCED Categories

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0511 - Biology", "0521 - Ecology", "0522 - Conservation and environmental management