Setting preliminary biometric baselines for new target sea cucumbers species of the NE Atlantic and Mediterranean fisheries

Commercial interest on sea cucumber species from the NE Atlantic and the Mediterranean is increasing. Holothuria polii, Holothuria tubulosa, Holothuria mammata and Holothuria arguinensis are the new target species. The scarce biological and ecological knowledge on these species along their geographical distribution, is a major problem for their fisheries management. To address it, we carried out a morphometric study to describe the baseline population size structure, focused on the length-weight relationship and size-weight distribution.In the NE Atlantic, the largest mean size and heaviest mean weight of H. mammata and H. arguinensis were found in localities with upwelling, but another factors could be influencing on these results. In the Mediterranean, Girona and Mallorca showed the heaviest specimens of H. polii, H. tubulosa and H. mammata, and the smallest were registered in Crete and Kusadasi. Significant differences in length and weight between populations were found for each species. These results could be linked with local environmental conditions. Size frequency distribution was multimodal for all species except for H. mammata; the weight frequency distribution was only unimodal for H. polii and H. mammata.This study provides novel data, helpful for stock and population assessment which could support the implementation of effective management for the European sea cucumber target species.