Measures for the Protection and Sustainable Exploitation of Marine Biological Resources in an Oligotrophic Fishing Ground (Crete Island, Greece, E. Mediterranean)

The present study is part of a project funded by the Greek Ministry of Agriculture in order to update the historical scientific data available for Messara Bay and propose measures for the protection and sustainable exploitation of its marine biological resources as this area used to be one of the most important fishing grounds in the Cretan continental shelf. Sampling was carried out over a grid of stations during three field surveys. In each survey, abiotic (e.g. nutrients, chloroplastic pigments, organic carbon) and biotic (e.g. macrobenthic flora and fauna, zooplankton, demersal fish) variables were measured and analysed. Results of the present study revealed that Messara Bay is an oligotrophic ecosystem invaded by the green macroalga Caulerpa racemosa var. cylindracea which has covered a large part of the seabed (30–80 m). Despite that fish diversity remains relatively high, fish abundance and biomass have dramatically decreased in comparison with similar data recorded 20 years ago. Based on the results of the present study, fishing effort should be reduced by 20% in order to protect and sustainably exploit the living resources of this oligotrophic fishing ground.