Deep-water fish distribution and habitat association in the Maltese FMZ

Abstract

Knowledge on deep-sea habitats inside the Maltese Fisheries Management Zone (FMZ) is scarce and mainly limited to information obtained through trawl surveys. The main aim of this project is to identify the distribution of fish assemblages and their respective habitat associations in the FMZ, at depth ranges of 200 m – 1000 m. The effect of habitat complexity and depth on fish composition is investigated. The data was collected using a Remotely Operated Vehicle (ROV) as part of the ‘LIFE BaĦAR for N2K’ project in 2015. The habitat complexity, microhabitat types and depth ranges within which fish species were found was recorded and analyzed. The Shannon-Weiner Diversity Index and Margalef Species Richness was highest in low complexity habitats. Depth had an overall effect on the fish assemblages exhibited across the different ranges. Whilst the Shannon-Weiner Diversity Index did not decrease drastically with depth, the fish species which were observed changed when moving from 200 m – 1000 m. The present study suggests that the researched area acts a biodiversity hotspot, indicating an urgent need for further research into the deep-sea environment around the Maltese Islands.