Promoting restoration of fish communities using artificial habitats in coastal marinas

Abstract

Rapid urbanization has become an area of crucial concern in conservation, owing to urban infrastructure impacts on natural ecosystems. Urban infrastructures are often poor surrogates for natural habitats, and a diversity of eco-engineering approaches has been trialed to enhance their ecological value.Marinas are among the most common human-made infrastructures found on the shoreline, and cause substantial habitat destruction within the sheltered coastal areas previously used as nursery grounds by many fish species. The present study aimed at testing the suitability of installing artificial habitats (Biohut®) in marinas to reinforce the nursery function of the Marchica coastal lagoon, which historically hosts many species of juvenile groupers, including the endangered dusky grouper Epinephelus marginatus.Our hypothesis – that artificial habitats, by increasing habitat complexity, enhance the ecological value of a marina – was strongly supported by our results. The Biohuts hosted a high relative density of juvenile dusky and comb groupers in comparison with natural habitats. They can, therefore, be considered as a reservoir for juvenile groupers, including the endangered dusky grouper, and are suitable to reinforce the nursery function of this coastal lagoon.Subsequently, Biohuts can act as a ready-made nursery area to support the creation of small marine reserves that can reinforce the grouper population re-colonization along the coast of North Africa, which is considered to be the region from which the individuals populating the north western Mediterranean originated, and thus provide for long-term recovery of the endangered dusky grouper.