Fish assemblages of Mediterranean marine caves.

Simona Bussotti,Patrice Francour,Paolo Guidetti,Antonio Di Franco,Carlo Nike Bianchi

doi:10.1371/journal.pone.0122632

Simona Bussotti, Patrice Francour + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0122632

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Journal: PloS one	Publication Date: Apr 13, 2015
Citations: 51	License type: CC BY 4.0

Affiliation: Université Côte d'Azur, CoNISMa

Abstract

Fish assemblages associated with 14 marine caves and adjacent external rocky reefs were investigated at four Marine Protected Areas (MPAs) along the coasts of Italy. Within the caves sampling was carried out in different sub-habitats: walls, ceilings, bottoms and ends of caves. On the whole, 38 species were recorded inside the 14 caves investigated. Eighteen species were exclusively found inside the caves: they were mainly represented by speleophilic (i.e. species preferentially or exclusively inhabiting caves) gobids (e.g. Didogobius splechtnai) and nocturnal species (e.g. Conger conger). Forty-one species were censused outside, 20 of which were shared with cave habitats. Apogon imberbis was the most common fish found in all 14 caves investigated, followed by Thorogobius ephippiatus (recorded in 13 caves), and Diplodus vulgaris and Scorpaena notata (both censused in 12 caves). Distinct fish assemblages were found between external rocky reefs and the different cave sub-habitats. New data on the distribution of some speleophilic gobids were collected, showing the existence of a pool of species shared by marine caves on a large scale (i.e. hundreds of km). Considering the uniqueness of cave fishes (18 exclusive species and different assemblage structures), the inclusion of marine caves among the habitats routinely investigated for fish biodiversity monitoring could facilitate the achievement of more comprehensive inventories. Due to their contribution to local species diversity and the shelter they provide to species valuable for conservation, marine caves should be prioritized for their inclusion not only within future MPAs through the Mediterranean Sea, but also into larger management spatial planning.

Highlights

Along the coasts of the Mediterranean Sea, especially in rocky limestone areas subject to karstic dissolution, submerged marine caves are widespread and mostly unexplored natural habitats [1]
Eighteen species were exclusively found inside the caves and were represented mainly by speleophilic gobids (e.g. Didogobius splechtnai) and nocturnal predator species (e.g. Conger conger)
Forty-one species were censused in the rocky reefs outside, 21 of which were exclusively found outside caves and 20 of which were shared with cave sub-habitats

Summary

Introduction

Along the coasts of the Mediterranean Sea, especially in rocky limestone areas subject to karstic dissolution, submerged marine caves are widespread and mostly unexplored natural habitats [1]. Because of the intrinsic variability and complexity of submerged marine cave systems, it is difficult to formally define them. Opening’ higher than 1, and 2) a width of the opening that should not exceed the mean width inside. Considering that benthic organisms living in coastal rocky habitats outside the caves usually compete for space occupation [8], [9], the presence of caves can be seen as increasing the availability of coastal rocky substrates (see [10])

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