Diversity of Coral Reef Fishes in the Western Indian Ocean: Implications for Conservation

Melita Samoilys,Pascale Chabanet,Robert Myers,Lorenzo Alvarez-Filip

doi:10.3390/d14020102

Abstract

Communities of coral reef fishes are changing due to global warming and overfishing. To understand these changes and inform conservation, knowledge of species diversity and distributions is needed. The western Indian Ocean (WIO) contains the second highest coral reef biodiversity hotspot globally, yet a detailed analysis of the diversity of coral reef fishes is lacking. This study developed a timed visual census method and recorded 356 species from 19 families across four countries in the WIO to examine patterns in species diversity. Species richness and composition differed most between the island countries of Madagascar and Comoros and both these locations differed from locations in Tanzania and Mozambique which were similar. These three regional groupings helped define WIO ecoregions for conservation planning. The highest species richness was found in Tanzania and Mozambique, and the lowest and most different species composition was found in Comoros. Biogeography explains these differences with naturally lower species diversity expected from the small, oceanic, and isolated islands of Comoros. Present day ocean currents maintain these diversity patterns and help explain the species composition in northeast Madagascar. Species distributions were driven by 46 of the 356 species; these provide guidance on important species for ongoing monitoring. The results provide a benchmark for testing future changes in reef fish species richness.

Highlights

Publisher’s Note: MDPI stays neutralSpecies are the fundamental units of ecosystems and species inventories and their distributions provide a foundation for understanding coral reef communities and their conservation [1,2]
The current study aimed to examine patterns in species richness of reef fishes to contribute to our understanding of the biogeography of the less studied western Indian Ocean (WIO) province
On a country-by-country basis, there was a marginally significant difference for Comoros (Chi-square = 3.9; df = 1; p = 0.049). This suggests that surveys from all locations in all four countries were adequate in providing representative values of total species richness, but there was some indication that an increase in the number of surveys in Comoros would improve the data

Summary

Introduction

Publisher’s Note: MDPI stays neutralSpecies are the fundamental units of ecosystems and species inventories and their distributions provide a foundation for understanding coral reef communities and their conservation [1,2]. Communities of reef-associated fish species reflect their biogeography, and this includes evolutionary history, sea surface temperature, and larval recruitment patterns driven by ocean currents [1,3,4,5]. These reef fish communities are changing due to global warming and overfishing, which are rapidly degrading coral reefs globally [6,7,8], driving declines in abundance and local extirpations of some species [9,10]. This province contains the second highest biodiversity hotspot in the Indo–Pacific, second to with regard to jurisdictional claims in published maps and institutional affiliations

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Conclusion