Abstract

Reef fish assemblages in the Caribbean are under increasing pressure from human activities. Inadequate enforcement of legislation coupled with unreliable and data-poor landings in Tobago have led to the unregulated exploitation of reef fish for decades. This study addresses the lack of data on major reefs. Visual observations of fish fauna were conducted from November 2011-May 2013 at open access reef sites (Speyside, Charlotteville, Culloden, Arnos Vale, Mt. Irvine, La Guira, Kilgwyn, Plymouth and Black Rock) and one protected area (Buccoo Reef Marine Park). Belt transects surveys were used to determine fish density, species diversity and abundance at the 10-15m depth contour. Fish sizes were converted to biomass using the length-weight relationship of fish W=aLb. Most fish assemblages were dominated by small herbivores (<15cm), in particular Pomacentridae and Scaridae. Few large predators (>40cm) e.g. Serranidae, were noted, which is indicative of fishing pressure. MDS ordination identified three fish assemblages: i) northeastern, ii) southwestern and iii) intermediate. The northwestern cluster (Speyside and Charlotteville) were most representative of reef fish assemblages across the entire island, and exhibited the highest species richness, diversity and biomass. However, the southwestern cluster the highest numerical abundance. The marine protected area contained higher fish biomass, abundance, diversity and richness, but it was only representative of reef fish assemblages on the southwest of the island and not the entire Tobago. Research on the reef fishery, particularly spear fishing, is recommended to determine impact. Rev. Biol. Trop. 62 (Suppl. 3): 169-181. Epub 2014 September 01.

Highlights

  • Coral reef fishes are the most diverse vertebrate communities on Earth (Jones, 1991) and their spatio-temporal distribution is influenced by a combination of complex biological and physical factors

  • Species from the families Pomacentridae, Labridae, Scaridae, Haemulidae, Acanthuridae and Serranidae were found at all locations, and together with Pomacentridae accounted for 90% of fish observed

  • This study examined variation in reef fish community structure across major reef systems in Tobago with the greatest differences occurring between reefs located in the northeastern and southwestern side of the island

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Summary

Introduction

Coral reef fishes are the most diverse vertebrate communities on Earth (Jones, 1991) and their spatio-temporal distribution is influenced by a combination of complex biological and physical factors. These factors include larval supply (Doherty, 1991), competition (Munday, Jones & Caley, 2001; Holbrook & Schmit, 2002), wave exposure (Fulton, Bellwood & Wainwright, 2005), depth (Srinivasan, 2003) and habitat complexity (Friedlander, Sandin, DeMartini & Sala, 2010). Disruption in the balance of reef fish assemblages can decrease coral cover and increase algal abundances (Roberts, 1995) Because of this importance, fishes are often a focus of monitoring and management programmes to evaluate the condition of reef communities (Green, Bellwood & Choat, 2009). Declining reef fish (abundance and biomass) as told in the oral history of Tobago, threatens the mainstay

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