Distribution of fish in seagrass, mangroves and coral reefs: life-stage dependent habitat use in Honduras

Jessica Jaxion-Harm,James Saunders,Martin R Speight

doi:10.15517/rbt.v60i2.3984

Abstract

Many coral reef fish exhibit habitat partitioning throughout their lifetimes. Such patterns are evident in the Caribbean where research has been predominantly conducted in the Eastern region. This work addressed the paucity of data regarding Honduran reef fish distribution in three habitat types (seagrass, mangroves, and coral reefs), by surveying fish on the islands of Utila and Cayos Cochinos off the coast of Honduras (part of the Mesoamerican barrier reef). During July 2nd - Aug 27th 2007 and June 22nd - Aug 17th, 2008, visual surveys (SCUBA and snorkel) were performed in belt transects in different areas: eleven coral reef, six seagrass beds, and six mangroves sites. Juvenile densities and total habitat surface area were used to calculate nursery value of seagrass and mangroves. A total of 113 fish species from 32 families were found during underwater surveys. Multi-dimensional analyses revealed distinct clusters of fish communities in each habitat type by separating fish associated with seagrass beds, mangroves, and coral reefs. Coral reefs showed the highest mean fish species richness and were dominated by adult fish, while juvenile fish characterized seagrass beds and mangrove sites. Habitat use differed widely at the fish species level. Scarus iseri (Striped Parrotfish), the most abundant fish in this study, were found in all three habitat types, while Lutjanus apodus (Schoolmaster Snapper) juveniles were located primarily in mangroves before migrating to coral reefs. Many species used seagrass beds and mangroves as nurseries; however, the nursery value could not be generalized at the family level. Furthermore, for some fish species, nursery value varied between islands and sites. Our results suggest that connectivity of seagrass, mangrove, and coral reef sites at a species and site levels, should be taken into consideration when implementing policy and conservation practices.

Highlights

Shallow coastal areas of tropical latitudes include a mosaic of habitats
Studies of Honduran reefs are limited to Clifton & Clifton (1998) who provided a comprehensive list of fish species found on the coral reefs of Honduran archipelago Cayos Cochinos, and Greenfield & Johnson (1990a, 1990b) who performed multiple habitat surveys focusing on fish from the blennioid and cardinalfish families
Distribution of fish found on seagrass beds, mangroves and coral reefs: Surveys found 113 species of fish from 32 families in the three habitat types

Summary

Introduction

Shallow coastal areas of tropical latitudes include a mosaic of habitats. The term ‘habitat’ was defined by Beck et al (2001) as “the area used by a species.” migrant species may use the whole coastal zone. In order to study the importance of nursery grounds, the present study categorized fish into three different life history strategies: habitat specialists (all life stages use a single habitat), habitat generalists (move freely between habitats), and ontogenetic shifters (habitat use is dependent on life stage) (Adams et al 2006). They were divided into juveniles versus adults. Ontogenetic shifters used nursery habitat (seagrass beds, mangroves) as juveniles, but were found primarily on reefs as adults; these fish species were classified as nursery species. The Honduran islands of Utila and Cayos Cochinos were chosen because they are surrounded by a diverse array of coral reefs, mangroves, and seagrass beds, including a simple isolated mangrove lagoon, coral with adjacent seagrass beds, and a highly connected coral-seagrass-mangrove continuum

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Results

Conclusion