AB 5:85-95 (2009)  -  DOI: https://doi.org/10.3354/ab00139

Structuring of Indo-Pacific fish assemblages along the mangrove–seagrass continuum

Richard K. F. Unsworth1,5,*, Samantha L. Garrard2, Pelayo Salinas De León3, Leanne C. Cullen4, David J. Smith5, Katherine A. Sloman2, James J. Bell3

1Northern Fisheries Centre, Department of Primary Industries and Fisheries, PO Box 5396, Cairns, Queensland 4870, Australia
2School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
3Centre for Marine Environmental and Economic Research, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
4CSIRO Sustainable Ecosystems, James Cook University, PO Box 12139, Earlville BC, Cairns, Queensland 4870, Australia
5Coral Reef Research Unit, Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK

ABSTRACT: Indo-Pacific mangrove swamps and seagrass beds are commonly located in close proximity to each other, often creating complex ecosystems linked by biological and physical processes. Although they are thought to provide important nursery habitats for fish, only limited information exists about their usage by fish outside of estuaries. The present study investigated fish assemblages in non-estuarine intertidal habitats where mangroves and seagrass overlap (the mangrove–seagrass continuum). Three habitats (mangrove, mangrove edge, seagrass) were sampled at 4 sites of the Wakatobi Marine National Park, Indonesia, using underwater visual census. Ninety-one species of fish were observed at a mean density of 130.1 ± 37.2 ind. 1000 m–2. Predatory fish (fish that feed on invertebrates and/or fish) were the most dominant feeding groups in the mangroves, whilst omnivores dominated on the mangrove edge and in the seagrass. Although the habitats along the mangrove–seagrass continuum were observed to be important for many fish, only 22 of the 942 coral reef species known within the area utilised mangroves as nursery habitat and only 15 utilised seagrass. Despite finding evidence that nursery grounds in mangroves and seagrass may not directly support high coral reef fish diversity, many of the coral reef nursery species found in this study are likely to be key herbivores or apex predators as adult fish on local coral reefs, and thus highly important to local fisheries. Although mangroves are not permanently inundated by the tide, this study highlights their importance as fish habitats, which at high tide support a greater abundance of fish than seagrass beds. In the light of the high rate of destruction of these habitats, their role in supporting fish assemblages requires consideration in marine resource management programs.


KEY WORDS: Mangrove–seagrass continuum · Seascapes · Connectivity · Fish assemblages · Trophic structuring · Juvenile habitats · Indonesia


Full text in pdf format  
Cite this article as: Unsworth RKF, Garrard SL, Salinas De León P, Cullen LC, Smith DJ, Sloman KA, Bell JJ (2009) Structuring of Indo-Pacific fish assemblages along the mangrove–seagrass continuum. Aquat Biol 5:85-95. https://doi.org/10.3354/ab00139

Export citation
Mail this link - Contents Mailing Lists - RSS
- -