Gulf and Caribbean Research Volume 19 Issue 1 January 27 A Comparison of Fish Assemblages Among Five Habitat Types Within a Caribbean Lagoonal System Ivan Mateo USVI Division of Fish and Wildlife William J. Tobias USVI Division of Fish and Wildlife DOI: 1.18785/gcr.191.3 Follow this and additional works at: http://aquila.usm.edu/gcr Part of the Marine Biology Commons Recommended Citation Mateo, I. and W. J. Tobias. 27. A Comparison of Fish Assemblages Among Five Habitat Types Within a Caribbean Lagoonal System. Gulf and Caribbean Research 19 (1): 21-31. Retrieved from http://aquila.usm.edu/gcr/vol19/iss1/3 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean Research by an authorized editor of The Aquila Digital Community. For more information, please contact Joshua.Cromwell@usm.edu.
A COMPARISON OF FISH ASSEMBLAGES AMONG FIVE HABITAT TYPES WITHIN A CARIBBEAN LAGOONAL SYSTEM Ivan Matro'and William J. Tobias USVI Division of Fish and Wildlife. Rainbow Plaza 45 Marshil!. Fredericksted, St Croix USVI 84 lcurrent Address, Department of Fisheries, Animal and Veterinary Science, University of Rhode Island, Kingston, RI 2881 USA Phone (41) 398-1742, Fax (41) 398-1742, E-mail imateo32@ IwtmaiLcom.. ABSTRACT Fish assemblages associated with patch reefs, rubble, seagrass, algal plain, and sandy habitats types were suldied at St Croix's Southeastern barrier reef lagoon using underwater visual census techniques. Higher species richness and fish density were observed over patch reefsjrubble habitat followed by seagrass, algal plain, and unvegetated sandy habitat types. Thalassoma bifasciatum, HaemuJon flavolineatum, and Acanthul1l$ chirurgus were the most common fishes in highly structured habitat types (patch reef, rubble). Halichoeres bivittatus, Sparisoma radian.v. newly settled grunts (l.e., Haemulon spp.), and juveniles of Dcyumr chrysurus were mainly associated with vegetated habitat types (seagrass, algal beds), while Xyrichtys martinicensis and Coryphopterus glaucofraenum were common over unvegetated sandy habitat types. Cluster ana1ysis among backreeflagoon habitat types based on the entire fish density data showed distinct associations of fish assemblages by habitat type, regardless of season. Fish assemblages in the more structured habitat types were similar to each other but different from unstructured vegetated, and unvegetated habitat types. These results suggest that differences in fish species richness and density in the backreef lagoon are related to habitat type. The ecological importance and need far protection of backreef lagoon habitat types are discussed in relation to their potential role as nurseries for many fish species. INTRODUCTION Nearshore ecosystems such as seagrass meadows, marshes, and mangrove lagoons supply many vital ecological functioils in coastal waters, including shoreline protection, and nutrient cycling (Ogden and Gladfelter 1983, Parrish 1989). Most notably, these ecosystems provide food and refuge that supports a great abundance and diversity of fishes as well as shrimp, oysters, crabs, and other invertebrates (Ogden and Ziemann 1977, Shulman 1984, Shulman 1985, Parrish 1989). In the Caribbean, it has generally been accepted that mangroves and seagrass meadows form important nurseries for juveniles of several reef fish species (Ogden and Gladfelter 1983, Parrish 1989, Nagelkerkcn et al. 2(), and juvenile coral reef fishes have been frequently observed in mangroves and seagrass meadows in the Caribhean (e.g., Baelde 199, Sedberry and Carter 1993, Appeldoom el al. 1997, Lindeman et al. 1998, Nagclkerkcn et al. 2(). The adults of these species have been ohserved on reef environments or in offshore waters. suggesting the migration of juvenile from the mangroves and seagrass beds to the reef or deeper waters at a certain age (Ogden and Ehrlich 1977, Weinstein and Heck 1979, Rooker and Dennis 1991, Appeldoom et ai. 1997, Lindeman et ai. 1998, Nagelkerken et al. 2(). Although numerous studies have been done on mangrove, seagrass, and coral reef systems, only recently researchers have investigated the connectivity among these coastal ecosystems (Sedberry and Carter 1993, Nagelkerken et ai. 2, Adams and Ebersole 2(2). Comparisons of nursery value among nearshore habitat types have usually focused on a single habitat (i.e., mangrove or seagrass) (Robblee and Zieman 1984, Baelde 199, Rooker and Dennis 1991) even though individual species may use many different habitats. Furthermore, emhayments and lagoons often not only contain mangroves and seagrass meadows, but a variety of other shallow-water habitats like algai plains, areas with bare sediment, sand-rubhle zones, or patch reefs. Seagrass meadows and mangroves may be less important as nurseries in regions where animals use alternative habitats successfully. Few studies have quantified the proportions of reef fishes that pass through these nursery habitats, and information concerning other hahitals that can be used as alternative nurseries are lacking. Thus, linkages of fishes between these baclcreef lagoon habitats remain largely unknown (Ogden and Gladfelter 1983, Birkeland 1985, Parrish 1989). Therefore, this study addresses the following questions: 1) Does species composition and abundance differ among baclcreef lagoon habitat types? 2) Which habitat types are used as nurseries by selected fish species? 3) Which backreef lagoon habitat types are utilized more by a fish species when mnltiple nursery habitat types are present? 4) Do fish species show an ontogenetic shift from nursery habitat types tu other baclcreef lagoon habitat types? 5) Do closely related fish species.how similar seasonal patterns in habitat use?
THB N RB GPB Caribbean Sea ST. CROIX Reef Habitat Atlantic Ocean 22
Cover (%) 7 6 5 4 3 2 1 Seagrass Sand Algal Plain Rubble Patch Reef Habitat types 23
24
25
Species richness 4 3 2 1 Patch reef Rubble Seagrass Algal plain Sand............. Fall Winter Spring Summer Season No. fish / m 2 8 6 4 2 Patch reef Rubble Seagrass Algal plain Sand........ Fall Winter Spring Summer Season Fall Rubble Summer Rubble Spring Rubble Winter Rubble Fall Coral Summer Coral Spring Coral Winter Coral Fall Algae Summer Algae Spring Algae Winter Algae Fall Seagrass Summer Seagrass Spring Seagrass Winter Seagrass 8 6 4 Dissimilarity 2 Fall Sand Summer Sand Spring Sand Winter Sand 26
25 A. chirurgus a 7 Haemulon spp. (Newly settled) b 2 15 6 5 4 1 5 3 2 1 No. Fish / 1 m 2 25 S. iserti c 1.6 O. chrysurus d 2 15 1 5 1.4 1.2 1..8.6.4.2. 4 35 3 25 2 15 1 H. flavolineatum 5 <3 cm 3-5 cm 5-1 cm >1 cm Size class (cm) e 6 H. plumierii f 5 4 3 2 1 <3 cm 3-5 cm 5-1 cm >1 cm Size class (cm) Patch Reef Rubble Seagrass Algal Plain Sand 27
.4 H. bivittatus (< 5 cm) a.8 H. bivittatus (5-1 cm) b.3.2.1......6.4.2. No. fish / m 2.3.25.2.15.1.5. H. bivittatus (> 1 cm).... c 1.5 1..5.. Haemulon spp. (< 5 cm)..... d.25.2.15.1.5.. Haemulon spp. (5-1 cm).. Fall Winter Spring Summer e.12.1.8.6.4.2... Haemulon spp. (> 1 cm).. Fall Winter Spring Summer f Season Season Patch reef Rubble Seagrass Algal plain Sand. 28
29
3
31