image: The sirajo goby has evolved suction cup-like pelvic fins that enable it to thrive in aquatic environments with fast-flowing water and steep waterfalls. view more
Credit: Patrick Cooney, North Carolina State University
A team of researchers led by North Carolina State University has made an enormous advance in the understanding of some of Puerto Rico's most remarkable ecosystems by conducting the first comprehensive study of the island's freshwater fish species. NC State's Dr. Thomas Kwak, who led the study, says many of these species "are hidden gems that have been largely ignored," and calls the research "a huge first step in conserving and protecting these fish and their habitat."
The study is the first-ever comprehensive population and habitat survey of freshwater fishes in Puerto Rico, Kwak says. The study focuses on identifying those features that support native fish populations, and distinguishing those features that make a system susceptible to invasion by exotic species. Kwak says the research will likely have a significant impact on how the Puerto Rican government makes decisions on issues ranging from fisheries management to water use and habitat management.
Kwak also hopes that the study raises the profile of the freshwater fishes in Puerto Rico both on the island itself and abroad as part of Puerto Rico's natural heritage. "Just letting the world know the fish are there is an accomplishment," Kwak says. "Many of these fish are very charismatic – they are unique and really worthy of conservation." For example, Kwak points to Puerto Rico's native Sirajo Goby – a brilliantly colored fish that has evolved sucker-like pelvic fins that allow it to climb steep waterfalls and even the sheer faces of some artificial dams.
The Puerto Rico Department of Natural and Environmental Resources funded the research with federal Sport Fish Restoration funds, and an overview of the study was presented at the American Fisheries Society (AFS) Annual Meeting in Ottawa, Ontario, earlier this year.
Kwak is a professor of biology at NC State, and a unit leader of the U.S. Geological Survey's North Carolina Cooperative Fish & Wildlife Research Unit. Other researchers involved in the study include: NC State research biologist Patrick Cooney, who was lead author for the AFS presentation; NC State graduate student Christin Brown; and Dr. Craig Lilyestrom, director of the Division of Marine Resources in Puerto Rico's Department of Natural and Environmental Resources.
Note to editors: The presentation abstract follows.
"Puerto Rico Stream Fishes: Sampling, Distribution, and Influential Factors"
Authors: Patrick B. Cooney, Dr. Thomas J. Kwak, Christin H. Brown, North Carolina State University; Dr. Craig G. Lilyestrom, Puerto Rico Department of Natural and Environmental Resources
Presented: August 21, 2008, at the 138th Annual Meeting of the American Fisheries Society in Ottawa, Ontario
Abstract: Puerto Rico is known for marine fisheries, but its freshwater habitats support a substantial number of species with fishery value. We conducted research in Puerto Rico streams to estimate stream fish populations and model their patterns related to physical habitat at multiple spatial scales. We employed a standardized fish sampling protocol using three-pass removal backpack or barge electrofishing at 81 stream sites to quantify fish and crustacean populations and measured instream, riparian, and water quality parameters. We quantified density of 24 fish species (10 native) and 15 crustacean species (11 shrimp, 3 crabs, 1 crayfish). The most abundant fish species were Agonostomus monticola (mountain mullet), Poecilia sphenops (Mexican molly), Poecilia reticulata (guppy) and Sicydium plumieri (sirajo goby). Mean fish species richness was 5.14 species per site, ranging from one species at three sites to 11 non-native species at one site. Based on our results and habitat measurements at the instream, riparian, and watershed scales, we developed a series of models explaining variation in fish community structure among sites and basins. This research is among the most comprehensive to study stream fishes and habitat in Puerto Rico and may facilitate outreach efforts and fishery and ecosystem management to sustain fish communities.