freshwater

A comparison of current and historical fish assemblages in a Caribbean island estuary: conservation value of historical data

Smith, K. L., Corujo Flores, I. and Pringle, C. M. (2008), A comparison of current and historical fish assemblages in a Caribbean island estuary: conservation value of historical data. Aquatic Conservation: Marine and Freshwater Ecosystems, 18: 993–1004. doi: 10.1002/aqc.920

Abstract: 
1. Historical data are often one of the only resources available for documenting and assessing causes of environmental change, particularly in developing regions where funding for ecological studies is limited. In this paper, previously unpublished data from a 1977 year-long study of the fish community of the Espiritu Santo estuary are presented. This dataset is among the oldest and most extensive surveys of a Caribbean island estuarine fish community. 2. A comparison of these historical data with data collected in June and July 2004 using identical sampling methods allowed description of potential long-term changes in the fish community, identification of vulnerable species, and assessment of potential drivers of change. 3. Results strongly suggest a decline in species richness and abundance in the Espiritu Santo estuarine fish community, with greater declines in freshwater-tolerant than marine or euryhaline species. Declines in freshwater inflow to the estuary, due to large-scale upstream water abstractions for municipal use, have increased since the initial 1977 survey. 4. This is the first study to examine long-term change in the fish community of a tropical island estuary. Results indicate that additional research and conservation efforts are needed to understand mechanisms of change and to protect Caribbean island estuarine fish communities.

Factors Influencing Tropical Island Freshwater Fishes: Species, Status, and Management Implications in Puerto Rico

Neal JW, Lilyestrom CG, Kwak TJ (2009) Factors influencing tropical island freshwater fishes: species, status, and management implications in Puerto Rico. Fisheries 37:546-554

Abstract: 
Anthropogenic effects including river regulation, watershed development, contamination, and fish introductions have substantially affected the majority of freshwater habitats in Europe and North America. This pattern of resource development and degradation is widespread in the tropics, and often little is known about the resources before they are lost. This article describes the freshwater resources of Puerto Rico and identifies factors that threaten conservation of native fishes. The fishes found in freshwater habitats of Puerto Rico represent a moderately diverse assemblage composed of 14 orders, 29 families, and 82 species. There are fewer than 10 species of native peripherally-freshwater fish that require a link to marine systems. Introductions of nonindigenous species have greatly expanded fish diversity in freshwater systems, and native estuarine and marine species (18 families) also commonly enter lowland rivers and brackish lagoons. Environmental alterations, including land use and development, stream channelization, pollution, and the impoundment of rivers, combined with nonnative species introductions threaten the health and sustainability of aquatic resources in Puerto Rico. Six principal areas for attention that are important influences on the current and future status of the freshwater fish resources of Puerto Rico are identified and discussed.
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