Our team of scientists studied how extreme weather events affect river fish in Puerto Rico. The island is ideal for examining the environmental and human impacts on freshwater fish because Puerto Rico has only nine native species and, unlike smaller Caribbean islands, many inland rivers – 46, to be exact.
Numerous exotic fish, introduced by humans over the past century, compete for limited food and habitat with Puerto Rican species like the waterfall-climbing sirajo goby, the streamlined mountain mullet and the bigmouth sleeper, a top river predator.Tom Kwak, Author provided
Because these same native fish are found throughout the Caribbean, their conservation is an important environmental priority for the region. Native fishes are perfectly adapted to their environment and provide services to humans, such as food and nutrient transport. Their presence indicates a healthy ecosystem and clean drinking water.
Thousands of exotic fish, which are physically adapted to survive drought – not extremely high river flows and flooding – were flushed far downriver during Hurricane Maria, even into the ocean. Many died from blunt force trauma or exposure to salt water.P. Gutierrez-Fonseca, Author provided
Native river fish, in contrast, were unaffected by the hurricane. Their body shape and behavior are designed to survive high, fast waters. Puerto Rican fish are actually hit hardest by drought, since they struggle to migrate for reproduction and to find food when waters are low.
Big hurricanes, in short, reset the balance in Puerto Rico’s rivers, favoring native fish over imported species. The same would hold true in rivers across the Caribbean.
So which fish will win the battle for resources in Caribbean waters? The answer may change with the weather.
With help from staff and graduate assistants Gus Engman, Bonnie Myers and Ámbar Torres, we are now conducting experiments to better understand the dynamics between native and exotic fishes in Puerto Rico. We plan to model the future balance between these species – and, hopefully, help keep the Caribbean’s native fish swimming.
- ^ disastrous for humans (www.washingtonpost.com)
- ^ river fish in Puerto Rico (pubs.er.usgs.gov)
- ^ environmental and human impacts on freshwater fish (academic.oup.com)
- ^ nine native species (www.tandfonline.com)
- ^ services to humans, such as food and nutrient transport (onlinelibrary.wiley.com)
- ^ indicates a healthy ecosystem and clean drinking water (pubs.er.usgs.gov)
- ^ Hurricane Maria hit the island (theconversation.com)
- ^ survive drought (www.frontiersin.org)
- ^ unaffected by the hurricane (esajournals.onlinelibrary.wiley.com)
- ^ catastrophic hurricanes (www.caribbeanclimate.bz)
- ^ increased drought (www.fao.org)
- ^ Sign up for The Conversation’s daily newsletter (theconversation.com)
Authors: Thomas J. Kwak, Professor, Unit Leader, North Carolina State University