Connecting Fish and Corals

A new study by UM Rosenstiel School researchers tracked the dispersal of coral and fish larvae on Caribbean reefs and found that fish populations are generally a more interconnected, cohesive unit on reefs than coral populations, with a few exceptions. The UM Rosenstiel School-led study is the first-of-its-kind to use a numerical modeling approach to address connectivity – the exchange of offspring and larvae between geographically disconnected populations – for multiple species with very different life histories.

Trunkfish in the Dry Tortugas. Photo Credit: Jiangang Luo/ UM RSMAS

Trunkfish in the Dry Tortugas. Photo Credit: Jiangang Luo/ UM RSMAS

Understanding connectivity is important for the management of species and networks of marine protected areas. Connectivity enhances resilience of the ecosystem to harmful events, such as bleaching, overfishing and hurricanes, by providing new recruits from distant locations to the damaged reefs.

“The study was motivated by the complexity of conservation efficacy for coral reef ecosystems that are composed of so many different species,” said Rosenstiel School Professor Claire Paris, corresponding author of the paper. “Larval connectivity models contribute valuable information for the protection of marine habitats, especially as the potential for further reef fragmentation and other physical changes to the environment alter both the habitat and the biology of coral reef organisms and their larvae.”

Using the Connectivity Modeling System (CMS), a Rosenstiel School open source numerical model developed in Paris lab, the study tracked larval exchange between more than 3,200 reef areas in the Caribbean for five different species of fish and coral over a five-year period. The researchers found that fish populations are generally more connected than coral populations, with the exception of reef-building corals, which share similar connectivity dynamics for some specific Caribbean regions. For these regions that were identified thanks to high-computing techniques, management can be similar for all species and reef conservation may rely on regional connectivity networks.  This is not the case for other regions that require more species-specific management practices, typically at more local levels as well.

Elkhorn Coral  Photo Credit: NOAA

Elkhorn Coral
Photo Credit: NOAA

The study was published as a Special Feature article in the March 3, 2014 issue of the journal Marine Ecology Progress Series. The paper’s authors include: UM alumni Daniel Holstein, currently a post-doctoral research associate at the University of the Virgin Islands’ Center for Marine and Environmental Studies, and well-known reef ecologist Peter Mumby.