Marine fisheries are economically and nutritionally important to people around the world.  Historically, these fisheries have been regulated based on single-species models.  Essentially, such approaches assume that larval recruitment (i.e. the number of larval fish that survive to become juveniles or adults each year) is dependent only on the number of spawning adults the previous year.  However, despite the best intentions of fisheries scientists and managers, this approach has proven insufficient for managing many species and many fisheries around the planet have crashed.

Ecosystem-based management starts with the assumption that larval recruitment depends on both adult biomass and other environmental variables, such as temperature, oxygen, prey availability, and predator abundance.  Consequently, it is crucial to understand how the entire environment is changing in time.  For instance, climate change is likely to lead to warming of the surface layers of the Gulf of Mexico.  These warmer temperatures will increase the metabolism (including growth rates and food requirements) of larval fish living in the same regions.  At the same time, warm surface temperatures lead to increased stratification which inhibits nutrient introduction to the surface ocean and depresses primary productivity.  Thus zooplankton (i.e. larval fish food) abundances may decrease at the same time that higher metabolism requires that larval fish need more food.

To address these issues, we use a diverse suite of oceanographic research.  Partnering with colleagues from multiple institutions (both in the U.S. and internationally), we have conducted field campaigns to quantify the impact of bottom-up limitation and plankton trophic structure on habitat suitability for larval bluefin tuna in the Gulf of Mexico and Indian Ocean.  Working with collaborators at Horn Point Laboratory, we are combining satellite remote sensing with individual-based models of crustaceans to predict changing zooplankton abundance.  Finally, we use ecological and biogeochemical models to simulate larval transport and development in a four-dimensional ocean and (with colleagues from other Florida institutions and NOAA SEFSC), we now plan to couple these models to Gulf of Mexico foodweb models for use in fisheries management.  These diverse approaches work synergistically to better predict how a changing environment will affect larval fish survive, and hence enable fisheries researchers to better manage their stocks for a sustainable future.