Funding Agency/Contractor: Lenfest Ocean Program
Duration: September 2012 - May 2015
Background: Jellyfish are major consumers of plankton in some ecosystems and may compete with forage fishes, such as Gulf menhaden, for this resource, particularly under rapid growth or "bloom" conditions when plankton prey are abundant. Scientists are increasingly concerned that overfishing may exacerbate naturally occurring jellyfish blooms by increasing plankton availability. This might tip the balance toward jellyfish dominance, which could have adverse economic and ecological consequences.
This project, led by Dr. Monty Graham of the USM Division of Marine Science and funded by the Lenfest Ocean Program, will explore a variety of metrics to represent jellyfish as an ecosystem indicator in five marine ecosystems: the Gulf of Mexico, the Northern California Current, the Bering Sea, the Peruvian Upwelling, and the Sea of Japan. Using existing datasets from these regions, we hope to model the relationships between jellyfish and forage fish and try to identify tipping points in the ecosystem. This work is highly collaborative, and Monty's team includes a diverse team of colleagues from USM, Oregon State University, Yale University, and the NOAA Northwest Fisheries Science Center.
Objectives: Our program will address five questions:
- What is the best metric, or set of metrics, to parameterize jellyfish-fish dynamics in ecosystem models?
- What is the role of jellyfish and Gulf menhaden as energy transfer pathways between plankton production and upper-level consumers in the Gulf of Mexico?
- Do energy flows in Gulf food web change significantly in response to variability in fish and jellyfish (i.e. biomass) caused by perturbations to the ecosystem such as overfishing or climate forcing?
- How do food web structure and energy transfer rates differ among the Gulf of Mexico, Northern California Current, and Bering Sea ecosystems?
- What is the degree of spatial overlap between jellyfish and menhaden in the Gulf of Mexico?