August 21, 2015
FI Scientists Julie Thayer and Amber Szoboszlai presented results of their research at the American Fisheries Society annual meeting (AFS) last week in Portland, Oregon. Information from those presentations was highlighted in a Nature News article. The article explains that resources such as the California Current Predator Diet Database (CCPDD; previewed in the August 14, 2015 post below) can be used as tools for ecosystem-based fisheries management. The CCPDD contains diet data for 119 predators that eat forage species. Data on predator-prey interactions are integral to ecosystem-based fisheries management because they chronicle the natural mortality of commercially valuable forage species due to predator consumption. This research is unique because it has indexed data on predator-prey interactions at the species level, allowing for greater transparency and data-accessibility, as well as case-by-case consideration of both commercially important species like Pacific hake, Chinook salmon, northern anchovy, and Pacific sardine, and species of conservation concern such as the brown pelican.
Julie and Amber have been utilizing this new resource on predator diet to generate bio-energetic and threshold models to describe the forage needs of California Current predators in light of ongoing ecosystem-level changes in the Pacific Ocean. Amber’s recent work that was presented at AFS last week focused on portraying bio-energetic predator consumption estimates of anchovy and sardine, both of which have populations in decline. Julie also presented her research at AFS; she has been developing threshold models to examine at what level of prey corresponding predator productivity declines. These models usually result in estimates that are much higher than what predators actually eat (bio-energetic consumption) because they require higher levels of prey in the system to be able to find their food. In combination, prey bio-energetic and threshold models can be used to estimate the forage needs system-wide for the full suite of California Current predators. In turn, we are working to provide the results of this research on the needs of predators to fisheries managers to complement their mandated efforts to implement EBFM that considers predator-prey interactions.