Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8627
Title: Exploring the implications of sardine harvest control, accounting for predator dynamics: A MICE model
Author: A. E. Punt, A. D. MacCall, T. E. Essington, T B Francis, Felipe Hurtado-Ferro, K. Johnson, I. C. Kaplan, Laura E. Koehn, P. S. Levin, William J. Sydeman
Publication Year: 2016
Journal: Ecological Modelling
Volume: 337
Issue: 79-95
Keywords: anchovy,brown pelican,California sea lion,California Current,Ecosystem base management,harvest strategies

Forage fish require an ecosystem approach regarding their management because they support fisheries and also many valued species in marine food webs.  Large ecosystem models are often used to evaluate potential consequences of forage fish fisheries, but there is seldom sufficient data to parameterize them, and full consideration of uncertainty is impossible. Models of Intermediate Complexity for Ecosystem assessment (MICE) provide a link between full ecosystem models and tactical (usually single-species) models used for the provision of fisheries management advice. MICE are ideal to form the basis for management strategy evaluations that compare the ability of candidate management strategies to achieve management goals, including those goals related to target fisheries and the broader ecosystem. A MICE model is developed for the California Current Ecosystem (CCE) that focuses on the fishery for the northern subpopulation of Pacific sardine and the indirect impacts that the fishery has on place-based predators, in particular brown pelican in the California Bight. The model includes three prey species (sardine, anchovy and ‘other forage’), ‘other prey’ and two predator species (brown pelican and California sea lion) and considers links between prey and predator populations through prey impacts on reproductive rate and survival. Parameterization of the model was facilitated by available monitoring data and assessment outputs. The model is then used to assess the ecosystem and fishery consequences of the current sardine management systems for Mexico, the USA, and Canada, with a focus on which sources of uncertainty are most consequential to understand and include in future modelling efforts. In general, the key sources of uncertainty to include in ecosystem assessments for the CCE are how prey populations impact predator demographic rates (reproduction and/or survival) and the extent to which the dynamics of prey populations are driven by environmental factors. Data are available for some of these sources of uncertainty for the CCE, but much uncertainty remains, necessitating exploration of sensitivity to alternative model formulations and parameter values when providing advice on management strategies to decision makers.

Theme: Ecosystem approach to improve management of marine resources
Foci: Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species.
Provide scientific support for the implementation of ecosystem-based management