Modeling Krill Distribution and Abundance


With respect to ecosystem-based management and protection (e.g., design of marine protected areas), it is important to understand, and if possible predict, the abundance and spatial distribution of key mid trophic level prey species.  Krill are an integral component of the California Current Ecosystem (CCE) that support commercially valuable as well as protected species.  It has been postulated that krill have affinities for particular bathymetric and hydrographic habitats (i.e. canyons, isobaths, fronts), but it is unclear how these factors collectively influence krill aggregations.  We surveyed the spatial distribution of krill using hydroacoustics in central-northern California and modeled their distribution in relation to bathymetric slope, distance from shelf break/canyon heads and fronts, phytoplankton/chl-a concentrations, and sea-surface height anomalies (eddy structures) using a Regional Ocean Modeling System (ROMS) coupled to an ecosystem model (CoSINE; Ocean Modeling GroupSantora et al. 2013), as well as an Individual-Based Model (IBM) parameterized for Euphausia pacifica (Dorman et al. 2005).  The model also outputs spatially-explicit distributions and can be used to understand "hotspot" formation.  This project has been supported by the NASA ROSES program and California Sea Grant.