Image Credit: Alli Cramer

Deep Data: Modeling Sixgill Shark (Hexanchus griseus) Movements

Abstract

Examination of species-environment relationships that determine broad-scale distribution patterns is a key focus of ecological research. Characterizing animal-habitat associations in the marine environment is particularly challenging given the opacity of the ocean, and addressing this question in marine systems has consequently lagged behind terrestrial systems. In this project, we have leveraged existing data on locations of a large marine predator, the Sixgill Shark, Hexanchus griseus, and linked that with the PNNL’s Salish Sea Model over the domain of shark movement in Puget Sound, Washington state. Twenty-nine Sixgill sharks were tracked from 2005-2009 across 130 hydrophone receivers with tags that reported not only individual presence but also depth. Temperature, salinity, and dissolved oxygen data were sampled from those locations and depths to generate a species distribution model for Sixgill sharks in the Puget Sound ecosystem. This study generated two key findings. First, the models indicate that sharks inhabit areas with higher salinity and exhibit temperature associations within Puget Sound that suggest a narrower behavioral preference than physiological limitations. Second, despite its course resolution and presence/absence character, passive telemetry data performs well in resolving species distribution models. Such results can be used to produce large scale, 3D maps of suitable habitat for marine species. Results establish that these acoustic technologies, when paired with sufficient environmental data, can extend analytical approaches common to terrestrial systems to the management and conservation of marine organisms.

Publication
at Salish Sea Conference.
Date
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