Date

Fall 2015

Document Type

Master's Thesis (Open Access)

Degree Name

Master of Science (M.S.)

Department

Science & Environmental Policy

First Advisor

James Lindholm

Abstract

Understanding the spatial distribution of marine species and the temporal and spatial scales of the processes that drive those distributions continues to be limited, but is increasingly more critical with the implementation of marine spatial planning. Lingcod (Ophiodon elongatus) are a common demersal fish found from southern Alaska to Baja California, and are exploited both commercially and recreationally across the entirety of their range. Due to stock declines, Lingcod are managed using a variety of fisheries management tools, including spatial management. This study represents a unique in situ investigation of demersal habitat utilization by Lingcod at the southern portion of their range (Point Arena to Morro Bay, California). We used ROV and towed camera sled derived underwater video imagery, coupled with high-resolution bathymetry data, and Generalized Linear Models to investigate: a) how Lingcod are distributed relative to seafloor habitats along California’s central coast, b) the extent to which any ontogenetic patterns varied significantly across those habitats, and c) how associations based on visual observations compare to those from landscape modeling analysis. We then extrapolated habitat associations, found in the landscape modeling analysis, beyond the sampled areas to broader areas of the coast by creating habitat suitability maps. The results of this study clearly depicted an ontogenetic shift in Lingcod habitat utilization across the southern end of its range. Lingcod shifted from primarily low relief, soft sediments as young to mixed substrates at intermediate ages and ultimately to primarily harder substrates as adults. However more nuanced associations were also discovered, such as year 2 Lingcod associating with wave relief in soft sediments. These results are important in the context of on-going marine spatial planning wherein further information on the habitat associations of targeted species can allow for more refined management.

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