Publication Date

Spring 2021

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Moss Landing Marine Laboratories

Advisor

Richard Starr

Keywords

Diet Study, Ecosystem-Based Fisheries Management, Gut Content Analysis, Lingcod, Stable Isotope Analysis, Trophic Ecology

Subject Areas

Conservation biology

Abstract

Dietary studies of fishes provide an understanding of predator-prey interactions and may be used to inform resource managers about food web dynamics. Along the West Coast of North America, Lingcod (Ophiodon elongatus) are top marine predators in rocky-reef habitats and support an economically important fishery. In this study, gut content and stable isotope analyses were used to evaluate differences in the diets of Lingcod collected in U.S. waters from Alaska to Southern California during 2016 and 2017. Overall, Lingcod consumed a wide variety of prey and exhibited both generalist and opportunist feeding strategies. Significant variability in Lingcod diets was driven by factors such as depth, region, sex, and total length. Male Lingcod caught in shallow depths consumed more lower trophic level prey items (e.g. cephalopods) and had more diverse diets. Female Lingcod caught in deep depths consumed more higher trophic level prey items (e.g. groundfishes) and had less diverse diets. Geographic variation in trophic level was associated with environmental conditions of sea surface temperature and primary productivity (i.e., chlorophyll a). Southern Lingcod fed more on cephalopods while northern Lingcod fed more on various fish groups. This study fills in data gaps in the trophic ecology of a top marine predator and can inform food web models and fisheries management.

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