Dissertation/Thesis Abstract

Causes and consequences of the movement of temperate reef fishes
by Freiwald, Jan, Ph.D., University of California, Santa Cruz, 2009, 218; 3394701
Abstract (Summary)

Movement defines how species interact with their environment and is fundamental to most ecological and evolutionary processes. Despite its importance to the fitness of individuals, the spatial structure and dynamics of populations, and the structure and connectivity of ecosystems, there has been little emphasis on the patterns and determinants of movement of temperate reef fishes in marine ecology. To investigate their movement I combined three approaches. An analysis of published movement distances of temperate reef fishes along the west coast of North America showed that movement distances of most species examined are characterized by a positively skewed frequency distribution and discrete ranges rather than by unbounded, diffusive movement rates. For 80% of the species the 75th percentile movement distance was less than three kilometers. Using acoustic telemetry, I experimentally investigated the effect of population density on the home range size of kelp greenling (Hexagrammos decagrammus ) and found a 55% reduction in home range size of male kelp greenling after their density was reduced by half. I acoustically monitored the movement and habitat use of kelp greenling, kelp rockfish (Sebastes atrovirens ) and blue rockfish (Sebastes mystinus).

Kelp rockfish and kelp greenling have small home ranges on scales of several hundred square meters. Blue rockfish did not show site fidelity at the spatial scale of this study. Red algae and kelp density were identified as important habitat variables in kelp greenling and kelp rockfish home ranges, respectively. Male kelp greenling home range size correlated inversely with the density of red algae whereas kelp rockfish home range size was positively related to changes in kelp abundance. Their contrasting responses were consistent with their use of the respective algae as foraging habitat and shelter. Limited and discrete movement ranges reinforce the spatial heterogeneity of reef fish populations created by larval settlement and post-settlement mortality, including fishing. Knowledge of how movement is influenced by local population density is critical to understanding how movement contributes to the regulation of local and regional populations. Effects of habitat variability on the movement of species are critical to their population ecology, species interactions and management in a changing environment.

Indexing (document details)
Advisor: Carr, Mark H.
School: University of California, Santa Cruz
School Location: United States -- California
Source: DAI-B 71/02, Dissertation Abstracts International
Subjects: Ecology, Conservation, Biological oceanography, Aquatic sciences
Keywords: Marine protected areas, Reef fishes, Temperate reefs
Publication Number: 3394701
ISBN: 978-1-109-63547-8
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