Nest site preference and intrasexual competition i

Authors: Milo D Adkison Michael B Ward Thomas P Quinn

Publish Date: 2013/08/06

Volume: 97, Issue: 4, Pages: 385-399

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Abstract

Many ecological circumstances present individuals with a conflict between the inherent benefits of a particular habitat and the costs incurred in acquiring or retaining use of the habitat in the face of competition For example the reproductive biology of female Pacific salmon Oncorhynchus spp led us to hypothesize that female nest site choice should reflect a compromise between the benefits of obtaining a high quality nest site and the cost of competing for and defending it To test this hypothesis we studied female sockeye salmon O nerka spawning on beaches in Iliamna Lake Alaska using a combination of snorkel surveys tagging behavior observations and models Females showed spatial preferences in nest site selection for shallower water where water circulation was higher aggressive competition in preferred areas was higher and there was evidence for costs associated with this increased competition Over the course of the season spawning activity shifted from shallower to deeper water consistent with a tradeoff between benefits for embryo survival associated with shallow sites and the costs of competing for them However it was also consistent with datespecific optimal sites related to the probability of embryo mortality for eggs spawned in shallow water late in the season due to annual cycles in lake level and temperatureWe thank Chris Foote Andrew Hendry Ray Hilborn Robin Waples Mark Kot and William Hershberger for reviews and advice Frank Leonetti for allowing us to preview his data those who assisted in the field Carol Woody Rebecca Bernard and Tom Rogers especially and the Pacific Seafood Processors’ Association for financial support of Bristol Bay salmon research Milo Adkison was supported by a H Mason Keeler fellowship

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