Aging fish otoliths recovered from Pacific harbor seal fecal samples

Fishery Bulletin, Oct, 2006 by Susan D. Riemer, Robert Mikus

Researchers should note that the digestive process does cause erosion of otoliths and can result in underestimation of fish ages. We did not attempt to determine how otolith-based age estimates were affected by erosion, but a carefully designed captive feeding study would be able to address this issue in the future. However, because there are few other methods to determine the age distribution of fish taken by pinnipeds, this technique is useful when describing the diet of seals and sea lions.

Acknowledgments

Funding for this project was provided by the National Marine Fisheries Service, Northwest Regional Office (with the assistance of the Pacific States Marine Fisheries Commission) and the Oregon Department of Fish and Wildlife, Marine Resources Program. We thank Bryan Wright, Robin Brown, and Monique Lance for their support of this project and the editing of an earlier draft of the manuscript. We thank Patty Burke and Mark Saelens for their input and support. We extend our thanks to our field staff Aicha Ougzin, Mark Dhruv, and Jonathon Scordino. We also thank Mark Karnowski and William Miller for their help with data and revisions. Finally, we thank the two anonymous reviewers who provided comments on this manuscript.

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