It’s all in their heads
Ann Arbor, MI — Ears are not just for listening, they can also tell a story. The use of fish earbones (called otoliths) is unlocking the mystery of the origins of Chinook salmon in Lake Huron.
The question of stream or hatchery origin of Chinook salmon has become a research priority for the Great Lakes Fishery Commission (commission). Previous research into the origins and migration of Chinook salmon in Lake Huron has been limited to hatchery fish implanted with coded wire tags. However, an increasing dominance of naturally reproduced fish (>80% of the fishery) has left a large unaccounted component of the fishery.
In 2007 a collaboration of Canadian and American researchers undertook a comprehensive project to investigate whether the use of chemical signatures captured by the otolith could identify the stream or hatchery of origin for Chinook salmon in Lake Huron. Otoliths have unique archival properties. Much like a tree, otoliths form growth rings and during growth these rings incorporate chemicals reflective of the environment in which the fish resides. These properties enable researchers to extract distinctive chemical profiles from the various environments experienced by a fish throughout its’ life. Otoliths of juvenile Chinook salmon from the 17 known spawning streams and seven hatcheries in Lake Huron were collected and analyzed. The results of this study show distinct chemical fingerprints between hatchery and wild fish, fish originating from different regions of the lake, and fish from individual streams or hatcheries. Furthermore these chemical fingerprints are distinct enough to accurately predict the origin of the individual fish.
"The findings from this research make it possible to predict the natal origins of any Chinook salmon caught in the Lake," says Stephen Marklevitz, a researcher at the University of Western Ontario. "Having the ability to identify the origins of Chinook salmon in the Great Lakes will allow the commission, and fishery managers, the ability to improve fishery management by better understanding the origin and movement of these fish."
The results of this research will be transferred to fishery managers in the US and Canada, addressing the challenges that managing Lake Huron, a binational Chinook salmon fishery, presents.
Original Publication Information
Results of this study, "Use of otolith chemistry to discriminate juvenile Chinook salmon (Oncorhynchus tshawytscha) from different wild populations and hatcheries in Lake Huron," are reported by Stephen A.C. Marklevitz, Brian J. Fryer, David Gonder, Zhaoping Yang, James Johnson, Ashley Moerke and Yolanda E. Morbey in Volume 37, No. 4, of the Journal of Great Lakes Research, published by Elsevier, 2011.
Contacts
For more information about the study, contact Stephen Marklevitz, University of Western Ontario, London Ontario Canada, N6A 5B7; smarklev@uwo.ca, (519) 661-2111 ext 88398.
For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, Environment Canada, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; jglr@ec.gc.ca; (306) 975-5310.
Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.