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Resource Ecology & Fisheries Management (REFM) Division

AFSC Quarterly
Research Reports
Jan-Feb-Mar 2008
ABL Reports
FMA Reports
NMML Reports
RACE Reports
REFM Reports
Quarterly Index
Quarterly Home

Age & Growth Program

Estimated production figures for 1 January
through 31 March 2008.  Total production
figures were 5,679 with 2,033 test ages and
126 examined and determined to be unageable.
Species  Specimens
 Flathead sole
 Northern rock sole
 Yellowfin sole
 Bering flounder
 Kamchatka flounder
 Walleye pollock
 Rougheye rockfish
 Shortraker rockfish
 Dusky rockfish
 Warty sculpin
 Yellow Irish lord


Tree Rings and Fish Otoliths

The analogy between tree rings and rings in fish otoliths is often used to explain how fish can be aged from otoliths. However, it is often not realized that the methods that have evolved for ageing tree rings can also be applied to otoliths. This realization was clarified when Oregon State University Professor Bryan Black explained the application of "dendrochronology," or the science of ageing from tree rings, in an AFSC seminar and miniworkshop given to the Age and Growth Program.

Bryan Black is working with AFSC age readers and the Status of Stocks Program in a collaboration that we hope will eventually assist in the ageing of some difficult to age rockfish species (e.g., shortspine thornyhead and shortraker rockfishes). Among the interesting things brought out in his talks, was how dendrochronology used unusually poor growth years as a kind of barcode to build time chronologies. Impressively, the bristlecone pine chronology extends back nearly 10,000 years. Bryan Black also explained how marine chronologies from rockfish and shellfish (geoduck), can be correlated with those found in mountain trees.

These interesting findings broaden our view of the ecosystem in which we live, play, and study.

By Dan Kimura

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