Growth and abundance of Pacific Sand Lance, Ammodytes hexapterus, under differing oceanographic regimes

Environmental Biology of Fishes
By: , and 

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Abstract

Dramatic changes in seabird and marine mammal stocks in the Gulf of Alaska have been linked to shifts in abundance and composition of forage fish stocks over the past 20 years. The relative value (e.g., size and condition of individual fish, abundance) of specific forage fish stocks to predators under temporally changing oceanographic regimes is also expected to vary. We inferred potential temporal responses in abundance, growth, and age structure of a key forage fish, sand lance, by studying across spatially different oceanographic regimes. Marked meso-scale differences in abundance, growth, and mortality existed in conjunction with these differing regimes. Growth rate within stocks (between years) was positively correlated with temperature. However, this relationship did not exist among stocks (locations) and differing growth rates were better correlated to marine productivity. Sand lance were least abundant and grew slowest at the warmest site (Chisik Island), an area of limited habitat and low food abundance. Abundance and growth of juvenile sand lance was highest at the coolest site (Barren Islands), an area of highly productive upwelled waters. Sand lance at two sites located oceanographically between the Barren Islands and Chisik Island (inner- and outer-Kachemak Bay) displayed correspondingly intermediate abundance and growth. Resident predators at these sites are presented with markedly different numbers and quality of this key prey species. Our results suggest that at the decadal scale, Gulf of Alaska forage fish such as sand lance are probably more profoundly affected by changes in abundance and quality of their planktonic food, than by temperature alone.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Growth and abundance of Pacific Sand Lance, Ammodytes hexapterus, under differing oceanographic regimes
Series title Environmental Biology of Fishes
DOI 10.1023/A:1016151224357
Volume 64
Issue 4
Year Published 2002
Language English
Publisher Springer
Contributing office(s) Alaska Science Center
Description 13 p.
First page 429
Last page 441
Country United States
State Alaska
Other Geospatial Gulf of Alaska, Kachemak Bay