Current Knowledge of the Early Life History of Arrowtooth
Flounder (Atheresthes stomias) in the Eastern Bering Sea:
With Comments on Kamchatka Flounder (A. evermanni)
Arrowtooth flounder are large, predatory flatfish that occur along the west coast of North America from central California to the Bering Sea. They are major predators of the commercially important fish walleye pollock, and in recent years abundance of arrowtooth flounder in the eastern Bering Sea has been increasing. The cause of this increase is unknown; however, factors influencing growth and survival of the early life stages have been hypothesized. These early life stages of arrowtooth flounder have been difficult to study in the eastern Bering Sea because the early life stages of its congener, Kamchatka flounder, are morphologically similar. Initial genetic work with collected larvae has shown that both arrowtooth flounder and Kamchatka flounder larvae are caught in the eastern Bering Sea and are quite often caught in the same hauls (Fig. 9). As a result, all specimens collected in the eastern Bering Sea have been identified as Atheresthes spp. until a method of visual identification can be presented. In this study we collected larval and early juveniles of both species from the eastern Bering Sea (2006-10), used genetic techniques to conclusively identify them, visually assessed specimens to identify species-specific morphological traits, and then used these identified specimens to study the ecology, distribution, and relative condition of arrowtooth flounder early life stages in the eastern Bering Sea. Results provided in this study are of the first comprehensive ecological data on arrowtooth flounder in the eastern Bering Sea.
Figure 9. Distribution of genetically identified specimens collected in the eastern Bering Sea.
By Lisa De Forest, Tracy Smart, Janet Duffy-Anderson, Ann Matarese,
Ron Heintz, Elizabeth Siddon, and Ingrid Spies