Alaska Fisheries Science Center Quarterly Report : January, February, March, 1993 Observations From a Submersible Shed New Light on Crab Behavior

Any scientist who has conducted trawl surveys has first hand knowledge that most organisms are not randomly distributed throughout their environments. This is especially true for crabs. Many tows produce few or no crabs at all, while some will plug the net with a "beetle-bomb" thousands of crabs, typically of the same sex and size. Observations made near Kodiak, Alaska, using the submersible Delta (Fig. 1) in 1991-92 have provided us with new insights into the behavior causing aggregations of Tanner crabs (Chionoecetes bairdi).