Age Determination of Red Deep-Sea Crab (Chaceon quinquedens) By Growth Ring Analysis

The age structure and growth rates of crustaceans are poorly understood because of their lack of true skeletal structures (e.g. shells, scales, otoliths). A recent development in crustacean aging is the discovery of growth rings or bands in calcified sections of the eyestalk and gastric mills. By examining these structures, accurate age estimates can be determined for the red deep-sea crabs (Chaceon quinqiedens). Red crabs support a minor commercial fishery along the continental shelf and slope of North America in water depths of 200-1800 m and at temperatures of 5–8°C. C. quinquedens are a data poor stock, due to insufficient data on their biology, abundance, growth, age, or reproduction. Eyestalks and gastric mills were removed, cleaned and embedded in epoxy, then sectioned longitudinally by a diamond-bladed Isomet saw. Sections were then mounted, polished, and viewed with a compound microscope. Rings were counted and compared between structures, and between paired eyestalks. Estimates of age composition will be used to improve data on growth, recruitment, migration, maturation, longevity and mortality, and will contribute greatly to improved stock assessment.