Dungeness crab are an important
predator and prey organism at all life history stages. They have pelagic
larvae (zoea and megalops stages) which are preyed on by many fishes,
including copper rockfish and coho and chinook salmon. Being planktivorous,
the larvae may be exposed to pollutants that are present in the water
column and plankton. Once they molt into the juvenile stage, they become
demersal, feeding in the benthic food web. They can readily adjust their
diet, but the younger/smaller crabs generally eat mollusks, progressing
to shrimp and then to fish as they age and grow. The adults have developed
an evolutionary niche for feeding on mud-sand substrate, thus providing
a food-web pathway through which contaminants can move from sediments
to humans. Dungeness crabs are relatively short-lived with a maximum
lifespan of 8 to 10 years. They move between estuaries and offshore
waters seasonally.
In a 2001 focus study, the
Fish Component monitored for the presence and severity of toxic contaminants
in this species at a limited number of sites in Puget Sound.
