Background

Deep-water species of king crabs are found in most oceans, especially in depths between 1,600 and almost 5,000 feet. There are shallower-water species, however, at higher latitudes.

Diet

The Alaska Department of Fish and Game compiles an impressive list of prey items for king crabs in general, from sand dollars and worms to detritus and algae. The menu depends on the given type's habitat preferences, biology and size.

A Specific Example

The Puget Sound king crab, a dramatically colored species ranging from Alaska to California, feasts mainly on echinoderms like sea urchins.

Age Preference

A study from the late 1980s in Argentina's Beagle Channel, analyzing the stomachs of 282 false southern king crabs, revealed information about diet and age in the crustaceans. Where adults comprised most of the population, algae and mollusks were the most common prey; in another location with more juveniles than adults, crabs more frequently selected hydrozoa, echinoderms and microorganisms.

Seasonal Feeding Variation

The same study from the Beagle Channel showed that false southern king crabs fed fairly consistently throughout the year except during their mating/moulting period.

Source:

King Crab Family Bigger Than Ever (EurekAlert)

Alaska King Crabs (Alaska Dept. of Fish & Game)

Lopholithodes mandtii (Walla Walla University)

Resource:

King Crabs Go Deep To Avoid Hot Water (ScienceDaily)

Feeding Habits of the False Southern King Crab