Feeding behaviour and functional morphology of the feeding appendages of red king crab Paralithodes camtschaticus larvae

The aim of the study was to examine the feeding mechanism of planktonic larvae (pre-zoea, zoeae I-IV) of the red king crab using a combination of morphological and behavioural data obtained under laboratory conditions. Feeding appendages and accompanying setal types of larvae are described, illustrated, and related to their functions during prey capture and ingestion. Descriptions are based on direct behavioural observations of larvae fed several types of food and on theoretical assumptions based on the morphology of the appendages and body parts involved in feeding. The pre-zoea is covered by embryonic cuticle and does not feed. Under laboratory conditions, zoeae I-IV show a mixed feeding strategy: they are able to feed by the capture of material suspended in the water column and by the collection of food objects from the substratum. Zoeae are able to capture and ingest a relatively wide range of particle sizes, from 100 µm to 2 mm, and are highly cannibalistic; they do not show true hunting behaviour and rely on an “encounter feeding” mechanism. An analysis of larval feeding behaviour is presented and its implications for larval cultivation are considered. Recommendations on possible sizes, concentrations and distribution of food objects in the rearing tanks are outlined.