TYPE-3 FUNCTIONAL-RESPONSE IN FILTER-FEEDING OF THE BURROWING SHRIMP UPOGEBIA-DELTAURA (LEACH)

The rate of filtration of the burrowing shrimp Upogebia deltaura (Leac h) (Thalassinidea, Decapoda) was studied in different concentrations o f suspended Artemia nauplii. U. deltaura showed a slow rate of filtrat ion (clearance) at low food particle concentrations, which can be seen as a way of avoiding unprofitable effort. The rate of clearance peake d (3.5 lh(-1)) in food concentrations comparable (when converted to c arbon) with levels normally encountered in algal blooms on the Swedish west coast. The maximum capture rate of 700-750 naupliih(-1) was hig h compared with literature data on metabolic rates, and indicated an a bility of U. deltaura to utilise temporary fluxes of suspended food in high concentrations.