DETECTION OF PHYTOPLANKTON PIGMENTS BY HPLC IN HYAS-ARANEUS LARVAE (CRUSTACEA, DECAPODA) - COMPARISON OF FIELD AND LABORATORY SAMPLES

The ingestion of phytoplankton by Hyas araneus larvae was shown by lig ht- and scanning electron microscopic examination of faeces and HPLC a nalysis of larvae collected from the field (zoea I) or cultivated in t he laboratory (zoea I, II). To date these larvae have been considered to be carnivorous. Three phytoplankton pigments were detected by HPLC: chlorophyll a (marker pigment for phytoplankton in general), fucoxant hin (marker pigment for Bacillariophyceae) and peridinin (marker pigme nt for Dinophyceae); also present were the degradation products of chl orophyll a (phaeophytin a and phaeophorbide a). The pigment compositio n of larvae collected from field samples showed that dinoflagellates w ere ingested in addition to diatoms. The pigment concentration in larv ae from field samples was lower than in laboratory-reared larvae, whic h may be due to lower algal concentrations in the field. The chlorophy ll a concentration in the larvae from the field ranged from 0.05 to 0. 5 ng.larvae-1, phaeophytin a from 2.1 to 8.2 ng.larvae-1 and phaeophor bide a from 0.1 to 0.4 ng.larvae-1. The fucoxanthin and peridinin conc entrations varied from 0.2 to 3.8 ng.larvae-1 and from 0.0 to 0.3 ng.l arvae-1, respectively. Similar values of dry weight and elemental comp osition in the zoea I were found in field samples and laboratory cultu res fed with diatoms exclusively.