The abundance and distribution of Caridea larvae was studied in Isafjord-deep, north-west Iceland, at approximately monthly intervals from February 1987 to February 1988. Zooplankton sampling was made at nine stations along the length of the fjord, while temperature and chlorophyll a measurements from one of the stations are also presented. Larvae of six species occurred in the samples, Eualus pusiolus and Pandalus borealis were most numerous constituting 62.8 and 25.9% of the larvae respectively. The other species were, in declining order of abundance, Pandalus montagui, Spirontocaris spp. (S. spinus and S. lilljeborgii) and Sabinea septemcarinata. Eualus pusiolus was of highest abundance in the outer and middle parts of the fjord, while P. borealis was most common in the middle and inner parts. The onset of hatching of all species in April-May appeared closely linked to the phytoplankton spring bloom, while the temperature in the fjord was by then near the annual low (2-3-degrees-C). Except for E. pusiolus, of which a small part of the population produced a second brood during the summer, most of the larvae had disappeared from the plankton by the middle of August. The monthly carapace growth of P. borealis larvae during the summer months was estimated to be approximately 1.0 mm.
