Seasonal variation of the plankton of Perseverance Harbour, Campbell Island, and the morphology of decapod crustacea larvae from the harbour

Abstract

Between March 1965 and February 1966 118 surface plankton samples were collected from Perseverance Harbour, Campbell Island (52°S). Samples from each month of the year were analysed and species presence was related to climate and hydrological factors. The seasonal occurrence of the hydromedusae Obelia geniculata and Phialella quadrata, and the ctenophore Pleurobrachia pileus is governed by a lower limit of 7°C surface sea temperature. However, Bougainvillia macloviana is present throughout the year. Larvae of the decapod crustacea are released immediately sea surface temperatures begin to rise from their winter minima. Spring samples are usually dominated by decapod crustacea larvae, but in 1967 abnormally low sea surface temperatures resulted in failure of breeding. Hermit crabs released larvae in both spring and autumn. Other crabs released larvae only in spring. The southerly range of the mysid Tenagomysis tenuipes and the stomatopod Heterosquilla spinosa is extended. Perseverance Harbour plankton is typical of inshore waters and is influenced both by New Zealand and circumpolar subantarctic faunas. The seasonal cycles are typical of temperate rather than antarctic waters. Larval stages of Munida subrugosa (Decapoda, Galatheidae) Pagurus campbelli, Pagurus sp.A and Porcellanopagurus edwardsi (Decapoda : Paguridae) and Halicarcinus planatus (Decapoda : Hymenosomidae) are described in detail.