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| Adema, J.P.H.M.; Creutzberg , F.; Noort, G.J. van. |
| INTRODUCTION Since April 1972 an ecological trawl-survey programme has been undertaken by the Netherlands Institute for Sea Research (NIOZ), Texel, in the southern North Sea with the R. V. "Aurelia". The main object is to obtain information on distribution, density, biomass and fluctuations of crawling or swimming demersal (epibenthic) fauna such as small fishes, shrimps, prawns, crabs, asteroids, ophiuroids and some gastropods, for the evaluation of the role of these carnivores in the benthic ecosystem of the southern North Sea. Sedimentological aspects of the area are described by Creutzberg & Postma (1979). Within the context of the present paper the most important feature is the mesh of 5 x 5 mm2 of the cod end of the 51/2 m beam-trawl used and the... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 42.74. |
| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/317267 |
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| Adema, J.P.H.M.; Huwae, P.H.M.. |
| INTRODUCTION Part XVI of the Fauna van Nederland, Isopoda & Tanaidacea (Holthuis, 1956), deals with 27 species of Isopoda occurring in salt and/or brackish water. According to Holthuis (1956) the occurrence in the Netherlands of two of these, Sphaeroma serratum (Fabricius, 1787) and Bopyrus squillarum Latreille, 1802, is very doubtful and will remain so, as the material on which the records were based is lost and no new records of these species have been published for the Netherlands. Since 1956 many new data were obtained for several of the remaining 25 species, while 12 species were found for the first time in Dutch waters or in the southern North Sea. The present paper deals with the more interesting finds. Part of the species mentioned here have... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 42.74. |
| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/317279 |
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| Adema, J.P.H.M.. |
| Until the appearance, in 1970, of the American crayfish Orconectes limosus (Rafinesque, 1817) in the Netherlands, only a single species of crayfish was known here: Astacus astacus (Linnaeus, 1758). Geelen (1978a, b) provided an extensive discussion on the distribution of the two species. On 13.vi.1980 the Rijksinstituut voor Visserijonderzoek of IJmuiden (National Institution for fishery Research, RIVO) presented the RMNH a freshwater crayfish with a request for identification. The specimen was caught by a fisherman in a freshwaterpond (named IJ) near Spaarndam, NW of Haarlem, province of Noord-Holland. The pond has an open connection with the Noorzeekanaal, the mostly brackish canal that connects Amsterdam with the North Sea. The crayfish, a male with a... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 42.74. |
| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/317236 |
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