Francesc Pagès

Relationship between zooplankton distribution, geographic characteristics and hydrographic patterns off the Catalan coast (Western Mediterranean)

We studied the distribution patterns of ten zooplankton taxa of the Catalan coast (Western Mediterranean) using data collected in six research cruises along the continental shelf from April to July and September to October 1983. Zooplankton biomass ranged from 0.2–0.4 mg m-3 to 48–60 mg m-3, the greatest values being recorded between April and May, when gelatinous zooplankton concentrations were consistently present along the edge of the continental shelf. We identified the main factors contributing to the observed pattern of zooplankton distribution as the high degree of environmental fluctuation close to the coast (thermal gradient from north to south), the structural heterogeneity inherent to the continental shelf, and the persistence of a hydrographical front along the margin of the shelf.

Distribution patterns of the mesozooplankton, principally siphonophores and medusae, in the vicinity of the Antarctic Slope Front (eastern Weddell Sea)

Abstract The composition, abundance and vertical distribution of mesozooplankton, particularly siphonophores and medusae (27 species), collected along two transects in the eastern Weddell Sea have been analysed. Both transects were characterized by a steep thermocline that on approaching the coastline defined the Antarctic Slope Front. The front acted as a strong boundary in the shelf-slope and caused a pronounced cross frontal gradient in the populations of cnidarians. Few species and low abundances were found in the upper cold waters and most of the populations concentrated in and below the thermocline. The analysis of the gastrozooids of the physonect siphonophore Pyrostephos vanhoeffeni showed a wide variety of prey but the relatively high contribution of krill larvae reveals a substantial trophic impact when both organisms co-occur.

Benthic diatoms as the major food source in the sub-Antarctic marine hydroid Silicularia rosea

Analysis of the gut contents and scanning electron microscopy examination of the benthic hydroidSilicularia rosea from intertidal communities of Potter Cove (King George Island, South Shetlands) suggest that diatoms are the principal source of food for this species. The great number of items captured daily by each polyp (a mean of 287 in January and 162 in December) and the benthic origin of these prey items suggest an adaptation to daily resuspension processes caused by tidal currents. This is an unusual trophic strategy for a benthic hydroid, which would result in an important degree of independence from the highly fluctuating planktonic food conditions in Antarctic waters.

The anthomedusan fauna of the Japan Trench: preliminary results from in situ surveys with manned and unmanned vehicles

dhugal lindsay, francesc pag es, jordi corbera, hiroshi miyake, james c. hunt, tadafumi ichikawa, kyohei segawa and hiroshi yoshida Japan Agency for Marine–Earth Science and Technology (JAMSTEC), Yokosuka, Japan, Institut de Ciencies del Mar (CSIC), Passeig Maritim de la Barceloneta 37–49, 08003 Barcelona, Catalonia, Spain, Carrer Gran, 90, 08310 Argentona, Catalunya, Spain, School of Fisheries Science, Kitasato University, Ofunato, Iwate 022-0101, Japan, Department of Biology, East Stroudsburg University, East Stroudsburg, PA 18301, USA, National Research Institute of Fisheries Research, Fisheries Research Agency, 2-12-4, Fuku-ura, Kanazawa-ku, Yokohama 236-8648, Japan, National Research Institute of Far Seas Fisheries, Fisheries Research Agency, 2-12-4, Fuku-ura, Kanazawa-ku, Yokohama 236-8648, Japan, deceased

Biological associations between barnacles and jellyfish with emphasis on the ectoparasitism of Alepas pacifica (Lepadomorpha) on Diplulmaris malayensis (Scyphozoa).

Ten specimens of the rare scyphozoan Diplulmaris malayensis Stiasny, 1935 have been found with cirripedes Alepas pacifica Pilsbry, 1907 attached to their surface. This association is interpreted as ectoparasitism because adult barnacles produce deep clefts in the scyphomedusan umbrella, the gonads of which show signs of being preyed upon by the barnacle. A review of the literature on barnacles attached to jellyfish is presented with an interpretation of the meaning of this uncommon association.

Effects of the 1997-98 El Niño on the Oceanographic Conditions and Zooplankton Community Structure in the Coastal Upwelling System Off Northern Chile

This study was supported by FONDECYT Grant 1000419, 5960002-1996 and PCCI CONICYT/CSIC 2000-2-083

Four new species of Hydromedusae (Cnidaria, Hydrozoa) from the coast of south‐western Africa

Four previously unknown species of hydromedusae are described from plankton samples collected during oceanographic cruises undertaken along the south‐western coast of Africa. The Anthomedusa Bythotiara capensis sp.n., known from a single specimen, was found in shallow waters of the Cape region (South Africa). The Leptomedusa Margalefia intermedia gen. et sp.n. collected in Namibian waters, possesses desmoneme cnidocysts. This category of cnidocysts is previously unreported in the Leptomedusae, but is common in Anthomedusae and in the limnomedusan family Proboscidactylidae. Margalefia seems to occupy a position intermediate between the families Tirannidae and Laodiceidae. Two species of Limnomedusae, Aglauropsis edwardsii sp.n. and Proboscidactyla menoni sp.n. were frequent at several stations in Namibian waters between depths of 50 m and the surface.

Short-term effects of coastal upwelling and wind reversals on epiplanktonic cnidarians in the southern Benguela ecosystem

Patterns in the distribution of epiplanktonic cnidarians collected along the west coast of South Africa during June 1986 were examined. Upwelling-favourable south-easterly winds prevailed prior to ...

Amphinema modernisme, a new Pandeid (Cnidaria: Anthomedusae) from the Southern Ocean

Abstract A new species of pandeid anthomedusa, Amphinema modernisme, is described from a single and complete specimen collected by a mid-water sediment trap placed at 500 m depth in open waters, over a 1066-m bottom in the Drake Passage near the South Shetland Islands. This new Amphinema is characterized by an egg-shaped apical chamber, partitioned by four narrow sacciform centrifugal prolongations of the radial canals, perradial gonads and cellular strands linking the radial canals to the exumbrella. Its morphological features are compared with those of the eight other species of the genus Amphinema and a new diagnosis for this genus is presented.

Picadura por coral de fuego: un riesgo asociado al turismo en aguas tropicales

2 pages, 1 figure.-- Este articulo se complementa con una replica publicada en Med Clin (Barc) 124(6): 238-239 (2005) https://dx.doi.org/10.1157/13071770