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| Buecher, E; Goy, J; Planque, Benjamin; Etienne, M; Dallot, S. |
| Fluctuations in the abundance of developmental stages and adults of the medusa Liriope tetraphylla were monitored from 1966 to 1993 in the bay of Villefranche-sur-Mer, Northwestern Mediterranean Sea. L. tetraphylla exhibited large interannual variations in both mean abundance level and seasonality, Cluster analysis was applied to classify as ''poor'', years with medium to scarce populations evenly distributed the year; as ''normal'', years with a population maximum during autumn as frequently observed in the Mediterranean; and as ''special'', years with strong population maxima localized in spring or summer. The changing jellyfish abundance levels appeared not to be reliably linked to long-term changes in sea water temperature and salinity, even if... |
| Tipo: Text |
Palavras-chave: Jellyfish; Liriope tetraphylla; Pelagia noctiluca; Long-term fluctuations; Mediterranean Sea. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20387/18054.pdf |
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| Baussant, T; Ibanez, F; Dallot, S; Etienne, M. |
| Between March and June 1988, a series of diurnal acoustic records was carried out using a 50 kHz echosounder on a transect crossing the density front of the Ligurian Sea, off Villefranche-sur-Mer (Mediterranean Sea). The depth, thickness and pattern of the sound scattering layers were studied with respect to physical (temperature, salinity and density) and biological (chlorophyll a) measurements made along the acoustic transect. Seasonal differences were observed. A surface scattering layer (SSL), from 0 to 100 m, and a main deep scattering layer (MDSL), located between 250 and 550 m, occurred permanently during the study. In spring, an intermediate scattering layer (ISL), about 50 m thick, occurred between the SSL and the MDSL. The ISL, a permanent... |
| Tipo: Text |
Palavras-chave: SOUND SCATTERING LAYERS; MEDITERRANEAN SEA; LIGURIAN SEA FRONT; CYCLOTHONE-BRAUERI (GONOSTOMATIDAE). |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00100/21164/18783.pdf |
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| Menard, Frederic; Fromentin, Jean-marc; Goy, J; Dallot, S. |
| This study describes the temporal fluctuations of doliolid populations sampled in the Bay of Villefranche-sur-Mer (Northwestern Mediterranean Sea) from 1967 to 1990. The abundance level of doliolids (strongly dominated by Doliolum nationalis and Dolioletta gegenbauri phorozooids) was estimated weekly according to Frontier's (1969) ordinal scale. Population abundance shows important interannual variations. The series displays a clear upward trend from the late 1960s to the early 1980s; thereafter, the abundances remain at a high and steady level. Five annual patterns of abundance level changes are identified, using cluster analysis. The influence of hydrological and meteorological conditions on doliolid abundance is tested using a Markov regression model... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20431/18098.pdf |
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| Dallot, S; Goy, J; Carre, C. |
| Planktonic carnivores (chaetognaths, ctenophores, medusae and siphonophores) collected in the upper 200 metres of the Ibero-Moroccan bay and the western Mediterranean were used to obtain a classification of stations in terms of distinct faunistic zones. The planktonic community of the central sector of the Mediterranean shows a progressive devolution of abundance with the gradual disappearance of meroplanktonic and budding species and the increase of oceanic forms (Sagitta bipunctata, Eudoxoides spiralis and Rhopalonema velatum ). These faunistic zones of the Mediterranean, from the Strait of Gibraltar to the Ligurian Sea, can therefore be interpreted in terms of succession, from an initial state of maximal diversity and abundance caused by the mixing of... |
| Tipo: Text |
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| Ano: 1988 |
URL: http://archimer.ifremer.fr/doc/00267/37813/35894.pdf |
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