ALBERT

Description: Pendant le mois d’Avril 1974 des prélèvements furent effectués dans la zone de marées le long de la côte Atlantique de l’Espagne et de la côte Portuguaise. Figure 1 donne un aperçu des espèces provenantes des stations visitées. Les tableaux II jusqu’à VI incl. montrent la nature du milieu, dans lequel les Gammares furent trouvés. Douze espèces furent rencontrées, dont Gammarus salinus est mentionné pour la première fois de l’Espagne et Chaetogammarus stoerensis de Portugal.

Description: During summer 1977 the distribution and ecology of amphipod Crustacea in the coastal plain of north Carolina were studied. Ecological data were collected in particular on Gammarus tigrinus, a North American species, which has been introduced in western Europe. The present gammarid, able to endure high water temperatures and adapted to a wide variety of salinities, is found in the more upstream parts of the estuaries in North Carolina. More downstream, at higher salinities, it is replaced by Gammarus palustris, while at very low salinities or in fresh water Gammarus fasciatus is commonly met.\nMoreover, some data are given on the distribution and ecology of several other amphipod species in the Beaufort region.

Description: Monthly samples of Gammarus fossarum have been taken in the Rh\xc3\xb4ne river system near Lyon, to determine the size composition and reproductive activity throughout the year. The acanthocephalan parasites of this gammarid species were also regularly collected. Furthermore, the intestinal tracts of a number of fishes (amongst others Thymallus thymallus), feeding mainly on Gammaridae, have been investigated for the presence of helminth parasites.\nG. fossarum reproduces throughout the year in the area near Lyon, but fluctuations in the rate of ovigerous females appear. A peak in the infestation of the gammarids by larvae of Pomphorhynchus laevis (Acanthocephala) occurred in autumn and a second peak, but a lower one, during spring. The fish hosts showed maximal infestations during the same periods, while during summer the incidence of Pom. laevis was low, both in the intermediate and in the final host.\nFrom the stomach contents of the fishes it seems that gammarids harbouring the invasive acanthocephalan larva (cystacanth) are selectively ingested.\nReproduction of G. fossarum seems not always to be inhibited at the presence of acanthocephalan larvae, since several infested female gammarids were found carrying eggs or juveniles in their brood pouch.\nThe occurrence of some other helminth parasites is recorded for the region near Lyon.

Description: The migration of G. zaddachi in La Slack, a small stream on the French Channel coast, and some physico-chemical properties of the river are discussed.\nIn laboratory experiments, the influence of the Cl- and Ca++ concentration on the survival-rate and reproduction of G. zaddachi was investigated. A raise in the Cl- concentration of the medium caused a significant improvement of the survivalrate. A raise in the Ca++ concentration also gives, although not significant, a higher survival-rate.

Description: The reproductive cycles of Chaetogammarus marinus and Eulimnogammarus obtusatus in northern Brittany are compared, as well as the environmental conditions under which these gammarids live. Both species show reproductive activity throughout the year. The maximum rate of ovigerous \xe2\x99\x80 \xe2\x99\x80 was established for E. obtusatus in the months of February-March (the coldest period of the year), for Ch. marinus in December. The former species showed the lowest rate in August (the warmest month of the year) and the latter species in March.\nEulimnogammarus obtusatus lives in the lower half of more exposed beaches and was rarely found on a substrate containing mud, contrary to Chaetogammarus marinus. It was established that the southern distribution limit of E. obtusatus lies in Brittany.\nEcological data are given on a number of other gammarid species from the tidal zone of the Atlantic coast of France.

Description: The distribution and the autecology of 10 species of the amphipod family Gammaridae in fresh and brackish waters in south-eastern France (d\xc3\xa9partements H\xc3\xa9rault and Bouches-du-Rh\xc3\xb4ne) are briefly described.

Description: Description d\xe2\x80\x99une nouvelle esp\xc3\xa8ce d\xe2\x80\x99Amphipodes, Echinogammarus pinksteri n. sp., appartenant aux Echinogammarus du groupe pungens. Ce Gammare provient d\xe2\x80\x99eau douce de la partie centrale de l\xe2\x80\x99 Italie (r\xc3\xa9gion d\xe2\x80\x99Avellino).

Description: A. The stations 1-5 situated in the head of the Dourduff-estuary (Brittany, France), have been sampled monthly at springtide during the period of May-October 1971. The data obtained this way show a shifting in the populations of Echinogammarus berilloni, Gammarus chevreuxi, and Gammausr zaddachi from the upstream part of the estuary to more downstream and vice versa during the months in which the present investigations have been executed (fig. 3). It appeared that E. berilloni can exist in the head of the estuary, as long as G. chevreuxi and G. zaddachi are few in number or absent (i.e., May-September). When in September the latter two species repopulate the most upstream part of the estuary, E. berilloni disappears from this river section and was found only farther upstream. Because it has been demonstrated that E. berilloni can sustain salinities up to 80% seawater (Vincent, 1966), the increased salinity in the head of the estuary, during the equinoctial springtides in autumn, can not explain the disappearance of this species in that part of the river. The reproduction period of E. berilloni falls during May and June.\nB. On several places in the estuary of the Dourduff samples have been taken both in the main stream and in the brooklets discharging into it. This sampling resulted in a survey of the distribution of gammarids in the estuary in correlation with some environmental factors (figs. 6 and 7).\nC. A microgeographical analysis has been executed in the non-estuarine part of the Dourduff and its ramifications. The distribution of species in this part of the river system is shown in figure 5.

Description: Pendant le mois d\xe2\x80\x99Avril 1974 des pr\xc3\xa9l\xc3\xa8vements furent effectu\xc3\xa9s dans la zone de mar\xc3\xa9es le long de la c\xc3\xb4te Atlantique de l\xe2\x80\x99Espagne et de la c\xc3\xb4te Portuguaise. Figure 1 donne un aper\xc3\xa7u des esp\xc3\xa8ces provenantes des stations visit\xc3\xa9es. Les tableaux II jusqu\xe2\x80\x99\xc3\xa0 VI incl. montrent la nature du milieu, dans lequel les Gammares furent trouv\xc3\xa9s.\nDouze esp\xc3\xa8ces furent rencontr\xc3\xa9es, dont Gammarus salinus est mentionn\xc3\xa9 pour la premi\xc3\xa8re fois de l\xe2\x80\x99Espagne et Chaetogammarus stoerensis de Portugal.

Description: Eleven species of helminth parasites (five acanthocephalans, five cestodes and one trematode) are reported from altogether sixteen fish hosts in the Rh\xc3\xb4ne River, N.E. of Lyon.\nThe most common parasite is Pomphorhynchus laevis, which occurs in all fish species examined. Echinorhynchus borealis seems to he restricted mainly to Burbot. Metechinorhynchus truttae was not frequently met with, but was very numerous in Grayling from the river Furans. Acanthocephalus anguillae was found in fishes from the so-called \xe2\x80\x9dl\xc3\xb4nes\xe2\x80\x9d (backwaters). A. lucii was rarely encountered during the present study. Of Cestoda, Caryophyllaeus laticeps is confined to fishes feeding on muddy substrates, Bathybothrium rectangulum was found in Barbel, and Eubothrium rugosum in Burbot. Proteocephalus torulosus is recorded from Dace and Chub, and Cyathocephalus truncatus from Trout and Grayling. The trematode Crepidostomum farionis occurred in the latter as well.