摘要:

SummaryThe efficacy of a strobe light and a combined strobe light/bubble curtain system was evaluated under turbid water conditions as a fish avoidance scheme. Three estuarine species commonly impinged at electric generating facilities along the Atlantic coast of the United States were tested: Atlantic menhaden (Brevoortia tyrannus), spot (Leiostomus xanthurus), and white perch (Morone americana). The strobe light/bubble curtain combination was the most effective system studied in all cases. An interesting phenomenon was that fish avoidance to strobe light systems increased with turbidity over the range tested (clear, 39–45 and 102–138 N

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00460.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryObservations were made of characteristic nursery areas along the southern and western coasts of Lake Kinneret, Israel, during the years 1982–84. Cyprinid and cichlid fingerlings were found to have different specific habitats. Most cyprinid species are of palaearctic origin, and prefer low water temperatures. Fingerlings of some species of cyprinids have exclusive habitats. A common characteristic of all the species is the direct relationship between body size and water depth.The presence of cichlid fingerlings in the nursery areas during the day is directly related to the occurrence of sunlight and to water temperature. An important finding was the time of dispersion of the cichlid fingerlings, which is when they attain a size ˜ 5 cm and weight of ˜ 3 g. Stocking of the lake with cichlid fingerlings below 3 g is not recommen

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00461.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe seasonal abundance and instantaneous natural and fishing mortalities of six species of grey mullets, namelyLiza subviridis, L. macrolepis, L. tade, Mugil cephalus, Valamugil buchananiand V.cunnesiuswere studied as a prelude for the management of their fishery in Negombo lagoon (7°10′N and 79°50′E).L. subviridiswas the most abundant of the grey mullet species in the commercial catches and accounted for 37% of the total grey mullet catch.M. cephaluswas the least abundant and constituted 6%. The annual catch of grey mullets was estimated to be around 23 000 kg (5.67 kg/ha); about 40 % of the total fish landings of the lagoon. The seasonal variation in the catch of different species of grey mullets appear to be related to their breeding seasons and spawning migrations. The highest value for instantaneous natural and fishing mortalities, which were 1.04 and 0.94 respectively were obtained forV. cunnesius.The lowest values for instantaneous natural and fishing mortalities which were 0.51 and 0.19 respectively were obtained forM. cephalus.The exploitation ratios calculated were less than 0.5 for all species other thanL. tadewhich suggest that the grey mullet populations excludingL. tadein this lagoon may presently be underexpl

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00462.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Summary7 days old larvae ofCoregonus lavaretusL. (local name: ‘Blaufelchen’) were fed on zooplankton that had been frozen at—18°C for 1 year. 4 times per day the pieces of frozen plankton were added into the preaeration tank thus providing that freshly thawed zooplankters were offered to the fish. Within 10 weeks the fish reached a total length of 30.5 ± 5.5 ram and an average dry weight of 22 mg. Within this period the survival was 45 % of the initial number.After a period of 7 weeks feeding on long‐term frozen pankton 400 fish were switched to living zooplankton and after 9 weeks 400 fish were switched to short‐term frozen plankton. The growth of those fish that were fed on living plankton was significantly faster than it was when frozen zooplankton was given.A switch of coregonids which were prefed on frozen zooplankton to dry diet proved to be successful as soon as the fish had reached a body leng

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00463.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryA comparative growth analysis of two sciaenid species(Plagioscion squamosissimusHeckeland Plagioscion montiSoares)in different water types of the Central AmazonThe growth of two sciaenid speciesP. squamosissimusandP. montiwas comparatively described in black and white water of the Amazon by determining the age by means of daily rings on otoliths. Growth was described according to v. Bertalanffy's and Pauly's equations. A comparison between black and white water proved the expected faster growth of white water fishes.

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00464.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe optimum conditions for staphylococcal co‐agglutination (CoA), latex agglutination (LA) and the fluorescent antibody test (FAT) for the identification ofRenibacterium salmoninarumisolated in culture were determined. Their sensitivities were then compared with that of the enzyme‐linked immunosorbent assay (ELISA). The ELISA was the most sensitive, followed by CoA, with the FAT and LA jointly the least sensitive. However, all four techniques were sufficiently sensitive for routine identification ofR. salmoninarum.The agglutination techniques (CoA and LA) were preferred because of their speed, ease of use and low c

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00465.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryTwo viruses have been isolated from tench (Tinea tinea) and from chub (Leuciscus cephalus). The agents replicated in EPC‐and FHM cells at 20°C forming syncytia and lysis. Electron micrographs of the virion revealed icosahedral particles with a double capsid and a size of 70–75 nm. The genome of the isolated viruses consisted of 11 segments of dsRNA. SDS‐PAGE migration patterns of the RNA revealed differences between the isolates and between the reoviruses of fishes. The isolates are serologically identical and they show serological relationships to the golden shiner virus (GSV) and to a lower extent to the chum salmon virus

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00466.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryInfestations ofLivonecasp. occur on the striped therapon,Helotes sexlineatus, in Kuwait waters. Infestation rate decreases as depth increases, and some infested fish were found in all samples examined; the occurrence of infested fish could not be used as a biological tag. One year and four year old fish were uninfested. Two and three year old fish showed different infestation rates (4.1% and 0.9 % respectively). No striped therapon carried more than one parasite.

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1987.tb00467.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY