摘要:

The patterns of accumulation of caesium‐137 from food by the tissues and organs of a marine teleost, the plaice (Pleuronectes platessa) and a freshwater teleost, the brown trout (Salmo trutta) are described and compared. Estimates of the biological half‐times and steady‐state concentrations are derived and individual organ intakes calculated. Rate constants are similar to those obtained from the accumulation from water studies. Plaice gut and liver have an 11 % increase and trout gut a 6 % increase in their share of the [137Cs] intake arising from accumulation from food, compared with that arising from the accumulation from water. These increases were balanced by decreases in the muscle share of the intake. The overall absorption of [137Cs] from food was 42% for plaice and 67% for

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03422.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A study was made of the biology ofS. maculatus. Results of gonadal examination of 347 males and 409 females suggest spawning takes place from October to April, a period associated with low salinities. First spawning takes place at ages I1 and/or III for both sexes. Sex ratio results suggest spawning may be promiscuous, males outnumbering females. Egg counts from 12 ripe females ranged from 26 057 to 149 736. A period of abundance from May to September may be associated with a post‐spawning feeding migration encompassing the island, possibly in a clockwise direction. Otolith were used to age 817 fish. Opaque and translucent rings are formed yearly. The translucent ring, representing a period of slow growth, is laid down during the spawning season. The fish can live for nine years with females growing faster than males. Growth parameters are compared with those obtained for Brazilian and Florida fish. Mortality rates were investigated and gill nets effected higher mortality rates than beach seines. Full recruitment takes place at age III for gill nets, and ages II and III for beach seine

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03423.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Milkfish,Chanos chnos, were sampled from two geographical areas in the Hawaiian Islands approximately 200 miles apart, from Pearl Harbor on Oahu, and Puako on Hawaii. Differences in the incidence of gastritis, a stomach inflammation, and electrophoretic patterns of nuclear lens proteins from fish of the two areas suggested they were separate populations. Genetically, the pattern frequencies indicated homogeneity in the Pearl Harbor fish and heterogeneity in the Puako fish. The former may be a small population in which homozygousity was produced through genetic drift. The genetic heterogeneity of the Puako fish may indicate a single large population or a mixture of populations. These observations support the hypothesis, previously deduced from field studies, that milkfish have many nearshore spawning areas over a wide geographical range and, therefore, little opportunity for genetic interchange between the fish from widely separated areas. Pearl Harbor fish had the highest incidence of gastritis, which appeared to be due to a combination of polluted water and a possible genetic susceptibility to disease from inbreeding.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03424.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Acrylamide gel electrophoresis indicates the presence of a group of proteins in the blood serum and liver of the female fish which are probably responsible for the accumulation of the proteid yolk in the ovary. Immunological tests confirm that these high molecular weight proteins are the protein yolk precursors synthesized in the female liver and transported by the blood serum to the ovary where they accumulate in the developing oocytes.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03425.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A reappraisal of oxygen uptake bySarotherodon mossambicuswas undertaken using a continuous flow respirometer. Measurements were obtained over the temperature range 16°C–37°C for fish weighing between 10 g and 150 g. Oxygen uptake was converted to energy equivalents (Qox) using the value 13.68 J mg O2–1and the routine metabolic energy expenditure can be described by the equationE=0.0086t2 0783M0 652whereEis the energy requirement for routine metabolism expressed in Jh‐1, tthe temperature in °C andMthe m

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03426.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Three‐hundred and thirty‐two fish of eight species (5Salmo salar, 68Salvelinus fontinalis, 32S. namaycush, 102Coregonus clupeaformis, 1Prosopium cylindraceum, 107Esox lucius, 14Catostomus catostomus, 3Couesius plumbeus) from the Smallwood Reservoir, Labrador, Canada, were examined for metazoan parasites, using conventional parasitological techniques.Fifteen genera of parasites were recovered (two of Monogenea, two of Digenea, four of Cestoda, three of Nematoda, two of Acanthocephala and two of Copepoda), these including seven new host records.Significant differences were noted in the prevalence of the various parasites which were common to the different species of fish examined. No differences were recorded in the parasite burden of male and female fish. There was no correlation between the number of parasite species per infected fish and host age except in the case ofSalvelinus namaycush. Food items of the fish examined were also no

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03427.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A reliable method for gynogenetic mass‐production has been developed in carp (Cyprinus carpioL.). The effect of different cold shock treatments applied after fertilization were examined. The yield of viable diploid gynogenetic animals could be significantly increased when the cold shock was applied 5 min or 15 min after fertilization. A negative correlation has been found between the effectiveness of these two treatments, so both were used on separate batches of eggs. By means of gynogenesis, the crossover frequency and map distance of the transferrin locus have been determined. Successful pilot experiments were made on grass carp (Ctenopharyngodon idellaVal.) and sheatfish (Silurus glanisL.) with respect to gynogenetic mass productio

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03428.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A decline in the growth rate of perch in Malham Tarn, Yorkshire, has occurred in recent times. This was found to coincide precisely with the resumption of stocking of brown trout, after a period of several years during which no stocking took place. In the absence of any other known correlating factor, it is suggested that the increase in population density of the trout may be responsible for the observed decline in perch growth.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03429.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

An unusual occurrence of a three‐spined stickleback,Gasterosteus aculeatus, is described from Ocean Weather StationIndiain the North‐east Atlantic. Previous records ofG. aculeatuscaught well offshore are summarised and reasons for these occurrences are suggested. Mention is made of the possibility of sticklebacks breeding in the open oc

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03430.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A total of 877 juvenile English sole (Parophrys vetulusGirard) from the Yaquina Bay estuary and742 juvenileandadultsole from the Pacific Ocean off Oregon were examined forparasites. Fifteen species of parasites were found in juvenile English sole on the estuarine nursery ground. Differences in the prevalence and intensity of parasite infection between size classes of juvenile sole and between sole occupying the upper and lower estuary were determined. An additional 14 parasite species were found in offshore English sole, bringing the total observed in all fish to 29 species. Parasites acquired only in the estuary included the microsporidanGlugea stephani, the acanthocephalanEchinorhynchus lageniformis, and the nematodePhilometra americana. Those acquired only in offshore areas included the trematodesOtodistomum veliporumandZoogonus dextrocirrus, the leechOceanobdellasp. and three species of copepods. An attempt to use parasite data to indicate the presence of distinct English sole stocks along the Oregon coast was inconclusive.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb03431.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY