摘要:

The conclusion from twoin vivoexperiments is that a significant proportion of the lactic acid, normally formed by glycolysis from glycogen and held in the muscle cells following exhausting exercise of the anaerobic swimming muscle of the teleost fishPleuronectes platessaL, is converted by gluconeogenesis to form glycogen in the recovering muscle.In the first experiment a technique for measurement of [3H]glucose turnover in the plaice was developed and applied to measure turnover in resting and exhausted fish. It is concluded that insufficient glucose was moved through the circulation to account for the rate of glycogen formation observed in the recovering exhausted muscle.In the second experiment, an intramuscular injection of [14C]lactate to exhausted fish revealed a direct uptake of [14C]lactate by the recovering muscle cells, and the incorporation of substantial proportions of lactate into the restored glycogen. Simultaneous use of [3H]‐mannitol allowed measurement of the isotope distribution between extra‐ and intracellular spa

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03641.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The size and species composition of zooplankton ingested by brown trout in Lough Sheelin was studied. Zooplankton and fish samples were taken simultaneously. The zooplankton samples consistedof Daphnia hyalinavar.galeata, Copepoda andBythotrephes longimanusin the proportion of 246: 10: 1. The entire stomach contents of the fish were examined with particular attention paid to the zooplankton component. The results indicated a high degree of selection forB. longimanus.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03642.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The premature transfer of juvenile Coho salmon into seawater results in high mortality and a reduction of growth (stunting) of a significant portion of the population while the remainder of the salmon continue to grow normally. Binding studies were conducted withI25I‐labelled tilapia (Sarotherodon mossambicus) growth hormone (tGH) to determine if differences in specific binding of tGH existed in membrane preparations of tissues of stunted and normal coho salmon. Membrane preparations of both liver and gill of stunted salmon obtained from stocks in California, Washington and British Columbia and kidney membrane preparations obtained from stunted salmon in California exhibited deficiencies in125I‐labelled tGH‐binding sites compared to corresponding membrane preparations of normal smolts. These results indicate that stunted coho salmon have a decreased ability to bind GH which may be reflected in perturbations in GH‐mediated pr

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03643.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Marked changes in the relative numbers of roachRutilus rulilus(L.), ruddScardinius erylhroplhalmus(L.) and perchPerca fIuviatilis L., in Slapton Ley, Devon, have been observed over the period 1967–1978. Historically, the lake had been dominated by rudd and perch; significant numbers of roach were not thought to be present until 1967. From then onwards the roach population exhibited a considerable expansion, apparently replacing the rudd, which had virtually disappeared by 1974. In 1975 extensive mortalities of roach were caused by the pseudophyllidean cestodeLigula intestinalisL. During 1976 and 1977 larger number of rudd, belonging to the 1975 and 1976 year classes, were present, suggesting that the roach mortalities might be giving the rudd a chance to recover. However, very few rudd were present during 1978, possibly because lower incidences of ligulosis during 1976–1978 had allowed the roach to recover from the main outbreak of the disease in 1975, and to replace the rudd for the second time. Evidence from trap catches indicated that the perch population had shown a consistent decline between 1970 and 1977. The major phase of this decrease occurred between 1971 and 1973, when the roach population was increasing the most rapidly. Comparisons were made with changes in fish populations in other localities. The major reason for the changes observed was thought to be a competitive relationship between the plankton feeding younger stages, with roach being the dominant species, although other factors may also have been invol

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03644.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Sarotherodon mossambicuswas exposed for up to 10 weeks to concentrations of Abate larvicide in excess of those produced during blackfly control in African rivers. Despite this treatment, several indicators of sub‐lethal poisoning, e.g. growth, plasma glucose, acetyl‐cholinesterase activity remained almost unchanged. A possible explanation for the low toxicity of Abate is gi

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03645.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The biology of a Scottish population of the spotted dragonetCallionymus maculatuswas studied from February 1975 to September 1976. The data were taken from monthly samples totalling over 700 fish trawled in 18–36 m on a soft mud bottom. Neither otoliths nor radial bones were found to be suitable for age determination, but evidence from other sources suggested that most growth takes place in the first two years of life and that males grow faster, but do not live as long (at least 3 years) as females (at least 5 years). Examination of the gonads showed that the spawning season probably lasts from April to September, that females mature earlier in life than males and are serial spawners. The males may reach first maturity at different ages. The sexes are markedly dimorphic. The rays of the dorsal, anal and caudal fins grow isometrically in females but growth of these organs in males is allo‐metric after maturity has been achieved. The fish feeds predominantly on polychaetes and amphipods, although bivalve molluscs, macruran decapods and ophiuroids also occur frequently in its diet. There is some difference in the diet between length classes, smaller fish taking fewer polychaetes and more amphipods than the larger individuals. The species is finally compared with other dragonets whose biology is kn

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03646.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The wigwag display of the juvenile brown trout (Salmo trutta, L) was analysed and found to be a ritualised display used specifically as a defensive manoeuvre in the aggressive interactions of groups of fish. Wigwag displays performed against fish of lower or equal social rank were highly effective as a defence but wigwags performed against higher ranking fish were less than 50% effective.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03647.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Metazoan parasites of whitefishCoregonus clupeaformisand ciscoC. artediifrom Southern Indian Lake, Manitoba were studied to reveal: species composition, differences with host age, sex, and location and season of capture. Whitefish hosted 19 species, 18 of which were also in cisco with generally lower intensity levels. Parasites exhibited definite patterns of abundance with host age and season, the primary causes being dietary and behavioural. No differences in parasite abundance existed between host sexes. Ranking of cisco parasites was significantly different between two sampling sites while whitefish parasites did not differ. Whitefish and cisco from sites 40 miles (64 km) apart had significantly different abundances ofTetracotyle intermediabut notTriaenophorus crassus. An increase in the abundance of copepod‐vectored cestodes with a concomitant decrease in abundance of amphipod‐vectored parasites is predicted after flooding and divers

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03648.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Ventilation frequency patterns ofTrinectes maculatus, Morone americanaandLeiostomus xanthuruswere used to evaluate potential thermal stress after exposure to moderate temperature increases. Fish acclimated to 5°, 15° and 25° C were exposed to a 5°C T; fish acclimated to 30° C were exposed to a 2.5° C A T. Ventilation frequencies were measured at each acclimation temperature before the fishes were exposed over a 15‐min period to the increased temperatures. Ventilation rates were then measured at the elevated temperatures for the next 24 h. Significant increases in rate frequency occurred after the temperature increases inT. maculatusandM. Americanaacclimated to 5°, 15° and 25° C and inL. xanthurusacclimated to 15°, 25° and 30°C. In general, rate frequencies increased as the temperature increased. Ventilation rates stabilized quickly at the higher temperatures and remained relatively constant throughout the remaining exposure period. Acclimated rate‐temperatures curves (R‐ T curves), acute R‐ T curves and Q10 temperature coefficients used to assess the significance of the changes in rate frequency and to compare the species in an ecologically meaningful way, showed that several adaptive types occurred among and between species. The Q,10's of the acute R‐ T curves, in most cases, were found to approximate those values derived for the acclimated R‐T curve. This suggests that the temperature increases had a negligible effect, that is, little or no

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03649.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

A cell was found in freshwater brook trout which was similar to a chloride cell as it was mitochondria‐rich with an extensive tubular network, but differed in having a dark cytoplasm, large round vesicles in the apical cytoplasm, and large membrane‐bound bodies near the nucleus. The base of the cell was separated from the basement membrane by cytoplasm from another epithelial cell. The cell was more rarely found in trout adapted to brackish water and salt wa

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03650.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY