摘要:

Grass carp were raised in 227‐1 indoor tanks at 3,5,7 and 9%osalinities and 18·5 and 29·5°C temperatures at a density of five fish per tank. Growth rate did not differ under these conditions. Food consumption was similar between temperatures at a given salinity but differed among the salinities with most food intake at the 5%o salinity. An average of 40% of grass carp survived for 180 or more

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02794.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The distribution, morphology and cytochemistry of the eosinophilic granule cells in the gut of the rainbow trout,Salmo gairdneri, were studied using light and electron microscopes. Granule cells were associated generally with the propria of the gut wall, the majority being arranged in a definitive layer, as a stratum granulosum. The cytoplasm of the eosinophilic granule cells contained numerous spherical, membrane‐bound, homogeneous electron‐dense granules, ranging from 0·1–1·3 urn in diameter. A portion of the cytoplasm located towards one pole of the cell was usually devoid of organelles other than ribosomes. Whatever their location, the eosinophilic granule cells were always associated with fixed connective tissue cells, referred to here as ‘ensheathing’ cells. Phospholipid, acid mucopoly‐saccharide and the activities of alkaline phosphatase, acid phosphatase, arylsulphatase and 5‐nucleotidase were demonstrated in the granules. It is hypothesized that the ‘ensheathing’ cells and eosinophilic granule cells constitute a part of the bod

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02795.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The food habits of the mudskipper,Pseudapocryptes dentatus(Val.) ranging from 43 to 205 mm in total length collected from the mudflats at Fao estuary, Iraq were studied. A combination of numerical, frequency occurrence and gravimetric methods was used to analyse the stomach contents, both qualitatively and quantitatively. The fish was found to be a strict herbivore and a frequent feeder. It fed solely on phytoplankton dominated by benthic forms. Diatoms were the most important food item in respect of both numerical and frequency occurrence methods comprising about 84% of the total number of phytoplankton organisms. The types of phytoplankton that contributed significantly to the diet were, in decreasing order of importance,Pleurosigma, Navicula, Nitzschia, Synedra, ClosteriopsisandOscillatoria. Larger fish had consumed lesser amount of food, and there was usually a gradual decrease in consumption with increase in size. The mudskipper consumed food ranging from 1·3 to 10·5% of its body weigh

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02796.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Using spleen and head kidney imprints, studies on erythropoiesis inChanna punctalushave been made describing each developmental stage with regard to its morphology, morpho‐metry and cytochemistry. This has been undertaken using the new techniques available for haematopoietic studies of fishes. These include autoradiography for information on DNA synthesis and Graham‐Knoll's benzidine method with Giemsa used as a counterstain for the differential staining of haemoglobin. Thus, a more definitive picture of the haematopoietic phenomenon inChanna punctatushas been evol

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02797.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Capture of muskellunge by angling resulted in a reduction of blood pH, elevated lactic acid concentrations, and a drop in total carbon dioxide and bicarbonate concentrations. The acidaemia was most severe immediately after capture and began to decline well before the blood lactate levels rose. Blood lactate levels were not as high as those characterizing fatigue in most other species. Recovery from the acidosis required 12 to 18 h and was accompanied by declines of 22% and 40% in haemoglobin and haematocrit levels respectively. With the exception of dying fish, there were only slight fluctuations in plasma sodium and potassium levels during recovery, indicating that there was no severe ionoregulatory dysfunction.Thirty per cent of all angled muskellunge died. The last stages immediately preceding death were characterized by declining blood pH and elevated potassium levels.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02798.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

In the Fond du Lac River, adult male Arctic grayling defend territories on the spawning ground for up to 7 days. Females do not defend territories and do not exhibit agonistic behaviour during the breeding season.The behaviour patterns exhibited by Arctic grayling during spawning are virtually identical to those exhibited by European grayling. The characteristic large dorsal fin of the grayling is of major importance during the spawning act.Less than 50% of all spawning attempts proceed to completion. Interference by other fish or the improper orientation of one fish may result in one member of the spawning pair moving away. Most often however, incomplete acts are the result of the female moving away for no apparent reason. Females may initially ‘test’ males or may simply not be ready to spawn when approached by males. Homosexual spawning attempts were rarely obser

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02799.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

A method for mass production of triploid carp was developed by the cold treatment of eggs after fertilization. Triploidy was demonstrated by cytophotometry and chromosome preparation techniques. Of the haploid embryos, 100% showed morphological abnormalities and died soon after hatching. Haploid embryos of maternal and paternal origin occurring in the course of cold treatment were distinguished by using a genetic marker. Among morphologically normal larvae, the frequency of triploidy was 100%, and the viability of the triploid embryos, larvae and the juvenile fish did not differ from the diploid control. Sex differentiation started in the triploid fish, but was greatly retarded. Gonad size and the small number of growing oocytes suggest that most of the triploid individuals will be sterile. Triploid carp grew at the same rate as diploid controls in the laboratory test.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02800.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Developing 1+ male Atlantic salmon parr were treated with methallibure and cyproterone acetate. Both these drugs failed to prevent gonad maturation but they did decrease the gonadotrophic cell size and lower plasma androgen levels. These results are discussed in relation to previous studies. It is concluded that gonadotrophic cells control gonadal androgen production, that cyproterone acetate is a central inhibitor of gonadotrophin production and that these two chemical agents could be effective as chemosterilants if administered early in gonad maturation cycle.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02801.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The natural recovery of trout (Salmo truttaL.) populations in an industrial river, the Ebbw Fawr, South Wales, has been depressed by problems of natural recruitment. Rainbow trout (Salmo gairdneriRichardson) eggs were planted in river gravels to assess the effects of siltation on salmonid spawning success. In reaches where siltation due to the coal industry has occurred, 98–100% of eggs died during incubation in the gravels. Experiments using standpipe techniques measured gravel permeabilities and rates of dissolved oxygen (DO) supply to artificially planted eggs, the results showed a strong dependence of hatching success and alevin size on these two parameters. The median lethal DO supply rate was about 50 μg cm‐

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02802.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The relationships between the maximum, daily food consumption, body weight and water temperature for the stickleback,Gasterosteus aculeatus L., and the minnow,Phoxinus phoxinus(L.), were studied. The two species occupy the same lakes in mid‐Wales, but differ in thatG. aculeatushas a true stomach whereasP. phoxinuslacks a true stomach.For both species, the relationship between food consumption (F) and body weight (W) could be described by the model: logeF=a + b logeW. The effect of temperature (T) could be incorporated in the form: logef=a+ b, logeW+b2logeT.These models were selected because they accounted for a high proportion of the variance in the dependent variable, and because an analysis of the residuals obtained after fitting a model showed no trends which would have signalled the inadequacy of the mode

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1980.tb02803.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY