摘要:

The swimbladder in the sand goby,Pomatoschistus minutus, collected in shallow waters of the Oslofjord, Norway, was studied. As the literature on swimbladders in gobies appeared to be confusing, a short review of relevant literature has been made. On average, the volume of the swimbladder in the sand goby expressed as percentage of the body weight was found to be 4·7 % in May and 2·5 % in June. The significance of this volume variation is discusse

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03513.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The gastric emptying time (G.E.T.) in turbot was investigated using X‐radiography and was found to decrease with temperature. Small fish processed a given ration, expressed as percent body weight, faster than large fish (G.E.T. was found to be proportional to (fish weight)0.364). Large meals in a given fish were processed at a faster rate than small meals. Gastric emptying rate (G.E.R.) was found to be proportional to (meal size g)0.613at 8° C and (meal size g)0.788at 19° C. These exponents are in agreement with a recently proposed model relating G.E.T. and G.E.R. to meal size (Fänge&Grove, 1978). Large fish emptied a meal of given absolute size from the stomach at a faster rate (g h−1) than small fish. Experimental meals diluted with kaolin were evacuated in significantly less time than a control diet, suggesting that turbot may adjust feeding rates when food quality

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03514.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The distribution, social behaviour, and feeding behaviour of juvenile Atlantic salmon were studied in a selection of stream and river habitats in northern Scotland using Scuba diving techniques. The results are discussed with respect to food acquisition and choice of feeding site. It is concluded that juvenile salmon feed predominantly on drifting material and that their daytime distribution reflects the current velocity related abundance of drift.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03515.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Immunoglobulin production in the primary and secondary immune response of brown trout to keyhole limpet haemocyanin has been investigated including the effect of dose size, route and number of injections, and the use of adjuvant. Antibody activity was found in the first fraction from Sephadex G200 and in the second from Sepharose 6B. Trout immunoglobulin had β2—Γ1electrophoretic mobility, and Sappof 16·7 and an approximate molecular weight of 670 000 daltons. It was sensitive to dithiothreitol and stable at 56°C for 30 min. Immunoglobulin concentrations were measured by single radial immunodiffusion with a specific rabbit antiserum. Sera from non‐injected trout had a mean immunoglobulin level of 7·3 ± 0·3 mg ml−1which accounted for 10% of the total serum protein. Phosphate buffered saline‐injected controls contained 6·7 ± 0·2. In fish given a single injection the mean concentration ranged from 7·5 to 12·9 and in those given more than one injection from 12·6 to 16·8. The use of adjuvant resulted in higher immunoglobulin concentrations. Neither dose nor route had any significant effect on the primary response. However, in the secondary response the intramuscular route resulted in significantly increased immu

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03516.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The structure of the oval in saithe is described with particular reference to its vascularisa‐tion. The extent of the capillary plexus was found to be greater than previously estimated, covering about 40% of the internal surface area of the bladder. Morphometric assessment of the capillary network enabled estimation of flow rate using the Poiseuille equation. The low potential flow suggested in this work may be a limiting factor in gas loss from the swimbladder and may place restraints on vertical migratio

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03517.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

In the management of saimonid populations it is often necessary to distinguish hatchery‐reared from wild stocks. This study examines the feasability of marking fish tissue by substituting a biologically rare element, strontium, for calcium.Sixteen‐month‐old hatchery‐reared coho salmon (Oncorhynchus kisutch, Walbaum 1792) were fed a diet, to which 10000 ppm stable strontium was added, for 60 days. Prior to their seaward migration in June 1976, the treated coho contained 32 times as much strontium in their vertebrae as did the control coho.Sixty‐eight precocious males‘jacks’ returned to the hatchery in the fall of 1976 and 1200 adults in the fall of 1977. Strontium‐treated ‘jacks’ contained 1·4 times as much strontium as did control ‘jacks’ however, treated and untreated fish could not be distinguished as adults. The reduction in the strontium concentration of the treated fish could be

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03518.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Light and electron microscopic studies of the morphological features of immature and mature rodlet cells inCatostomus commersoniare presented emphasizing the cells' association with epithelial tissues. The peripheral fibrillar layer is lacking from the apex and from the base of the cell. A cytoplasmic extension from the base may be a feeding mechanism whereby the rodlet cell obtains nutrient at the expense of adjacent cells leaving intercellular spaces often containing myelin figures. RNAase digestion studies demonstrate the presence of RNA in the electron dense rodlet core.The structure and histochemistry of the rodlets which do not appear to disintegrate upon expulsion from the cell are compared to the cytoplasmic inclusions of both normal fish cells and protozoan parasites. The possible association of the rodlet cell with various pathological conditions is briefly reviewed and the authors conclude that it is premature to disregard the possibility that this cell could be a parasite or infective agent.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03519.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

An account is given of damage to the gills of trout which involved reduction in total filament length and consequently reduced respiratory surface area. It was noted that fish with the greatest gill damage tended to ventilate the gills by active swimming (ram ventilation) to a greater extent than those with more normal gills.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03520.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The abilities of threadfin shad (Dorosoma petenense) in using chemosenses to detect the scents of conspecifics, a predator and food were tested in the laboratory. Shad did not respond to the scents of conspecifics or a predator; possibly because both shad and their predators out‐swim such cues as chemical scents that are transmitted slowly through the water. Shad showed a strong attraction to the scents of food. In feeding, chemosenses may be used for filter feeding on microscopic food and for locating food beyond the range of visio

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03521.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Rainbow trout (Salmo gairdneri) were infected with an inoculum of infected blood containing 106Cryptobia salmositica.Parasitaemia was cyclical with a major peak at 14–21 days and a smaller peak at 42 days. The first peak of parasitaemia was correlated with low glucose, plasma proteins, and haematocrit levels. During this time clinical symptoms (exophthalmia, ascites, pale liver and gills) of the pathogenic condition were observed. The partial disappearance of the parasites from the blood was corrrelated with their appearance in the peritoneal cavity. As plasma glucose, proteins, and haematocrit levels returned towards control values, the oedema and gill paleness declined. Examination of the liver and spleen showed an exudate of fibrous matrix on their exterior surfaces. In addition, the presence of 2–4×103mm−3Cryptobiain asymptomatic surviving fish suggests that a chronic parasitaemia can be tol

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03522.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY