摘要:

Studies were conducted on the effect of human chorionic gonadotropin (HCG), testosterone and desoxycorticosterone acetate (DOCA) on the histological picture of the nucleus preopticus (NPO), hypophysis and gonads of male European eels. It was ascertained that none of the injections used changed the content of the Gomori‐positive material within the NPO cells. HCG and testosterone injections altered the histological picture of the hypophysis and injections of HCG influenced the gonads by accelerating their maturity. The injections of DOCA did not change the histological picture of the hypophysis and gonads in male eel

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04143.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The size distribution and numbers of oocytes were examined in samples of ovaries from two sites and in fish in tanks whose past spawning activities were known. In an upland stream in northern EnglandCottus gobiowould seem to be an annual spawner, maturing a single batch of eggs each year. In a more productive stream in southern England, where the reproductive life is short, fish mature and lay a succession of batches of eggs during a long spawning season. The physiological and ecological implications of these characteristics are discussed.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04144.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Furunculosis was induced in brook trout,Salvelinus fontinalis, by experimental inoculation withAeromonas salmonidda.The levels of blood enzymes were determined and the most significant modifications were observed for aldolase, creatine phosphokinase and ornithine carbamyl transferase. Alkaline phosphatase, glutamic‐pyruvic transaminase and glutamic‐oxalacetic transaminase showed minor modification. There was no significant change of activity for acid phosphatase, cholinesterase, lactic dehydrogenase, phosphohexose iso‐merase, isocitric dehydrogenase and aminopept

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04145.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A quantitative description of the effects of sublethal concentrations of cadmium, chromium and zinc on the swimming activities of the bluegill is presented. Locomotor activities of fish in 0.1 and 0.25 mg 1−1cadmium are respectively 1.5 and 7.8 times the activities of control fish. Fish in 0.5 mg 1−1cadmium, a concentration killing 30% in two weeks, were less active than controls. Fish in 0.05, 2.4 and 24.0 mg 1−1chromium were respectively 1.2, 3.6 and 6.5 times as active as controls. Fish in 0.1 and 5.0 mg 1−1zinc were respectively 1.3 and 3.8 times as active as controls. Thus metals effect hyperactive locomotor responses by the bluegill in a concentration‐dependent rel

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04146.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The occurrence of larvalAnisakisin North Sea herring was examined during the period 1965‐1972 using a sampling method which yielded comparable data for all eight years. Data on abundance of infestation in several herring stocks pointed to remarkable fluctuations over the study period with an increase in the period 1966‐1968 followed by a decrease in the period 1968‐1972. Of various hypotheses that may explain this situation, it is concluded that changes in the migration behaviour of the herring may be responsible. Other data and statistics are discussed with special reference to variations in infestation level in different samples and to the occurrence of adult nematodes in marine ma

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04147.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Preparations of peripheral blood of 58 species of fish, mostly teleosts, were examined for the presence of granulocytes. Heterophils are commonly found but eosinophils are rare and metachromatic basophils never seen. Granulocytes (PAS‐GL) with periodic acid‐Schiff positive granules, were observed in 30 species representing marine and freshwater, and ‘primitive’ and ‘advanced’ types. It is postulated that the PAS‐GL is the piscine forerunner to the heparin and histamine‐containing metachromatic basophil/mast cell of hig

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04148.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The lactate dehydrogenase isoenzyme patterns have been studied in the axial muscles of the sharksEtmopterusandGaleus.Samples from red, intermediate and white muscle fibres were run separately on a polyacrylamide slab‐gel. Both sharks have three isoenzymes; all three are present in the red and intermediate fibres, while the white fibres contain only the two slowest‐moving isoenzymes. The red fibres of both sharks contain most of the fastest‐moving isoenzyme.The isoenzymes have a high tolerance towards urea; the slow moving isoenzyme is inhibited at about 2murea, the next isoenzyme at 4‐6 M urea, and some activity of the fast‐moving isoenzyme is still present at 10 M urea in the incubation medium. The LDH distribution in the fibre types is studied by histochemistry on frozen

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04149.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Laboratory brook trout were used to evaluate, refine, or develop biochemical procedures for the analysis of fish blood. Analytical values were obtained for the following blood properties: total and differential leucocytes and erythrocytes; erythrocyte and plasma proteins (by electrophoresis); plasma refractive index; erythrocyte sedimentation rate; erythrocyte osmotic fragility; blood surface tension and density; haemoglobin; and packed cell volume. These blood factors are discussed with reference to fish health and disease and to changes caused by deleterious quantities of water pollutants.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04150.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Terapon jarbua, a marine teleost attaining a length of 25 cm, is abundant in the estuaries of the tropical and subtropical Indian Ocean. Fish scales removed from living fish are the most important food and represent the utilization of a niche previously unrecorded in the marine environment. Laboratory experiments show thatT. jarbuacan digest fish scales which have a relatively high energy content of 2cal mg−1and further that the scales are removed only from living fish and not collected off the bottom or from dead fish. The scales are taken under natural conditions from fish larger thanT. jarbuaand slow swimming species are favoured.T. jarbuaalways attacks the lateral surface of the prey species and scales are removed mainly from the posterior region of the body, particularly around the caudal peduncle. A variety of species are attacked. The black longitudinal stripes ofT. jarbuafade during feeding but in the presence of conspecifics darken. This colour pattern, which is unique among south east African estuarine fish, together with the small size ofT. jarbuascales, may prevent autopredation. It is suggested that the scale‐eating habit ofT. jarbuaarose as a modified form of predation or as an extension of ‘cleaning’ ectoparasites from the scales of larger fish. Ectoparasites are relatively common in the diet ofT.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04151.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A study has been made of the effects of salinity, starvation and salinity‐starvation interactions on the structure of the alimentary canal of immature rainbow troutSalmo gairdneriRichardson. Intestinal and rectal cross‐sectional areas and the height of the intestinal villi increased with salinity. The thickness of none of the tissue layers measured in the intestine and rectum, including the columnar epithelium and the tunica propria, was influenced by salinity. There was a significant negative correlation between salinity and mucous cell distribution density in both the intestine and rectum. In trout acclimatised to salinities of 15.0 p.p.t. (parts per thousand) and above, there was a high incidence of deep depressions in the columnar epithelium. The oesophagus and stomach were not visibly affected by salinity.There was a marked decrease in intestinal and rectal cross‐sectional area and height of intestinal villi with starvation except in 32.5 p.p.t. sea water. Mean intestine epithelial cell height decreased with starvation at 32.5 p.p.t. A 48 day period of starvation had little effect on the posterior oesophagus and the cardiac st

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04152.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY