摘要:

An increasing incidence of fish mycobacteriosis was detected in Chinook salmon held in fresh water at the Snobs Creek Hatchery. ThisMycobacteriumsp. infection has been passed on to the Fl generation possibly through an ovarian pathway, either by the egg or more likely through infected ovarian fluid. There is no evidence that the diet was the source of infection.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04085.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Techniques for the quantitative and qualitative analysis of the commensal bacterial flora of fish are reviewed. The literature concerning the commensal bacterial flora of fish indicates that teleost skin often features 102–07organisms per cm2of skin, representing the following taxa, in descending numerical order,Achromobacter, Pseudomonas, Flavo‐bacteriumandCytophagaspecies also coryneform organisms. Actively feeding teleosts appear to have an alimentary canal bacterial flora similar to that of the skin and gills, often there are from 103–108organisms per 1.0 g, wet weight, of tissue. According to the limited data available for elasmobranchs Gram–positive bacteria are the predominant component of the bacterial flora on the skin of sharks, though the bacterial flora of North Sea skate (Rajaspp.) is reported as being similar to that of teleosts. The commensal flora of fish, particularly of teleosts, is related to their environment and is influenced by environmental changes that affect the quality of the water. Regular monitoring of the water of commercial fish ponds and aquaria for bacterial quality, temperature, dissolved oxygen concentration and pH, combined with a base–line knowledge of the water's quality, may provide an advanced indication of the presence of bacteria potentially able to produce diseased conditions, and factors that will enhance the

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04086.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Studies on inducing sexual maturity in European eel males have been made. The fish were kept in fresh or artificial sea water at a temperature of 20°C, and hormonal injections were given. Among the hormones used, the positive results were obtained with human chorionic gonadotropin. All the male eel injected with this hormone produced sperm containing living spermatozoa. The quality of sperm of the males kept in fresh water was poorer in comparison with the sperm of the males kept in the artificial sea water

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04087.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A sexual dimorphism was found in the epidermis of hatchery‐reared brown trout. The epidermis of both male and female fish undergoes rhythmical changes in thickness during successive spawning cycles. For most of the year the male has a significantly thicker epidermis than the female. During the spawning period (December and January) there is a highly significant drop in the concentration of mucous cells in the epidermis of the male brown trout. These findings are discussed in the light of our knowledge of the skin structure in other salmonid fish and in relation to possible hormonal factors influencing the epidermis of teleost

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04088.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Haemoglobin concentrations, haematocrit values, red blood cell counts, red blood cell diameter, erythrocyte sedimentation rate and plasma haemoglobin concentration were measured on the air‐breathing mud eelAmphipnous cuchi

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04089.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

In acute toxicity tests based on the loss of positive rheotaxis, the relationship between exposure time and bis (tri‐n‐butyltin) oxide concentration was determined forSalmo gairdneriandTilapia rendalli. This relationship may be represented by two superimposed rectangular hyperbolas(X‐d) (Y‐b)=ccorresponding to two poisoning mechanisms. The 24‐h EC50is 30.8 μg/1 for trout and 53.2 μg/1 forT. rendalli. A histopathological study onS. gairdnerishows concentrations from 5.85 to 0.0117 mg TBTO/1 resulted in damage to the gill epithelium. At low concentrations a degeneration of the cornea and damage to the epithelial cells of bile ducts were also observed. Prior to a loss of positive rheotaxis and with concentrations from 0.023 to 1.17mg/l, the packed cell volume, the haemoglobin concentration and erythrocyte count increased. Determination of the mean cell volume showed swelling took place at 1.17 mg/1 but shrinkage was observed at 0.053 mg/1. These results indicate that TBTO interfered with the process of respiration. A ‘safe level’ (0.1 μg/1) is proposed for schisto

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04090.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The whiting (Merlangius merlangus) is an important commercial species from the West Coast of Scotland. This paper describes the distribution, abundance, age composition and growth of juvenile whiting which are found in the inshore areas and sea lochs. No spawning was observed in the areas and it is assumed there was an active migration of whiting from the open sea. They were first caught by the bottom trawl in July, reached maximum abundance in November and December and thereafter declined in numbers until few remain by early summer. An exception to this occurs in Loch Etive and possible explanations for the fact that whiting tend to remain for longer periods and grow at a slower rate in this loch are discussed.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04091.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Books Reviewed in this Article:THE DERMATOLOGY OF FISHES–A BIBLIOGRAPHY by John M. Hatton, Ronald J. Roberts and Alistair M. Bullock.AN ILLUSTRATED KEY TO FRESHWATER AND SOIL AMOEBAE by F. C. Page.SOUND RECEPTION IN FISHES Edited by William N. Tavolga.THE HEALTH OF THE OCEANS by Edward D. Goldberg.FISHES OF THE WORLD by Joseph S. Nelson.THE EGGS AND PLANKTONIC STAGES OF BRITISH MARINE FISHES by F. S. Russell.DISEASES OF MARINE AQUARIUM FISHES, Edited by Mark P. Dulin.A FIELD GUIDE TO THE MEDITERRANEAN SEA SHORE, by W. Luther and K. Fiedle

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04092.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY