摘要:

Poecilia latipinnawas subjected to varying hydrostatic pressures in the laboratory which demonstrated the following points. The hyperbaric chamber is a suitable apparatus for testing gas gland secretion in this teleostean fish. Oxygen concentration within the swim bladder increased with increasing hydrostatic pressure. Pressures encountered by fishes at various levels of the water column and their effects on oxygen concentration in the swim bladder may be simulated in the laboratory.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03900.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Survival time of brook trout (Salvelinus fontinalisMitchill) at low pH was directly related to size, and inversely related to temperature. Between pH 2.50 and 3.25 an increase in pH by increments of 0.25 each led to a 2–3 fold increase in survival time. At higher pH's (3.25–3.75) elevations in pH by the same increments each produced a 3–5 fold increase. Brook trout tested at pH 3.35 and 3.50 showed maximum survival times in June‐August. Members of seven inbred lines of brook trout were tested for acid tolerance; the lines differed markedly providing strong evidence that acid tolerance is hereditary. Tests involving either intercrossed or backcrossed offspring of tolerant or intolerant parentals demonstrated intermediate survival in 12.5% of all experiments and heterosis in 66.7% of the tests. Differences in survival of inbred lines were the most marked at pH 3.25. Exposure for 1 week at pH 3.75 resulted in a 20–25% decrease in survival time of 18 fish tested at pH 2.50 and 3.00. Out of a total of 24 trout (17 g) tested at pH 3.75 two highly tolerant individuals were still alive after 6.1 weeks. Thus it is likely that a strain resistant to a pH below 4.1, the previously recorded lower limit, can be developed by selective

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03901.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The surface area of two closely related mudfish species have been determined by coating the animals with masking tape. The results indicate thatLabeo capensisspecimens above 95 g body weight have a larger surface area than correspondingL. umbratusanimals. The same is true for the fin surface area above 50 g body weight. Below these weightsL. umbratusspecimens have higher surface areas. The body surface area ofL. capensisis always lower than that ofL. umbratusin the range studied.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03902.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Ulcerations of the skin associated with haemorrhagic petechiae of liver and kidneys, were the main signs of disease affecting salmon and brown trout in Norway. A death rate of 15–20% was estimated for the 5 month period of mid‐March‐August, although mortalities occurred throughout the year. Bacteriological examinations, involving 36 isolates, suggested the causual organism to be aPasteurellaalthough the DNA homology examination gave a G.C. ratio of 55.6 % which is high forPasteurellaas a

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03903.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

A qualitative comparison of species compositions, relative abundances, diversity and growth was made between tidal pool fishes collected in Port Renfrew, British Columbia and Bruels Point, California. The two most preponderant cottid speciesOligocottus maculosusandClinocottus globicepswere aged using vertebrae, from which back calculated growth values were obtained. Species from Port Renfrew were found to have a higher diversity index, greater species composition and abundance. No growth differences were found between the two localities despite the 1120 km (700 miles) separating then.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03904.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Sera from approximately 10 000 Atlantic salmon collected from rivers in the British Isles have been analysed. Polymorphism at the transferrin locus was observed and the distribution of the transferrin alleles provides further evidence supporting the presence of two races of salmon first postulated by Payneet al.(1971a).

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03905.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

This is a study of the reproductive biology and morphology of the pituitary gland of the osteoglossid fishScleropages formosus(Müller&Schlegel). The fish spawn in the Tasek Bera waterways of Pahang, Malaysia during the rainy season beginning in August. Young fish are incubated in the mouth of the male parent until free‐swimming. Males mature in their 2+ year, when 30–45 cm in length. In mature specimens the testis is small, and little sperm is produced. Some females mature in their 2+ year, although at that time, most have only reached the stage of secondary oocyte production. The chorion and follicular granulosa of secondary oocytes are deeply invaginated into the cytoplasm. All fish spawn in their 3+ year, when 45–60 cm in length. The single ripe ovary contains 20–30 ova, each 1.9 cm in diameter. No fish of 4+ years were caught, which may be the result of mortality or emigration, or due to extraneous causes such as selectivity in the fishing techniques used.The pituitary gland accords with the generalized teleost pattern and embryonic development. There is no saccus vasculosus. Adrenocorticotropic cells predominate in the proadenohypophysis, and somatotropic and luteotropic cells occur here. The mesoadenohypophysis contains gonadotropic and somatotropic cells; the former grow large in ripe specimens, so that the mesoadenohypophysis becomes much enlarged. The metaadenohypophysis contains relatively few cells, much neurohypophyseal ramification, and is deeply penetrated by the third ventricle of t

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03906.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The experiments dealt primarily with routine metabolic rates of schooling juvenile Atlantic menhaden,Brevoortia tyrannus(Latrobe), in flowing‐water respirometers and were designed to obtain baseline data for energy flow models and studies on the effects of sublethal stresses. The relationship of body weight to oxygen consumption as well as the effect of temperature (10–25°C), salinity (low, 5–10 p.p.t. and high,>28 p.p.t.), time since last fed and darkness on the routine metabolic rate was examined. The effect of salinity on growth of menhaden larvae into juveniles was also me

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03907.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The lympho‐reticular tissues in the plaice were investigated for their phagocytic properties on colloidal carbon after its intraperitoneal injection. Fish were killed at intervals ranging from 10 min to 25 days after injection. Although peritoneal macrophages constituted a large population of phagocytic cells, most of the carbon apparently gained access to the circulation as free particles and phagocytosis was performed predominantly by the ellipsoids of the spleen, the network of reticulo‐endothelial (RE) cells throughout the haemopoietic tissue of the kidney, and by the RE cells occupying intermuscular spaces in the atrium of the heart. The cardiac macrophages rapidly emigrated from the organ while the carbon containing macrophages in the kidney and spleen formed aggregates in the lymphoid areas, either within or outwith pre‐existing aggregates of melano‐macrophages.The possible significance of phagocyte aggregations, including melano‐macrophages, in association with lymphoid elements in the kidney and spleen is discussed in the context of immune m

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03908.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The effects of starvation and force‐feeding on certain tissue and blood constituents were studied in the Northern pike,Esox luciusL. Starvation resulted in a reduction of liver and muscle glycogen and liver lipid. Blood glucose concentration and haematocrit were reduced, total plasma cholesterol levels were increased, while the levels of plasma free fatty acids (FFA), amio acid nitrogen and protein remained unaltered. No significant changes were observed in either muscle protein, muscle water or the response to amino acid loading during the starvation period.The force‐feeding of pike starved for 3 months resulted in liver lipid and muscle glycogen being increased to levels higher than those observed in freshly‐captured fish. Liver glycogen, however, increased to values only slightly higher than those of starved animals. Furthermore, while force‐feeding had little effect on plasma FFA or protein concentrations, blood glucose, plasma cholesterol and haematocrit returned to the levels found in freshlycaptured fish and those of amino acid nitrogen were higher.The results indicate that pike are well adapted for periods of prolonged starvation and that hepatic and extra‐hepatic lipid and glycogen stores serve for metabolic needs during food shortage, while body protein is conserved. The endocrine basis for these changes in the tissue and blood constituents is

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1976.tb03909.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY