摘要:

A comparative study of the signs of lindane poisoning and of hypoxia in trout,Salmo truttaL., showed that the symptoms of both causes of death are similar. The rapid fading of gill colour within 2 h of death is characteristic of both treatments and distinguishes these from other causes of death. Vascular congestion and cellular damage of the liver is common to both treatments. The causes of death may be distinguished by the behaviour of the fish before death and by study of their effects on the gills. Hypoxic fish showed increased ventilatory activity, but other activity decreased. Exposure to lethal levels of lindane caused hyperactivity, convulsions, ataxia and intermittent paralysis. Although gill damage in both cases was slight it was distinctive. Lindane caused disarray of the secondary lamellae, and exposure to low dissolved oxygen levels caused breaks in the lamellar epithelium. This was only clearly visible under electron microscopical examination.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02918.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

This study examines the histological significance of a testicular anomaly among hatcheryraised lake trout,Salvelinus namaycush, introduced into Lake Ontario as yearlings and subsequently recaptured at ages ranging from 4 to 7 years. The anomaly has been termed a constriction. Histological examination revealed that lake trout with constricted testes demonstrated delayed cycles of spermatogenesis throughout the testes at spawning time compared with normal testes. Constrictions were formed when spermatogonia within an adjacent group of lobules failed to undergo mitosis, hypertrophied and were subsequently resorbed. The walls of these lobules subsequently collapsed and were resorbed and replaced by dense fibrous connective tissue. The significance of these observations in relation to hormonal mechanisms and its potential effect upon reproduction in these fish is discussed.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02919.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Digestibility values were determined for diets of varying protein content fed to Arctic charr. The use of these values, in conjunction with food intake data made possible the study of the effects of various parameters on the control of food consumption. Dietary energy content may be more important than protein content in regulating consumption. The regulation of food intake may be partially mediated through factors influencing gastric emptying coupled with mechanisms monitoring dietary metabolizable energy.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02920.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Since the development of mid‐water trawls in the mid‐1960s, the lumpsucker,Cyclopterus lumpus, has been found to occur frequently in mid‐water. Records from cruises of English research vessels show that lumpsuckers occur pelagically from the southern North Sea to about 80°N off Spitsbergen, usually in the upper 50–60 m, and often over abyssal depths of the Norwegian Sea and the north‐eas

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02921.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Free‐living nematodes—Panagrellussp.,Turbatrix aceti, Caenorhabditis elegansandC. briggsae—wereeach fed to the fishDaniosp. and the process of their digestion, in the fish alimentary canal, was studied by light and electron microscope.Almost no identifiable nematodes were found in the fish gut when the digestion period was 3 h or more, except for buccal capsules of the four studied species, males' spicules ofPanagrellussp. andTurbatrix acetiand egg‐capsules of theCaenorhabditisspecies. These structures could serve as indicators that the nematodes had been preyed on and digested by the fish.Differences in the mode of digestion were noticed between the various species of nematodes studied, after a period of 0·5–1 h, in the fish gut. InPanagrellussp. andT. acetidisintegration of the soft inner tissues occurred mostly at the anterior or posterior ends of the nematode's body, while inCaenorhabditisthe majority of digested nematodes were affected at both ends or evenly along the entire body. Digestion seemed to be initiated mostly at the nematodes' body apertures: mouth, anus or cloaca, and vulva which could be due to a more vulnerable cuticle around those areas. Disintegration proceeded from the soft inner parts to the more resistant cuticle that was finally disintegrated. Of the three layers of cuticle the most resistant were the external cortex and the ba

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02922.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A new species of liparidid,Paraliparis hystrix, is described from the slope waters (255–1140 m) to the west of Britain, in the area 49–59°N and 07–18°W. This pallid species is not uncommon, and is represented by a strong imbalance of females. Specimens close to ovulation have been collected in all seasons and have an estimated mean fecundity of

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02923.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Pathological and histopathological changes induced by infection ofChilodonella hexasticha(Kiernik) in wild and cultured cichlid fishes from Israel and South Africa are described. Heavy infection resulted in emaciation and mass mortalities. Infection in the gills caused severe degeneration, necrosis and consequent degradation of the branchial epithelium and occlusion of the capillaries. Infection also induced massive proliferation of chloride and mucus cells and also caused hyperplasia of the lining filamental epithelium. However, epithelial hyperplasia was counteracted by the extreme process of degradation of the epithelial layer and as a result was either limited in extent or occurred in an uneven pattern.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02924.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The kidneys of similar sized rainbow trout from freshwater and seawater environments were examined and several parameters of renal corpuscular morphology were measured, The glomeruli of the seawater trout were significantly smaller and contained significantly fewer red blood cells than those of the freshwater fish. There was also some evidence of a decreased number of renal corpuscles per unit area, and an increased proportion with no apparent capsular space in the seawater trout.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02925.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

There are two types of haemolytic activity against heterologous red blood cells in the sera of fishes including salmonids: a specific antibody‐dependent complement‐mediate activity ‘CH50’ and a natural, non‐specific activity ‘SH50’. Sera of coho salmon,Oncorhynchus kisutch, masu salmon,O. masou, rainbow trout and steelhead trout,Salmo gairdneri, were assayed for CH50and SH50activities by incubation at 30°C for 60 min with goldfish red blood cells (GFRBC) sensitized with the rainbow trout antiGFRBC serum and unsensitized GFRBC for CH50and SH50, respectively. SH50activity was usually half that of CH50in each serum. In healthy individuals, both CH50and SH50activities were confined to a narrow range specific for each species. While EDTA abolished both haemolytic activities, moieties of the activities remained in the presence of EGTA. Incubation with lipopolysaccharide and zymosan reduced both CH50and SH50activities. Fish serum possessed a natural, powerful bactericidal action, which forAeromonas salmonicidawas proportional to the level of SH50activity. Changes in the SH50activity were related to starvation and infectious diseases. The SH50activity decreased as the diseases (furunculosis and vibrios

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02926.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Salmon embryos, age 48–81 days post‐fertilization (dpf), were incubated under three different temperature and photoperiod regimes to test the effects of incubation conditions on otolith ring deposition. Otolith rings were first observed at 50 dpf and certain developmental events were marked by distinct, heavy rings. The rate of ring deposition increased with increasing temperature and exposure to light, ranging from 0·50 to 2·33 rings per day. The possible relation to physiological activity as measured by oxygen consumption is disc

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02927.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY