摘要:

Mebendazole, trichlorfon, and a combination of these two drugs were evaluated for anthelmintic properties against the external monogenetic trematodes of fish,Gyrodactylus elegansandDactylogyrus vastator. Mebendazole effectively removedG. elegansafter a 24‐h. exposure to 0·01 mg l‐1, but it had no effect onD. vastatorup to 2·0 mg l‐1. Trichlorfon was 95% effective onD. vastatorbetween 0·4 and 1·6 mg l‐1after a 24‐h exposure, but it had no effect onG. elegansup to 2·0 mg l‐1. A combination of mebendazole at 0·4 mg l‐1and trichlorfon at 1·8mgl‐1was 100% effective on both parasites. Trichlorfon appeared to inhibit the action of mebendazole onG. elegans, but mebendazole had no apparent inhibition on the action of trichlorfon toD. vastator. The minimum effective exposure time was 24 h and shorter exposure times, even at high dose levels, were not effective. The combination had no apparent toxic effect on fish, except possibly catfish, and field tests in various geographical areas of the United States showed that the combination was

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03931.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The histochemical pattern of red, pink and white muscle of fish living in fresh, brackish, and salt water is reported. The muscle fibres were stained routinely during the year for lactate dehydrogenase (LDH), menadione α‐glycerophosphate dehydrogenase (Mα—GPDH), succinic dehydrogenase (SDH), myosin adenosine triphosphatase (myosin ATPase), phosphorylase, lipids and glycogen. The pink and red muscles contain more glycogen and lipids and have a higher SDH activity, which is in accord with their aerobic metabolism and function in sustained swimming activity. The acid labile myosin ATPase activity characteristic of fast twitch fibres is present in the white fibres of most species, however in the white muscle ofGobius paganellusthe enzyme activity is stable to both acid and alkali and, in addition, there is a scattered distribution of different fibre types in red and, especially, pink muscle. A study of seasonal variation patterns of myosin ATPase in white muscle of mugilidae over a period of two years has demonstrated, in late summer, the appearance of new small diameter fibres, with a high acid stable enzyme activity, that develop into the large diameter acid labile f

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03932.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Histological observations were made on the changes occurring in the haddock ovary during maturation. The influence of varying food rations on the numbers of eggs released was considered. Oocyte development was found to be a continuous asynchronous process until the beginning of spawing, i.e. stage V when vitellogenesis became synchronized and there was no further initiation of new development. It is suggested that the upper limit of potential fecundity was determined before stage II, however the actual numbers of eggs spawned could still be reduced during later stages in response to a poor food supply.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03933.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The effect of ration on the growth of the three‐spined stickleback,Gasterosteus aculeatus, was studied over the temperature range 3·19°C, which corresponded to the range in their natural habitat. With anad libration, the specific growth rate increased with temperature. The relationship between specific growth rate and ration at a given temperature was curvilinear. Regression models were used to predict the maximum, optimum and maintenance rations at each temperature. Whereas maximum ration increased rapidly with temperature, the optimum and maintenance rations were relatively insensitive to temperature. A regression model was used to describe the overall relationship between specific growth rate and ration, temperature and body weight. This model predicted that at low rations, growth rate decreased with temperature, whereas at high rations, growth rate increased slightly with temperature. The gross growth efficiency increased rapidly with rations above maintenance ration up to a maximum at the optimum ration and declined at higher rations. The maximum gross growth efficiencies were at high temperatures and rations about half of the maximum ration. The maximum net growth efficiencies occurred at relatively low temperature and at rations just above maintena

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03934.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Trout were sampled in six afferent streams of Windermere during the spawning season. The main migration of adult trout into the streams took place during early November. Length‐weight relationships and scale‐fish length relationships are given. There was no significant difference in length for age or sex between cohorts within streams. Three groups of fish could be identified depending on whether the fish entered the lake at 1+, 2+, or 3+ years. The percentage number of the population entering the lake at each of these ages was 16, 70 and 14%, respectively. After the fish had migrated from the streams their growth in length fitted the von Bertalanffy growth model. Fish entering the lake at 1+ and 2+ years had similarA.95values (6·31 and 6·97 years) as the latter grew slightly faster in the lake. Those entering the lake at 3+ years grew at a slower rate to the other two groups but achieved a longer ultimate length. Faster growing fish had higher instantaneous mortality rates. Twenty‐eight to 29% of the males remaining in the stream at 1+ years became sexually mature. Faster growing females became sexually mature earlier. Only those fish which entered the lake at 1+ years grew close, during their early years before sexual maturity, to the theoretical maximum given by Elliott'

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03935.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The segregation of plaice,Pleuronectes platessa, into groups of uniform size can be used to reduce the formation of size hierarchies, even under conditions of limited food supply. When access to food was limited the fish responded by becoming hyperphagic. This resulted in an increase in growth rate following an initial growth check. However, even after hyperphagic adaptation, intermittently fed fish grew at slower rates than those allowed more frequent access to food. Hyperphagia was accompanied by an increase in relative stomach weight and gastric capacity but did not affect fat storage and proximate chemical composition.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03936.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The enzyme activity per unit liver wet weight, the specific activity and the total liver activity level of glutamate dehydrogenase (GDH) and two transaminases (GOT and GPT) were studied during vitellogenesis and pregnancy. A steady level of activity was observed during the short summer vitellogenesis and during early pregnancy. During mid‐term pregnancy in October the activity level significantly increased.Administration of 5 and 100 μg oestradiol increased serum vitellogenin, total liver protein and the liver somatic index during late pregnancy. Oestradiol decreased activity and specific activity of the enzymes. However, expressing activity as total hepatic enzyme activity units in fish of standard body weight oestradiol had no effe

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03937.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A single intraperitoneal injection of any one of several polycyclic aromatic hydrocarbons given to young Amazon mollies induces massive enlargement of the spleen. This enlargement is the result of splenic tissue being partially or wholly replaced by proliferating thyroid tissue. The pharyngeal thyroid gland is stimulated but to a lesser degree. No exuberant thyroid tissue is found at any other extrapharyngeal site. We discuss the possible causes of this finding.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03938.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The nutrient level of Lake Kariba is governed by the Zambezi river which provides about 70% of its water supply. Other tributaries are richer in nutrients and have an appreciable local effect. This is shown by the catches ofLimnothrissa miodonwhich increase after strong flows in the Sanyati river. This is in contrast to natural lakes such as Lake Tanganyika and may be an important management factor in Lake Kariba and other man‐made lakes. Possible periods of poor rainfall could thus reduce theLimnothrissayield in Lake Karib

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03939.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The activity of myofibrillar ATPase declined with length in the five species examined (Merlanogrummus aeglefinisL.,Merrluccius merlucciusL.,Physis blennoidesBrunnich,Pleuronectes platessaL. andMerlangius merlangusL.). This decline was related to a decrease in thein vitromuscle contraction rate and appeared to be a scale rather than an age effect. Actomyosin was extracted fromMerlangius merlangusL. to investigate the length related changes in the myofibrillar protein.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1982.tb03940.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY