摘要:

Three different fractions of fish pituitary extract obtained by molecular sieving of the whole pituitary extracts on Sephadex G‐100 (Sinha, 1969a) have been tested for effectiveness in inducing spawning of members of the carp family. Fish differing in their spawning habits were chosen‐bighead carp and silver carp do not spawn at all in captivity, whereas Puntius and common carp spawn freely. Gravid fish injected with the second fraction alone showed courtship behaviour and ovulated viable eggs. None of the fish injected with the first fraction or the third fraction showed any courtship behaviour nor did they ovulate. The second fraction from the pituitary extract of free spawner or non‐spawner, immature or mature, male or female was found effective in inducing spawning in both the free spawner and non‐spawner gravid females. Clearly this suggested that this fraction contains either an active gonadotropin or a gonadotropin releasing factor. However, unlike the free spawner, these non‐spawners do not breed in captivity unless injected with an additional amount of the second fraction or the whole pituitary material. The cause of this is still difficult to explain. Synthetic mammalian hormones such as FSH, LH, mixed mammalian anterior pituitary and chorionic hormone, ACTH and posterior pituitary hormones have failed to induce courtship behaviour and ovulation. Oxytocic activity of the fractions showed that there was no correlation between spawning activity and the rat uterus activity. Also these fractions did not contain any appreciable amount of arginine vasotocin. Thus it is suggested that isotocin/arginine vasotocin is not the principle responsible for spawning in t

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03682.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

D(+)‐Glucose penetration in trout erythrocytes was studied with osmotic and tracer methods.Results give no evidence for a carrier mediated diffusion system like that concerned with glucose permeability as in human red cells. The data show that glucose fails to stimulate erythrocyte respiratio

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03683.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The estuarine gobyGillichthys mirabilisbehaviorally thermoregulates when placed in a laboratory temperature gradient. Avoidance of temperatures above 23°C is the most evident component of this thermotaxis. Temperature preferences of non‐acclimated fish do not vary significantly as a function of season; nor does temperature acclimation alter the preferendum. Varying the temperature range of the gradient apparently modifies thermotaxis. Negative phototaxis evidenced by this species is subjugated by thermal preferences. Temperature preference does not vary diurnally. The heat resistance of this species was determined; there is no apparent relationship between heat resistance and temperature preferen

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03684.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The seasonal variations in the diet of adult gwyniadCoregonus clupeoides pennantii=C. lavaretusfrom Llyn Tegid, North Wales were studied. Stomachs were examined to determine fullness, volume and identity of contents.A clear seasonal cycle in food intake was found. Feeding rates were low from January to April but increased during the summer (May‐June) and remained at a high level until December. The period of low feeding intensity coincided with the time of spawning and the time of annulus formation of both scales and otoliths. The diet showed seasonal changes and two main periods were distinguished : December to July, when the fish fed mainly on bottom fauna, and August to November, when the diet included both bottom fauna and midwater and surface foods.The gwyniad were shown to be opportunistic in feeding, the composition of the diet reflecting availability of food items rather than selective feeding on the part of the fis

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03685.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Larval stages of the parasiteDiplostomum spathaceumcause blindness in rainbow troutSalmo gairdneri(Richardson.) The adult parasite is found in the intestine of various species of gulls, and larval stages are found in various species of snails belonging to the genusLymnaea.A field trial was carried out at Lodge Reservoir, near Chelsmford, Essex to test the effectiveness of chemical control of the snailLymnaea peregra.The molluscicide, Frescon, was applied in the first instance to the whole of the reservoir to give a concentration of 0.025 p.p.m. in the water using a motorized applicator mounted at the rear of a small boat. A second treatment was carried out when only the periphery of the lake was sprayed to a distance of 5 m from the banks to give a concentration of 0‐1 p.p.m.NoL. peregrawere found in samples taken 10 days after the second application of Frescon and it is concluded that this snail had been virtually eliminated from the reservoir. No mortality of trout was observed. Some of the sticklebacksGasterosteus aculeatusL. were killed and this may be attributable to uneven distribution of molluscicide near the margin of the reservoir. There were no apparent side‐effects on aquatic invertebrates or other wild life.Five months after treatment some re‐population of the shoreline byL. peregrawas observed, and applications of Frescon may therefore need to be repeated on several occasions during the season to maintain an effective level of control. However, where snail pests are confined mainly to the margin of such bodies of water, peripheral treatment may be effective and would be relatively inexpe

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03686.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Batches of trout have been introduced into Chelker Reservoir in Yorkshire in the autumn and spring since the 1870's for angling purposes. Six batches of tagged, hatchery‐reared brown troutSalmo truttaL. were introduced from autumn 1966 to spring 1969. During the angling season fish introduced in the spring give better catches than those stocked in the autumn. At the beginning of the season the larger fish in the spring batch are caught more often than the smaller fish from the same batch. The larger fish in the autumn batch are caught more often than the smaller fish from that batch throughout the season. The population, available to the angler from the shore was estimated to be 1491 in 1968, with 722 fish/km of shoreline. More fish survive to a second year in the reservoir than is apparent from the number of tags returned. Fish introduced in the spring usually begin growing before those introduced in the autumn, thereafter growth rates varied. The growth rate was independent of the number offish stocked up to the numbers put in.Batches of tagged trout were retained at the hatchery up to nine months to gain relevant experience of post‐tagging mortalities, tag loss rate and effect of tags on gro

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03687.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Segregated populations ofTilapia zilliiandTilapia esculentawere kept in artificial ponds. Supplementary food was given and phytoplankton was encouraged by the addition of superphosphate and ammonium sulphate fertilisers. The fry were cropped regularly in an attempt to control population size. A control population ofT. zilliiwas also established in which none of these procedures were carried out.The growth ofT. esculentawas found to be dependent upon the phytoplankton density of the pond whilstT. zilliisuccessfully utilized the supplementary food and grew well. TheT. esculentapopulation also produced more fry than theT. zilliipopulation. The comparative advantages of planktrvorous/brooders and herbivorous/guarders in fish culture are considered.Despite the fecundity of the species used a population of known composition was maintained by manual cropping of the fry.The addition of ammonium sulphate to the ponds caused blooms of phytoplankton which in turn had effects upon the base reserves and pH of the water, and probably caused some reduction of oxygen concentration beneath surface scums. This last point is used to explain the changes in phosphate and calcium content of the water also observed.The low oxygen concentration frequently noted in the mornings probably affected the feeding behaviour of the fishes, and was low enough to have affected metabolism directly.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03688.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Studies on the vertical distribution of vendaceCoregonus albula(L.), smeltOsmerus eper‐tanus(L.) and bleakAlburnus alburnus(L.) in lakes have been carried out with the application of an echo sounder and then compared with control catches of fish and plankton, Methods and results have been discussed. Some remarks have been made on taking these species of fis

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03689.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Book reviewed in this articleBIOLOGICAL STUDIES OF THE ENGLISH LAKES by T. T. MacanOCEANOGRAPHY AND MARINE BIOLOGY. An annual review. Vol. 7. Edited by Harold BarnesA SYMPOSIUM ON THE DISEASES OF FISHES AND SHELLFISHES edited by S. F. SnieszkoADVANCES IN MARINE BIOLOGY Vol. 8 edited by Sir Frederick S. Russel and Sir Maurice Yonge.MARINE ECOLOGY, Volume 1, ENVIRONMENTAL FACTORS, PART 1 edited by 0. Kinne.TRAITE DE PISCICULTURE by Marcel HuetFISH PHYSIOLOGY VOL. Ill REPRODUCTION AND GROWTH, BIOLUMINESCENCE, PIGMENTS AND POISONS edited by W. S. Hoar and D. J. Randall.A BIBLIOGRAPHY OF PARASITES AND DISEASES OF FISHES OF CANADA: 1879–1969 by L. Margolis.INFEKTSIONNIE BOLEZNI RIB I BOR'BA S NIMI, [INFECTIOUS DISEASES OF FISHES AND THEIR CONTROL]. Pod redaksiei Prof. Bauera.CIRCULATION IN FISHES by G. H. Satchell.BIOETHICS, BRIDGE TO THE FUTURE by Van Rensselaer Potte

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1971.tb03690.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY