摘要:

Rainbow trout were fed gossypol acetate or cottonseed meals containing gossypol for 14 months. Toxic effects were indicated by growth depression, reduced hematocrit, hemo‐globin, and total plasma protein. Histological changes were noted, particularly in the liver and kidne

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03288.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Sera from salmon Sulnio salar L. suspected of U.D.N.‐infection were tested (by double gel diffusion) against antigens prepared from diseased salmon tissues andSuprolegniu. Precipitating antibodies to the fungus were found in 93 % of the salmon, but only 66% of these fish were colonized by fungus. The antibodies were detected in parr and adult salmo

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03289.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

From April 1967 until July 1968 the life history of the nematodeRughiduscuris acuswas followed in the natural environment of the River Bystfice. The incidence, intensity of infec‐tion, and also the maturation of the nematode in the definitive host (Saimo truttu m. fario) indicate that the life history of this parasite exhibits an obvious annual cycle, when adult egg‐producing female nematodes are present only from May until the beginning of July. This seasonal rhythm is largely due to changes in the food composition of the definitive host, although the effects of other factors cannot be excluded. In the River BystHce the main intermediate hosts of R. ucus are the bullhead (Cottus gobio) and the Siberian sculpin (Cottuspoecilopus) in the trout zone of the river and the stone Ioach (Noernacheilus barbutulus) in the lowland reaches. Larvae of the species Prodiamesa olivacca (Diptera: Chironomidue) were found to act as reservoir hosts for the second‐stage larvae ofRaphiduscuris

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03290.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

A collection of shore fishes from Guernsey, Channel Tslands, is described. Fourteen species of fish are represented in the collection, many of thein rarely recorded from Guernsey before this. The factors governing the distribution of some of the species found are briefly discussed in the light of their occurrence here and elsewhere on the coasts of north‐west Europ

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03291.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Pelagic fish populations in Lake Tanganyika consist mainly of two small clupeid species and four centroponiid species which prey on them. Exploitation with purse‐seines began in the southeast arm in 1962 and catches were sampled up to early 1969. Inshore clupeid populations were also sampled with a scoop‐net (lusenga of the kind used in the traditional inshore fishery.Clupeid biomass reached annual maxima around September. One clupeid species,Stolothrissatanganicae Regan, dominated pelagic catches except in 2 years when about equal quantities of the other clupeid,Limnothrissa miodonBlgr. were caught. Numbers of each predator (three species of Lates and Luciolates stappersii Blgr.) decreased from 1963 to 1966 and remained low thereafter. The clupeid catch rose from 1964 to 1967 and remained high in 1968. The average nightly catch weight per year of all species together altered relatively little. Changes in population size distributions occurred.Sampling methods were concluded to be valid for clupeid populations, but probably indi‐cated only general changes in predator populations. Clupeid life‐cycles are mostly accomplished within a year, and appear closely related to the periodic and spatial variations in plankton production. The two species are competitive and can replace one another in the pelagic zone. Certain distribution patterns of the clupeids and of the predator young are believed to be adaptations to severe predation. Low replacement rates under fishing pressure account for the decline of predator species, and the clupeid increase resulted from reduction in predation. A fairly stable exploited phase has apparently been reached in which clupeid biomass is much greater and predator biomass much less than in the natural state. The data encourage certain predictions. Similar major trends occurred in the much larger fishery in the Burundi sector of t

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03292.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

The response of adult mullet to artificial hypophysalion, immediately before the onset of the spawning migration was studied. Both males and females received intraperitoneal injec‐tions of mullet or salmon pituitary homogenates wth ACTH or Synahorin (APE+HCG) three times per week for 12 days. At the outset, conlrol females were in the tertiary yolkstage with a low mean GSI of 7.6, while males gave thick, non‐dispersing milt. Two of fourfemales receiving one salmon pituitary plus 25 RU Synahorin per injection spawnedspontaneously in laboratory aquaria. Released eggs were buoyant, well formed and had a mean diameter of 570μm. Egg fertility could not be ascertained due to protracted contact with sea water. Spawned females extruded a meinbranous tissue ‘plug’ from the cloaca1 region which was subsequently retracted. The remaining experimental females were refractory to treatment and histological examination of the ovaries revealed a predominance of atretic oocytes. All males were refractory to treatment and milt hydration was not achieved. It is suggested that induction of early spawning is possible especially with higher doses of pituitary homogenates and Synahorin. [Oceanic lnstitute Contribution No, 62 Sea Grant Program

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03293.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

A quantitative assessment of the demand by the parasiteSchistocephalus solidus(Miiller, 1776) upon its secondary host,Gasterosteus aculentusL., was obtained by comparing the energy budgets for infected and non‐infected fish. Observations on the energy trans‐formations during feeding, assimilation, growth and respiration of fishes indicated some overall effects of the parasite upon host metabolism.Infection resulted in a greater depletion of host food reserws, shown by a marked in‐crease in mortality of parasitized fish during starvation. When fedad libitumuponTubifex, differences were recorded in the feeding and assimilation rates of fish. By comparison, no significant differences were detected in the respiratory expenditure of infected and non‐infected hosts. The computation of energy budgets indicated that fish bearing parasites characteristically exhibited a higher gross efficiency than did fish without parasites. How‐ever, subtraction of the calculated effect due to the presence of worms, suggested that the efficiency of infected fish alone, that is, without their parasites, was actually lower than the efficiency of uninfected fish. It is considered therefore that the apparent greater energy turnover in a parasitized fish is due to the parasite being more efficient in its energy trans‐formations than

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03294.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

The gross pathology and histopathology of a series of 150 cases of UDN disease ofsalmon Safmo sulurL. from a number of Scottish rivers is described. The lesions appeared first as small grey areas on the heads of affected fish, which gradually enlarged in size, ulcerated and became infected with fungus of theSaprolegniugroup. Histologically, the earliest lesion was an acantholysis of the suprabasal cells of the epidermis developing into transient bullae which rapidly sloughed to produce a raggcd irregular epiderm's. Once the base‐ment membrane was breached secondary infection by fungi rapidly ensued.The histopathology, in the early stages, was consistent with possible viral infection, or anoxic atrophy but it was considered that the most similar lesion from mammalian experi‐ence, was that of thePemphigusgroup of dermato

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03295.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03296.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1970.tb03297.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY