摘要:

Norway pout (Trisopterus esmarkii) were collected during a trawling survey of inshore waters of the west coast of Scotland. 0–group fish were first taken by the bottom trawl in late summer and since there was no evidence of local spawning it was inferred that a migration from the open sea had occurred. The distribution and age composition of the stock was related to depth. The young fish migrated from the shallower stations during their first winter but persisted for a second winter at some of the deeper stations.There was a marked seasonal variation in the quality of the diet and in the intensity of feeding. The most important food organisms were copepods, decapod larvae, mysids and euphausiids. Diurnal variations in the intensity of feeding were minimal in August but the quality of the food in the stomachs was dependent on the time of sampling. The converse was observed in January when feeding was at a maximum between dusk and dawn but the quality of the food remained fairly constan

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04073.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Catecholamines are present in the late embryonal and early larval developmental stages (alevin) of the rainbow trout. Changes in the alevin behaviour can be related to the catecholamine concentrations.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04074.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Food selection by youngCatla catlafrom a tropical fish pond was studied by computing the electivity indices for various types of planktonic food organisms. The fish was found to be a selective feeder. A positive selection was observed for cladocerans, copepods and nauplii larvae. Among the rotifers, however,KeratellaandBrachionuswere positively selected whileRotariawas completely avoided.High electivity indices for some and low for the other genera were observed within each group of phytoplankton. Strict stenophagism seemed to occur for certain phytoplanktonic organisms.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04075.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Class 0 and class 1 striped mullet,Mugil cephalus, were collected from May 1970 to June 1971 to study development, seasonal abundance of parasite populations, and distribution of gill parasites. Crustacean parasites observed wereErgasilus lizae, E. versicolor, E.funduli, Bomolochus concinnus, Brachiella oblonga, Caligus mfimaculatus, Clavella inversa, Lernaeeni–cus longiventris, Argulus funduliandA. chesapeakensissp.n. Cressey. Cyclipoid copepods initially infected class 0 mullet in late spring and populations were characterized by surges in intensity at 6 to 8 week intervals. Caligoid copepods initially infected class 0 mullet in late summer and fall or appeared only on class 1 mullet. Intensity remained low, but they were observed consistently. Branchiurans were rarely observed on class 0 mullet and occurred consistently at low intensity on class 1 mullet. Study of distribution of five gill parasites indicated a high degree of gill habitat subdivision, but competitive exclusion was not observe

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04076.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The effects of the anaesthetic, MS‐222, on the microhaematocrit value of freshwater fish have been examined. Blood containing MS‐222 showed a higher haematocrit value than blood without the anaesthetic and haemolysis occurred in the former after a variable time depending on the concentration. The results are discussed in relation to previous findi

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04077.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A systematic procedure is provided for determination of D‐amino acid oxidase (EC 1.4.3.3) activity in fish tissues. Activity was surveyed in crude liver homogenates of twenty‐three species of fish. Activity ranged from 0‐047 to 3‐12 units (ρmol product produced per min) per gram wet weight of tissue. Activity was highest in liver, with significant levels occurring in kidney and pyloric caecae. It was below the limit of detection in brain, heart, spleen, testis, gill filaments, and muscle. Some properties of the enzyme from sockeye salmon,Oncorhynchus nerka(Walbaum), were studied. Knowledge of occurrence and levels of D‐amino acid oxidase in fish may be useful to fish aquaculturists contemplating supplementation of feed with racemic mixtures of a

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04078.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The toxicity of cadmium to sticklebacks was determined over a wide range of concentrations. The 96 h LC50 was found to be 6.5 mg Cd I−1. The shape of the time‐concentration curve suggests that cadmium may have two toxic mechanisms. The median period of survival for fish infected with the plerocercoids of the cestode,Schistocephalus solidus, was found to be considerably shorter than for non‐parasitized fish. This observation is considered in the light of the known effects of 5.soliduson its

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04079.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Channel catfish,Ictalurus punctatusRafinesque, injected intraperitoneally with 2‐methyl‐quinoline sulphate (QdSO4) or 3‐trifluoromethyl‐4‐nitrophenol (TFM) eliminate most of the dose of these compounds by extra‐renal routes. Patterns of renal excretion of Na+, K+, Ca2+, Mg2+, and Cl−(ρEq kg−1h−1) appeared to be associated with the ‘stress’ of the urine collection technique rather than with the elimination of either compound. Concentrations of Na+, K+, Ca2+, Mg2+, and Cl−(mEq/1) were determined in urine, plas

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04080.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The effect of short‐term stress on blood clotting times, cell counts, haematocrits, and blood glucose levels was studied in a hatchery strain and wild type rainbow trout,Salmo gairdneri.Blood clotting times declined and thrombocyte counts, haematocrits, and blood glucose levels increased after stress in both strains of trout. The wild type of rainbow trout, however, required less time to recover from the stress than the hatchery strain of rainbow trout. The implications of a stress activated blood coagulation system in fish are discusse

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04081.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Gill‐net surveys were made weekly from May 1971 to April 1974 in Plover Cove Reservoir, Hong Kong and the results analysed to determine the fish species composition in the reservoir, the seasonal fluctuation of catches and the length frequency distribution of some major species.Over 20 species were represented in the fish fauna including almost all the naturally occurring species as well as the stocked species. Of the twenty species, some were collected regularly in gill‐net samples while others occurred rarely.Sarotherodon (Tilapia) mossam‐bicus(Peters) was the dominant species and contributed the main bulk of the catch. This species also showed distinct age groups in the reservoir and modal changes occurred seasonally. Thus, among the fish species studied onlyS. mossambicusshowed a steady and progressive increase in abundance in the reservoir and the full development of this fish population with its wide range of feeding habits should be benef

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1977.tb04082.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY