摘要:

(1) The Na, K, Ca, Mg concentration of blood serum have been studied in nearly 60 fish species from various waterbodies (the Neva, Lake Dal'nee, the Volga, Lake Baikal, the White Sea, the Black Sea, the Barents Sea etc.). In fishes (Cyprinidae, Percidae, Siluridae etc.) from fresh water (Lake Dal'nee, the Baikal, the Neva) with low 0.18–0.24 mEq/1 Na concentration Na content in blood serum was lower than in closely related species from fresh water (the Volga, Lyutoga River) with larger Na concentration–nearly 0.5–1 mEq 1. Blood serum of marine teleosts Na concentration (156–210 mEq/1) was higher than in migrating and freshwater species (90–174) mEq/1) and it did not depend on seawater salinity: Barents Sea–465, White Sea–255, Black Sea–227 mEq/1.(2) Rather a considerable specific variation of ion concentration was found in blood serum of fishes from different families living in the same water body (Lake Baikal: Cyprinidae 90–95 mEq/1, Percidae 114 mEq/1, Salmonidae 126–129 mEq/1 etc.; the Volga: Siluridae 139 mEq/1, Percidae 142–150 mEq/1, Clupeidae 174 mEq/1).(3) No relation has been detected between K, Ca and Mg concentrations in blood serum of fishes and the concentrations of these ions in the environment.(4) Na concentration in the blood serum of sockeye salmon juveniles (101 mEq/1) migrating seaward was less than in adult fishes (132 mEq/1) returning to the lake to spawn. Na concentration in the blood of non‐migrating salmonids (Oncorhynchus nerkaadult residual 104 mEq/1,Salvelinus alpinusjuvenile 140 mEq/1, adult residual 141 mEq/1) changed insig‐ nificantly during life history. Notable hypopotassemia was observed in spawning time in Salmonidae.(5) The comparison of blood serum ion concentration in males and females of fishes from different taxonomic groups (Acipenseridae, Salmonidae, Cyprinidae) showed

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05098.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

This study was undertaken to discern the effects of cortisol and human chorionic gonadotrophin (HCG) on ovulation in ayu,Plecoglossus altivelis(Temminck&Schlegel), with special reference to water and ion changes. Cortisol as well as HCG was very effective in inducing ovulation of ayu. The best response was obtained with 10 mg of cortisol. In combination of cortisol and HCG, the effective dosage of cortisol was less than when cortisol was used singly. In fish which received cortisol and/or HCG, both the gonadosomatic index (GSI) and the percentage increase in body weight were significantly greater when compared to the control. The increase in body weight appeared to be due to an ingestion of water in fish treated with hormone, as described in our previous report. At ovulation there was a high sodium content in the ovary of fish treated with hormone, whereas a low sodium content was seen in the muscle. It appears that the fish imbibes some water resulting in hydration of the oocytes with concurrent ion movement during maturation and ovulation. These results suggest that gonadotrophin and cortisol may exert their initial effect on the oocytes in a direct or indirect manner, possibly acting to affect the sodium transport system or to alter passive permeability of the egg membrane.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05099.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The behaviour of the lesser sandeel,Ammodytes marinus(Raitt), has been investigated using a photographic method of recording activity. Three main states of activity were recognized: (1) swimming, (2) partially emerged from the sand, or (3) completely buried in the sand. When food was present there was a basic diurnal rhythm of activity; during the dark period most of the fish remained buried in the sand and in the light period they emerged to swim and feed. In the absence of food the level of swimming activity during the light period was extremely low, while the level of partial emergence activity increased. The fish appear to be visual feeders and those which were buried in the sand did not appear to be able to detect the presence of food in the water by means of olfaction. There was usually a low level of partial emergence activity during the dark period, which tended to increase in the few hours before the lights were switched on. The timing of this increase was thought to be related to an internal clock. The basic diurnal rhythm of activity shown in the laboratory experiments is discussed in relation to the marked diurnal variation in the catch of sandeels in the fishery. It is concluded that the failure to catch sandeels at night is due to their remaining buried in the sand.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05100.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The behaviour of the lesser sandeel,Ammodytes marinus(Raitt), has been investigated at light intensities of 1, 10, 100 and 1000 lux, using a photographic method of recording activity. The level of swimming activity was high at 1000 and 100 lux, declining to a very low level at 1 lux. It was concluded that this was due to the limiting effect of light on feeding. The threshold light intensity for swimming activity in the tank was estimated as being approximately 20 lux but it was considered that in the area of the sandeel fishing grounds the threshold might be higher than this, in the region of 100 lux. The number of hours light per day above 20 and 100 lux at a depth of 15 m in the area of the Outer Dowsing sandbank (53°30′N, 01°00′E) was estimated for the various months of the year. It was shown that during the winter the light intensity does not normally reach 100 lux and only exceeds 20 lux for a few hours each day. It is suggested that this could limit swimming activity and accessibility at this time of year. Measurements were made of the penetration of light into sand and it was concluded that fish which are buried might be able to detect light, possibly via the pineal

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05101.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The behaviour of the lesser sandeel,Ammodytes marinus(Raitt), has been investigated at 5, 10 and 15° C, using a photographic method of recording activity. The activity patterns at 10 and 15° C were very similar, there being a high level of swimming activity during the light period, which fell to a low level at 5° C. It was also lower at 10° C at the end of the experiment than at the beginning and it is suggested that this might have been due to an increase in the fat contents of the fish. The feeding rate of the fish was measured and showed aQ10of 2.08 for the temperature range 5–15° C. The annual cycle of activity ofA. marinusis discussed in relation to seasonal changes in food availability, light and temperature, and in the fat content of the fish. It is concluded that after spawning in the December–January period the fish remain buried in the sand until April, because of the limiting effect on swimming and feeding activity of the environmental factors in the intervening period. The proportion of fish available for capture at the start of the fishery in April is related mainly to temperature, but food (as measured by numbers of copepods) light intensity and photoperiod are by then increasing rapidly. After July the fishery ceases and it is thought that this is because the fish have entered an overwintering stage, during which they remain buried in the sand. This phase is also thought to be associated with the maturation of the gonads in readiness for the winter spawning. The factors causing the fish to enter this stage are as yet undetermined but may be related to the attainment of a certain level of fat

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05102.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Mummichogs,Fundulus heteroclitus(L.) accumulated Cd 115m (NO3)2from synthetic seawater solutions during a period of 25 days, but the rate of whole body accumulation decreased with increasing concentrations of stable Cd2+in the medium. Viscera were the major repository of Cd 115m during uptake, especially gastrointestinal tract and to a lesser extent liver. Loss in whole body radioactivity over a post‐treatment interval of 180 days in cadmium‐free seawater was about 90%, with gallbladder and especially liver most influential in the excretion processes; this pattern was unchanged by the level of stable Cd2+present in the medium during uptake. The significance of this and other observations in terms of field monitoring of cadmium utilizing teleosts as indicators is discus

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05103.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

One hundred and sixty eight species of parasite are listed from 36 species of freshwater fish from Britain and Ireland, and notes on their distribution are provided. A list of hosts together with the parasites recorded from them is also given. Although almost twice as many species are listed as in the most recent published reference list, the parasite fauna of Britain appears to be considerably poorer in number of species than that of mainland Europe, and that of Ireland poorer still. The distribution of most species, apart from two endemic species and a very few which have clearly been introduced into Britain in recent years from America or the mainland of Europe, appears to show no peculiarities and is probably contiguous with that of their hosts.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05104.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Food intake, growth and food conversion of young, O‐group herring were studied at two temperatures and feeding regimes over a period of 19 weeks. The food intake of fish fed to satiation twice daily showed considerable variation. Food intake per fish at 14.5° C was about three times that at 6.5° C, and was generally much higher than in most other species of fish studied. The mean increase in wet weight over the 19‐week period was 0.581 g/week at 14.5° C and 0.236 g/week at 6.5° C in fish fed to satiation and 0.094 g/week at 6.2° C and a ration of 1.3% of the body weight. Growth depensation was found to occur even in fish fed to satiation. The changes in specific growth rate, that is the percentage increase in weight/day, showed similar trends at different temperatures and food regimes. The mean conversion efficiency of fish on a ration of 1.3% at 6.2° C was higher than that of fish fed until satiation, at 14.5 and 6.5° C. The conversion efficiency of fish fed to satiation at 14.5° C showed a distinct decrease with increasing weight while at 6.5° C such a clear trend was not observed. In general, the conversion efficiency of young herring were found to be much lower than that of most other species studied. The weight exponent of the quantitative relationship between food intake and body weight at 14.5° C was 0.744. The total metabolic expenditure at 14.5° C, calculated using Winberg's (1956) ‘utilization coefficient, gave a weight e

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05105.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The capture of a specimen of the bluefish–Pomatomus saltatrix, (L. 1758) off Ballycotton, Co. Cork, Ireland (Lat. 8°W, Long. 51°50′N) is reported. Some diagnostic features and measurements of the specimen are given. This would appear to be the first record of the species for the Eastern Atlantic, north of

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05106.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

A histologic and electron microscopic study was made on selected organs from channel catfishIctalurus punctatus(Rafinesque) fingerlings that were experimentally infected with channel catfish virus (CCV). Histopathology was characterized by necrosis and haemorrhage in kidney and liver, and haemorrhage in the spleen and gastrointestinal tract. Virus replication occurred in nuclei of cells in the kidney, liver and spleen. Intranuclear inclusion bodies consisting of geometric crystalline arrays and lamellar structures were associated with virus replication.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1974.tb05107.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY