摘要:

A short‐term study from October 1975 to April 1976 was carried out by keeping 10 carp in two separate cages (five in each) at each of the three sites, namely, Wraysbury Reservoir, Ryemeads Sewage Lagoon and Deephams Sewage Lagoon (Fish unit). Fish were not artificially fed. Blood samples were collected at monthly intervals. Activities of the following hepatic microsomal enzymes, aminopyrine demethylase, p‐nitro‐reductase, UDP‐glucurony! transferase and 1‐leucyl‐p‐naphthylamide splitting enzymes were measured; cytochromeP450and microsomal protein contents were also estimated.The levels of androgens, oestrogens and corticoid hormones were measured in the circulating blood at monthly intervals. Results indicated that there was (a) no significant increase in the activities of all the enzymes measured except for an increase in cytochromeP450in the fish kept at Deephams Sewage treatment works, (b) no significant increase in microsomal protein content at the three sites and (c) no significant changes in the levels of plasma androgens, oestrogens and corticoids of the circ

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03605.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Sets of scales with the relevant information were collected by the Irish Specimen Fish Committee from large or specimen brown trout taken by angling from Loughs Mask, and Corrib. The relationship between lengths and age were determined for those fish for which the necessary information was available. It was concluded that those fish destined to become specimens (10 lb or over in weight) had adopted a fish‐eating habit to enable them to maintain a high rate of growt

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03606.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

A histochemical study of the distribution of alkaline phosphatase in the skin of the Common goby,Pomatoschistus microps, showed that the enzyme is present in the dermis, not in the epithelium, and is more pronounced around the growing edge of the scale and below the fibrillary plate. The intensity of the enzyme reaction is higher in regenerated scales. In conjunction with the phenologyof P. microps, a method was adopted to measure the enzyme activity in the skin, including scales, for successive months over a period of two years. Enzyme activity displayed seasonal fluctuations which were closely related to both body and scale growth. Enzyme activity also reflected other phenological cycles during the life‐span ofP. microp

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03607.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Data is presented concerning the growth of roach in a South Lancashire lake. Results from a sample of roach in May 1969 indicate the slowest growth rate for which published records are available. A comparison of the length/age and weight/age relationships between data for May 1969 and May/June 1971 yields significant between‐year differences indicating an increase in the growth rate during that period. A study of the growth history of individual year classes using back‐calculated values from operculum measurements suggests that for both sexes the observed increase in the rate of growth commenced after the 1965–67 period during which very weak year classes were produced. The mean length of females appears to have been larger than that of males from the age of four onwards but the 95% confidence intervals are almost totally overlapping for each pair of values and a statistical comparison of growth rates between the sexes indicates no significant differences. Data for the sexes combined is compared with published results from other British and Continental w

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03608.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The thickness of the skin of Atlantic salmon increases throughout the first two years of life. This increase involves, principally, an increase in the connective tissue of the dermis, and occurs independently of sexual maturity. The concentration of mucous cells in the epidermis changes seasonally, being least during the winter period. No sexual dimorphism is observed in these features among sexually immature fish. The epidermis of precociously mature male parr is thicker and contains more mucous cells than that of sexually immature individuals.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03609.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The influence of social rank on changes inLepomis macrochirusbehaviour brought about by exposure to sublethal concentrations of cadmium and zinc was studied. Significant changes occurred in the frequency of eight of the nine behavioural acts quantified. The effects of metals on the behaviour of individuals was often related to the individual's social status in the hierarchies that had formed. The majority of agonistic behaviours (nips and nudges) were performed by dominant individuals and the majority of comfort behaviours (coughs, yawns, jerks, jerk swimming, fin flickering and chafes) occurred in subordinate individuals. These differences occurred during the control period as well as the treatment period and are thought to be in part caused by socially induced stress.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03610.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Splenic antibody‐producing cells were produced by rainbow trout that had been exposed to O‐antigens extracted fromYersinia ruckeriandAeromonas salmonicidaby adding the concentrated antigen preparation directly into the water of the tank holding the fish for a flush exposure. This method was compared with the proven techniques of exposure: intraperitoneal injection or a 2 minute immersion of the fish in the antigen preparation. Dosage experiments showed that the production of antibody‐producing cells was induced by the immersion of trout for 2 minutes in water with 5.0 μg/ml‐1 (or more) with theY. ruckeriO‐antigen, or 500 μg ml‐1 (or more) of theA. salmonicidaO‐antigen. Similar differences were evident when the respective antigens were added direct

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03611.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Inbreeding depression was observed in Half and Full sib matings (Inbreeding Coefficient 0.125 and 0.25) of Zebra Danios (Brachydanio rerio). Inbreeding at these levels reduced fertility, survival to 30 days, and length at 30 days. There was an increase in the incidence of crippled fry. No effect of inbreeding on either number of eggs per spawn or hatchability were found.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03612.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The effect of porcine calcitonin on the plasma calcium of the freshwater Indian murrel,Channa punctatusBloch has been studied. An injection of 200 MRC mU of porcine calcitonin was given intraperitoneally, while control fish received the gelatin carrier. A significant hypocalcaemia was noted I h after calcitonin treatment (P<0.001). The plasma calcium had returned to the normal level by the 6th h.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03613.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Grass carp were raised in 227 1 indoor tanks at 12.8, 18.3, 23.9 and 29.4° C temperatures, each experimental condition received five fish. Five grass carp were also raised in a 1135 1 tank maintained at 29.4° C representing low stocking density (29.4° C‐L). Food consumption, food conversion, and growth of carp were not different among the 18.3, 23.9, and 29.4° C experimental conditions with identical stocking density. The least growth and food consumption were noted for the fish at the 12.8° C temperature. The fish at the low stocking density had the best growth and maximum food consu

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1979.tb03614.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY