摘要:

Previous investigations have shown that mammalian prolactin has a pronounced effect on lipid deposition in teleost fishes (e.g. Meieret al.,1971; de Vlaming&Sage, 1972). Prolactin can be either lipogenic or lipolytic depending on when during the day it is injected. Studies were initiated to determine whether the diurnal effects of prolactin on lipid metabolism inFundulus similisvary with season or photoperiod acclimation. Data presented here indicate that the diurnal rhythm of response to prolactin persists in the pre‐spawning and post‐spawning seasons ifF. similisis maintained on a long photoperiod. When animals are acclimated to a short photoperiod, treatment with mammalian prolactin either early or late in the photoperiod causes lipid depletion. Homogenates of the portion of the pituitary containing only prolactin cells cause lipid depletion inF. similiswhen injected early during a long photoperiod, but stimulate lipogenesis if injected late in the photoperiod; these results imply that fish prolactin may be involved in lipid metabolism. Furthermore, prolactin activity in the pituitary ofF. similisvaries diurnally.In vitrostudies of lipid metabolism inNotemigonous crysoleucasandIctalurus natalissuggest that the liver may be one of the target organs for prolac

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04644.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Life cycle experiments with the tapewormBothriocephalussp. from carp were carried out usingCyclops abyssorumSars as the intermediate host. The eggs expelled from gravid segments were embryonated but not fully developed. Hatching of the coracidia occurred by the third day. Procercoid development was completed after 8–10 days. Comparing the results and descriptions of previous authors, it is suggested that the cestode belongs toBothriocephalus acheilognathiYamaguti, 1934 according to the priority of nam

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04645.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

A deeper water species of the Mediterranean‐Atlantic gobiid genusPomatoschistus, P. norvegicus(Collett, 1903), is redescribed from syntype material, including details of the lateral‐line system and a summary of geographical distribution. The systematic status ofP. norvegicusis briefly discussed with reference to the other nominal species,P. minutus(Pallas) andP. lozanoi(De Buen), of the‘P. minutus’

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04646.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Scale and length/weight data from 2071 Llyn Tegid grayling and 1803 River Dee grayling were used for age and growth determinations. The time of scale annulus formation varied from autumn in some years to spring in other years. Seasonal changes in length, weight and the condition factor were described. The main growth period was from spring to autumn with very little growth occurring during the winter. Annual growth in length was back‐calculated from scale measurements, and von Bertalanffy's model was fitted to the resulting length for age data. Comparisons were made between the specific growth rates and ultimate lengths (Lx) of Llyn Tegid and River Dee grayling, and between the growth of male and female grayling. Males grew faster than females after the onset of sexual maturity. Calculated lengths were converted to weights using a combined length/weight relationship for Llyn Tegid and River Dec grayling. Changes were evident in this relationship throughout the life of the fis

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04647.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

The development of carp gonads in warm water (23°C) aquaria under controlled conditions is described. In this environment males mature at 6 months of age. Females ripen at 14 months, and by 15 months 25% of these have started to spawn, whereas under natural conditions female European carp do not ripen until they are 4 years old. Fishes do not lay all their eggs at once, as evinced by the finding of partly‐spent ovaries. Sexual maturation of the ovaries has been described in six stages, based on histological changes, and associated with changes in the female gonado‐somatic index and the maximum ova diameter. The maturation of testes occurs in four stages. The percentage incidence of each stage of ovarian maturation has been calculated for the 6th to the 15th month. Larger fishes become sexually mature before smaller fi

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04648.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Newly hatched larvae of the California killifish (Fundulus parvipinnis) reared in the laboratory, were tolerant of salinities from fresh water to 70‰. Their salinity tolerance was influenced by incubation salinity; larvae hatched in lower incubation salinities exhibited greater freshwater tolerance than those hatched in higher salinities. In gradual acclimation tests, the upper median lethal salinity for the larvae was 130‰. Freshwater tolerance of the larvae decreased with age; yolk sac larvae were completely tolerant of fresh water while larvae more than 15 days old were least resist

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04649.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Voltages associated with heartbeat were transmitted by radio from free‐swimming rainbow trout (Salmo gairdneri.) Variability in the bradycardia response associated with the hypoxic state was observed and appeared to be related to the normal activity state of the fish. Bradycardia as a physiological mechanism was discussed on the basis of this findin

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04650.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

It had been predicted that eels would disappear from Lake Kariba because juveniles would be unable to surmount the dam which was closed in 1958. This prediction has been proved wrong. In 1970–71 an abundant population of eels was discovered in the lake, mostly at depths from 25–40 m. The eels have intermingled characters of both the mottledAnguilla nebulosa labiataand the plain‐coloredA. mossambica. A clear separation of these two taxa was impossible and therefore conspeciflc status of these two species is suspected; the nameA. n. labiatais retained for the population.The age structure of the eel cohorts suggests that juveniles surmount the dam in their second year of life and then spend approximately 7 years in streams of the lake drainage. The fastest maturing individuals which are in best condition then emigrate to the ocean, whereas the slower maturing eels remain in the lake longer. The oldest eel in the samples was 18 years old.The catch per unit of effort for hoopnets was 2.35 kg in the upper part of the lake and 0.41 kg for the lower part of the lake. The density at Namazambwe was assessed at 46 eels per 1 ha. The unexploited eel population of Lake Kariba could form a valuable res

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04651.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

Rates of oxygen consumption by parasitized and unparasitized sticklebacks were recorded at three levels of activity in February and August. Negative correlations were demonstrated between specific respiratory rates and fish body weights. At routine and maximum activity, infected fish consumed more oxygen than uninfected fish. At minimum activity levels no significant differences in respiration rates were detected. Seasonal variation in respiration rates was attributed to acclimation. Difficulties of determining specific respiration rates for parasitized organisms are discussed and attempts are made to assess the physiological basis of the respiratory and behavioural characteristics of infected fish.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04652.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

The effect of one intraperitoneal injection of 1.33 ml of CCl4per kg of fish was studied. Two experimental series were performed and studied for 10 days (with diluent) and 24 h (pure CCl4) periods. LDH, GOT, GPT, GR, GDH, CPK, G‐6‐Pase, and AlkPase were studied. The activity of all enzymes in blood increased: LDH (four times the control), GOT (two times), GPT (three times); they reached a maximal activity 12 h after injection of diluted CCl4. The levels of some enzymes were also examined in the liver. With pure CCl4, maximal enzyme activity in blood occurred earlier (6 h). A 6 to 10 times increase was observed for GOT, GPT, LDH, GR, and GDH. Histopathological observations were correlated with these enzymes studies.AnAeromonasdisease characterized by the destruction of the dermis, the exposure of the muscle, and by the presence of numerous petechiae in the liver enabled us to examine the relationships between naturally induced tissue damage and enzyme levels in blood. The levels of seven blood enzymes were determined and the most significant modifications were observed for LDH and CPK. which increased their concentration from 3 to 7 times respectively. A pyruvate saturation test demonstrated that LDH was probably from liver as it was observed after CCl4poisoning. The contribution of such biochemical studies in fish research is evalua

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1975.tb04653.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY