摘要:

The incidence and histochemical features of melano‐macrophage centres in the spleen of the teleost fishD. annulariswere studied with respect to starved and fed fish. Tissue catabolism following complete starvation appears to induce formation of new centres containing melanin and lipofuscin pigments. However, a change in the amount of melano‐macrophages was also recorded in fed fish, suggesting that some other factor(s), internal to fish, may affect the presence of such structures within the spleen ofD. annula

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05851.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Macrophage exudates in the Japanese eel, Anguillu japonica, were induced by intraperitoneal injection with a mixture of Edwnrdsiella bacterin, proteose peptone and liquid paraffin, and the opsonic effect of antiserum and complement on the phagocytic activity of the macrophages was studied.The macrophages contained a round nucleus with a nucleolus, and an agranular cytoplasm with projecting processes. These cells showed phagocytosis of sheep red blood cells (SRBC). An opsonic effect of antiserum was recognized in terms of a significant increase of macrophage phagocytic activity against SRBC treated with antiserum relative to that against SRBC treated with inactivated normal serum. Complement, however, did not enhance the phagocytic activity of macrophages.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05852.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The diets and prey selection of six species of tuna baitfish (the engraulidsStolephorus devisiandS. heterolobus, three dussumierids of genus Spratelloides, and the apogonid Archamiazosterophora. were examined at two heavily fished and one unfished site in the Solomon Islands. All species ate almost exclusively nektonic zooplankton, especially crustaceans. Calanoid copepods were the most importantpreyofallspeciesexceptA. zosterophora, whichateagreater biomassoflarvalfish. Baitfishcould be divided into two groups according to prey taxa: the apogonid A. zosterophora and the engraulids S. devisi and S. heterolobus ate similar prey in similar proportions; the three dussumierid species (Spratelloides) ate smaller zooplankton and a greater proportion of calanoids than the other species.The size of prey eaten differed greatly between baitfish species. A. zosterophora ate larger prey than other species. The twoStolephorusspecies ate similar‐size prey, which were larger than the prey of the three species of Spratelloides. Among the Spratelloides, S. delicatulus ate smaller prey than the other two species. All species differed in the size of calanoids, carids and brachyurans they ate. In all cases, prey differed more by the minimum dimension (width) than by volume. There were significant relationships between fish length and prey width and volume, except for Archamia. However, in terms ofvolume, the prey ofStolephorusincreased with fish size at a much greater rate than in Spratelloides species.Baitfish diets were compared to the zooplankton available. Prey selection by the three Spratelloides species and two Sfolephorus species was density‐dependent for all common prey types, althoughStolephoruspositively selected hyperiid amphipods and brachyurans. Archamia showed strong negative selection for calanoids and selected larger zooplankters, including fish larvae and carids, avoiding smaller, more common, prey.Overall baitfish density and zooplankton density did not correlate at either of the heavily fished sites. Nor were there consistent differences for any species in diet or changes in prey selection between the heavily fished and unfished sites. This suggests that, in these lagoons, commercial baitfish catches are not directly influenced by the composition or density of p

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05853.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Golden perch larvae were stocked into a pond and inundated floodplain system in south‐eastem Australia to determine movement patterns of the larvae onto and off the floodplain area. A total of 428 larvae were caught moving from the floodplain into the pond whereas only 18 were collected moving in the reverse direction. Thirty one larvae were caught at open water sites in the pond and floodplain, but only three were collected from sites on the floodplain which provided shade, timber or water flow. Transect samples from the pond also yielded more larvae than samples from floodplain transects, indicating a distinct spatial dispersion pattern in favour of the pond.Spatial dispersion patterns of golden perch larvae appear to correspond with gradients in water quality between the pond and floodplain habitats. Stratification occurred in the pond but did not develop on the floodplain. Water on the floodplain was cooler, harder and contained less oxygen than surface water from the pond. Die1 oscillations occurred in water temperature, pH, dissolved oxygen, carbon dioxide and acidity, but there was no significant corresponding pattern in the distribution of larvae.Dispersion of golden perch larvae between pond and floodplain habitats is not random, and may be actively influenced by local‐scale variations in water qual

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05854.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Food consumption, gut transit times and assimilation efficiencies of the temperate fishesLipophrys pholisandParablennius sanguinolentus(Blenniidae) andGobius cobitis(Gobiidae. when fed the green algaUlva lactucawere determined at four temperatures in the laboratory. Food consumption increased and gut transit times decreased with increase in temperature in all three species. Assimilation efficiencies for algal carbon and nitrogen did not vary with temperature inG. cobitis. Carbon but not nitrogen assimilation efficiency varied with temperature inP. sanguinolentus, and both carbon and nitrogen assimilation efficiencies changed broadly with temperature inL. pholis, the most omnivorous of the three fishes. Assimilation efficiencies of all three species were generally within the previously reported ranges for herbivorous marine fishes. These species are thus clearly capable of extracting energy from algal food sources.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05855.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Antibody activity specific to antigens (PSA, DSA and BGG) which served for immunization of mothers could be measured in extracts of 0‐9‐day‐old embryos spawned by these mothers, using a modified ELISA. The level of antibody activity in embryos varied according to the interval of time between mother immunization and spawning. This activity peaked between 14 and 37 days post‐immunization, then it underwent a significant gradual decrease. The activity of the extract was found to be specific only to the antigen which served for the mother immunization and could be adsorbed only by these antigens. The need of mother immunization against selected pathogens for the prevention of larvae and fry mortality is di

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05856.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Larvae of amphidromous gobies migrate to the sea as passive drift. In order to identify the diel drift pattern (DDP) of each species, we conducted 24 hour collections in different sections ofthree rivers. The DDPs ofdifferent species at each sampling station were almost identical, but the DDP of each species varied among stations, depending on the topographical features of water‐courses. Downstream migration occurred throughout the day in steep water‐courses while it was nocturnal with a peak in number soon after sunset in gentle gradients in the plain and was also nocturnal with a small amount of day time drifting between the two gradients. It is suggested that the larvae drifting from the upper parts of the river in daytime halted their migration in a pool with low flow rate until twili

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05857.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Problems in cichlid systematics call for new characteristics to be exploited. Scale surface morphology and squamation patterns could provide novel and useful information. A comparative study comprising 105 African, 10 American, and eight outgroup species was conducted to identify the most useful scale and squamation characters within the family and to clarify their phylogenetic significance. A great number of obviously genetically fixed characters were established. At least IS scale granulation types could be identified, proving to be ofparticular value for systematic purposes. Squamation patterns on the head, breast and fins were also found to be of interest in this context. Different character states are described and their distribution is reviewed, together with a discussion of their plesiomorphic status. From the results it can be concluded that for the Cichlidae scale and squamation studies can be valuable tools in investigating phylogenetic relationships.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05858.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Zinc and copper were detected in several tissues of fresh and saltwater fish. Liver concentrations varied widely, with respect to the storage and detoxication functions of the organ. In muscular tissues the two metals are linked to aerobic metabolism being higher in the heart and lower in the white muscle. High levels of zinc were found in the female gonad, while in the brain zinc has been shown to be more constant and possibly regulated better than copper. In sea bass supplemented with artificial diets no correlation was found between the metal content in the diet and that of the tissue. In goldfish attempts using gel filtration to isolate specific metal binding proteins of low molecular weight gave negative results, the metals were mostly bound to ligands excluded from the gel.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05859.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Morphological studies on the effect of low pH on egg shells (chorion) of rainbow trout,Oncorhynrhus mykissWalbaum (formerlySalmo gairdneri), and brown trout, Salmo trutta f.farioL., showed that the plugs of the outer layer of the chorion, which block the channels of the underlying layer, developed distinctive vacuolization at low pH exposure. This may lead to loss of chorional semi‐permeability. Chorions were incompletely degraded at low pH inducing hatching problems. Partially hatched alevins showed only a small local zone of dissolution of the chorion around the head of the embryo preventing the larvae from being free

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1990.tb05860.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY