摘要:

Animals breeding only once late in life should spend most of the time during their one reproductive season attempting to reproduce. Contrary to this prediction, we found that the individuals of three species of sticklebacks (Pisces: Gasterosteidae) spent very short periods of time on their breeding ground. Tidal flooding of the site controlled patterns of fish immigration and emigration. Inundations early in the breeding season brought in new immigrants which replaced most resident fish. However, towards the end of the breeding season there was less immigration and a higher percentage of the residents remained in their pools. We expected to see movements among pools by surplus males searching for sites to establish a territory; instead, few fish moved among pools, and most of those that did were females. A high energetic cost of breeding in this unstable habitat may best explain these residency patterns.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04980.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Light and electron microscopy were used to document the degree of glomerular development in 10 species of Antarctic notothenioid fishes. When combined with results of previous studies, data revealed that 16 of 20 species inhabiting subzero sea water were aglomerular. One subantarctic and two temperate species were pauciglomerular, and an additional temperate species had a moderate number of glomeruli. Renal corpuscles were variable in number and diameter among the pauciglomerular species, and most had few patent glomerular capillaries. Radiolabelled markers indicated that the glomerular filtration rate was low in the pauciglomerularNotothenia angustata, ranging from 0.005 to 0.124 ml h−1kg−1in eight specimens. Arterial perfusion of Microfil demonstrated that arteries supplying aglomerular and pauciglomerular kidneys were confined largely to the periphery of the organ, and glomerular capillaries were absent or few in number. As ancestral notothenioids probably had glomerular kidneys, data from 20–25% of the fauna suggest that there has been an evolutionary loss of glomeruli in many species. The pattern of glomerular reduction is consistent with the hypothesis that the selective advantage of aglomerularism is in the urinary conservation of small molecular weight antifreeze glycopeptide compounds that are vital to survival in sub‐zero Antarctic

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04981.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Levels of tryptophan (TP), serotonin (5‐hydroxytryptamine, 5HT) and 5‐hydroxyindoleacetic acid (5HIAA) have been determined in the brains of wild brook trout,Salvelinus fontinalis(Mitchill), and brown trout,Salmo truttaL., using high performance liquid chromatography with electrochemical detection. Immediately prior to spawning, adult female brook trout exhibit higher levels of 5HT in the brain than adult males, immature brook trout and immature brown trout. After spawning, the highest levels of TP are found in spent males, which also have higher levels of 5HT in the brain than spent females and immature brook trout. Immature brook trout exhibit higher levels of 5HIAA than prespawning adults. This difference disappears after the spawning season. Serum protein levels and condition factors are lower in spent female brook trout; however, haematocrit values for both sexes remain unchanged after spawn

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04982.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A total of 2215 specimens ofIlisha africana(Bloch) were examined for the food habits of the species off the Lagos coast, Nigeria. Their food consisted mainly of crustaceans, fish and molluscs; less important in the stomach contents were insects, annelids, chaetognaths, coelenterates, urochordates and phytoplankton. The incidence of nematodes in the stomachs was low. Monthly variation of food as well as variation with fish size and water depth were examined, as was the relationship of food composition to components of the plankton fauna. Feeding habits ofI. africanawere compared with thoseSardinella maderensis(Lowe),Galeoides decadatylus(Bloch),Brachydeuterus auritus(Val.) andVomer setapinnis(Mitchill); there was an overall diversity in the diets of these fish species.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04983.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The metacercariae ofCentrocestus formosanus(Nishigori 1924) occur on the gills of freshwater fishes in association with blood vessels. The microecology of the metacercariae on the gills of the cyprinid fishAplocheilus panchax(Ham.&Buch.) was investigated. The cysts showed a preference for anterior gills and for the dorsal section of each gill. Variations in the density of infection, season and size of the fish do not affect the spatial distribution of metacercariae. It is presumed that ventilation water currents spread the cercariae onto the anterior gills and then the cercariae actively select the preferred habitat.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04984.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Coregonus peled(Gmelin) embryos at the eyed stage were immersed in tetracycline hydrochloride (TC) solution (600 mg l−1) and fluorescent marks on the otoliths from fish were identified under a UV light microscope. Three weeks after treatment, when the larval fish had hatched, multiple primordia of the sagitta had fluorescent bands whose locations suggest that calcification begins before formation of the otolith's core. Upon hatching, increments were few or absent, and daily increments started forming after hatching. In coregonid larvae immersed in TC solution immediately after hatching, the fluorescent band was only 1 day's growth increment wide in the otolith. The age of larvae based on ring counts after marking corresponded to the actual age, but further studies are required. Triple marks due to 35‐h immersions in TC solution separated by 5–7 day feeding periods were clearly readable in the otoliths. One month after treatment the fluorescent marks were identified under UV light on otoliths from every fish. In treated embryos, 38% of fish had marks 3 months after TC immersion, whereas in treated larvae 60–80% of fish grown up to 38.7 mm were

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04985.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The structure of the pseudobranch of the golden orfe is described from light‐ and electron‐microscopical observations. It is characterized as a covered pseudobranch overlaid by a mucous membrane. The pseudobranch of the golden orfe has no respiratory function, but the electronmicroscopical results indicate that it could function endocrinally by registering and regulating salinity or osmolarity. The epithelial cells are represented by pseudobranch‐type cells. No chloride cells were seen. Rodlet cells are located near blood vessels at the base of the pseudobranch and in the covering epithelial layer, together with mucous cells and mast cells. In the endothelial intima of the arteries the so‐called Weibel‐Palade bodies are

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04986.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Peroxidase activity in the granulocytes of eels was investigated using o‐tolidine, paraphenylene‐diamine‐pyrocatechol, and 4‐chloro‐l‐naphthol as substrates, and cyanide, azide and aminotriazole as inhibitors. Most circulating neutrophils ofAnguilla australisRichardson, 1848 andA. dieffenbachiiGray. 1842 showed no peroxidase activity at pH 7.6 and pH 9.0, but a few neutrophils, thought to be mature, were positive. Another granulocyte in the anterior kidney, spleen, parasitized gill tissue and, rarely, the blood contained a cyanide‐resistant, azide‐inhibited, peroxidase and was tentatively identified as the eosinophil. Neutrophils ofA. anguilla(L.) showed granular peroxidase activity which was inhibited by cyanide. The eosinophil was not observed.Absence of peroxidase from most circulating neutrophils inA. anguillaandA. dieffenbachii, and its pattern in the neutrophil precursors and mature neutrophils ofA. anguilla, may be due to two morphologically indistinguishable granule types. Primary peroxidase‐negative granules occur in precursors and immature neutrophils and secondary peroxidase‐positive granules in mature neutrophils of all three eels. Circulating neutrophils in New Zealand eels seldom mature and are theretore peroxidase‐negative, whereasA. anguillaneutrophils are mature and are usually peroxidase‐positive.Impairment of microbicidal activity in neutrophils lacking

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04987.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The leucocytes of three anguillid eels were studied using enzyme cytochemistry. Leucocytes were stained for peroxidase, alkaline phosphatase, acid phosphatase, aryl sulphatase, β‐glucuronidase, N‐acetyl‐β‐glucosaminidase, β‐galactosidase, lysozyme, a variety of non‐specific esterases, chloroacetate esterase and two proteases. All cells were negative for aryl sulphatase, β‐glucuronidase, N‐acetyl‐β‐glucosaminidase, and β‐galactosidase. Very few neutrophils, thought to be mature, and all eosinophils contained peroxidase‐positive granules, and some monocytes showed very weak peroxidase staining. All leucocytes lacked alkaline phosphatase, but all cells except lymphocytes and thrombocytes ofA. dieffenbachiicontained acid phosphatase. Neutrophil acid phosphatase released into phagosomes was associated withEscherischia colibacteriolysis. Neutrophils also secrete lysozyme and, with monocytes, produce and secrete a variety of esterases. The possible interaction of lysozyme, acid phosphatase and esterases

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04988.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Female lumpsuckers,Cyclopterus lumpusL., have blue‐green blood serum and subcutaneous gelatinous tissue; the male's are red/magenta in colour. The female serum contains a chromoprotein with biliverdin as the prosthetic group; the male serum contains the same biliverdin pigment but this is normally masked by a red pigment, probably phycoerythrin. The female serum also contains the red pigment but at a much lower concentration than in the male. These bile pigments are probably formed by the breakdown of haem in the liver. Lumpsucker gall bladders are relatively small and do not enlarge during starvation. Storage of bile pigments in the serum and subcutaneous jelly may have arisen in response to the problems of regular long‐term starvation. The pigments now appear to have an additional sexual signalling funct

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1986.tb04989.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY