摘要:

Striped sea bream,Lithognathus mormyrusL., are hermaphoroditic protandrous fish. Sex ratios are given for length and age classes, indicating the males change sex mainly at lengths between 25.0 and 32.5 cm, in age classes 4 to 7, with more than 30% of the population changing sex in age class 6 to 7. Males were also observed up to a length of 34.5 cm. Length‐weight relationship showed no significant difference from isometric growth in winter (b = 3.05) and a negative allometric growth in summer (b = 2.69). The age composition was established using the Bhattacharya method and additional observations of annual rings on scales. Six age classes were obtained from Kaštela Bay (age 3: 21.7 cm, age 4: 26.5 cm, age 5: 28.4 cm, age 6: 30.3 cm, age 7: 31.6 cm, age 8: 33.4 cm) and from Mirna Bay (age 2.5: 19.4 cm, age 3.5: 24.1 cm, age 4.5: 26.9, age 5.5: 29.4 cm, age 6.5: 31.3 cm, age 7.5: 32.8 cm). Von Bertalanffy's growth equation was fitted to these mean length‐at‐age data resulting in parameter values of L∞= 36.2 cm, K = 0.297, t0=−0.08 for Kašela Bay and L∞= 37.3 cm, K = 0.262, t0=−0.3

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00001.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

WildSeriola dumeriliiwere collected in the South Mediterranean Sea during the 1990, 1991 and 1992 spawning seasons. Macroscopic and cytological characteristics of ovary and testis were analysed. Depending on the presence and the number of oocytes at different stages, a five point maturity scale was proposed for ovarian maturity. Nine maturity stages of the oocytes are described. Oocyte size‐frequency distribution has shown a group synchronous ovarian development type. The testes have a typical lobular‐type structure. Depending on lobules and sperm duct development and on the abundance of germ cells, testis maturity was classified in four stages. Maturity rate according to age and size was also determined. 100% of 1‐year‐old fish show immature gonads. The proportion of females with mature ovaries was 0, 12.5, 84.6 and 100% at the age of 2, 3, 4 and 5 years respectively. The proportion of males with mature testes was 14.3, 40, 80 and 100 at the same age. The median standard length at which 50% of the fish attained maturity is 109 and 113 cm SL in males and females respe

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00002.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Ten‐day‐old African catfish larvae,Clarias gariepinus, were stocked in aquaria at 5, 13, 22, and 30 larvae per liter with fish at each density being fed three and six times per day over 35 days. Fish were fed with an artificial diet in excess of their satiation requirements at each feeding. Every week total length was determined for samples of 25 fish per tank and all fish were counted at weekly intervals. Behaviour patterns were categorized into timed behaviour (i.e. resting, swimming and browsing), and frequency events e.g. number of contacts, aggressive contacts and number of head or body attacks. Fish at the lowest density grew faster than fish at the other densities. Feeding frequency had no effect on growth. With increasing densities fish less frequently changed timed behaviour patterns while spending a greater percentage of the time swimming. Aggressive behaviour was highest at the lowest density but remained uninfluenced at densities greater than five fish per litre. The high feeding frequency provoked a higher rate of aggressive contacts than the low feeding frequency. A suggested explanation was that these fish were more often in anticipation of food and consequently more active between feedings. In summary, it was shown that density had an effect on duration behaviour patterns such as resting and swimming, while feeding frequency significantly influenced frequency events, in particular the rate of aggressive behaviour. The study contributes to an understanding of factors influencingC. gariepinusjuvenile behaviour and suggestions for follow‐up experiments are disc

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00003.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Using the rotiferBrachionus calyciflorusand the cladoceransCeriodaphnia rigaudi, Moina macrocopaandDaphnia carinataas prey (food) species, the capture success (CS), frequency of feeding and total daily food intake of rohu (Labeo rohita) and singhi (Heteropneustes fossilis) larvae were determined. The CS in both rohu and singhi was a direct function of their age as well as hunger level, but at any given age it was inversely related to prey size. The larvae fed more or less continuously, even during the night hours. Gut evacuation rates were slower in singhi than in rohu. The daily food consumption rates in rohu and singhi larvae were 13.3% and 17.7% at age 6 days, and 8.0 and 10.1% of the dry body weight at age 12 days, respectively. Although as adults rohu and singhi have distinct food niches, they did not differ significantly in the larval stages in the parameters studied. The implications of these findings for larval rearing in the aquaculture of rohu and singhi are discussed.

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00004.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The age and growth of the cottid fishClinocottus globicepsGirard from tidepools at Helby Island, British Columbia, Canada were investigated with the aid of whole saccular otoliths (sagittae); ages were validated by marginal increment analysis. Four hundred and twenty five specimens were examined from 214 females and 211 males. Marginal increment analysis on specimens with one to three opaque zones suggested an annual ring deposition in sagittae during the late autumn and spring months.TheC. globicepspopulation was composed of individuals from less than 1 year to 5 years of age for fish measuring between 5–120 mm standard length. Growth was faster for younger than for older age groups. Lengths‐at‐age data were fitted to the Gompertz growth model, and estimates of the model parameters L0, G and g were 26.7 mm 1.58 and 0.30 for pooled cohorts, respectively. The highest levels of growth occurred during late spring and early summer, when water temperatures were at maximum and food was most abundant. The lowest levels of growth occurred during the autumn and winter m

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00005.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The reproductive biology ofPatagonotothen tessellata(Richardson 1845) in the Beagle Channel, Tierra del Fuego, Argentina was analysed from weekly captures over a 3‐year period (1987–1989). The spawning periods and lengths thereof were analysed using GSI curves and monthly percentage distributions of maturation stages. Two gonadal maturation cycles and two spawning periods (winter and summer) within 1 year were defined. Also discussed is whether the same specimens are able to mate successfully in winter and summer, and whether the reproductive effort varies between the seasons. Male parental behaviour and the likely consequences on their energy levels are conside

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00006.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The skin and muscle chemical comparisons from normal and golden coloured African sharptooth catfish,Clarias gariepinus, of two different size (± 360 and ± 1500 g live mass) groups are reported. The skin of the golden strain is shown to be that of an albino that contains no melanin. Size has a stronger influence than strain on the proximate, fatty acid, amino acid and mineral profiles of both the skin and muscle. For both strains, the larger size class had statistically (P>0.05) lower muscle moisture and higher total lipid content than the smaller size class. There was no significant difference in the muscle protein content (16.7–17.6% wet mass basis) between and within the strains and size classes. The skin has higher concentrations of glycine, proline and hydroxyproline than the muscle. The major fatty acids in both the skin and muscle were palmitic (>23%) and oleic (>28%). Of the muscle minerals, potassium was significantly (P>0.05) higher in the larger size class for both strains. The lack of any tangible difference in the muscle chemical composition of both strains therefore makes the golden catfish strain more attractive for the fresh fish consu

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00007.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The cytochemistry and staining of granula in peripheral blood granulocytes in healthy carp (Cyprinus carpioL.) are described. Blood smears were stained for periodic acid‐Schiff (PAS), peroxidase, oxidase, alkaline and acid phosphatase, α‐naphthyl‐acetate esterase, α‐naphthyl‐butyrate esterase, naphthol‐AS‐chloroacetate esterase (AS‐D), naphthol‐AS‐acetate esterase and β‐glucuronidase. Different granula types were shown by triazid‐staining (eosinophil and neutrophil granula) and methylenblue‐staining for basophil granulation. Toluidinblue‐staining was used for basophil granulocytes. Lipids were shown by the Sudan‐black‐reaction. Four granulocyte subpopulations are described: neutrophil, heterophil, basophil and eosinophil granulocytes. Neutrophils possess all tested granula types, whereas heterophil and basophil granulocytes show only basophil granula. Neutrophils and heterophils show no activity of the tested esterases with the exception of AS‐D. Only neutrophils were peroxidase‐positive. Alkaline phosphatase and β‐glucuronidase were not detected in granulocytes. Basophils and especially eosinoph

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00008.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Granulation staining and cytochemistry of peripheral blood monocytes in healthy carp (Cyprinus carpioL.) are described. Blood smears were stained for periodic acid‐Schiff (PAS), peroxidase, oxidase, alkaline and acid phosphatase, α‐naphthyl acetate esterase, α‐naphthyl‐butyrate esterase, naphthol‐AS‐chloroacetate esterase (AS‐D), naphthol‐AS‐acetate esterase and β‐glucuronidase. For representation of different granulations triazide‐staining for eosinophil and neutrophil granules and aqueous methylere‐blue staining for basophil granules were used. Lipids were shown by sudan‐black‐reaction. Monocytes showed only basophil granulation and weak lipid reaction. All tested enzymes were detected, with the exception of peroxidase. The PAS reaction f

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00009.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The thermal preference of juvenile spotted grunter,Pomadasys commersonnii(Haemulidae), was determined in a horizontal thermal gradient. Temperature preference was tested over a range of 17–31°C at three salinities. The modal temperature preferenda at 5, 12 and 35 ppt were 25°C, 24.5°C and 25°C, respectively. They were not significantly different. The thermal preferendum of this species was found to be between 24°C and 25°C. Supplementary experiments were conducted to test the stability of the final thermal preferendum. Initial observation of the behaviour of juvenile spotted grunter indicated the presence of a strong circadian rhythm. However, diel variation in activity did not influence temperature preference. These data are important for the development of a culture protocol for this euryhaline

ISSN:0175-8659    

DOI:10.1111/j.1439-0426.1995.tb00010.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY