1000 resultados para Fishes Fertility


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A computer program was developed for the identification of the teleost fish eggs that may be found in the pelagic zone of the Black Sea. The program identifies eggs of 70 species, using up to 28 descriptive characters, and may be adapted for use outside of the Black Sea.

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The relationship between length (L) and weight (W) was estimated for 80 species belonging to 50 families of marine fishes from the shelf and upper slope of southern Brazil (lat. 28°S - 34°S). Sample sizes (n) for different species ranged from 11 to 14 741 specimens collected from commercial landings and research surveys. The fit of the equations (W=aLb) with a and b parameters estimated from regular and functional regression (of log-transformed weight and length data) as well as from a non-linear iterative process using the quasi-Newton algorithm were compared. The non-linear method gave the most accurate estimates in terms of residual sum of squares. Differences were less than 2.3% for n>500 compared with predictive regressions and 1.5% compared with functional regressions. No difference was observed between both predictive and functional regressions. Determination coefficients (r2) increased with sample size, and the highest r2 were obtained for 50fishes.

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Details are given of a new software package MAXIMS which may be used to estimate the daily food consumption of fish. The software estimates the feeding times, the rates of ingestion and evacuation and related parameters. Two applications of the program are described. The first pertains to anchovy (Engraulis ringens ) with one feeding period per day, and the second one to juvenile cod (Gadus morhua ), which feed during dawn and dusk.

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Length-weight relationships of 73 fish populations, covering 20 families, 28 genera and 40 species inhabiting freshwater ecosystems in Nigeria, were estimated (73 cases) or assembled from the literature (20 cases), and tested for difference between ecosystem types, There were no significant differences in the exponent of these relationships between lotic and lentic systems.

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Length-weight relationships (LWR) of 76 fish populations, distributed among 11 families, 18 genera and 22 species, inhabiting coastal (marine/brackish water ) ecosystems in Nigeria were estimated (39 cases) or assembled from the literature (37 cases). The mean exponent (b = 2.912) is significantly less than 3. While the frequency distribution of a was positively skewed, that of b was approximately normal. The mean a and b data are also presented by fish genera and families.

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Length-weight relationships were calculated for nine fish species from Lake Volvi (Macedonia, Hellas), caught with gillnets of five different mesh sizes between October 1995 and October 1996. In addition, length-weight relationships for 24 Greek freshwater fish species and one hybrid were also obtained from the literature. The values of the exponent of the length-weight relationships for all fish species examined ranged between 2.14 and 3.70 (mean = 3.12; SE=0.0321), and the median value was 3.19.

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The parameters a and b of the length-weight relationship of the form W=aL super(b) were estimated for 13 fish species sampled in a seagrass meadow in Negros Oriental, Philippines. Also, to facilitate conversions, the relationship between total length and standard length for the 13 species is given.

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This preliminary compilation presents vital parameters for 22 species of freshwater fish from Lake Kariba. The majority of the growth parameters are derived from tables in Balon and Coche's "Lake Kariba: a man-made tropical ecosystem in central Africa". The rest of the parameters are compiled from more recent sources and unpublished data.

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This paper presents a checklist of reef fishes of West Sumatra and adjacent provinces. The list includes 362 species of 143 genera and 46 families and contains seven new records and nine probable new species for Indonesia. It also uses information from sources only available in Bahasa Indonesia. The relative paucity of the fish fauna in West Sumatra seems to be related to the habitat destruction caused by illegal fishing with explosives or poisons such as cyanide.

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Length-weight relationships of 316 reef and lagoon fish from New Caledonia (SW Pacific Ocean) belonging to 68 families are computed. A total of 43,750 individuals was used for this purpose. Fish were sampled by different techniques such as rotenone poisoning, handline and bottom longline fishing, gill and trammel nets, and trawling in various isotopes (coral reefs, lagoon bottoms and mangroves).

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Length-weight relationship (LWR) parameters of 72 species of fishes and 15 species of cephalopods caught in the Balearic Islands demersal fishery are reported. This is the first compilation of LWR for these groups in the Balearic Islands.

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Six enzyme systems coding for 10 loci and 6 proteins were examined in the blood of Polypterus senegalus, Clarias lazera, Tilapia nilotica and Protopterus annectens, using electrophoresis. Six loci were polymorphic in all the four species, three polymorphic in three species and one polymorphic in T. nilotica. Four protein loci were monomorphic in all the four species with variants in P. senegalus and T. nilotica. Haemoglobin can be used as a species-specific marker. Polymorphism was 53-56 per cent and average heterozygosity was 0.1-0.15.

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Earlier findings on epizootic ulcerative syndrome (EUS) and the present observation of the authors on transmission of EUS to snakehead (Channa sp.) without skin damage provide evidence to suggest that the invasive fungus associated with EUS is a primary pathogen.

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Conservation and the potential and need for aquaculture of three major fish (Catlocarpio siamensis, Probarbus spp. and Pangasius gigas) of the Mekong River are discussed. Different steps being undertaken by the Cambodian government in doing such activities are highlighted.

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The parameters a and b of the length-weight relationship of the form W = a.Lb were estimated for 15 fish species caught along the coastline of Jordan in the Gulf of Aqaba. The sampling was carried out between July 1999 and January 2001. Data from 1 000 fish individuals (identified to eight families and 15 species) were used for this purpose.