Biology and assessment of the painted sweetlips (Diagramma pictum (Thunberg, 1792)) and the spangled emperor (Lethrinus nebulosus (Forsskål, 1775)) in the southern Arabian Gulf

The population biology and status of the painted sweeplips (Diagramma pictum) and spangled emperor (Lethrinus nebulosus) in the southern Arabian Gulf were established by using a combination of size-frequency, biological, and size-at-age data. Transverse sections of sagittal otoliths were characterized by alternating translucent and opaque bands that were validated as annuli. Comparisons of growth characteristics showed that there were no significant differences (P>0.05) between sexes. There were well defined peaks in the reproductive cycle, spawning occurred from April to May for both species, and the mean size at which females attained sexual maturity was 31.8 cm fork length (LF) for D. pictum and 27.6 cm (LF) for L. nebulosus. The mean sizes at first capture (21.1 cm LF for D. pictum and 26.4 cm LF for L. nebulosus) were smaller than the sizes for both at first sexual maturity and those at which yield per recruit would be maximized. The range of fishing-induced mortality rates for D. pictum (0.37−0.62/yr) was substantially greater than the target (Fopt=0.07/yr) and limit (Flimit=0.09/ yr) estimates. The range of fishing-induced mortality rates for L. nebulosus (0.15/yr to 0.57/yr) was also in excess of biological reference points (Fopt=0.10/yr and Flimit=0.13/yr). In addition to growth overfishing, the stocks were considered to be recruitment overfished because the biomass per recruit was less than 20% of the unexploited levels for both species. The results of the study are important to fisheries management authorities in the region because they indicate that both a reduction in fishing effort and mesh-size regulations are required for the demersal trap fishery.

Consumption to biomass (Q/B) ratio and estimates of Q/B-predictor parameters for Caribbean fishes

Estimates of the Q/B ratio and parameters of equations to 'predict' Q/B values for 116 fish stocks in the Gulf of Salamanca, Colombia are presented. A compilation of these estimates available for Caribbean Sea fishes (264 stocks) is also provided for comparison purposes. General trends in the value of Q/B resulting from differences in the equation and parameter values used are briefly discussed.

Overview of Mark-recovery Studies on Adult and Juvenile Atlantic Menhaden, Brevoortia tyrannus, and Gulf Menhaden, B. patronus

Extensive mark-recapture studies using internal ferromagnetic tags have been conducted on Atlantic menhaden, Brevoortia tyrannus, and Gulf menhaden, B. patronus. From 1966 through 1969, 1,066,357 adult Atlantic menhaden were tagged; subsequently, from 1970 through 1987, 428,272 juveniles of this species were tagged. Similarly, from 1969 through 1971, 75,673 adult Gulf menhaden were tagged; concurrently from 1970 through 1985, 236,936 juveniles were tagged and released. This report provides an overview of the history of the tagging program, methodologies for both release and recovery activities, a summary of release areas and number of fish tagged within each area, and a review of assumptions necessary for the analysis of this type of mark-recovery data. The resulting data sets have proven to be highly useful for a variety of analyses ranging from determination of migratory patterns and population structure to estimating mortality rates. The relatively wide range of acceptance of tagging results by laymen, industry, and analysts alike have made these data extremely useful for management-oriented analyses.

Descriptions of larval, prejuvenile, and juvenile finescale menhaden (Brevoortia gunteri) (family Clupeidae), and comparisons to gulf menhaden (B. patronus)

Larval and juvenile development of finescale menhaden (Brevoortia gunteri) is described for the first time by using wild-caught individuals from Nueces Bay, Texas, and is compared with larval and juvenile development of co-occurring gulf menhaden (B. patronus). Meristics, morphometrics, and pigmentation patterns were examined as development proceeded. An illustrated series of finescale menhaden is presented to show changes that occurred during development. For finescale menhaden, transformation to the juvenile stage was completed by 17−19 mm standard length (SL). By contrast, transformation to the juvenile stage for gulf menhaden was not complete until 23−25 mm SL. Characteristics useful for separating larval and juvenile finescale menhaden from gulf menhaden included 1) the presence or absence of pigment at the base of the insertion of the pelvic fins; 2) the standard length at which medial predorsal pigment occurs; 3) differences in the number of dorsal fin ray elements; and, 4) the number of vertebrae.

Preservation of fish by freezing and glazing. Pt. 3. Effect of freezing, glazing and frozen storage on the B-vitamins and essential minerals present in the fish flesh

The changes occurring in moisture, thiamine, riboflavin niacin, phosphorus, iron and calcium in pomfret, surmai and frozen mackerel, glazed with ascorbic acid, citric acid, sodium chloride, glucose, sodium nitrite and kept under frozen storage were studied up to 6 months and results reported.

Economics of operation of 38' G.R.P. fishing vessels issued by the A.D.B. Fisheries Project: a case study

The author gives a financial and economic valuation of the operation of vessels in the 38 foot GRP class. He discusses particularly the materials and methods of fishing they use, species composition of their catches, their rate of return, break-even analysis, financial and social analysis.

Distribution of vitamin B-12 in some fishes and marine invertebrates

Distribution of vitamin B-12 in the skeletal muscle of several marine and fresh water fish and marine invertebrates are reported. The vitamin B-12 content of white muscle of various fish ranges between 0.05 and 1.5 micrograms. The elasmobranch fish, such as sharks and rays, has a lower levels of vitamin B-12. The distribution of vitamin B-12 in the red muscle, heart, brain and liver of various fish is also shown. Content in red muscle varies between 3 and 22 micrograms, averaging 8 micrograms. The values show that the heart is a rich source of vitamin B-12. Internal organs are also rich in vitamin B

Effect of two green algae species (Chlorella sp. & Scenedesmus obliquus) enriched with B group vitamins on food chain of Rutilus frisii kutum (Kamensky, 1901) fry

The Effect of two freshwater green algae species Chlorella sp. & Scenedesmus obliquus enriched (from the beginning of culture and after 96 hours) with different dosages of B group vitamins (0, 0.5, 1, and 2 ml of enriching solution per each liter of algae medium) on fecundity of Daphnia magna and growth of Rutilus frisii kutum fry were investigated in a research from spring, 2008 to autumn, 2009. First, each of the green algae species were cultured purely and massively in the Zander (Z-8+N) medium and then the nutritional value (the amount of protein, lipid, and carbohydrate) of enriched algae were meausered. In this study, enriching of Chlorella sp. & S. obliquus with a suitable mix of B group vitamins significantly improved their nutritive value. So the highest amount of nutritional value of Chlorella sp. was obtained because of enriching with dosage 0.5 ml.l-1 (366.654Kcal) and for Scenedesmus obliquus with dosage of 1 ml.l-1 (376.95Kcal). The acquired amount from control group showed an increase of respectively 42% and 11%. According to the results, increased dosages of enriching solution caused Daphnia fecundity to increase (at both stages : enrichment from the beginning of culture and after 96 hours). So the highest average of D. magna reproduction rate was obtained through being fed with Chlorella sp. and S. obliquus enriched with dosage of 2 ml enriching solution per liter of algae medium. The average fecundity of D. magna fed with Chlorella sp. enriched with dosage of 2 ml.l-1 enriching solution from the beginning of culture and after 96 hours was obtained respectively 2.128 ± 0.375 and 2.1 ± 0.69 and the average fecundity of D. magna fed with S. obliquus enriched with dosage of 2 ml enriching solution from the beginning of culture and after 96 hours was obtained respectively 2.128 ± 0.375 and 2.1 ± 0.69 which showed respectively an increase of 61 ٪, 91٪, 77 ٪, and 83٪ in proportion to the acquired amount from control group. When enriching solution was added to either algae culture medium from the beginning of culture, showed statistically significant differences (P<0.05) between dosages of 0 and 2 ml.l-1, 1 and 2 ml.l-1, and 0.5 and 2 ml enriching solution per each liter of Chlorella sp. culture medium and between dosages of 0 and 1 ml.l-1, and 0 and 2 ml enriching solution per each liter of S. obliquus culture medium. The highest average of body weight gain percentage and specific growth rate of kutum fry was obtained respectively 21.19%, 26.63%, 1.92, and 2.34 from the beginning of culture and after 96 hours with dosage of 1 ml B group vitamins per each liter of Chlorella sp. culture medium, which showed respectively an increase of 50%, 70%, 46%, and 62% in proportion to the acquired amount from control group. In the cases which Chlorella sp. were grown in the medium containing vitamin, from point of view of the average percentage of weight and specific growth rate of kutum fry significant differences were observed on the basis of the result of One-way ANOVA between dosages of 0 and 1, 1 and 2 , 0.5 and 1 ml B group vitamins per each liter. The highest average of body weight gain percentage and specific growth rate of kutum fry was obtained respectively 32.02%, 29.42%, 2.78, and 2.34 from the beginning of culture and after 96 hours with dosage of 2 ml B group vitamins per each liter of S. obliquus culture medium, which showed respectively an increase of 32%, 19%, 28%, and 17% in proportion to the acquired amount from control group. In the cases which S. obliquus were grown in the medium containing vitamin, from point of view of the average percentage of weight and specific growth rate of kutum fry significant differences were observed on the basis of the result of One-way ANOVA between dosages of 0 and 1, 0 and 2. According to the results of the present research we can say that considerable enhancement in the quality of the food of D. magna can be made by manipulation of the nutritional value of fresh water unicellular green algae with suitable mixture of B group vitamins, so that both the fecundity of D. magna will increase and the nutritional requirements of the kutum fry will be filled in this way.

The history of fish communities, biodiversity and environment of Lake Victoria and the lessons learnt

The first fishery survey of Lake Victoria was conducted between 1927 and 1928 (Graham 1929). Atthat time, the lake had a diverse fish fauna and the fishery was dominated by two endemic tilapiine cichlids; Oreochromis esculentus (Graham 1929) and O. variabilis (Boulenger 1906). There were a number of other species such as Protopterus aethiopicus Heckel 1851, Bagrus docmac (Forsk.) 1775, Clarias gariepinus (Burchell), Barbus species, mormyrids, Synodontis spp, Schilbe intermedius (Linn.) 1762 and Rastrineobola argentea Pellegrin, 1904 that were also abundant in the lake most of which made a significant contribution to the fishery (Graham 1929, Worthington 1929, 1932, Kudhongania & Cordone 1974). Haplochromine cichlids were represented by at least 300 species more than 99% of them endemic (Greenwood, 1974; Witte et al., 1992 a & b). The fishery of Lake Victoria was similar to that of lakes Kyoga and Nabugabo (Worthington 1929; Trewavas 1933; Greenwood 1965, 1966; Beadle 1962, 1981). There were also important fisheries on the inflowing rivers of Lake Victoria, the most important of which were Labeo victorianus and Barbus altianalis (Cadwallader 1965). The small sized species notably Rastrineobola argentea and haplochromines cichlids were not originally commercially exploited.