Variation in the isotopic signatures of juvenile gray snapper (Lutjanus griseus) from five southern Florida region

Measurements of 18O/16O and 13C/12C ratios in the carbonate of juvenile gray snapper (Lutjanus griseus) sagittal otoliths collected during 2001–2005 from different southern Florida regions indicated significant variations in the ratios between Florida Bay and surrounding areas. Annual differences in isotopic composition were also observed. Classification accuracy of individual otoliths to a region averaged 80% (63% to 96%), thereby enabling the probability of assigning an unknown individual to the appropriate juvenile nursery habitat. Identification of isotopic signatures in the otoliths of gray snapper from Florida Bay and adjacent ecosystems may be important for distinguishing specific portions of the bay that are crucial nursery grounds for juveniles. Separation of gray snapper between geographic regions and nursery sites is possible and has the potential to establish a link between adult gray snapper present on offshore reefs and larvae and juveniles at nursery habitats in Florida Bay or adjacent areas.

Tarpon atlanticus in Colombia: a big fish in trouble

The natural history of Tarpon atlanticus (Valenciennes 1846) is reconstructed based on published information. Tarpon is a remarkable fish because of its peculiar larvae, large adult size, migration patterns and its capability to breathe atmospheric air. Destructive fisheries - some using dynamite - have much reduced the population of tarpon along the Caribbean coast of Colombia, and some catch data are presented which document this.

Length-weight relationship of five serranids from Palawan Island, Philippines

The parameters a and b of the length-weight relationship (LWR) of the form W=aLb are presented for five species of serranids belonging to the genus Cephalopolis. The fish samples used for the study were caught by hook and line, fish corrals, and spearguns during August 1995 to December 1998 from the waters around Palawan Island, Philippines. Information on the LWR of six fishes from other studies conducted in Palawan is also provided.

Length-weight relationships of five species of the family Sparidae in the Gulf of Guinea

Length-weight relationships are presented by sex and by country for five species of the family Sparidae (Pugrus caeruleostictus, Pagellus bellottii, Dentex canariensis, Dentex congonensis, Dentex angolensis) sampled in April 1990 during the Guinea '90 trawling survey off Sierra Leone, Liberia, Cote d'Ivoire and Ghana.

Transforming aquatic agricultural systems towards gender equality: a five country review

Aquatic agricultural systems (AAS) are systems in which the annual production dynamics of freshwater and/or coastal ecosystems contribute significantly to total household income. Improving the livelihood security and wellbeing of the estimated 250 million poor people dependent on AAS in Bangladesh, Cambodia, the Philippines, the Solomon Islands and Zambia is the goal of the Worldfish Center-led Consortium Research Program (CRP), “Harnessing the development potential of aquatic agricultural systems for development.” One component expected to contribute to sustainably achieving this goal is enhancing the gender and wider social equity of the social, economic and political systems within which the AAS function. The CRP’s focus on social equity, and particularly gender equity, responds to the limited progress to date in enhancing the inclusiveness of development outcomes through interventions that offer improved availability of resources and technologies without addressing the wider social constraints that marginalized populations face in making use of them. The CRP aims to both offer improved availability and address the wider social constraints in order to determine whether a multi-level approach that engages with individuals, households and communities, as well as the wider social, economic and political contexts in which they function, is more successful in extending development’s benefits to women and other excluded groups. Designing the research in development initiatives to test this hypothesis requires a solid understanding of each CRP country’s social, cultural and economic contexts and of the variations across them. This paper provides an initial input into developing this knowledge, based on a review of literature on agriculture, aquaculture and gender relations within the five focal countries. Before delving into the findings of the literature review, the paper first justifies the expectation that successfully achieving lasting wellbeing improvements for poor women and men dependent on AAS rests in part on advances in gender equity, and in light of this justification, presents the AAS CRP’s conceptual framew

Cheshire stillwaters. Summary results of 1997 data Oak Mere, Betley Mere and Marbury Big

This is the Cheshire stillwaters. Summary results of 1997 data Oak Mere, Betley Mere and Marbury Big from the National Rivers Authority, June 1998. In May 1997, a Stillwaters meeting was held to discuss the way forward in stillwaters monitoring. It decided upon the establishment of a three year rolling programme, in which three stillwaters would be monitored three times a year, every third year. The stillwaters where chosen due to water quality (i.e potential polluted / sensitive waters), fisheries and ecological interests. The Still waters chosen for the first year (1997) were Oak Mere, Betley Mere and Marbury Big Mere. The surveys were aimed to produce a comprehensive study of the still water through monitoring a variety of parameters. Algal, zooplankton and water chemical samples were taken three times a year, (April, July and September). In addition, fisheries surveys were taken in July and marginal invertebrate surveys taken in September.

Stillwaters monitoring programme. Summary results 2001 and 2002

This is the Stillwaters monitoring programme. Summary results 2001 and 2002 from the Environment Agency North West. Until January 2001 the South Area Stillwaters Sampling Programme consisted of a rolling programme where five to six stillwaters were sampled three times a year (spring, summer and autumn). However, this method was not yielding the water quality information required for long term monitoring. Local weather conditions influence short-term water quality events, e.g. algal blooms, nutrient consumption, stratification, super-saturation etc, so results from one day sampling could only be regarded as individual ‘spot’ samples. Therefore year-on-year comparisons could not be made. It was decided that long-term water quality monitoring of the stillwaters would benefit more from sampling nutrient abundance over winter months. This would give an insight into the carry-over of nutrients available for algal growth the following year and so year-on-year productivity could be assessed. Survey results shown in this report were from: The Mere, Rostherne Mere, Melchett Mere, Tabley Mere, Tatton Mere, Hatchmere, Oak Mere, Black Lake, Chapel Mere, Bar Mere, Oss Mere, Marbury Big Mere, Comber Mere and Betley Mere.

Analysis of the retailer value chain segment in five governorates

This study is the third output of the SDC-funded “Improving Employment and Income through Development of Egyptian Aquaculture” (IEIDEAS), a three-year project being jointly implemented by the WorldFish Center and CARE International in Egypt with support from the Ministry of Agriculture and Land Reclamation. The aim of the study is to gather data on the retailer segment of the aquaculture value chain in Egypt, namely on the employment and market conditions of the women fish retailers in the five target governorates. In addition, this study provides a case study in Minya and Fayoum of the current income levels and standards of living of this target group. Finally, the study aims to identify the major problems and obstacles facing these women retailers and suggest some relevant interventions.

A five-year study of the striped bass fishery of Maryland, based on analyses of the scales

The striped bass, or rock as the species is called in the Chesapeake area, ranks high in value and volume among the commercially important fish taken in Maryland waters and, in addition, is highly prized as a game fish by sportsmen. Interest in the marked fluctuations characteristic of the species stimulated the investigation begun in October, 1941.

Reproductive biology of the blue swimmer crab (Portunus pelagicus, Decapoda: Portunidae) in five bodies of water on the west coast of Australia

Portunus pelagicus was collected at regular intervals from two marine embayments and two estuaries on the lower west coast of Australia and from a large embayment located approximately 800 km farther north. The samples were used to obtain data on the reproductive biology of this species in three very different environments. Unlike females, the males show a loosening of the attachment of the abdominal flap to the cephalothorax at a prepubertal rather than a pubertal molt. Males become gonadally mature (spermatophores and seminal fluid present in the medial region of the vas deferentia) at a very similar carapace width (CW) to that at which they achieve morphometric maturity, as reflected by a change in the relative size of the largest cheliped. Logistic curves, derived from the prevalence of mature male P. pelagicus, generally had wider confidence limits with morphometric than with gonadal data. This presumably reflects the fact that the morphometric (allometric) method of classifying a male P. pelagicus as mature employs probabilities and is thus indirect, whereas gonadal structure allows a mature male to be readily identified. However, the very close correspondence between the CW50’s derived for P. pelagicus by the two methods implies that either method can be used for management purposes. Portunus pelagicus attained maturity at a significantly greater size in the large embayment than in the four more southern bodies of water, where water temperatures were lower and the densities of crabs and fishing pressure were greater. As a result of the emigration of mature female P. pelagicus from estuaries, the CW50’s derived by using the prevalence of mature females in estuaries represent overestimates for those populations as a whole. Estimates of the number of egg batches produced in a spawning season ranged from one in small crabs to three in large crabs. These data, together with the batch fecundities of different size crabs, indicate that the estimated number of eggs produced by P. pelagicus during the spawning season ranges from about 78,000 in small crabs (CW=80 mm) to about 1,000,000 in large crabs (CW=180 mm).