984 resultados para By-catch


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Tese de Doutoramento, Ciências do Mar (Ecologia Marinha)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

OBJECTIVE: The increasingly dominant performance of smaller-sized female gymnasts and increased magnitude of training beginning at an early age have prompted public and medical concerns, especially from an auxological perspective. The objective of this review is to determine if gymnastics training inhibits growth of females. DATA SOURCES: An extensive research of MedLine (PubMed interface) along with cross-referencing was conducted using the Text and MeSH words "gymnastics" in combination with "growth," "maturation," "body height," "body weight," and "growth plate." Our analysis is limited to English articles only.
STUDY SELECTION: All published studies that included data related to the research questions were included. MAIN RESULTS: Although data from three historical cohort studies indicate that female gymnasts are short even before they begin training, clinical reports and cohort studies do suggest that some female gymnasts experience attenuated growth during training followed by catch-up growth during periods of reduced training or retirement. There is conflicting evidence whether the "catch-up" is complete. There were no studies reporting prevalence or incidence of inadequate growth. Three cohort studies provide evidence of reduced growth but training was not partitioned from other confounding factors in the gymnastics environment. Although there is a paucity of studies examining the link of dietary practices with diminished growth in female gymnasts, a review of related dietary literature indicates the potential for insufficient energy and nutrient intake among female gymnasts.
CONCLUSIONS: Elite level or heavily involved female gymnasts may experience attenuated growth during their years of training and competition followed by catch-up growth during reduced training schedules or the months following retirement. However, a cause-effect relation between gymnastics training and inadequate growth of females has not been demonstrated.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The membrane pacemaker hypothesis predicts that long-living species will have more peroxidation-resistant membrane lipids than shorter living species. We tested this hypothesis by comparing the fatty acid composition of heart phospholipids from long-living Procellariiformes (petrels and albatrosses) to those of shorter living Galliformes (fowl). The seabirds were obtained from by-catch of commercial fishing operations and the fowl values from published data. The 3.8-fold greater predicted longevity of the seabirds was associated with elevated content of peroxidation-resistant monounsaturates and reduced content of peroxidation-prone polyunsaturates and, consequently, a significantly reduced peroxidation index in heart membrane lipids, compared with fowl. Peroxidation-resistant membrane composition may be an important physiological trait for longevous species.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Despite decades of conservation efforts on the nesting beaches, the critical status of leatherback turtles shows that their survival predominantly depends on our ability to reduce at-sea mortality. Although areas where leatherbacks meet fisheries have been identified during the long distance movements between 2 consecutive nesting seasons, hot-spots of lethal interactions are still poorly defined within the nesting season, when individuals concentrate close to land. Here we report movements of satellite-tracked gravid leatherback turtles during the nesting season in Western Central Africa, South America and the Caribbean Sea, which account for about 70% of the world population. We show that during and at the end of the nesting season, leatherback turtles have the propensity to remain over the continental shelf, yet sometimes perform extended movements and may even nest in neighbouring countries. Leatherbacks exploit coastal commercial fishing grounds and face substantial accidental capture by regional coastal fisheries (e.g. at least 10% in French Guiana). This emphasises the need for regional conservation strategies to be developed at the ocean scale—both at sea and on land—to ensure the survival of the last leatherback turtles.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Monitoring the abundance and distribution of taxa is essential to assess their contribution to ecosystem processes. For marine taxa that are difficult to study or have long been perceived of little ecological importance, quantitative information is often lacking. This is the case for jellyfish (medusae and other gelatinous plankton). In the present work, 4 years of scyphomedusae by-catch data from the 2007-2010 Irish Sea juvenile gadoid fish survey were analysed with three main objectives: (1) to provide quantitative and spatially-explicit species-specific biomass data, for a region known to have an increasing trend in jellyfish abundance; (2) to investigate whether year-to-year changes in catch-biomass are due to changes in the numbers or in the size of medusa (assessed as the mean mass per individual), and (3) to determine whether inter-annual variation patterns are consistent between species and water masses. Scyphomedusae were present in 97% of samples (N=306). Their overall annual median catch-biomass ranged from 0.19 to 0.92gm-3 (or 8.6 to 42.4gm-2). Aurelia aurita and Cyanea spp. (Cyanea lamarckii and Cyanea capillata) made up 77.7% and 21.5% of the total catch-biomass respectively, but species contributions varied greatly between sub-regions and years. No consistent pattern was detected between the distribution and inter-annual variations of the two genera, and contrasting inter-annual patterns emerged when considering abundance either as biomass or as density. Significantly, A.aurita medusae were heavier in stratified than in mixed waters, which we hypothesize may be linked to differences in timing and yield of primary and secondary productions between water masses. These results show the vulnerability of time-series from bycatch datasets to phenological changes and highlight the importance of taking species- and population-specific distribution patterns into account when integrating jellyfish into ecosystem models.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Knowledge of the environmental factors influence on the spatial-temporal variation of fishes is important to fisheries management and conservation. Thus, the aim of this work was to analyze the influence of the abiotical factors on the spatial-temporal distribution of Paralonchurus brasiliensis (Pisces, Sciaenidae) caught by-catch with the shrimp fishing of Ubatuba and Caraguatatuba regions, north coast of São Paulo State. The fishes were captured every month from January to December 2002. Samples were collected by otter trawl at 5, 10, 15, 20, 25, 30 and 35m depths. The temperatures (surface and bottom), salinities (surface and bottom), sediment features and organic matters were verified for each depth. During all period of the study 12.642 specimens of P. brasiliensis were captured at Ubatuba and 17.166 at Caraguatatuba, which totalized the biomass of 267 for the first and 339kg for the other region. The females outnumbered males in fish population. The greatest values of biomass and number of individuals were registered at the summer and autumn seasons, while the lowest values were observed at the winter and spring seasons. The greatest abundances were found from 15 to 25m depth. In this study, it was verified that P. brasiliensis is a coastal waters associate species. The spatialtemporal distribution of P. brasiliensis is affected by intrusion of SACW and depth for the coastal region and by depth and sediment in sheltered areas such as Caraguatatuba

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Patterns of population dynamics of Loligo plei and Loligo sanpaidensis in Southeastern Brazil were investigated with samples obtained from commercial catches and research cruises from 1999 to 2000 and from 2002 to 2003. Size and maturity Structure of the two species varied according to depth and season. Body size decreased with depth for L plei, whereas for L. sanpaidensis size increased with depth LIP to 100 m and decreased again in deeper areas. GSI and incidence of mature animals decreased with depth in both species. L. plei females matured at a larger size in summer, while size at maturity in L. sanpaulensis was greater in autumn. For L. plei, reproductive events Occurred in the late winter and spring, in depths up to 40 m, and during summer in inshore waters. L. sanpaidensis increased reproductive activity ill Summer, winter and spring between depths of 30 and 80 Ill. The presence of high proportions of immature Squid offshore Suggests that juveniles might develop in these areas and, upon maturation, migrate back to inshore waters to spawn, particularly in spring and Summer. However, differences found in aggregation patterns in different depth strata, as well as the seasonal differences found in the size structure of L. plei and L. sanpaidensis, Could ultimately be due to Changes in the water Column related to food availability. Considering that L. plei and L. sanpaidensis are both caught as by-catch by shrimp trawlers throughout file year, we also discuss hypotheses on the life cycle of the species and its implications for fishery management. We recommend measures to protect squid spawning grounds by creating spring and summer protected areas where trawling would be prohibited until 60 m depth, i.e. in the area and time of year when mature individuals concentrate.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Elasmobranchs are an important by-catch of commercial fisheries targeting bony fishes. Fisheries targeting sharks are rare, but usually almost all specimen bycatched are marketed. They risk extinction if current fishing pressure continues (Ferretti et al., 2008). Accurate species identification is critical for the design of sustainable fisheries and appropriate management plans, especially since not all species are equally sensitive to fishing pressure (Walker & Hislop 1998). The identification of species constitutes the first basic step for biodiversity monitoring and conservation (Dayrat B et al., 2005). More recently, mtDNA sequencing has also been used for species identification and its use has become widespread under the DNA Barcode initiative (e.g. Hebert et al. 2003a, 2003b; Ward et al. 2005, 2008a; Moura et al 2008; Steinke et al. 2009). The aims of this work were: 1) identify sharks and skates species using DNA barcode; 2) compare species of different provenance; 3) use DNA barcode for misidentified species. Using DNA barcode 15 species of sharks (Alopias vulpinus, Centrophorus granulosus, Cetorhinus maximus, Dalatias licha, Etmopterus spinax, Galeorhinus galeus, Galeus melastomus, Heptranchias perlo, Hexanchus griseus, Mustelus mustelus, Mustelus punctulatus, Oxynotus centrina, Scyliorhinus canicula Squalus acanthias, Squalus blainville), 1 species of chimaera (Chimaera monstrosa) and 21 species of rays/skayes (Dasyatis centroura, Dasyatis pastinaca, Dasyatis sp., Dipturus nidarosiensis, Dipturus oxyrinchus, Leucoraja circularis, Leucoraja melitensis, Myliobatis aquila, Pteromylaeus bovinus, Pteroplatytrygon violacea, Raja asterias, Raja brachyura, Raja clavata, Raja miraletus, Raja montagui, Raja radula, Raja polystigma, Raja undulata, Rostroraja alba, Torpedo marmorata, Torpedo nobiliana, Torpedo torpedo) was identified.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The Ecosystem Approach to Fisheries represents the most recent research line in the international context, showing interest both towards the whole community and toward the identification and protection of all the “critical habitats” in which marine resources complete their life cycles. Using data coming from trawl surveys performed in the Northern and Central Adriatic from 1996 to 2010, this study provides the first attempt to appraise the status of the whole demersal community. It took into account not only fishery target species but also by-catch and discharge species by the use of a suite of biological indicators both at population and multi-specific level, allowing to have a global picture of the status of the demersal system. This study underlined the decline of extremely important species for the Adriatic fishery in recent years; adverse impact on catches is expected for these species in the coming years, since also minimum values of recruits recently were recorded. Both the excessive exploitation and environmental factors affected availability of resources. Moreover both distribution and nursery areas of the most important resources were pinpointed by means of geostatistical methods. The geospatial analysis also confirmed the presence of relevant recruitment areas in the North and Central Adriatic for several commercial species, as reported in the literature. The morphological and oceanographic features, the relevant rivers inflow together with the mosaic pattern of biocenoses with different food availability affected the location of the observed relevant nursery areas.