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Local Fishermen (local + fishermen)
Selected AbstractsMorphometry and sexual dimorphism of the coastal spotted dolphin, Stenella attenuata graffmani, from Bahía de Banderas, MexicoACTA ZOOLOGICA, Issue 4 2004Laura Sanvicente-Añorve Abstract External measurements and size differences between the sexes were examined in the coastal spotted dolphin, Stenella attenuata graffmani, in Bahía de Banderas, on the Mexican Pacific coast. The dolphins were collected by local fishermen and 29 external characteristics were measured by members of the Marine Mammals Laboratory, University of Mexico. The length of each characteristic with respect to total length was analysed through adjustment of the data to a power equation. A stepwise discriminant analysis was applied to the absolute values and to those expressed as proportions to analyse the differences between the sexes. Results indicate that growth in these dolphins is generally negatively allometric, and most of the characteristics measured were, in both absolute and proportional terms, greater in male dolphins than in female dolphins. As found in many species of odontocetes, the discriminant analysis showed that the main differences between the sexes for this coastal subspecies include the relative positions of the umbilicus, the genital aperture and the anus. The morphometric data provided by this study, corresponding to 29 specimens of S. a. graffmani collected in a restricted locality of the Mexican Pacific coast, are particularly interesting to studies documenting latitudinal morphological differences in the coastal spotted dolphin. [source] Fisheries of two tropical lagoons in Ghana, West AfricaFISHERIES MANAGEMENT & ECOLOGY, Issue 6 2004H. R. Dankwa Abstract, The fisheries of two coastal lagoons, Keta and Songor, were studied as part of Ghana Coastal Wetlands Management Project (GCWMP) aimed at sustainable exploitation of wetland resources. Fish samples were obtained with seine nets and cast net as well as from local fishermen. Water quality parameters (pH, dissolved oxygen, temperature and turbidity) were similar in the two lagoons, except for salinity, which was significantly different (P < 0.001). Despite their close geographical proximity, the two lagoons supported different fish assemblages with the blackchin tilapia, Sarotherodon melanotheron Rüppell, and the redchin tilapia, Tilapia guineensis (Bleeker), being the most important commercial fishes in both lagoons. The number of individuals for each species in Songor Lagoon were far more abundant, with densities several orders of magnitude higher than in Keta Lagoon. However, both species were significantly larger (P < 0.01) in the latter [15,121 and 25,157 mm standard length (SL)] than in the former lagoon (30,102 and 15,95 mm SL) for S. melanotheron and T. guineensis respectively. Over-fishing, use of small-size mesh nets, limited mixing of marine and fresh water were some of the factors limiting fish production in both lagoons. [source] Ecology and exploitation pattern of a landlocked population of sand smelt, Atherina boyeri (Risso 1810), in Trichonis Lake (western Greece)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2001I. D. Leonardos Age, growth, mortality and exploitation pattern of sand smelt, Atherina boyeri (Risso 1810), in Trichonis Lake (western Greece) were studied from samples taken from catches of local fishermen. Individuals ranged between 44 and 109.53 mm in total length (TL). Age determinations based on scale readings show that the population has a 4-year life cycle. Sand smelt grows allometrically (b=3.18) and relatively rapidly, achieving 52.3% of the growth during the first year; thereafter the annual growth rate drops quickly. The von Bertalanffy growth parameters for all individuals are: L,=112.40 mm, k= 0.42 years,1,,, to=,0.40 years. The total mortality rate was Z=1.65 years,1 and the natural mortality rate M=1.07 years,1. The exploitation rate indicates that the population is rather underexploited (E=0.35). [source] Prediction and verification of possible reef-fish spawning aggregation sites in Los Roques Archipelago National Park, VenezuelaJOURNAL OF FISH BIOLOGY, Issue 4 2010J. Boomhower This study attempts to predict and verify possible spawning aggregation sites and times in the Los Roques Archipelago National Park, Venezuela, based on physical reef characteristics and the knowledge of experienced local fishermen. Three possible aggregation sites were selected for monitoring based on satellite images, low-cost bathymetric mapping and interviews with experienced local fishermen. Abundances and sizes of 18 species that are known to form reproductive aggregations were monitored at these sites using underwater visual census for 7 days after each full moon from February to August, 2007. While spawning events were not observed, possible indirect evidence of spawning aggregations was found for Lutjanus analis at Cayo Sal and Boca de Sebastopol, Lutjanus apodus at Cayo Sal, Lutjanus cyanopterus at Cayo Sal and Piedra La Guasa and Epinephelus guttatus at Bajo California and Cayo de Agua. Additionally, indirect evidence was identified for the past existence of a spawning aggregation of Epinephelus striatus in the northern part of the archipelago, which may have been eliminated by overfishing c.15 years ago. Bathymetric mapping showed that the shelf edge at sites monitored in this study was shallower than at spawning aggregation sites in other parts of the Caribbean, and that sites were not proximal to deep water. While this study does not prove the existence or locations of spawning aggregations of reef fishes in the archipelago, it does add insight to a growing understanding of generalities in the relationship between seafloor characteristics and the locations of transient reef-fish spawning aggregations in the Caribbean. [source] The influence of human disturbance on California sea lions during the breeding seasonANIMAL CONSERVATION, Issue 6 2009K. Holcomb Abstract California sea lions Zalophus californianus occupy 26 islands in the Gulf of California (GoC), Mexico. Although human presence is prohibited on these islands without a government permit, the law is not enforced and tourism to the islands is increasing. Tourists, along with local fishermen, often come ashore to get close to the animals, which may disrupt behaviors critical for reproduction. In this paper, we report the results of an experimental study on the behavioral effects of human disturbance on California sea lions in the GoC. To document effects, we recorded sea lion behavior immediately before and in 10-min intervals for up to an hour after experimental human disturbance. Our results showed few behavioral responses of sea lions to human disturbance. Adult females and juveniles demonstrated immediate responses, but these were not consistent between years, apparent an hour after disturbance, or evident across other age and sex classes. These results suggest that California sea lions may be resilient to human disturbance and a possible flagship species for ecotourism, but further studies of the physiological and population-level effects of human disturbance are needed. [source] Using Oral History Techniques in A NOAA Fisheries Service (NMFS) Education and Outreach Project: Preserving Local Fisheries Knowledge, Linking Generations, and Improving Environmental LiteracyANNALS OF ANTHROPOLOGICAL PRACTICE, Issue 1 2007Susan Abbott-Jamieson Oral historical interviews are a core activity in a successful outreach and education project piloted by the National Oceanic and Atmospheric Administration (NOAA)'s National Marine Fisheries Service (NMFS) in two Maine high schools between 2003 and 2005. Through interviews with local fishermen and others in fishing-related industries, Local Fisheries Knowledge (LFK) Pilot Project students have explored the connections between fisheries, the marine environment, their communities, and their own lives, while documenting and preserving the knowledge and experiences of local residents for future generations. This article describes the pilot project's use of oral history methods, and discusses the project's role in three agency interest areas: (1) public outreach, (2) education, and (3) documenting fishing communities' lifeways and local fisheries knowledge. [source] Contributions of ethnobiology to the conservation of tropical rivers and streamsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2008R.A.M. Silvano Abstract 1.This study aimed to link basic ethnobiological research on local ecological knowledge (LEK) to the conservation of Brazilian streams, based on two case studies: original data on LEK of fishermen about freshwater fish in the Negro River, Amazon, and previously published data about LEK of farmers on the ecological relationship between forest and streams in the Macabuzinho catchment, Atlantic Forest. 2.Information was obtained from fishermen through interviews using standard questionnaires containing open-ended questions. Informants for interview were selected either following some defined criteria or applying the ,snowball' method. 3.Fishermen's LEK about the diets and habitats of 14 fish species in the Negro River provided new biological information on plant species that are eaten by fish, in addition to confirming some ecological patterns from the biological literature, such as dependence of fish on forests as food sources. 4.In the Atlantic Forest, a comparison between farmers' LEK and a rapid stream assessment in the farmers' properties indicated that farmers tended to overestimate the ecological integrity of their streams. Farmers recognized at least 11 forest attributes that correspond to the scientific concept of ecosystem services. Such information may be useful to promote or enhance dialogue among farmers, scientists and managers. 5.These results may contribute to the devising of ecosystem management measures in the Negro River, aimed to conserve both rivers and their associated floodplain forests, involving local fishermen. In the Atlantic Forest, we proposed some initiatives, such as to allow direct economic use of their forests to conciliate conflicting perceptions of farmers about ecological benefits versus economic losses from reforestation. Despite their cultural, environmental and geographical differences, the two study cases are complementary and cost-effective and promising approaches to including LEK in the design of ecological research. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||