Applications of generalized additive model (GAM) to satellite-derived variables and fishery data for prediction of fishery resources distributions in the Arabian Sea   总被引：2，自引：0，他引：2  

H. U. Solanki  Dhyey Bhatpuria  Prakash Chauhan 《国际地球制图》2017,32(1):30-43

This study aims to illustrate how remotely sensed oceanic variables and fishing operations data can be used to predict suitable habitat of fishery resources in Geographic Information System. We used sea surface height anomaly (SSHa), sea surface temperature (SST), chlorophyll concentration (CC), photosynthetically active radiation (PAR) and fishing depth as predictor variables. Fishery data of Indian squid (Loligo spp.) and catfish (Tachysurus spp.) for study period (1998–2004) were segregated randomly to create training and validation. Catch was normalized into Catch per unit Effort (kg h^?1). Generalized additive modelling was performed on training data and then tested on validation data. Suitable ranges of SST, CC, SSHa and PAR for different species distributions were derived and integrated to predict their spatial distributions. Results indicated good match between predicted and actual catch. Monthly probability maps of predicted habitat areas coincide with high catch of the particular month for the study period.  相似文献   

Global fisheries subsidies: An updated estimate     

《Marine Policy》2016

The aim of this paper is to provide an updated estimate of global fisheries subsidies. It builds on earlier estimates and methodologies to re-estimate and discuss the various types of subsidies provided by governments around the world. The results suggests that total subsidies were about USD 35 billion in 2009 dollars, which is close to the earlier estimate of 2003 subsidies once they are adjusted for inflation. Capacity-enhancing subsidies constituted the highest category at over USD 20 billion. For all regions, the amount of capacity-enhancing subsidies is higher than other categories, except for North America, which has higher beneficial subsidies. The analysis reveals that fuel subsidies constitute the greatest part of the total subsidy (22% of the total), followed by subsidies for management (20% of the total) and ports and harbors (10% of the total). Subsidies provided by developed countries are far greater (65% of the total) than those by developing countries (35% of the total) even though the latter lands well above 50% of total global catch. Asia is by far the greatest subsidizing region (43% of total), followed by Europe (25% of total) and North America (16% of total). Japan provides the highest amount of subsidies (19.7% of total), followed by the United States and China at 19.6% of total.  相似文献   

Interactions between whale sharks,Rhincodon typus Smith, 1928 (Orectolobiformes,Rhincodontidae), and Brazilian fisheries: The need for effective conservation measures     

《Marine Policy》2016

This study reports three interaction events between the whale shark (Rhincodon typus) and fisheries in Brazilian waters. Two events were described as incidental captures in a gillnet fishery on the northern coast of Rio de Janeiro State, in southeastern Brazil. The last event took place at the Royal Charlotte Oceanic Bank (RCOB), in the southern region of Bahia State, where five fishermen filmed their interaction with a juvenile specimen. For one of the incidental captures, the fish was landed and consumed by locals, and for the other, the shark was released. In the RCOB, the fishermen touched the whale shark with their hands, wooden sticks and even rode on it. In addition, 74 interviews were conducted with fishermen from Bahia about sightings and possible interactions with R. typus. According to statements made by the fishermen, although not frequent, the conduct reported for the RCOB occasionally takes place in the region. Evaluating information of this nature is important to support government plans that regulate fishing activities in order to reduce incidental captures and the harassment of whale sharks. Encouraging the participation of fishermen in a collaborative monitoring program for R. typus may be a good way to better understand the threats to the species at a reduced cost, particularly for developing countries, such as Brazil.  相似文献   

Fishers’ knowledge indicates short-term temporal changes in the amount and composition of catches in the southwestern Atlantic     

《Marine Policy》2016

The scarcity of data on fish catches difficult management of small-scale fisheries in developing countries. This study applies fishers’ knowledge to investigate temporal changes in the amount (biomass) and composition (major ecological categories) of fishing resources exploited by small-scale coastal fisheries in the southeastern Brazilian coast. Four hypotheses were investigated: (1) The amount of fish caught reported by fishers would decrease over time. (2) Older fishers would report higher fish catches than younger fishers. (3) Recent interviews would mention large-sized predators less often. (4) Recent interviews would mention less high valued fishing resources. Interviews with 421 fishers in 36 communities in the southeastern Brazilian coast were analyzed, covering a time span of 14 years, from 1995 to 2009. The hypothesis 1 was confirmed, 3 was partially confirmed, while 2 and 4 were not confirmed. Fishers’ age was unrelated to all variables. The results from fishers’ interviews indicated the temporal trends of: (1) a decrease in the biomass of fish caught; (2) an increase in the occurrence of smaller fish and invertebrates in the catch; (3) an increase of high value fishing resources; and (4) maintenance of large predators. The first two indicators suggest excessive fishing, but the later indicators (3 and 4) suggest that the socioecological system of the southeastern Brazilian coast had not yet undergone major ecological shifts.  相似文献   

Effects of metals and sediment particle size on the species composition of the epifauna of Pinna bicolor near a lead smelter,Spencer Gulf,South Australia     

Trevor J. Ward  Peter C. Young 《Estuarine, Coastal and Shelf Science》1984,18(1):79-95

Pinna bicolor (Mollusca: Pelecypoda) were transplanted between four sites near a lead smelter. The species composition of their epifauna (sessile and mobile) was examined in relation to characteristics of both sediments and seston at the sites. Seventy-two taxa were distinguished in the epifaunal community. Substantial differences were found in the short-term sensitivity of some of the species to concentrations of Cd, Pb and Zn in sediments and to sediment particle size. The short-term sensitivity of many species to metals or sediment particle size explained their long-term distribution pattern. Twenty-three taxa were identified as significantly characterizing the faunal differences. Of these, eleven (four molluscs, four bryozoans, two barnacles and one ascidian) were affected by both sediment metal concentration and particle size, and eight (four molluscs, one bryozoan, one polychaete, one hydroid and one barnacle) were affected by metal contamination but not particle size. Of all fauna examined, the Bryozoa were the most metal-sensitive. Four species, Smittina raigii (Bryozoa), Galeolaria sp. 1 (Polychaeta), Epopella simplex (Cirripedia) and Monia ione (Pelecypoda) were identified by their short- and long-term sensitivity to metal contamination, and absence of sensitivity to sediment particle size, as suitable species for monitoring the effects of metal contamination on the epifauna. The implications of the results for toxicity-testing are discussed.  相似文献   

Factors Influencing Fish Composition in an Australian Intermittently Open Estuary. Is Stability Salinity-Dependent?     

S. P. Griffiths 《Estuarine, Coastal and Shelf Science》2001,52(6):739

The ichthyofauna of the intermittently open Shellharbour Lagoon in southeastern Australia was sampled over 14 months to investigate factors influencing species composition. Zostera capricorni and bare sand habitats were sampled every two months with a fine-mesh seine. Of the 10 277 fish caught representing 19 families and 27 species, the most numerically dominant species were Pseudogobius olorum and Pseudomugil signifer. The most abundant economically important species were Acanthopagrus australis, Mugil cephalus and Myxus elongatus. Mean number of fish and species was significantly higher over Zostera than bare sand during months immediately after the estuary opened when juvenile marine fishes recruited, demonstrating the estuary's nursery function. In contrast to other intermittently open estuaries in Australia and South Africa, Shellharbour Lagoon's fish assemblage appears resilient to perturbation and does not undergo distinct seasonal variations. This may be a result of the estuary's short open phases providing less opportunity for marine fishes to enter. Perhaps more importantly, the less dramatic fluctuations in salinity between open and closed phases maintains salinity at a level intermediate of the tolerances of both marine and estuarine fishes.  相似文献   

Objectives of fisheries management: case studies from the UK, France, Spain and Denmark     

Simon Mardle  Sean Pascoe  Jean Boncoeur  Bertrand Le Gallic  Juan J. García-Hoyo  Ins Herrero  Ramon Jimenez-Toribio  Concepcin Cortes  Nuria Padilla  Jesper Raakjaer Nielsen  Christoph Mathiesen 《Marine Policy》2002,26(6)

The main objectives of fisheries management are generally similar throughout the world. These are often stated in policy documents such as the Common Fisheries Policy and the Magnuson–Stevens Fishery Conservation and Management Act. However, at the local level often the key objectives of management are more detailed, characterised by both the overriding management structure and the status and type of fishery concerned. In this paper, we consider case study fisheries from the UK, France, Spain and Denmark to compare some of the various types of fisheries and fisheries management systems that exist in the European Union. From this, we define the key objectives for each management system.  相似文献   

Flexible management of fishing rights and a sustainable fisheries industry in Europe   总被引：3，自引：0，他引：3  

Steffen Hentrich  Markus Salomon   《Marine Policy》2006,30(6):712-720

Although overexploitation of commercial fish stocks in European waters has been in the public debate now for more than 20 years, the European Union has so far failed to implement sustainable fisheries management. Millions in subsidies paid to the fishing industry have led to significant excess capacity in the fishing fleet. Various feeble attempts to stop overexploitation of marine resources have failed. The cause is that fishing policy is highly dominated by short-term socioeconomic interests. There is an urgent need for a new fisheries management system in Europe that supports reductions in the fishing fleet, increases responsibility among fishers and guarantees long-term conservation of natural marine resources.Transferable rights to fish have proved a reliable and effective means of creating incentives to conserve marine resources. By strengthening individual fishing rights under flexible quota management systems, the EU Member States could, within the Common Fisheries Policy, make a significant contribution to conserving fish stocks, to reducing excess capacity and to raising the profitability of the fisheries industry. A closer look at existing reservations against a flexible management system shows most of the objections to be overstated or capable of resolution.  相似文献   

The Privatization of the Oceans by Rognvaldur Hannesson     

Henry Frew 《The Professional geographer》2007,59(1):156-156

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Microhabitat use by endangered Iberian cyprinids nase Iberochondrostoma almacai and chub Squalius aradensis     

José M. Santos  Maria T. Ferreira 《Aquatic Sciences - Research Across Boundaries》2008,70(3):272-281

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