304 resultados para Fish habitat improvement


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(PDF contains 3 pages.)

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Seagrass communities are among the richest and most productive, photoautotrophic coastal systems in the world. They protect and improve water quality, provide shoreline stabilization, and are important habitats for an array of fish, birds, and other wildlife. Hence, much can be gained by protecting and restoring these important living resources. Human’s impact on these vital resources from population growth, pollution, and physical damage from boating and other activities can disrupt the growth of these seagrasses communities and have devastating effects on their health and vitality. Inventory and monitoring are required to determine the dynamics of seagrasses and devise better protection and restoration for these rich resources. The purpose of this seagrass workshop, sponsored by NOAA’s CSC , USGS, and FMRI, was to move toward greater objectivity and accuracy in seagrass mapping and monitoring. This workshop helped foster interaction and communication among seagrass professionals. In order to begin the process of determining the best uniform mapping process for the biological research community. Increasing such awareness among the seagrass and management communities, it is hoped that an improved understanding of the monitoring and mapping process will lead to more effective and efficient preservation os submerged aquatic vegetation. (PDF contains 20 pages)

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This compendium presents information on the life history, diet, and abundance and distribution of 46 of the more abundant juvenile and small resident fish species, and data on three species of seagrasses in Florida Bay, Everglades National Park. Abundance and distribution of fish data were derived from three sampling schemes: (1) an otter trawl in basins (1984–1985, 1994–2001), (2) a surface trawl in basins (1984–1985), and (3) a surface trawl in channels (1984–1985). Results from surface trawling only included pelagic species. Collections made with an otter trawl in basins on a bi-monthly basis were emphasized. Nonparametric statistics were used to test spatial and temporal differences in the abundance of species and seagrasses. Fish species accounts were presented in four sections – Life history, Diet, Abundance and distribution, and Length-frequency distributions. Although Florida Bay is a subtropical estuary, the majority of fish species (76%) had warm-temperate affinities; i.e., only 24% were solely tropical species. The five most abundant species collected, in descending order, by (1) otter trawl in basins were: Eucinostomus gula, Lucania parva, Anchoa mitchilli, Lagodon rhomboides, and Syngnathus scovelli; (2) surface trawl in basins were: Hyporhamphus unifasciatus, Strongylura notata, Chriodorus atherinoides, Anchoa hepsetus, and Atherinomorus stipes; (3) surface trawl in channels were: Hypoatherina harringtonensis, A. stipes, A. mitchelli, H. unifasciatus, and C. atherinoides. (PDF file contains 219 pages.)

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Submersible surveys at numerous reefs and banks in the northwestern Gulf of Mexico (NWGOM) were conducted as part of the Sustainable Seas Expedition (SSE) during July/August 2002 to identify reef fish communities, characterize benthic habitats, and identify deep coral reef ecosystems. To identify the spatial extent of hard bottom reef communities, the Flower Garden Banks National Marine Sanctuary (FGBNMS) and the U.S. Geological Survey (USGS) mapped approximately 2000 km2 of the Northwestern Gulf of Mexico (NWGOM) continental shelf during June 2002 with high-resolution multibeam bathymetry. Previous investigations conducted on the features of interest (with the exceptions of East and West Flower Garden and Sonnier Banks, accessible by SCUBA) had not been conducted since the 1970s and 1980s, and did not have the use of high-resolution maps to target survey sites. The base maps were instrumental in navigating submersibles to specific features at each study site during the Sustainable Seas Expedition (SSE)—a submersible effort culminating from a partnership between the National Atmospheric and Oceanic Administration (NOAA) and the National Geographic Society (NGS). We report the initial findings of our submersible surveys, including habitat and reef fish diversity at McGrail, Alderdice, and Sonnier Banks. A total of 120 species and 40,724 individuals were identified from video surveys at the three banks. Planktivorous fishes constituted over 87% by number for the three banks, ranging from 81.4% at Sonnier Banks to 94.3% at Alderdice Bank, indicating a direct link to pelagic prey communities, particularly in the deep reef zones. High numbers of groupers, snappers, jacks, and other fishery species were observed on all three features. These sites were nominated as Habitat Areas of Particular Concern (HAPC) by the Gulf of Mexico Fishery Council in March 2004. Data obtained during this project will contribute to benthic habitat characterization and assessment of the associated fish communities through future SCUBA, ROV, and submersible missions, and allow comparisons to other deep reef ecosystems found throughout the Gulf of Mexico and western Atlantic Ocean.

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As part of a multibeam and side scan sonar (SSS) benthic survey of the Marine Conservation District (MCD) south of St. Thomas, USVI and the seasonal closed areas in St. Croix—Lang Bank (LB) for red hind (Epinephelus guttatus) and the Mutton Snapper (MS) (Lutjanus analis) area—we extracted signals from water column targets that represent individual and aggregated fish over various benthic habitats encountered in the SSS imagery. The survey covered a total of 18 km2 throughout the federal jurisdiction fishery management areas. The complementary set of 28 habitat classification digital maps covered a total of 5,462.3 ha; MCDW (West) accounted for 45% of that area, and MCDE (East) 26%, LB 17%, and MS the remaining 13%. With the exception of MS, corals and gorgonians on consolidated habitats were significantly more abundant than submerged aquatic vegetation (SAV) on unconsolidated sediments or unconsolidated sediments. Continuous coral habitat was the most abundant consolidated habitat for both MCDW and MCDE (41% and 43% respectively). Consolidated habitats in LB and MS predominantly consisted of gorgonian plain habitat with 95% and 83% respectively. Coral limestone habitat was more abundant than coral patch habitat; it was found near the shelf break in MS, MCDW, and MCDE. Coral limestone and coral patch habitats only covered LB minimally. The high spatial resolution (0.15 m) of the acquired imagery allowed the detection of differing fish aggregation (FA) types. The largest FA densities were located at MCDW and MCDE over coral communities that occupy up to 70% of the bottom cover. Counts of unidentified swimming objects (USOs), likely representing individual fish, were similar among locations and occurred primarily over sand and shelf edge areas. Fish aggregation school sizes were significantly smaller at MS than the other three locations (MCDW, MCDE, and LB). This study shows the advantages of utilizing SSS in determining fish distributions and density.

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Investigation on the effects of explosive shock on marine life. Necessary that the "commercial" effects, the actual damage to commercially important stocks of fish and shellfish, be evaluated. Equally important are the "biological" effects, the immediate physical effects of shock waves on animals and the indirect effects on future stocks. Indirect effects might include the diversion of migratory stocks from an area, or actual damage to the habitat, rendering it unfit for sedentary or non-migratory native species. Interruption of the food chains in an area by destruction of forge forms or vegetation. (PDF contains 43 pages)

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There is an increasing demand for fish in the world due to a growing population, better economic situation in some sectors, and greater awareness of health issues in relation to food. Since capture fisheries have stagnated, fish farming has become a very fast growing food production system. In this presentation, the author gives an overview of the technologies that are available for genetic improvement of fish, and briefly discuss their merit in the context of a sustainable development. He also discusses the essential prerequisites for effective dissemination of improved stock to farmers. It is concluded that genetic improvement programs based on selective breeding can substantially contribute to sustainable fish production systems. Furthermore, if such genetic improvement programs are followed up with effective dissemination strategies, they can result in a positive impact on farmers' incomes.

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Since 1991, the certification, release and maintenance of new species for aquaculture have become part of the national policy in China. During the past 15 years, this policy has been conducted and improved and has begun to show its significant role in Chinese fisheries. This paper describes the updated system of certification, release and maintenance of new species for aquaculture in China.

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Many sources of information that discuss currents problems of food security point to the importance of farmed fish as an ideal food source that can be grown by poor farmers, (Asian Development Bank 2004). Furthermore, the development of improved strains of fish suitable for low-input aquaculture such as Tilapia, has demonstrated the feasibility of an approach that combines “cutting edge science” with accessible technology, as a means for improving the nutrition and livelihoods of both the urban poor and poor farmers in developing countries (Mair et al. 2002). However, the use of improved strains of fish as a means of reducing hunger and improving livelihoods has proved to be difficult to sustain, especially as a public good, when external (development) funding sources devoted to this area are minimal1. In addition, the more complicated problem of delivery of an aquaculture system, not just improved fish strains and the technology, can present difficulties and may go explicitly unrecognized (from Sissel Rogne, as cited by Silje Rem 2002). Thus, the involvement of private partners has featured prominently in the strategy for transferring to the public technology related to improved Tilapia strains. Partnering with the private sector in delivery schemes to the poor should take into account both the public goods aspect and the requirement that the traits selected for breeding “improved” strains meet the actual needs of the resource poor farmer. Other dissemination approaches involving the public sector may require a large investment in capacity building. However, the use of public sector institutions as delivery agents encourages the maintaining of the “public good” nature of the products.

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Ichthyofauna of the coastal «10 m depth) habitat of the South Atlantic Bight were investigated between Cape Fear, North Carolina, and the St. John's River, Florida. Trawl collections from four nonconsecutive seasons in the period July 1980 to December 1982 indicated that the fish community is dominated by the family Sciaenidae, particularly juvenile forms. Spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) were the two most abundant species and dominated catches during all seasons. Atlantic menhaden (Brevoortin tyrannus) was also very abundant, but only seasonally (winter and spring) dominant in the catches. Elasmobranch fIShes, especially rajiforms and carcharinids, contributed to much of the biomass of fishes collected. Total fish abundance was greatest in winter and lowest in summer and was influenced by the seasonality of Atlantic menhaden and Atlantic croaker in the catches. Biomass was highest in spring and lowest in summer, and was influenced by biomass of spot. Fish density ranged from 321 individuals and 12.2 kg per hectare to 746 individuals and 25.2 kg per hectare. Most species ranged widely throughout the bight, and showed some evidence of seasonal migration. Species assemblages were dominated by ubiquitous year-round residents of the coastal waters of the bight. Diversity (H') was highest in summer, and appeared influenced by the evenness of distribution of individuals among species. (PDF file contains 56 pages.)

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Sediment sampling was used to evaluate chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) spawning habitat quality in the South Fork Trinity River (SFTR) basin. Sediment samples were collected using a McNeil-type sampler and wet sieved through a series of Tyler screens (25.00 mm, 12.50 mm, 6.30 mm, 3.35 mm, 1.00 mm, and 0.85 mm). Fines (particles < 0.85 mm) were determined after a l0-minute settling period in Imhoff cones. Thirteen stations were sampled in the SFTR basin: five stations were located in mainstem SFTR between rk 2.1 and 118.5, 2 stations each were located in EF of the SFTR, Grouse Creek, and Madden Creek, and one station each was located in Eltapom and Hayfork Creeks. Sample means for fines(particles < 0.85 mm) fer SFTR stations ranged between 14.4 and 19.4%; tributary station sample mean fines ranged between 3.4 and 19.4%. Decreased egg survival would be expected at 4 of 5 mainstem SFTR stations and at one station in EF of SFTR and Grouse Creek where fines content exceed 15%. Small gravel/sand content measured at all stations were high, and exceed levels associated with reduced sac fry emergence rates. Reduction of egg survival or sac fry emergence due to sedimentation in spawning gravels could lead to reduced juvenile production from the South Fork Trinity River. (PDF contains 18 pages.)

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Mozambique tilapia (Oreochromis mossambicus) is an indigenous tilapia species in southern Africa, until now the majority of genetic research has been carried out on Asian species of tilapia but this project aims to look at this African species. Those most suited to further development in aquaculture in southern Africa have now been identified. The genetic characterisation of strains has been completed. This information has aided the choice of strains for use in small scale aquaculture and for genetically male tilapia (GMT) production. They will form the basis of future strategies for further genetic improvement, and management of genetic diversity of Mozambique tilapia. The information will also contribute towards responsible management and development of genetic resources, particularly with regard to indigenous species of tilapia. Good progress has been made with the adaptation and implementation of producing the supermale fish required to produce all male offspring, resulting in faster growing populations of tilapia. The presence of the project and its associated activity has been a catalyst for a surge in interest in tilapia culture throughout southern Africa. [PDF contains 183 pages]

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The traditional approach to fish handling, preservation and processing technology in inland fishery is critically examined using the experience in Kainji Lake as a model. The need to uplift the fishermen technology is emphasized with the ultimate expectations of improvement in fish quality

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Aspects of the Nigerian fishing industry are outlined to explain the concept of fishing systems viability which is often influenced by a combination of factors including biological productivity, as well as technical, economic and social factors. The productivity of the aquatic environments can be increased by the construction and installation of artificial reefs and fish aggregating devices. These man-made structures provide shelters, food and breeding grounds for fin fish and shell fish. The habitat enhancement techniques are appropriate, efficient, cheap and simple strategic options for increase in fish production. Recommendations for effective utilization and long term management are outlined.

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The packaging containers and means of transportation for Nigerian smoke-dried fish from harvesting all through the post-harvest chain were described. Sacks, paper cartons, wooden rackets, cane and bamboo baskets were predominantly used packaging containers. Means of transportation ranged from wheelbarrows, motorcycle, lorries, to pick-up vehicles and trucks. The major area of improvement is seen in packaging at the wholesale level. To overcome the constraints within the system, both the public and private sectors must provide effective services that benefit fishermen, processors, wholesalers, retailers, organisation and other key participants that make the work. Suggestions for reducing post harvest losses and improving the efficiency of the existing distribution system, based on the various need of the stake holders and the socio-cultural settings of the application were proffered