Inland fisheries resources and the current status of aquaculture in Sri Lanka

The aim of this working paper was to evaluate the potential of different fisheries enhancement and aquacultural systems to benefit marginal farmers who manage small rainfed irrigation systems in the lowland Dry zone of Sri Lanka. Analysis was based on secondary data and key informant interviews with professional fishermen and marginal farmers in N.W Province. [PDF contains 57 pages]

Recovery and status of shortnose sturgeon in the Hudson River

Shortnose sturgeon (Acipenser brevirostrum), an endangered species, has experienced a several-fold increase in abundance in the Hudson River in recent decades. This population growth followed a substantial improvement in water quality during the 1970s to a large portion (c. 40%) of the species' summertime nursery area. Age structure and growth were investigated to evaluate the hypothesis that improvements in water quality stimulated population recovery through increased survival of young of the year juveniles. Specimens were captured using gill nets bi-monthly from November 2003 to November 2004 (n = 596). Annuli in fin spine sections were used to generate estimates of sturgeon age. Based upon a marginal increment analysis, annuli were determined to form at an annual rate. Age determinations yielded a catch composed of age 5-30 years for sizes 49-105cm Total Length (n = 554). Individual growth rate (von Bertalanffy coefficients: TL, = 1045mm, K = 0.07) for the population was similar to previous growth estimates within the Hudson River as well as proximal estuaries. Hindcast year-class strengths, based upon a recent stock assessment (Bain et al. 2000) and corrected for gill net mesh selectivity and cumulative mortality indicated high recruitments (28,000-43,000 yearlings)during 1986-1992, which were preceded and succeeded by c.5-year periods of lower recruitment (5,000-1 5,000 yearlings). Recruitment patterns were corroborated by trends in shortnose sturgeon bycatch from a Hudson utilities-sponsored monitoring program. Results indicated that Hudson River shortnose sturgeon abundance increased due to the formation of several strong year-classes occurring about five years subsequent to improved water quality in important nursery and forage habitats in the upper Hudson River estuary. (PDF contains 108 pages.)

Fishery dynamics and present status of the yellowfin tuna population of the Eastern Pacific Ocean

ENGLISH: From morphometric data, tagging results and reaction of the stock to fishing, it is inferred that the yellowfin tuna of the Eastern Pacific form a distinct population which intermingles little, if at all, with populations to the westward. Excellent statistics of catch and effort, and records of total catch, available since 1934, during rapid growth of the fishery, have made possible application of a generalized mathematical predator-prey model to estimate the effect of fishing on the population, and the average abundance and yield corresponding to different amounts of fishing effort, and also to estimate the rate of fishing mortality per unit of effort. From serial samples of size composition of catches, and from tagging experiments, it has been possible to determine rates of growth and of total mortality. These kinds of information permit application of the catch-per-recruit model of Beverton and Holt. Combination of the results of application of the Beverton and Holt model and of the generalized predator-prey model, leads to inference of the relationship between stock size and recruitment. The form of the relationship is remarkably similar to the theoretical model developed by W. E. Ricker. These studies, based on the data of the near-surface fishery by baitboats and purse seiners, indicate clearly that the increased intensity of fishing has caused diminution of the stocks to the point where they are somewhat "overfished"-that is, incapable of supporting the maximum sustainable average harvest. SPANISH: De los datos morfométricos, de los resultados de las marcaciones y de la reacción del stock a la pesca, se infiere que el atún aleta amarilla del Pacífico oriental forma una población diferente que se mezcla poco, si es que llega a mezclarse, con las poblaciones del oeste. Las excelentes estadísticas de la captura y el esfuerzo y los registros de la pesca global disponibles desde 1934, durante el rápido crecimiento de la pesquería, han hecho posible la aplicación de un modelo matemático generalizado depredador-presa para estimar el efecto de la pesca en la población y el promedio de la abundancia y del rendimiento correspondientes a los diferentes valores del esfuerzo de pesca, y también para estimar la tasa de la mortalidad de pesca por unidad de esfuerzo. Gracias a las muestras en serie de la composición de tamaños de las capturas y a los experimentos de marcación, ha sido posible determinar las tasas del crecimiento y de la mortalidad total. Estos tipos de información permiten la aplicación del modelo de la captura-porrecluta de Beverton y Holt. La combinación de los resultados de la aplicación del modelo de Beverton y Holt y del modelo generalizado depredador-presa, conduce a la inferencia de la relación entre el tamaño del stock y el reclutamiento. La forma de la relación es notoriamente similar al modelo teórico desarrollado por W. E. Ricker. Estos estudios, basados en los datos de la pesquería cerca de la superficie efectuada por barcos de carnada y rederos, indican claramente que el aumento de la intensidad de la pesca ha causado la disminución de los stocks hasta el punto de dejarlos algo "superexplotados", o sea, incapacitados para mantener una producción máxima promedio. (PDF contains 50 pages.)

Towed vehicles: undulating platforms as tools for maping coastal processes and water quality assessment, Seaside, California, February 5-7,2007. Workshop proceedings

The Alliance for Coastal Technologies (ACT) Workshop on Towed Vehicles: Undulating Platforms As Tools for Mapping Coastal Processes and Water Quality Assessment was convened February 5-7,2007 at The Embassy Suites Hotel, Seaside, California and sponsored by the ACT-Pacific Coast partnership at the Moss Landing Marine Laboratories (MLML). The TUV workshop was co-chaired by Richard Burt (Chelsea Technology Group) and Stewart Lamerdin (MLML Marine Operations). Invited participants were selected to provide a uniform representation of the academic researchers, private sector product developers, and existing and potential data product users from the resource management community to enable development of broad consensus opinions on the application of TUV platforms in coastal resource assessment and management. The workshop was organized to address recognized limitations of point-based monitoring programs, which, while providing valuable data, are incapable of describing the spatial heterogeneity and the extent of features distributed in the bulk solution. This is particularly true as surveys approach the coastal zone where tidal and estuarine influences result in spatially and temporally heterogeneous water masses and entrained biological components. Aerial or satellite based remote sensing can provide an assessment of the aerial extent of plumes and blooms, yet provide no information regarding the third dimension of these features. Towed vehicles offer a cost-effective solution to this problem by providing platforms, which can sample in the horizontal, vertical, and time-based domains. Towed undulating vehicles (henceforth TUVs) represent useful platforms for event-response characterization. This workshop reviewed the current status of towed vehicle technology focusing on limitations of depth, data telemetry, instrument power demands, and ship requirements in an attempt to identify means to incorporate such technology more routinely in monitoring and event-response programs. Specifically, the participants were charged to address the following: (1) Summarize the state of the art in TUV technologies; (2) Identify how TUV platforms are used and how they can assist coastal managers in fulfilling their regulatory and management responsibilities; (3) Identify barriers and challenges to the application of TUV technologies in management and research activities, and (4) Recommend a series of community actions to overcome identified barriers and challenges. A series of plenary presentation were provided to enhance subsequent breakout discussions by the participants. Dave Nelson (University of Rhode Island) provided extensive summaries and real-world assessment of the operational features of a variety of TUV platforms available in the UNOLs scientific fleet. Dr. Burke Hales (Oregon State University) described the modification of TUV to provide a novel sampling platform for high resolution mapping of chemical distributions in near real time. Dr. Sonia Batten (Sir Alister Hardy Foundation for Ocean Sciences) provided an overview on the deployment of specialized towed vehicles equipped with rugged continuous plankton recorders on ships of opportunity to obtain long-term, basin wide surveys of zooplankton community structure, enhancing our understanding of trends in secondary production in the upper ocean. [PDF contains 32 pages]

Artisanal and inshore fisheries development in Nigeria: Status paper on the FAO/UNDP Project NIR/77/001

The UNDP/FAO supported Federal Fisheries Project for the Development of Artisanal and Inshore Fisheries in Nigeria has the specific objective of increasing fish production through an integrated approach aimed at upgrading the rural coastal fishermen and improving their living conditions. The project has an operating life-span of three years and envisages a total outlay of nearly N3 million in terms of personnel and services. This paper attempts to review the activities of the project during the first two years of the operational phase and highlight some of its specific achievements.

Keynote address on production, utilization and marketing in fisheries status and opportunities

Fish production from Nigeria comes mainly from 3 sources, namely - artisans engaged in either part-time or full-time fishing, commercial trawlers fishing in inshore and offshore waters, and fish farming in enclosures (ponds, tanks and raceways). An account is given of the current situation in Nigeria, considering over exploitation of fish, the fish's environment, fish utilization, and fish marketing

Survey on the status of Computational Design research and practice

This report presents the results from a survey of current practice in the use of design optimization conducted amongst UK companies. The survey was completed by the Design Optimization Group in the Department of Engineering at Cambridge University. The general aims of this research were to understand the current status of design optimization research and practice and to identify ways in which the use of design optimization methods and tools could be improved.

Small-scale fisheries development in Nigeria: Status, prospects, constraints/recommended solutions

The small-scale fisheries sector has been contributing immensely towards domestic fish production in Nigeria. Despite considerable contributions by the small-scale fisherman of Nigeria, with few exceptions, they continue to live at the margin of subsistence. This paper attempts to review the sector and propose strategies of integrated approach towards small-scale fisheries development in order to ensure that efforts at improving the rural fisheries succeed in over-coming identified constraints which include socio-cultural, political, economic, technological and other barriers

An evaluation of the trophic status of the Shen Reservoir by an analysis of phytoplankton composition and water characteristics

In an effort to evaluate the production potential of an artificial impoundment, the phytoplankton of the Shen reservoir was sampled from November 1981 to June 1982 at three stations during three periods of distinct seasonal hydrographic characteristics. The samples were subsampled and quantified. Most of the phytoplankton were identified to the species level. There were in all 53 species comprising Chlorophyceae contributing 36.70% with species of Volvox, Pediastrum, Closterium, Staurodesmus and Ankistrodesmus as dominant species in this group. The Cyanophyceae contributed 30.00% with species of Microcystis, Nostoc , and Oscillatoria as the dominant species. An analysis of temporal and spatial changes in composition and abundance of the various groups showed that these were influenced by water temperature, sampling period and station. Based on the trophic status of the most abundant species, the composition of the phytoplankton is indicative of a tropical reservoir with a moderate productivity for fish culture

Present status and potentials of inshore and offshore pelagic fisheries in the capture and processing industries of Nigeria

Apart from activities of some foreign-based vessels, commercial exploitation of pelagic fishery resources in Nigeria has been limited to inland and inshore waters. Estimated potential for the inshore pelagic fishery is 70,000-90,000 tonnes while the small pelagic resources in the near offshore as well as tuna and tuna-like fishes further offshore have potentials of about 10,000 metric tonnes each. Despite the abundance of tuna within and adjoining the Nigerian EEZ, and its importance in the international market, only foreign-flagged vessels take advantage. In addition, the inshore pelagic fisheries in Nigeria have for long remained underexploited. The most common processing method has remained the age-old traditional smoke-drying, which is inadequate resulting in colossal waste through denaturation and incessant infestations by insects and moulds among other causes. The use of modern smoking techniques coupled with effective distribution systems can undoubtedly reduce waste. However, these are often not within the reach of most artisanal processors. It is proposed that the organised private sector should invest on simple but proven processing equipment such as smoking kilns. The inshore pelagic fish species and other small fishes can sustain cottage canning industries sited in fishing villages/settlements while larger canning factories should be based on offshore resources. Modalities for successful investments are highlighted, while a major consideration is given to joint ventures

Status of policies on fish hygiene in Nigeria

An examination is made of fish health policy formulation in Nigeria. Such policies are necessary to protect fish a living aquatic resources and also fish food at harvest because of the immense nutritional, social and economic benefits derivable by man from fish. Fish health policies must recognize the implications of aquatic environment pollution, the dangers of bad fishing methods and application of harmful fishing gears and appliances and post-mortem handling practices

Technological status and development prospects of small-scale fishing crafts in Nigerian coastal water

A study of fishing crafts was conducted in some coastal states of Nigeria to elucidate findings on the existing crafts as the baseline for further developments. Based on the technical designs, three types of fishing crafts were identified; planked, dug-out and half dug-out canoes. The planked canoes have the largest cubic number and dug-out canoes the least. At loadwater line, the ratio of freeboard to draft was 2 : 1 for planked canoes, indicating reserved buoyancy. Trim of planked canoe is by stern; the beam-length ratio for dug-out canoes showed high drag. Most of the sea-going canoes have U-shaped bottom hull profile capable of withstanding the rigours of surf landing and displayed good stability against longitudinal water wave. Gunwale and thwarts provided respectively the longitudinal and transverse strength of planked and half dug-out canoes. With its characteristics 'weight low down' construction, planked canoe represent the climax of small scale fishing crafts developments in Nigerian coastal waters. It's only draw back is durability. Further improvement in this canoe should be aimed at increasing the hull size and stiffness, water tightness of deck by coating, caulking, fastening, increasing level of motorization and installation of deck working equipments. Experimental design and use of fibre glass, aluminium and ferrocement hulls, together with improved planked canoe is highly advocated

An appraisal of the current status of the fisheries of Eleiyele Reservoir by its fisheries cooperatives

In a study undertaken to evaluate the status of the fisheries of Eleiyele Reservoir (Nigeria) between 1995 and 1997, thermal stratification was observed to breakdown between December and March. Of the physico-chemical variables, transparency was positively correlated (p<0.05) with primary productivity, conductivity and dissolved oxygen concentration. Primary productivity ranged between 0.38mgC/m super(2)/d and 3.OmgC/ m super(2)/d, being lowest in April. BOD values ranged between 1.3mg-2.2mgO/l indicative of clean unpolluted water. Nine fish species belonging to the families Cichlidae, Centropomidae and Mochokidae were identified. Cichlids were the most abundant with Hemichromis species being predominant. Fishing was only carried out in the reservoir during the dry season months of November to April. Fish landing data for the reservoir, obtained from the Fisheries Division of the Ministry of Agriculture and Natural resources, Oyo State, in conjunction with comparative data from the Cooperative fishermen was low. It demonstrated a decreasing trend from January to April and during the period between 1985 and 1996, when compared with data collected in 1985 and 1986 from a previous similar study. Reasons for the low fish yield from the reservoir are discussed and compared with other Nigerian reservoirs