Producing tilapia in small cage in West Africa

This document is part of a series of 5 technical manuals produced by the Challenge Program Project CP34 “Improved fisheries productivity and management in tropical reservoirs”. The Water Research Institute (WRI) in Akosombo, Ghana, is working to bring cage aquaculture technology to smallholder farmers. The stocking, feeding and cage-construction technology piloted by WRI is now being widely adopted in the Lower Volta basin in Ghana. The results of WRI research over the period 2005-2009 are presented here as a guide to potential investors. (PDF contains 19 pages)

Information and knowledge sharing

The Guidelines provide a special focus on information and knowledge sharing and its current and potential role in supporting implementation of the Code of Conduct for Responsible Fisheries. They expand on relevant principles and standards set forth in the Code and make practical suggestions about ways to ensure that this role can be enhanced. The issues involved in the flow of information between different stakeholder groups include topics as diverse as information policy frameworks and information and communication technology infrastructure, hence coverage is introductory. Some of the constraints involved in the cycle from the creation, production, dissemination and availability of information and knowledge to its effective use and sharing by the present generation as well as its preservation for the future are presented. The special circumstances and requirements of stakeholders in developing countries are recognized in accordance with Article 5 of the Code. A separate chapter on small-scale fisheries and aquaculture looks in more detail at the special situation and information needs of the sub-sector. The Guidelines aim to foster a better understanding of the issues involved to ensure that stakeholders obtain the essential information that they need and that they make available their own information and knowledge for the public good. (PDF contains 115 pages)

Code de Conduite pour une Peche Responsable

La pêche, y compris l'aquaculture, apporte une contribution fondamentale à l'alimentation, à l'emploi, aux loisirs, au commerce et au bien-être économique des populations du monde entier, qu'il s'agisse des générations présentes ou futures, et devrait, par conséquent, être conduite de manière responsable. Le présent Code définit des principes et des normes internationales de comportement pour garantir des pratiques responsables en vue d'assurer effectivement la conservation, la gestion et le développement des ressources bioaquatiques, dans le respect des écosystèmes et de la biodiversité. Le Code reconnaît l'importance nutritionnelle, économique, sociale, environnementale et culturelle de la pêche et les intérêts de tous ceux qui sont concernés par ce secteur. Le Code prend en considération les caractéristiques biologiques des ressources et de leur environnement, ainsi que les intérêts des consommateurs et autres utilisateurs. Les Etats et tous ceux impliqués dans le secteur de la pêche sont encouragés à appliquer ce Code de manière effective. (PDF contains 53 pages)

Genetic improvement and utilisation of indigenous tilapia in southern Africa: final technical report, December 1st 1998 to June 31st, 2002

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]

The improved management of small-scale cage culture in Asia: final technical report

The purpose of the project is to develop sustained small-scale cage fish culture in inland and coastal waters through improved understanding of the social, institutional and resource environment of resource poor groups. Two Asian countries, Bangladesh (inland systems) and Vietnam (marine), were studied with this workshop bringing together both sides of the project together with representatives of collaborative institutions, government departments and universities. Addressing the overall aim of producing guidelines for the planning and extension of cage aquaculture in Asia a combination of group work and plenary discussion was conducted producing the following outputs. 1) An assessment of cage aquaculture potential, 2) Development options for small-scale cage culture, 3) A review of tools and methodologies and 4) Policy initiatives for sustainable cage culture development. Key issues raised were the use of outputs as a guide to be adapted to regional circumstances to facilitate farmer and extension worker discussion and not as a rigid methodology. The degree of linkage between development, research and government institutions was also considered a crucial factor in benefiting the research and development of cage culture at the local, regional and national level and vital in affecting the future policies by both development and government institutions. [PDF contains 242 pages]

Survival, growth, and yield of brown trout stocked as fingerlings in Hot Creek, California

Four groups of fin clipped brown trout (Salmo trutta) fingerlings were planted in Hot Creek over a six year period. Survival and growth were estimated by fall and/or spring mark-and-recapture surveys. Yield to the angler for two of the tour groups stocked was estimated by stratified random creel surveys. Fingerling survival from the midsummer stocking period to fall averaged 51 %. Overwinter survival from young-of-the-year to yearling fish averaged 49%. Angler harvest of two groups of fingerlings stocked at densities of 16,082 fish/mile averaged 1,704 trout/mile (10.6%) and 194 lbs/acre. Abundant cover and microhabitat suitable tor young trout, ice-free winters, and rapid growth were factors viewed as contributing to high yields. Results do not suggest a change is needed in the general policy of not stocking brown trout fingerlings in California streams. Results do show that fingerlings stocked in Hot Creek, and presumably other productive streams with abundant cover, can effectively fill a void created by limited recruitment. (PDF contains 24 pages.)

Cooperative artificial propagation programs for salmon and steelhead, 1996-1997

Fourteen cooperative fish rearing and planting programs for salmon and steelhead were active from July 1, 1996 through June 30, 1997. For all programs, 208,922 steelhead trout, (Oncorhynchus mykiss), 10,334,457 chinook salmon,(O. tshawytscha),and 60,681 coho salmon(O. kisutch) were planted. (PDF contains 24 pages.)

Silver King Creek Paiute cutthroat trout restoration, 1991 through 1993

Silver King Creek, Alpine County, is the native range of the Federally-threatened Paiute cutthroat trout, Oncorhynchus clarki seleniris. Paiute cutthroat currently inhabit Coyote Valley and Corral Valley creeks, which are tributaries to Silver King Creek below Llewellyn Falls, and also Silver King Creek and tributaries aboye Llewellyn Falls. Rainbow trout, O. mykiss, were introduced into the basin during 1949 and became hybridized with Paiute cutthroat. Chemical treatments attempted by the California Department of Fish and Game (CDFG) in 1964 and 1976 failed to eliminate hybrid trout. A chemical treatment project was again conducted by the CDFG from 1991 through 1993 to eliminate hybrid trout from within the range of Paiute cutthroat. This report presents a summary of events for the first two years of the Silver King Paiute Cutthroat Trout Restoration Project; a more thorough analysis is made of the third and final year of the project. (PDF contains 39 pages.)

Fisheries marketing systems and consumer preferences in Puttalam District Sri-Lanka

The aim of this study was to understand the current and historic market situation for inland fish and it’s substitutes in order to identify which of the various production opportunities presented by the seasonal tank resource might have greatest relevance for marginal communities in the Dry-zone. Regional and sub-regional market networks for fish and meat products were investigated, ranking and scoring exercises used to characterise consumer demand in rain-fed areas of North West Province and secondary data sources were used to assess historic patterns of demand and supply [PDF contains 57 pages]

Nutrient dynamics of seasonal tanks in the dry zone of Sri Lanka in relation to their hydrological regimes

Village tanks are put to a wide range of uses by the rural communities that depend on them for their survival. As the primacy of irrigation has decreased under these tanks due to a variety of climatic and economic reasons there is a need to reevaluate their use for other productive functions. The research presented in this paper is part of a programme investigating the potential to improve the management of living aquatic resources in order to bring benefits to the most marginal groups identified in upper watershed areas. Based on an improved typology of seasonal tanks, the seasonal changes and dynamics of various water quality parameters indicative of nutrient status and fisheries carrying capacity are compared over a period of one year. Indicators of Net (Primary) Productivity (NP): Rates of Dissolved Oxygen (DO) change, Total Suspended Solids (TSS): Total Suspended Volatile solids (TVSS) ratios are the parameters of principle interest. Based on these results a comparative analysis is made on two classes of ‘seasonal’ and ‘semi-seasonal’ tanks. Results indicate a broad correlation in each of these parameters with seasonal trends in tank hydrology. Highest productivity levels are associated with periods of declining water storage, whilst the lowest levels are associated with the periods of maximum water storage shortly after the NW monsoon. This variation is primarily attributed to dilution effects associated with depth and storage area. During the yala period, encroachment of the surface layer by several species of aquatic macrophyte also has progressively negative impacts on productivity. The most seasonal tanks show wider extremes in seasonal nutrient dynamics, overall, with less favourable conditions than the ‘semi-seasonal’ tanks. Never the less all the tanks can be considered as being highly productive with NP levels comparable to fertilised pond systems for much of the year. This indicates that nutrient status is not likely to be amongst the most important constraints to enhancing fish production. Other potential management improvements based on these results are discussed. [PDF contains 19 pages]

Taxonomy and distribution of the boring sponges (Clionidae) along the Atlantic coast of North America

Covers the history of the study of boring sponges, taxonomy and distributions. Also includes identification of species, descriptions, key, references and plates. (PDF contains 30 pages)

Technologies and Methodologies for the Detection of Harmful Algae and Their Toxins, St Petersburg, Florida, Oct 22-24 2008 : workshop proceedings

The Alliance for Coastal Technologies (ACT) Workshop "Technologies and Methodologies for the Detection of Harmful Algae and their Toxins" convened in St. Petersburg, Florida, October 22- 24, 2008 and was co-sponsored by ACT (http://act-us.info); the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET, http://ciceet.unh.edu); and the Florida Fish and Wildlife Conservation Commission (FWC, http://www.myfwc.com). Participants from various sectors, including researchers, coastal decision makers, and technology vendors, collaborated to exchange information and build consensus. They focused on the status of currently available detection technologies and methodologies for harmful algae (HA) and their toxins, provided direction for developing operational use of existing technology, and addressed requirements for future technology developments in this area. Harmful algal blooms (HABs) in marine and freshwater systems are increasingly common worldwide and are known to cause extensive ecological, economic, and human health problems. In US waters, HABs are encountered in a growing number of locations and are also increasing in duration and severity. This expansion in HABs has led to elevated incidences of poisonous seafood, toxin-contaminated drinking water, mortality of fish and other animals dependent upon aquatic resources (including protected species), public health and economic impacts in coastal and lakeside communities, losses to aquaculture enterprises, and long-term aquatic ecosystem changes. This meeting represented the fourth ACT sponsored workshop that has addressed technology developments for improved monitoring of water-born pathogens and HA species in some form. A primary motivation was to assess the need and community support for an ACT-led Performance Demonstration of Harmful Algae Detection Technologies and Methodologies in order to facilitate their integration into regional ocean observing systems operations. The workshop focused on the identification of region-specific monitoring needs and available technologies and methodologies for detection/quantification of harmful algal species and their toxins along the US marine and freshwater coasts. To address this critical environmental issue, several technologies and methodologies have been, or are being, developed to detect and quantify various harmful algae and their associated toxins in coastal marine and freshwater environments. There are many challenges to nationwide adoption of HAB detection as part of a core monitoring infrastructure: the geographic uniqueness of primary algal species of concern around the country, the variety of HAB impacts, and the need for a clear vision of the operational requirements for monitoring the various species. Nonetheless, it was a consensus of the workshop participants that ACT should support the development of HA detection technology performance demonstrations but that these would need to be tuned regionally to algal species and toxins of concern in order to promote the adoption of state of the art technologies into HAR monitoring networks. [PDF contains 36 pages]

Johann Heinrich von Thünen: Leben und Werk des Namenspatrons des neuen Bundesforschungsinstituts für Ländliche Räume, Wald und Fischerei

A new concept for resource oriented federal research within the competence of the German Ministry of Food, Agriculture and Consumer Protection was implemented in 2008. The Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries is one of 4 newly established large scale federal research institutions. It comprises the former Federal Research Centre for Fisheries, the Federal Research Centre for Forestry and Forest Products and large parts of the Federal Agricultural Research Centre. The institute is named after Johann Heinrich von Thünen, a famous national economist and social reformer of the 19th century. He developed the first serious treatment of spatial economics (the so-called Thünen rings) and the basics of the theory of the natural pay.

The Crappies

The names: bachelor, campbellite, white bass, camp lighter, sac-a-lait, silver crappie, speckled bass, tinmouth, bar fish, Oswego bass, razorback, grassback, shiner, john demon, calico bass, strawberry bass and "crap'pee," along with 10-20 others, all refer to two rather than one species of fish. Most Maryland fishermen when applying these time honored names do not realize they are referring to two distinct species of fish. These species are the black crappie, Pornoxis nigromaculatus, and the white crappie, Pornoxis annulars. Contrary to common belief, the white crappie does not change into a black crappie during parts of the year nor are these two fish just color phases of one species. Crappies are members of the freshwater sunfish family of fishes, Centrarchidae. (PDF contains 4 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.)