Ruwan Kanya reservoir in Kano State as a model small scale sport fishing ground

The paper examined the Ruwan Kanya Reservoir in Kano State. It gave a background information on the fisheries of the lake. Also discussed is tilapia transplantation from Jakara to Ruwan Kanya reservoir. The transplantation revealed a tremendous improvement on the Lake fisheries species now recorded include Lates niloticus, Tilapia, Hydrocynus, Gnathonemus, Mormyrops mabpterurus and others. The proximity of the Ruwan Kanya Reservoir to Tiga Lake and the tourism resort near it, affords the place a good opportunity to serve as a good sport fishing ground. Procedures for transforming the reservoir to sport fishing ground have been advanced

A review of diseases associated with cage culture systems: diagnosis and control in smale scale fish farming

Fish cage culture is a rapid aquacultural practice of producing fish with more yield compared to traditional pond culture. Several species cultured by this method include Cyprinus carpio, Orechromis niloticus, Sarotherodon galilaeus, Tilapia zilli, Clarias lazera, C. gariepinus, Heterobranchus bidorsalis, Citharinus citharus, Distochodus rostratus and Alestes dentes. However, the culture of fish in cages has some problems that are due to mechanical defects of the cage or diseases due to infection. The mechanical problems which may lead to clogged net, toxicity and easy access by predators depend on defects associated with various types of nets which include fold sieve cloth net, wire net, polypropylene net, nylon, galvanized and welded net. The diseases problems are of two types namely introduced diseases due to parasites. The introduced parasites include Crustaseans, Ergasilus sp. Argulus africana, and Lamprolegna sp, Helminth, Diplostomulum tregnna: Protozoan, Trichodina sp, Myxosoma sp, Myxobolus sp. the second disease problems are inherent diseases aggravated by the very rich nutrient environment in cages for rapid bacterial, saprophytic fungi, and phytoplanktonic bloom resulting in clogging of net, stagnation of water and low biological oxygen demand (BOD). The consequence is fish kill, prevalence of gill rot and dropsy conditions. Recommendations on routine cage hygiene, diagnosis and control procedures to reduce fish mortality are highlighted

Intensive small scale cage, pen and enclosure fish production systems: towards 2010

A brief review of most of the publications by the author and other relevant workers on the three water-based fish culture systems was made. The present status of the culture systems in the National Food/Fish Programmes was highlighted. Strategies were advanced towards a successful implementation of the intensive water-based culture systems project as a contribution towards alleviating poverty, hunger and malnutrition under the concept of VISION 2010

Environmental hazards to small scale fisheries resources management in Nigeria

This paper examined the environmental hazards limiting sustainable small-scale fisheries development in Nigeria. Observation has showed that hazards range from pollution of the aquatic habitats by domestic and urban sewage and garbage, agro-chemicals, industrial pollutants, crude oil spillage etc. In an attempt to maximize catch, many migrant and part-time fisher folks indulge in highly destructive and obnoxious fishing practices with adverse impact on fisheries resources. These have constituted significant environmental hazards. Discharges of waste from aquacultural practices in to rivers and lakes have also been identified as sources of environmental hazards. Some aquatic weeds such as water hyacinth are sources of hazards. The effects of environmental hazards on small-scale fisheries resources may be direct arising from the toxicity of pollutants or indirect as a result of ecosystem modification. Some of the effects of pollutants on the aquatic environment and fish have been discussed in the paper

Design, operation and economics of a small-scale hatchery for the larval rearing of sugpo, Penaeus monodon Fab.

One of the major problems in the mass production of sugpo is how to obtain a constant supply of fry. Since ultimately it is the private sector which should produce the sugpo fry to fill the needs of the industry, the Barangay Hatchery Project under the Prawn Program of the Aquaculture Department of SEAFDEC has scaled down the hatchery technology from large tanks to a level which can be adopted by the private sector, especially in the villages, with a minimum of financial and technical inputs. This guide to small-scale hatchery operations is expected to generate more enthusiasm among fish farmers interested in venturing into sugpo culture.

Financial analysis of small-scale fish farming enterprises to alleviate poverty in homestead

This paper focuses on the financial analysis involved in setting up of fish farming on a small-scale in a homestead. About 0.5 acres of land was used for the construction of pond which as a stock of Clarias spp/ Heterobranchus spp and Tilapia spp at the ratio of one to three for a period of 12 months. The land/land development cost is N26,500.00, pond construction cost, N35,700.00, equipment cost, N2,650.00 and stock/Input requirement cost N155,727.00 while the revenue from sales is N376,000.00. A cash flow analysis is also calculated for the fish farm, which is N155,423.00 for first year cash flow, and appropriate profit/mosses were calculated for five-year production cycle of N1,036,515.00 million. At the end appreciable profit is realized from the enterprises. This type of enterprises is viable for small-scale farmers to practices and adopted for financial support for their family

Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration

Projects of the scope of the restoration of the Florida Everglades require substantial information regarding ecological mechanisms, and these are often poorly understood. We provide critical base knowledge for Everglades restoration by characterizing the existing vegetation communities of an Everglades remnant, describing how present and historic hydrology affect wetland vegetation community composition, and documenting change from communities described in previous studies. Vegetation biomass samples were collected along transects across Water Conservation Area 3A South (3AS).

Aquatic insects as target organisms for the study of effects of projected climate change in the British Isles

The chief objectives of this brief review are to collate and synthesise quantitative information on the temperature requirements of aquatic insects, and to identify species, and groups of species, that could be useful indicators of climate change and predictors of the ecological effects of change. It arose from the first phase of the Terrestrial Initiative in Global Environmental Research (TIGER), a five-year, NERC Community Programme on the role of the terrestrial biosphere in the science of global change. This phase involved the identification of criteria for selecting species suitable for the study of effects of projected climate change in the British Isles. Field and laboratory studies are reviewed, and criteria for selection of species for future research are suggested. The literature survey shows that no species of aquatic insect can be found to meet all three criteria, but information on the British stoneflies and their eggs already satisfies two of them.

Effects of a flash-flood on channel morphology and some insects of a small stony stream in the Peak District, Derbyshire

In this paper, some observations are made following a flash-flood that occurred in Stake Clough, a small tributary of the River Goyt, during the evening of 6 August 1996. The site was visited eight times between 8 August - 30 October 1996 to take samples and make observations on the stream. The flood scoured the bed of Stake Clough but more significantly, caused it to change course along the middle part of the floodplain. Initially after the flood, the numbers of insects in all stretches of the stream channel were low (100-200 m super(2)), but then gradually rose to population densities approaching ten times this figure. The benthos was dominated by the Chironomidae and also leuctrid stoneflies (Leuctra nigra, L. hippopus and L. inermis). On 8th August 1996, 12 mesh bags, each containing oak leaves, were placed in the stream and collected after 24 hours. These were also dominated by chironomids, and contained relatively high numbers of the caddis, Potamophylax cingulatus.

Littoral vegetation of Lake Tohopekaliga: community descriptions prior to a large-scale fisheries habitat-enhancement project

An extreme dry-down and muck-removal project was conducted at Lake Tohopekaliga, Florida, in 2003-2004, to remove dense vegetation from inshore areas and improve habitat degraded by stabilized water levels. Vegetation was monitored from June 2002 to December 2003, to describe the pre-existing communities in terms of composition and distribution along the environmental gradients. Three study areas (Treatment-Selection Sites) were designed to test the efficacy of different treatments in enhancing inshore habitat, and five other study areas (Whole-Lake Monitoring Sites) were designed to monitor the responses of the emergent littoral vegetation as a whole. Five general community types were identified within the study areas by recording aboveground biomasses and stem densities of each species. These communities were distributed along water and soils gradients, with water depth and bulk density explaining most of the variation. The shallowest depths were dominated by a combination of Eleocharis spp., Luziola fluitans, and Panicum repens; while the deeper areas had communities of Nymphaea odorata and Nuphar luteum; Typha spp.; or Paspalidium geminatum and Hydrilla verticillata. Mineralized soils were common in both the shallow and deep-water communities, while the intermediate depths had high percentages of organic material in the soil. These intermediate depths (occurring just above and just below low pool stage) were dominated by Pontederia cordata, the main species targeted by the habitat enhancement project. This emergent community occurred in nearly monocultural bands around the lake (from roughly 60–120 cm in depth at high pool stage) often having more diverse floating mats along the deep-water edge. The organic barrier these mats create is believed to impede access of sport fish to shallow-water spawning areas, while the overall low diversity of the community is evidence of its competitive nature in stabilized waters. With continued monitoring of these study areas long-term effects of the restoration project can be assessed and predictive models may be created to determine the efficacy and legitimacy of such projects in the future.

Scale-Dependent Habitat Selection of Nesting Great Egrets and Snowy Egrets

Foraging habitat selection of nesting Great Egrets ( Ardea alba ) and Snowy Egrets ( Egretta thula ) was investigated within an estuary with extensive impounded salt marsh habitat. Using a geographic information system, available habitat was partitioned into concentric bands at five, ten, and 15 km radius from nesting colonies to assess the relative effects of habitat composition and distance on habitat selection. Snowy Egrets were more likely than Great Egrets to depart colonies and travel to foraging sites in groups, but both species usually arrived at sites that were occupied by other wading birds. Mean flight distances were 6.2 km (SE = 0.4, N = 28, range 1.8-10.7 km) for Great Egrets and 4.7 km (SE = 0.48, N = 31, range 0.7-12.5 km) for Snowy Egrets. At the broadest spatial scale both species used impounded (mostly salt marsh) and estuarine edge habitat more than expected based on availability while avoiding unimpounded (mostly fresh water wetland) habitat. At more local scales habitat use matched availability. Interpretation of habitat preference differed with the types of habitat that were included and the maximum distance that habitat was considered available. These results illustrate that caution is needed when interpreting the results of habitat preference studies when individuals are constrained in their choice of habitats, such as for central place foragers.

A report on the population structure of adult salmon and sea trout in the River Lune using scale samples - with reference to historical data.

During 1993, a comprehensive data set of scale readings, length and weight measurements was established for migratory salmonids on the River Lune. This information was collected using three methods of fish capture: 1. The Lune estuary commercial nets. 2. River Lune Forge weir fish trap. 3. River Lune rod catch scale returns. Additional information was contributed by the Kent, Leven and Duddon rod and commercial fisheries. The data shows that the salmon stock in 1993 was dominated by two year old smolts. This varies from year to year. The sea trout population displays a normal population curve in terms of numbers of fish in each age and weight class. The growth rate of salmon and sea trout is very similar even though salmon have the benefit of high sea feeding.

Report on the analysis of salmon scale samples returned by anglers on the Rivers Ribble and Hodder

Fisheries technical staff from the North West Central Area of the National Rivers Authority (NRA) currently provide a service for the ageing of salmon scales from fish caught by anglers on the Rivers Ribble and Hodder in order to gather information on the biological characteristics of the salmon population on the River Ribble system in terms of weight, freshwater age and sea age. At the beginning of each fishing season, scale envelopes are distributed by the NRA to angling clubs and some individual anglers. Scales taken from salmon caught on the rivers are returned to the NRA Central Area Office by the anglers, or more often, by NRA bailiffs. The age of each fish caught is then determined by the identification and counting of annuli for both the river and sea zones on the scale. Information is provided by the angler on the scale packet concerning the length and weight of the fish caught, and the date, location and method of capture. Both this information and the age of the fish is recorded on a database. These data can be used to investigate the distribution, and exploitation patterns of the different age classes of the salmon stock within the river system. This report is principally concerned with the scale samples received in 1994, although comparison is also made with samples from 1993 and 1992. References to data will all relate to that received in 1994 unless an alternate year is stated.

The significance of scale patterns and scale readings in the life history and habits of the salmon

This brief reports highlights the significance of scale readings of salmon. The reasons for colour change of scales and scale rings are briefly explained. Scale readings of salmon fry from the River Lune in the north west of England are presented. The salmon was captured in 1957/58.