Fishery resource surveys: beyond length-weight relationship models

Fisheries resource surveys are regular management tools for rational exploitation of commercial fisheries. In a growing number of cases, the use of these resource surveys has been largely restricted to assessment of the relative well being of fish stocks and the potential yields of such fisheries. This paper seeks to demonstrate that the data from such surveys can also be easily used to evaluate species diversity of such fisheries, both in terms of species richness and equitability of distribution. Using published data on two freshwater and two marine fisheries as case studies, Shannon-Wiener Diversity Function and Simpson's Index were computed for each of these fisheries. These biodiversity indices gave a deeper insight into the environmental status of each of these fisheries, beyond what the length-weight relationship models can reveal. Generally, while the marine fisheries showed more species richness, the freshwater fisheries apparently had more stable and equilibrated fish communities

Coarse fish in Scotland: a threat or a resource?

This brief article summarizes the ecological role of non-salmonid fishes in Scottish fresh waters. Most government-sponsored research has focused on the ecologically valuable salmonids in this area, yet non-salmonid species are widely distributed in Scotland and play an important ecological role in freshwater ecosystems. The fish fauna of Scotland differs from other parts of the British Isles by being more impoverished following the end of the last Ice Age, ca. 10 000 years ago.

Temporary ponds in the UK; a critical biodiversity resource for freshwater plants and animals

The importance of ponds for biodiversity in Britain has been demonstrated by a number of studies. However, most of the research and interest has been directed at permanent waterbodies, and temporary ponds have been largely neglected. In this article the author present some preliminary findings from a project which aims to fill some of the many gaps in our knowledge of temporary ponds in Britain. The project, which runs for three years until the end of 2001, aims specifically to investigate the ecology of temporary ponds in England and Wales by describing (i) their wetland plant and macroinvertebrate communities, (ii) their physico-chemical characteristics, and (iii) their value as a biodiversity resource. The article focuses on the assessment of temporary ponds as a biodiversity resource and briefly considers aspects of species richness, rarity and distinctiveness. Where possible, temporary ponds are compared with other waterbody types, mainly permanent ponds from the National Pond Survey (NPS), to give the results a broader context.

Studies on the submerged plant community in Lake Biwa. I. Distribution and productivity of Egeria densa. A submerged plant invader in the south basin [Translation from: Physiol.Ecol.Japan 17, 283-290, 1976]

Egeria densa (PLANCH.) ST. JOHN, a submerged plant invader, forms a wide submerged plant zone, particularly along the west coast of the south basin, Lake Biwa. The macrophyte occupies over 82% of the plant zone in the basin and its biomass reaches 93% of the total. The estimated annual net production was approximately 1 kg dry wt./m2 in a dense area, which is about 4.5 times as much as the net production by phytoplankton in an offshore area of the basin. Although the area covered by the macrophyte is only 5.8% of the total of the basin, it produced about one-tenth of the total annual primary production. In the most productive season Egeria produced 46% of the total primary productivity. Thus, the macrophyte never be neglected when one considers the energy flow or material circulation in the basin. This study was initiated in order to clarify the role of submerged macrophytes, particularly E. densa, in Lake Biwa. The following points are reported in this paper: the distribution of macrophytes in the south basin; seasonal change in standing crop of E. densa; seasonal change in values related to production, utilizing a model proposed by Ikushima with its parameters experimentally determined.

Improved fisheries productivity and management in tropical reservoirs

The main objective of this 3.5 year project was to increase the productivity of reservoir fisheries and provide sustainable livelihoods to the rural poor through a series of interventions in tropical reservoirs. The main project activities focused on two reservoirs in the Indo-Gangetic basin (Dahob in Madhya Pradesh, and Pahuj in Uttar Pradesh, both in India), the Lake Nasser in Egypt as part as the Nile basin, and the Volta Lake in Ghana as part as the Volta basin. The project also encompassed an initial data inventory from a wide variety of tropical reservoirs within the three basins, and the detailed assessment of the selected reservoirs, including market evaluation and post-capture improvements. (PDF contains 117 pages)

The Marine Science Library, Resource Center : poster presentation

The first concept of a new library was introduced in 2001 by a faculty member at the University of Texas Marine Science Institute. The suggestion for the construction of a new library was based on two specific reasons: existing library is located in one of the most vulnerable buildings to hurricane damage and the library has outgrown its current space. This presentation provides a general overview of the current status and changing needs of the Marine Science Library and how the idea of a new library finally became a reality

Towards integrated island management: lessons from Lau, Malaita, for the implementation of a national approach to resource management in Solomon Islands: final report

Solomon Islands has recently developed substantial policy aiming to support inshore fisheries management, conservation, climate change adaptation and ecosystem approaches to resource management. A large body of experience in community based approaches to management has developed but “upscaling” and particularly the implementation of nation-wide approaches has received little attention so far. With the emerging challenges posed by climate change and the need for ecosystem wide and integrated approaches attracting serious donor attention, a national debate on the most effective approaches to implementation is urgently needed. This report discusses potential implementation of “a cost-effective and integrated approach to resource management that is consistent with national policy and needs” based on a review of current policy and institutional structures and examination of a recent case study from Lau, Malaita using stakeholder, transaction and financial cost analyses.

Using productivity and susceptibility indices to assess the vulnerability of United States fish stocks to overfishing

Assessing the vulnerability of stocks to fishing practices in U.S. federal waters was recently highlighted by the National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration, as an important factor to consider when 1) identifying stocks that should be managed and protected under a fishery management plan; 2) grouping data-poor stocks into relevant management complexes; and 3) developing precautionary harvest control rules. To assist the regional fishery management councils in determining vulnerability, NMFS elected to use a modified version of a productivity and susceptibility analysis (PSA) because it can be based on qualitative data, has a history of use in other fisheries, and is recommended by several organizations as a reasonable approach for evaluating risk. A number of productivity and susceptibility attributes for a stock are used in a PSA and from these attributes, index scores and measures of uncertainty are computed and graphically displayed. To demonstrate the utility of the resulting vulnerability evaluation, we evaluated six U.S. fisheries targeting 162 stocks that exhibited varying degrees of productivity and susceptibility, and for which data quality varied. Overall, the PSA was capable of differentiating the vulnerability of stocks along the gradient of susceptibility and productivity indices, although fixed thresholds separating low-, moderate-, and highly vulnerable species were not observed. The PSA can be used as a flexible tool that can incorporate regional-specific information on fishery and management activity.

Feasibility of adopting aquaculture without detriment to existing farming practices: a case of Bangladesh farming systems

Integrating agriculture aquaculture that would draw inputs from on farm sources is viewed as a viable option to improve the productivity, income and resource use efficiency of existing farms in Bangladesh. To assess the existing resource availability, use pattern and efficiency before introducing new aquaculture technology within the existing farm systems, a survey of 330 pond operating farm households was conducted in six selected unions from two thanas (subdistricts) of Bangladesh.

Pig dung as pond manure: effect on water quality, pond productivity and growth of carps in polyculture system

Pig dung was used as manure at 18 and 36 t/ha/year in carp polyculture (without supplementary feeding) for 270 days. It was observed that pig dung at both the levels did not degrade the physico-chemical properties (pH, dissolved oxygen and alkalinity) of water. The nutrient (phosphates and nitrates) level of water was higher in manured ponds than control ponds (no manuring, only supplementary feeding). Further, plankton levels (phyto- and zooplankton) were also significantly higher in manured ponds. The growth of Catla catla and Labeo rohita was significantly more in manured ponds than in control ponds. Growth of Cirrhinus cirrhosus and Cyprinus carpio was significantly more in ponds manured with pig dung at 18 t/ha/year than in control ponds and the growth of Ctenopharyngodon idellus was significantly more in control than in manured ponds.

Management of mangrove areas in Calauag Bay, Quezon Province, Philippines

The findings are presented of a study conducted in Calauag Bay, Quezon Province, Philippines in order to estimate resource rent of mangrove areas converted to fishpond production. The rents were calculated based on the technology practised by the farmers and the prices of inputs and outputs that prevailed during the study period. The major causes of mangrove depletion are cutting of mangroves for fuelwood and charcoal and clearing for fishpond development. It was concluded that there is justification for the government to increase the feed which could be used to rehabilitate the inland-coastal fisheries to improve productivity and ensure sustainability of the ecosystem for future generations.

Rice field fisheries: a resource for Cambodia

Small-scale fisheries in and around rice fields in the lowland areas of Cambodia are greatly underestimated and undervalued. Their contribution to the protein requirements of the poor rural households is significant. In Svay Rieng province, they could provide 65-75% of the animal protein requirements of these households. The value could well be around 40% of the value of rice production. It is, therefore, important that these natural stocks and the fisheries are managed well and that developmental activities explicitly consider their impact on these fisheries.

Traditional institutions and their role in the contemporary coastal resource management in the Pacific Islands

A discussion is presented on the role played by customary marine tenure (CMT) institutions in the regulation of fisheries in the Pacific Ocean Islands. Particular reference is made to the system in operation in Marovo Lagoon, in the Solomon Islands, whereby a number of defined clans control resource use within defined areas of land and sea. It is believed that such systems have considerable capacity for handling and adapting to new circumstances, thereby becoming potentially important tools in the contemporary management of fisheries and of the coastal zone in general.

Economic incentives for water resource management in the Pak Phanang river basin of southern Thailand

The study examines the existing water allocation methods and other policies that provide constraints or incentives for the most efficient use of water resources. Given the production condition of the local people, and the technical and physical attributes of water resources, the principal hypothesis of this study is that the benefits obtained from fresh water resources in the study area can be improved through better resource management.

Mangrove rehabilitation and coastal resource management: a case study of Cogtong Bay, Philippines

The Cogtong Bay experience represents a bold attempt to pursue a shared responsibility between the government and local residents for rehabilitating coastal resources. Some of the factors that provided the impetus to co-management arrangements were the recognition of resource management problems, dependence on coastal resources for livelihood and the desire for more sustainable resource use. This paper draws attention to the importance of legitimate user/property rights, vigilant law enforcement efforts, common commitment among stakeholders and continuing support from local leadership in viable co-management arrangements.