Estimating consumption rates of juvenile sandbar sharks (Carcharhinus plumbeus) in Chesapeake Bay, Virginia, using a bioenergetics model*

Using a bioenergetics model, we estimated daily ration and seasonal prey consumption rates for six age classes of juvenile sandbar sharks (Carcharhinus plumbeus) in the lower Chesapeake Bay summer nursery area. The model, incorporating habitat and species-specific data on growth rates, metabolic rate, diet composition, water temperature (range 16.8−27.9°C), and population structure, predicted mean daily rations between 2.17 ±0.03 (age-0) and 1.30 ±0.02 (age-5) % body mass/day. These daily rations are higher than earlier predictions for sandbar sharks but are comparable to those for ecologically similar shark species. The total nursery population of sandbar sharks was predicted to consume ~124,000 kg of prey during their 4.5 month stay in the Chesapeake Bay nursery. The predicted consumption rates support the conclusion that juvenile sandbar sharks exert a lesser top-down effect on the Chesapeake Bay ecosystem than do teleost piscivores and hu

Fish consumption pattern in major freshwater fisheries provinces of Cambodia

Production and consumption of fish were estimated for a one year period during 1995-96 using a sample of 5 117 households. The sample was taken from a study area covering 83 sample communes in 51 fishing districts belonging to eight freshwater fisheries provinces. About 39% of households in fishing dependent communities were actively involved in fishing. Of the total fishing households, 14% took part in commercial fishing using middle-scale fishing gear. Average annual catch per household for middle-scale and family fishing was 3 319 kg and 647 kg, respectively. Nearly 40% of the fish catch was consumed within the communes. The per capita consumption of fresh fish by fishing households (49.7 kg/yr) was higher than that of non-fishing households (39.9 kg/yr). Including processed fish, the total fish consumption by the fishing dependent communes was estimated at 75.6 kg per capita per annum. Given this high rate of fish consumption, development interventions must consider the role of fisheries in ensuring a sustainable livelihood and food security to Cambodia's growing population.

Fisheries rehabilitation in post-tsunami Aceh: Status and needs from participatory appraisals

The widespread and long-term nature of the tsunami damage in Aceh province, Indonesia has threatened the continued use of coastal and fisheries resources. This article describes the application of the Rapid Appraisal of Fisheries Management System (RAFMS) methodology and presents key findings from the participatory appraisals in 15 study sites. The focus is on changes in the number and types of fishing boats and fishing effort, consumption and marketing flow patterns and community perspectives on livelihood options. The level of aid (for new boats), mainly from international organizations, has been unevenly distributed with the number of boats in 13 of 15 villages still being well below the pre-tsunami levels. A focus on supplying small vessels may put increased fishing pressure on the near-shore zone. Consumption data and marketing flows suggest that most fishing villages are supplying outside markets and adding considerably to the wider food security of the province. Despite the tsunami, marine fisheries-related livelihoods are still preferred, although there are indications for the potential expansion of livelihoods into the culture of new species. Alternative resource-based livelihoods need to be tested and refined to fit the needs of the current conditions in Aceh to provide viable options for eliminating hunger and reducing poverty.

Consumption to biomass (Q/B) ratio and estimates of Q/B-predictor parameters for Caribbean fishes

Estimates of the Q/B ratio and parameters of equations to 'predict' Q/B values for 116 fish stocks in the Gulf of Salamanca, Colombia are presented. A compilation of these estimates available for Caribbean Sea fishes (264 stocks) is also provided for comparison purposes. General trends in the value of Q/B resulting from differences in the equation and parameter values used are briefly discussed.

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.

Estimating the food consumption of fishes: one step in linking a species with its ecosystem

Details are given of a new software package MAXIMS which may be used to estimate the daily food consumption of fish. The software estimates the feeding times, the rates of ingestion and evacuation and related parameters. Two applications of the program are described. The first pertains to anchovy (Engraulis ringens ) with one feeding period per day, and the second one to juvenile cod (Gadus morhua ), which feed during dawn and dusk.

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.

Food consumption/biomass ratios of the pelagic fish community of Lake Malawi/Niassa

An empirical model relating food requirements to morphometric indices of metabolic rate was used to calculate consumption/biomass ratios (Q/B) for 16 species of fish that make the pelagic fish community in Lake Malawi/Niassa. The Q/B/year varied from 3.31 to 9.82, with the large catfish (Dinotopterus nyasensis) having the lowest and a small cyprinid (Engraulicypris sardella) having the highest Q/B ratio. Direct estimates of Q/B for four of the most abundant species, based on analysis of diel feeding patterns, ranged from 4.20 to 24.70; the extreme values in this range representing replicate studies on the same species, the predatory cichlid Rhamphochromis longiceps. Previous studies that indicated exceptionally low Q/B ratios (1.0) in pelagic cichlids from Lake Malawi are not supported by this more recent work.

A new approach for analyzing and comparing coastal resource systems

ICLARM has recently developed a strategic Plan for International research on living aquatic resources management which identifies tropical coastal resource systems as one of its areas of research emphasis. Details are given of a new approach for analysing and comparing coastal resource systems - the coastal cross-section concept. Agroecosystems analysis and farming systems research were used as a basis for the development of this concept.

Impact evaluation of community-based coastal resource management projects in the Philippines

The benefits of decentralizing the management of coastal resources to local governments and resource users have long been recognized, but the best systems for coastal resources management depend on many factors. A number of community-based management and co-management projects were started in the Philippines in the early 1980s. This report describes a comparative assessment of these projects to determine where improvements can be made in the design of future community-based coastal resource management projects. Early and continuing involvement by project beneficiaries is one of the factors that contributes to the success of the project development, implementation, and evaluation.

The eggs of marine crabs - an unexploited resource

Marine crabs belonging to the family Portunidae form bycatch of shrimp trawlers in India. They are sold at low prices and consumers discard eggs and consume the meat. The paper details the nutritional value of eggs of Portunus pelagicus.

The Ahupua'a concept: relearning coastal resource management from ancient Hawaiians

Isolated in the middle of the Pacific Ocean, Hawaii was one of the last areas to be reached by "western" explorers; as a consequence, some ancient traditions were preserved in Hawaii well into the 19th and 20th centuries, providing an opportunity to learn from a surviving indigenous culture. An account is given of the division of the islands into various units and their exploitation. The smallest major divisions were the "ahupua'as," which spread out at the base along the shore and were self-sufficient units. In this way the ancient Hawaiians recognized the relationship between the land and sea, rainfall and vegetation, nutrients and runoff and preserved the integrity of the delicately balanced ecosystem of which they were a part and upon which they relied for their every need. Modern parallels to this ancient system are broken and irregular; the reorganization of the "ahupua'a" system marked the beginning of the decline of Hawaiian ecosystems. Although steps are being taken to remedy the present situation, Hawaii now ranks among the highest in the nation for its levels of pollution, endangered species and disappearing habitats. More and more, the model for improved management is being sought in the revival of ancient traditions.