Showing papers on "Fishing published in 2001"

Marine Fisheries Ecology

Abstract: 1. Marine fisheries ecology: an introduction2. Marine ecology and production processes3. Fished Species: life histories and distribution4. Population structure in space and time5. Fishing gears and techniques6. Fishers: socioeconomics and human ecology7. Single species stock assessment> 8. Multi-species assessment and ecosystem modelling9. Getting the data: stock identity and dynamics10. Getting the data: abundance, catch and effort11. Bioeconomics12. Fishing effects on populations and communities13. Bycatches and discards14. Impacts on benthic communities, habitats and coral reefs15. Fisheries interactions with birds and mammals16. A role for aquaculture?17. Management and Conservation optionsReferences

Systematic distortions in world fisheries catch trends

Abstract: Over 75% of the world marine fisheries catch (over 80 million tonnes per year) is sold on international markets, in contrast to other food commodities (such as rice). At present, only one institution, the Food and Agriculture Organization of the United Nations (FAO) maintains global fisheries statistics. As an intergovernmental organization, however, FAO must generally rely on the statistics provided by member countries, even if it is doubtful that these correspond to reality. Here we show that misreporting by countries with large fisheries, combined with the large and widely fluctuating catch of species such as the Peruvian anchoveta, can cause globally spurious trends. Such trends influence unwise investment decisions by firms in the fishing sector and by banks, and prevent the effective management of international fisheries.

Cultivation/depensation effects on juvenile survival and recruitment: implications for the theory of fishing

Abstract: Large, dominant fish species that are the basis of many fisheries may be naturally so successful due partly to "cultivation effects," where adults crop down forage species that are potential compet...

Interactions of pelagic cnidarians and ctenophores with fish: a review

Abstract: Medusae, siphonophores and ctenophores (here grouped as ‘pelagic coelenterates’) interact with fish in several ways. Some interactions are detrimental to fish populations, such as predation by gelatinous species on pelagic eggs and larvae of fish, the potential competition for prey among pelagic coelenterates and fish larvae and zooplanktivorous fish species, and pelagic coelenterates serving as intermediate hosts for fish parasites. Other interactions are positive for fish, such as predation by fish on gelatinous species and commensal associations among fish and pelagic coelenterates. The interactions range from beneficial for the gelatinous species (food, parasite removal), to negative (predation on them). We review existing information and present new data on these topics. Although such interactions have been documented frequently, the significance to either fish or pelagic coelenterate populations is poorly understood. The effects of pelagic coelenterates on fish populations are of particular interest because of the great importance of fisheries to the global economy. As fishing pressures mount, it becomes increasingly important to understand how they may influence the balance between pelagic coelenterates and fish.

Fish as food: aquaculture's contribution. Ecological and economic impacts and contributions of fish farming and capture fisheries.

Abstract: Historically, the oceans were considered limitless and thought to harbour enough fish to feed an ever‐increasing human population. However, the demands of a growing population, particularly in poorer countries, now far outstrip the sustainable yield of the seas. At the same time as fishing has become more industrialised, and wild fish stocks increasingly depleted, aquaculture production—fish and shellfish farming—has grown rapidly to address the shortfalls in capture fisheries. But aquaculture has come under intense scrutiny and criticism as environmentalists fear that it could cause significant environmental problems and further impact wild species that are already threatened. Indeed, both capture fisheries and aquaculture must have environmental costs—all human activities of significant scale do—but it is necessary to fairly evaluate and compare the ecological and economic impact of both. In fact, a thorough analysis shows that the ecological threat of aquaculture is much lower than continuing to supply the majority of fish protein from wild capture. Fish is a vital source of food for people. It is man's most important single source of high‐quality protein, providing ∼16% of the animal protein consumed by the world's population, according to the Food and Agriculture Organisation (FAO) of the United Nations (1997). It is a particularly important protein source in regions where livestock is relatively scarce—fish supplies <10% of animal protein consumed in North America and Europe, but 17% in Africa, 26% in Asia and 22% in China (FAO, 2000). The FAO estimates that about one billion people world‐wide rely on fish as their primary source of animal protein (FAO, 2000). > A consistent source of fish is essential for the nutritional and financial health of a large segment of the world's population Fish also has substantial social and economic importance. The FAO estimates the value of fish traded internationally to be US$ 51 …

Effects of marine reserve characteristics on the protection of fish populations: a meta‐analysis

Abstract: Meta-analyses of published data for 19 marine reserves reveal that marine protected areas enhance species richness consistently, but their effect on fish abundance is more variable. Overall, there was a slight (11%) but significant increase in fish species number inside marine reserves, with all reserves sharing a common effect. There was a substantial but non-significant increase in overall fish abundance inside marine reserves compared to adjacent, non-reserve areas. When only species that are the target of fisheries were considered, fish abundance was significantly higher (by 28%) within reserve boundaries. Marine reserves vary significantly in the extent and direction of their response. This variability in relative abundance was not attributable to differences in survey methodology among studies, nor correlated with reserve characteristics such as reserve area, years since protection, latitude nor species diversity. The effectiveness of marine reserves in enhancing fish abundance may be largely related to the intensity of exploitation outside reserve boundaries and to the composition of the fish community within boundaries. It is recommended that studies of marine reserve effectiveness should routinely report fishing intensity, effectiveness of enforcement and habitat characteristics.

Fishing down Canadian aquatic food webs

Abstract: The mean trophic level (TL) of fish landed in fisheries on the east and west coasts of Canada is declining by 0.03–0.10·decade–1, similar to global trends. This finding is based on data from United Nations Food and Agriculture Organization and the Canadian Department of Fisheries and Oceans and other Canadian sources for the period 1873–1997. Significant rates of decline in mean TL were obtained even when key species — Atlantic cod (Gadus morhua) on the east coast and Pacific herring (Clupea pallasi) and Pacific hake (Merluccius productus) on the west coast — were omitted from the analysis. Fish taken in inland water fisheries did not exhibit a decline in mean TL. Two models were developed, based on length and age, respectively, for correcting TL estimates of individual species for the effects of changes in body size due to changes in fishing mortality. Both produced corrections that were small relative to changes in mean TL that resulted from changes in species composition of the catch over time. Overall...

Making Space for Community Resource Management in Fisheries

Abstract: The dominant discourse of fisheries science and management, bioeconomics, places the behavior of individual fishermen operating on an open-access commons at the center of its understanding of fisheries resources and the fishing industry. Within this discourse, fishermen are the sole actors and the fishery is the fixed stage for an inevitable ‘tragedy of the commons.’ Starting from these particular assumptions of both subject and space, bioeconomics proposes solutions to fisheries crisis that differ sharply from fishers’ perceptions of the resource and their desires for management. These divergent understandings of both the natural and social environments are reflected in the maps produced by fisheries scientists/managers and those produced by fishers themselves. Remapping fisheries in terms of fishers’ perceptions and scales of operation reveals diverse natural landscapes and communities in which the dominant discourse charted only quantities of fish and individual fishermen. The landscape of fishing comm...

Rapid Decline of Nassau Grouper Spawning Aggregations in Belize: Fishery Management and Conservation Needs

Abstract: The Nassau grouper (Epinephelus striatus) and other reef fishes aggregate in large numbers at specific locations and times to spawn. In Belize, as in the rest of the Caribbean, about one-third of the grouper spawning aggregations have disappeared due to overfishing. One of the last spawning aggregations still viable in Belize has decreased from 15,000 to fewer than 3,000 Nassau groupers in the last 25 years, a decline of more than 80%. The spawning aggregation was still open to fishing in January 2001, with a fishing quota of 900 groupers, which represented about 30% of the aggregation. The actual catch was at least 300 groupers. Fisheries models predict that, if fishing continues, the spawning aggregation will disappear by 2013, and the fishery will be abandoned by 2009 at the latest. Unsustainable fishing will eliminate the spawning aggregations in Belize, with subsequent negative effects on the grouper populations in the region. Since most of the spawning aggregations in Belize have now been f...

Inland fisheries : ecology and management

Abstract: Fish from inland waters provide a major source of animal protein, particularly in areas far removed from the sea. The current high demand for fish, and the increased awareness of the role of the environment in supporting human well being, have led to a situation where attitudes to inland water resources are rapidly changing. This change is part of a larger preoccupation for the long-term stability of ecosystems as well as a concern for the capacity of existing freshwater resources to meet human needs. Compiled by Robin Welcomme for the Food and Agriculture Organization of the United Nations, with contributions from several internationally known and respected scientists, this exciting book covers, in depth, the nature of inland waters, the fish populations that live within them, their utilization by fishing industries, and the fishing techniques that these industries use. Comprehensive coverage is also given to evaluation of resources and social and economic issues, management of fisheries and environment, biodiversity and conservation, enhancement, rehabilitation and legislative issues. Fully international in its coverage, "Inland Fisheries" is an essential reference manual for all those involved in inland waterway and fisheries management including fisheries officers, environmental scientists and ecologists, aquatic scientists, those working in rivers and lakes authorities and fish and wildlife departments of governments and universities.

Understanding the cultures of fishing communities : a key to fisheries management and food security

Abstract: The purpose of this paper is to help fisheries officials gain a clearer understanding of small-scale fishing community cultures. By doing so, they will be better prepared to develop more successful management policies and practices, and to help people in such communities to improve their livelihoods. The paper suggests methods that might help fisheries managers to obtain reliable information about fishing cultures in an ethical manner, including the rapid acquisition of important information while working within tight budgetary and time constraints. It also gives recommendations on how the foregoing objectives can be achieved, underscoring the importance of sustaining small-scale fishers' rights of access to resources and integration of cultural considerations into fisheries-management policies and practices. Six contemporary case studies from distinct cultural regions of the world are annexed, richly exemplifying many of the issues discussed in the paper.

The Precautionary Approach and risk management: can they increase the probability of successes in fishery management?

Abstract: Considerable progress has been made in the implementation of the Precautionary Approach to the protection of fish stocks, but applying the Precautionary Approach to the protection of fishing commun...

Escaped salmon in the inner seas, southern chile: facing ecological and social conflicts

Abstract: During heavy storms in 1994–1995, salmon farms in southern Chile lost several million fish from the most commonly farmed species, rainbow trout (Oncorhynchus mykiss), coho salmon (Oncorhynchus kisutch), and Atlantic salmon (Salmo salar). To determine the abundance and distribution of such exotic salmon populations in the wild and their effect on native organisms, we conducted experimental fishing, in six locations in the salmon farming regions (41°–46° S) in the inner seas of Chiloe (X Region) and Aysen (XI Region), between November 1995 and December 1996. At the same time, we collected information from salmon farms and insurance companies about escaped individuals. During the experimental fishing we captured 2602 coho salmon, 984 trout, and 271 Atlantic salmon. Captures of the three species declined through the duration of the study; thus in November 1996 we captured <10% of initial catches. Population projections based on three possible mortality rates (0.4, 0.8, and 1.2) predicted the disappearance of salmon by year 2000, and the highest mortality rate was the best predictor of the observed available biomass in 1996. Thus, artisanal fishing may control escaped salmon. Of the three species, coho salmon had the best chances of becoming established in the remote XI Region where the artisanal fishing pressure was less intense. The three salmon species showed feeding similarities, since each kept feeding on pellets beneath the farms, particularly Atlantic salmon, while coho salmon showed greater preference for schooling fish, and rainbow trout fed more often on crustaceans. Thus, the three species, particularly coho salmon, could compete with native southern hake and mackerel. As a management approach to avoid salmon colonization and naturalization in southern Chile, local artisanal fishing should be encouraged because it is probably the most efficient way to remove escaped individuals and reduce the chance of populations becoming self-sustaining.

Modelling the impact of fishery by-catches on albatross populations

Abstract: Summary 1 Several albatross species, including the wandering albatross Diomedea exulans, have shown marked declines in abundance throughout their range. These seabirds are frequently taken as by-catch in longline fisheries and this mortality has been implicated in the population declines. 2 We developed a deterministic, density-dependent, age-structured model for assessing the effects of longlining on wandering albatross populations. We used demographic data from field studies at South Georgia and the Crozet Islands, data on albatross abundance from 1960 to 1995, and reported effort data from the tuna longline fisheries south of 30° S, to model estimated by-catch levels and other population parameters in the model. 3 The model used two alternative assumptions about patterns of at-sea distribution of wandering albatross (uniform between 30° S–60° S; proportional to the distribution of longline fishing effort between these latitudes). 4 Our model was able to predict reasonably closely the observed data from the Crozet Islands wandering albatross population, but the fit to the South Georgia population was substantially poorer. This probably reflects: (i) greater overlap in the Indian Ocean than in the Atlantic Ocean between the main areas of tuna longline fishing and the foraging ranges of wandering albatrosses from the Crozet Islands and South Georgia, respectively; and (ii) greater impact of poorly documented longline fisheries, especially the tuna fisheries in the south Atlantic and the Patagonian toothfish Dissostichus eleginoides fishery, within the foraging range of wandering albatrosses from South Georgia. 5 The model results suggest that the marked decline in both populations, and subsequent recovery of the Crozet Islands population (but not the continued decline of the South Georgia population), can be explained by the tuna longline by-catch. They further indicate that populations may be able to sustain some level of incidental take. However, the likely under-reporting of fishing effort (especially in non-tuna longline fisheries) and the delicate balance between a sustainable and unsustainable level of by-catch for these long-lived populations suggest great caution in any application of such findings.

Predation and competition: the impact of fisheries on marine-mammal populations over the next one hundred years

Abstract: We discuss the potential for commercial fisheries to adversely impact ≥1 population of marine mammal by the end of the 21st century. To a large degree, patterns over the last 50 years regarding human population growth, success and failure in marine-fisheries management, and life history and status information on marine mammals are the basis for 6 predictions. First, annual worldwide landings of fish and shellfish by the end of the 21st century will be less than 80 million tons. Second, virtually all of the predictions regarding species composition and energy flow within a marine community, based on models developed to date with incomplete information on species abundance, food habits, genetic effects of fishing, and variability of predator food habits, will prove wrong on a decadal or longer time scale. Third, the most common type of competitive interaction between marine mammals and commercial fisheries will be that in which commercial fisheries adversely affect a marine-mammal population by depleting localized food resources without necessarily overfishing the target species of fish (or shellfish). Because of this, the number of extant populations and species richness of marine mammals will be reduced by the end of the 21st century, and coastal populations and species will be affected more negatively than will noncoastal species. Fifth, predator control programs designed to reduce local populations of marine mammals will be common without changes in existing forms of fishery management. Finally, protein from marine mammals will become a more important component of the human diet than it currently is.

Bony fishes part 4 (labridae to latimeriidae), estuarine crocodiles, sea turtles, sea snakes and marine mammals

Abstract: This multivolume field guide covers the species of interest to fisheries of the major marine resource groups exploited in the Western Central Pacific. The area of coverage includes FAO Fishing Area 71 and the southwestern portion of Fishing Area 77 corresponding to the South Pacific Commission mandate area. The marine resource groups included are seaweeds, corals, bivalves, gastropods, cephalopods, stomatopods, shrimps, lobsters, crabs, holothurians, sharks, batoid fishes, chimaeras, bony fishes, estuarine crocodiles, sea turtles, sea snakes and marine mammals. The introductory chapter outlines the environmental, ecological and biogeographical factors influencing the marine biota as well as the basic components of the fisheries in the Western Central Pacific. Within the field guide, the sections on the resource groups are arranged phylogenetically according to higher taxonomic levels such as class, order and family. Each resource group is introduced by general remarks on the group, an illustrated section on technical terms and measurements and a key or guide to orders or families. Each family generally has an account summarizing family diagnostic characters, biological and fisheries information, notes on similar families occurring in the area, a key to species, a checklist of species and a short list of relevant literature. Families that are less important to fisheries include an abbreviated family account and no detailed species information. Species in the important families are treated in detail (arranged alphabetically by genus and species) and include the species name, frequent synonyms and names of similar species, an illustration, FAO common name(s), diagnostic characters, biology and fisheries information, notes on geographical distribution and a distribution map. For less important species, abbreviated accounts are used. Generally, this includes the species name, FAO common name(s), an illustration, a distribution map and notes on biology, fisheries and distribution. Each volume concludes with its own index of scientific and common names.

A spatially disaggregated, length-based, age-structured population model of yellowfin tuna (Thunnus albacares) in the western and central Pacific Ocean

Abstract: A spatially disaggregated, length-based, age-structured model for yellowfin tuna (Thunnus albacares) in the western and central Pacific Ocean is described. Catch, effort, length-frequency and tagging data stratified by quarter (for the period 1962–99), seven model regions and 16 fisheries are used in the analysis. The model structure includes quarterly recruitment in each region, 20 quarterly age classes, independent growth patterns for juveniles and adults, structural time-series variation in catchability for all non-longline fisheries, age-specific natural mortality, and age-specific movement among the model regions. Acceptable fits to each component data set comprising the log-likelihood function were obtained. The model results suggest that declines in recruitment, and as a consequence, population biomass, have occurred in recent years. Although not obviously related to over-exploitation, the recruitment decline suggests that the productivity of the yellowfin tuna stock may currently be lower than it has been previously. Recent catch levels appear to have been maintained by increases in fishing mortality, possibly related to increased use of fish aggregation devices in the purse-seine fishery. A yield analysis indicates that average catches over the past three years may have slightly exceeded the maximum sustainable yield. The model results also reveal strong regional differences in the impact of fishing. Such heterogeneity in the fisheries and the impacts on them will need to be considered when future management measures are designed.

Are deepwater fisheries sustainable? — the example of orange roughy (Hoplostethus atlanticus) in New Zealand

Abstract: The deepsea environment is generally regarded as being one of low energy and productivity. Species exploited at depths of over 600 m like orange roughy ( Hoplostethus atlanticus ), oreos (e.g. Allocyttus niger , Pseudocyttus maculatus ), and macrourid rattails (e.g. Coryphaenoides rupestris , Macrourus berglax ) have slow growth rates and high longevity compared to traditional commercial species from the continental shelf. They have low levels of sustainable yields, are vulnerable to overfishing, and have slow recovery rates. Yet, they are often high-value species, and this has maintained interest in developing new fisheries for deepwater species. In New Zealand waters orange roughy has been fished for 20 years. Familiar patterns of rapid fishery development with large catches, followed by contractions in stock distribution, and reductions in catch levels as the stocks become over-exploited, have occurred. Quotas in a number of New Zealand fisheries were reduced in the early 1990s, and this enables an insight into how stocks respond with reduced levels of exploitation, and how resilient and sustainable these fisheries may be in the long term. Examples are given for several New Zealand and Australian orange roughy fisheries. Changes in abundance, fishery performance, and biological characteristics are examined. In some cases fish stocks appear to be holding their own, and are supporting relatively stable catch rates, but in others stocks are still declining. There are few signs of biological compensation, and recruitment levels appear to be low. Lack of good data on levels and patterns of recruitment is a major source of uncertainty in current stock assessments, and a principal concern for long term sustainability of such fisheries

Degradation of marine ecosystems and decline of fishery resources in marine protected areas in the US Virgin Islands

Abstract: The large number of marine protected areas (MPAs) in the Caribbean (over 100) gives a misleading impression of the amount of protection the reefs and other marine resources in this region are receiving. This review synthesizes information on marine resources in two of the first MPAs established in the USA, namely Virgin Islands National Park (1962) and Buck Island Reef National Monument (1961), and provides compelling evidence that greater protection is needed, based on data from some of the longest running research projects on coral reefs, reef fish assemblages, and seagrass beds for the Caribbean. Most of the stresses affecting marine resources throughout the Caribbean (e.g. damage from boats, hurricanes and coral diseases) are also causing deterioration in these MPAs. Living coral cover has decreased and macroalgal cover has increased. Seagrass densities have decreased because of storms and anchor damage. Intensive fishing in the US Virgin Islands has caused loss of spawning aggregations and decreases in mean fish size and abundance. Groupers and snappers are far less abundant and herbivorous fishes comprise a greater proportion of samples than in the 1960s. Effects of intensive fishing are evident even within MPA boundaries. Although only traditional fishing with traps of ‘conventional design’ is allowed, commercial trap fishing is occurring. Visual samples of fishes inside and outside Virgin Islands National Park showed no significant differences in number of species, biomass, or mean size of fishes. Similarly, the number of fishes per trap was statistically similar inside and outside park waters. These MPAs have not been effective because an unprecedented combination of natural and human factors is assaulting the resources, some of the greatest damage is from stresses outside the control of park managers (e.g. hurricanes), and enforcement of the few regulations has been limited. Fully functioning MPAs which prohibit fishing and other extractive uses (e.g. no-take marine reserves) could reverse some of the degradation, allowing replenishment of the fishery resources and recovery of benthic habitats.

Reactions of harbor porpoises Phocoena phocoena and herring Clupea harengus to acoustic alarms

Abstract: Small cetaceans are susceptible to incidental mortality in the various forms of gillnet fisheries throughout their range. Research conducted since 1994 has shown that acoustic alarms (pingers) emitting high-frequency pulsed sounds effectively reduce the number of harbor porpoise Phocoena phocoena casualties in sink gillnets. However, the mechanisms behind the effects of pingers were still not understood. Until now, advantages and risks associated with their widespread use could not be evaluated. Here we present the results of 2 field experiments: (1) theodolite-track- ing of harbor porpoises exposed to a single PICE-pinger in Clayoquot Sound, Vancouver Island, Canada and (2) herring Clupea harengus capture rates in surface gillnets equipped with and without acoustic alarms (Dukane Netmark 1000, Lien, PICE) in the Baltic Sea herring fishery at Rugen Island, Germany. Our results show that harbor porpoises do not seem to react to an experimental net in their foraging area (n = 172 groups, median group size = 2 porpoises). Porpoise distance from the mid-point of the net was distributed around a median of only 150 m (range 4 to 987 m). A net equipped with an acoustic alarm, however, was avoided (n = 44 groups) within audible range (distance distribution median = 530 m, range 130 to 1140 m). The porpoises were thus effectively excluded from the ensoni- fied area. Herring, one of the main prey species of harbor porpoises, were not affected by the acoustic alarms tested (n = 25 407 fish captured). The advantages and risks of using acoustic alarms to mitigate by-catch are discussed.

Jellyfish fisheries in southeast Asia

Abstract: A few large jellyfish species in the order Rhizostomeae constitute an important food in Chinese cooking. For more than 1700 years, they have been exploited along the coasts of China. Such jellyfish became an important fishery commodity of Southeast Asian countries in the 1970s with increasing demand from the Japanese market. Recently, Japan has imported 5400–10000 tons of jellyfish products per year, valued at about 25.5 million US dollars, annually from the Philippines, Vietnam, Thailand, Malaysia, Indonesia, Singapore and Myanmar. Judging from the type names at market and the external appearance of the semi-dried products, the edible jellyfish harvest in Southeast Asia is composed of more than 8 species. They are caught by various kinds of fishing gear including setnets, drift-nets, hand-nets, scoop-nets, beach-seines and hooks. The fishery is characterized by large fluctuations of the annual catch and a short fishing season that is restricted from two to four months. The average annual catch of jellyfish between 1988 and 1999 in Southeast Asia is estimated to be about 169000 metric tons in wet weight and the worldwide catch is approximately 321 000 metric tons. Needs for future study on the biology of rhizostome jellyfish are discussed as they relate to understanding population fluctuations.

Visions for Recreational Fishing Regulations

Abstract: We review sportfishing regulations in Minnesota and across North America and discuss potential visions for the future of sportfishing regulations. Creel limits are ubiquitous across North America and they have been generally set arbitrarily with little biological justification. Anglers may not accept reductions in creel limits that actually decrease total harvest. Length-based regulations are now common and most North American sport fish management agencies had numerous water-specific length-based regulations. The future of fishing regulations could continue to get more complex but there are substantial shortcomings to this future. We present four visions of the future of freshwater recreational fishing, and we pose the question “Does the fact we are managing a pleasure sport mean that we need to rethink our fisheries management philosophy?” Future management of sport fish may rely less on biology and more on social science as we learn to optimize angler satisfaction. Although biology should be t...

Paleocoastal marine fishing on the Pacific Coast of the Americas: perspectives from Daisy Cave, California.

Abstract: Analysis of over 27,000 fish bones from strata at Daisy Cave dated between about 11,500 and 8500 cal B.P. suggests that early Channel Islanders fished relatively intensively in a variety of habitats using a number of distinct technologies, including boats and the earliest evidence for hook-and-line fishing on the Pacific Coast of the Americas. The abundance of fish remains and fishing-related artifacts supports dietary reconstructions that suggest fish provided more than 50 percent of the edible meat represented in faunal samples from the early Holocene site strata. The abundance and economic importance of fish at Daisy Cave, unprecedented among early sites along the Pacific Coast of North America, suggest that early maritime capabilities on the Channel Islands were both more advanced and more variable than previously believed. When combined with a survey of fish remains from several other early Pacific Coast sites, these data suggest that early New World peoples effectively used watercraft, captured a diverse array of fish, and exploited a variety of marine habitats and resources.

Fishing Effort Allocation and Fishermen's Decision Making Process in a Multi-Species Small-Scale Fishery: Analysis of the Conch and Lobster Fishery in Turks and Caicos Islands

Abstract: In this paper we analyze the fishing effort allocation of fishermen in the artisanal fisheries of the Turks and Caicos Islands (British West Indies). These fishermen use a free-diving technique to simultaneously exploit the local stocks of queen conch and spiny lobster. Using an integrated framework combining a set of analytical tools within a multi-disciplinary holistic approach, we attempt to identify the biological, economic, and social mechanisms which govern the fishermen's effort allocation between the two targeted stocks. The analysis shows that the seasonal dynamics of the whole system are essentially dictated by the very remunerative lobster fishery. Although this result tends to espouse the predictions of classical economic theory, a closer analysis reveals that the economic rationality approach does not entirely explain the observed fishermen behavior. Information from a series of socio-anthropological surveys shows that the fishermen's decision making is further influenced by collective and individual constraints related to the specific diving abilities required to operate in the two fisheries and by the socio-historico-cultural environment within which the fishing community has been evolving over the last century.

Management issues in the Lake Victoria watershed

Abstract: Lake Victoria is the largest lake in Africa (68 800 km2) and is the eighth largest lake in the world by volume. The three East African countries of Tanzania, Uganda and Kenya share Lake Victoria and its resources. The total annual catch of fish from the lake ranges between 400 × 106 kg and 500 × 106 kg, bringing these riparian countries a combined annual income of approximately US$250 000–500 000 from exports alone. Approximately 30 million people live in the riparian region and the catchment, with about 2 million of these depending directly or indirectly on fishing activities. Tragically, Lake Victoria’s extremely diverse fauna was decimated in only 30 years following the introduction of non-native Nile perch in the early 1960s. An estimated 200 endemic cichlid species became extinct. Dramatic increases in overfishing, pollution from various sources, effects of noxious water weeds and other associated problems threaten the sustainability of the lake’s resources and the economies of the riparian governments and peoples. Regulations governing Lake Victoria’s resources are different in each country. The laws concerning treatment of effluents from point sources in the three countries are not harmonized, neither are implementation or enforcement provisions. The governments of Kenya, Uganda and Tanzania have begun to put in place regional mechanisms to address the lake’s many problems including the creation of a permanent regional international institution through the establishment of the Lake Victoria Fisheries Organization (LVFO). A strategic vision document and action plans have been developed. Efforts are being made at local, national and regional levels to control the water hyacinth, including manual pulling, mechanical harvesting and introduction of weevils that weaken hyacinth root systems. To address the problem of overfishing, fishermen committees at landing beaches have been put in place. Each country has committed to take all necessary measures including legislation to implement the decisions of the LVFO governing bodies. All three countries have agreed to adopt and enforce legislation and regulations prohibiting the introduction of non-indigenous species to the lake and to enforce existing regulations regarding fisheries. A Global Environment Facility project which provides funding to the Lake Victoria Fisheries Organization addresses land use management, catchment forestation, fisheries research and management, water hyacinth control, industrial effluent treatment and municipal waste treatment.

Use of Telemetry Methods to Estimate Natural and Fishing Mortality of Striped Bass in Lake Gaston, North Carolina

Abstract: Natural mortality can substantially affect fish population dynamics, but the rate is difficult to estimate because natural deaths are rarely observed and it is difficult to separate the effects of natural and fishing mortality on abundance. We developed a new telemetry approach for estimating natural and fishing mortality rates and applied it to the population of striped bass Morone saxatilis in Lake Gaston, North Carolina and Virginia. Our analyses were based on a sample size of 51 telemetered striped bass that were known to be alive and in Lake Gaston at least 1 month after capture and surgery. Relocations of live fish and fish that died of natural causes were used to estimate natural and fishing mortality rates and the probability of relocating telemetered fish. Fishing mortality rates varied seasonally, but few natural deaths were observed, so the best model incorporated a constant annual instantaneous natural mortality rate (M; ±SE) of 0.14 ± 0.02. With the uncertainty in model selection acc...

Feeding habits of wild and escaped farmed Atlantic salmon, Salmo salar L., in the Northeast Atlantic

Abstract: Jacobsen, J. A., and Hansen, L. P. 2001. Feeding habits of wild and escaped farmed Atlantic salmon, Salmo salar L., in the Northeast Atlantic. – ICES Journal of Marine Science, 58: 916–933. The stomach contents of 2992 wild and 863 putative escaped farmed Atlantic salmon caught on floating long-lines in a Faroese research fishery in the late autumn (November–December) and winter (February–March) in the Northeast Atlantic (63–66N and 1–10W) during three consecutive fishing periods 1992/1993–1994/1995 were analysed. Hyperiid amphipods of the genus Themisto, euphausiids and mesopelagic shrimps are important sources of food for salmon in the autumn period and various mesopelagic fish as lantern fishes, pearlsides and barracudinas become equally important during the late winter period. The occasional presence in the stomachs of larger fish such as herring, blue whiting and mackerel is not considered to be evidence that these fish are a main source of food for salmon in the sea north of the Faroes. The proportion of stomachs containing food was significantly lower during autumn (53%) than during winter (78%). However, temperature-dependent evacuation rates could partly explain the apparent lower stomach content during the autumn, since the average ambient sea-surface temperature is 7C in autumn compared to 3C in winter. There was evidence of selective foraging. Fish were preferred over crustaceans, and amphipods were chosen over euphausiids. Large salmon (3+SW) tended to be more piscivorous than smaller fish. There was no difference in condition factor, number and weight proportions of prey, or in diet between wild and escaped farmed salmon, which suggests that escaped farmed salmon adapt well to the ‘‘wild’’ life in the ocean. 2001 International Council for the Exploration of the Sea

Fishing on ecosystems: the interplay of fishing and predation in NewfoundlandLabrador

Abstract: In the early 1990s, Atlantic cod, a major component of the Newfoundland–Labrador ecosystem, suffered a stock collapse, and other groundfish stocks such as American plaice and yellowtail flounder se...

Designing Marine Reserve Networks Why Small, Isolated Protected Areas Are Not Enough

Abstract: For a fish, the north coast of Jamaica is a lonely place. Fishing intensities are so high that most fish are caught long before they reach maturity. Coral reefs there are festooned with traps, hooks, and nets, while spearfishers hunt all day to depths of more than fifteen meters. Diving these reefs, one is struck by the absence of fish bigger than 15 cm and by the abundance of tiny fish, mostly species of little commercial interest. What is truly amazing about Jamaica is that there are any fish at all!