Showing papers on "Fishing published in 1993"

On the Dynamics of Exploited Fish Populations

Abstract: Series foreword AJ Pitcher Foreword D Pauly Part One: Fundamentals of the theory of fishing, illustrated by analysis of a trawl factoy Introduction:- theoretical methods in the study of fishery dynamics The basis of a theoretical model of an exploited fish population and definition of the primary factors Mathematical representation of the four primary factors Recruitment Natural mortality Fishing mortality Growth A simple model giving the annual yield in weight from a fishery in a steady state Adaptation of the simple model to give other characteristics of the catch and population Part Two: Some extensions of the simple theory of fishing Recruitment and egg-production Natural mortality Fishing mortality and effort Growth and feeding Spatial variation in the values of parameters movement of fish within the exploited area Mixed populations:- the analysis of community dynamics Part Three: Estimation of parameters Relative fishing power of vessels and standardisation of commercial statistics of fishing effort Estimation of the total mortality coefficient (F + M), and the maximum age, t* Seperate estimation of fishing and natural mortality coefficients Recruitment and egg-production Growth and feeding Part Four: The use of theoretical models in a study of the dynamics and reaction to exploitation of fish populations Application of population models of part one Application of population models of part two Principles and methods of fishery regulation Requirements for the regulation of the North Sea Demersal fisheries Appendices Bibliography and author index Subject index List of amendments compiled by the American Fisheries Society

Pacific Salmon Production Trends in Relation to Climate

Abstract: Pink (Oncorhynchus gorbuscha), chum (O. keta), and sockeye salmon (O. nerka) represent approximately 90% of the commercial catch of Pacific salmon taken each year by Canada, Japan, the United State...

A Repeated Nested-Logit Model of Atlantic Salmon Fishing

Abstract: Participation and site choice for Atlantic salmon fishing are modeled in the context of a repeated three-level nested-logit model. Consumer's surplus measures are derived for different levels of species availability in the Penobscot River, the most important salmon river in New England. For comparison, six other travel-cost models are estimated. These include restrictive cases of the nested-logit model, a partial demand model, and two single-site demand models. Comparisons across these models indicate the importance of modeling the participation decision, including income effects, and of adopting a nested-logit structure rather than a single-level logit structure.

Cod spawning on a migration highway in the north-west Atlantic

Abstract: FIVE hundred years of fishing and fifty years of research have produced only vague accounts of the spawning and migrations of Atlantic cod (Gadus morhua) off Newfoundland in the north-west Atlantic1. Here I report the discovery of 'spawning columns' and a 'highway' used by cod to traverse the northeastern Newfoundland Shelf during annual springtime feeding migrations. Sea research using echosounders2,3 showed that cod spawned in dense shoals (to one fish per m3) that featured midwater spawning columns comprised of pairs of fish. Immature joined mature post-spawning cod to migrate in large (scales of tens of kilometres and hundreds of millions of fish) size-structured aggregations led by larger 'scouts'. Cod traversed the cold waters of the shelf along a deep highway of warm oceanic water (2–2.5 °C). During migration, fish spacing appeared to maximize search volumes while maintaining visual contact. Aggregations fragmented when prey (capelin Mallotus villosus; shrimp, Pandalus spp.) were encountered.

Recent trends in estuarine fisheries: Predictions of fish production and yield

Abstract: Trends in global and United States fish catches were examined to determine the status of estuarine fisheries yields relative to those from other ecosystems. Potential marine fish production, based upon primary production relationships, was estimated globally and for specific marine ecosystems, including estuaries. While global fish catches increased substantially during the past two decades and continued to increase through 1989, catches of estuarine-dependent species have peaked or stabilized. In the United States, total catches have increased but many estuarine-dependent fisheries have declined, although the declines in catches are no more dramatic than those of heavily-fished continental shelf species. Overfishing probably is the primary cause of declines in estuarine and shelf fisheries. A few estuarine-dependent species of the United States have experienced substantial increases in harvests since 1970, for example, Pacific salmons, menhaden, and penaeid shrimps. The percentage contribution of major estuarine fisheries to the United States commercial catch declined between 1970 and 1990, although the yield of these species increased substantially. Global marine fisheries production at trophic level 2.5 was estimated to be 1,359 million tons. Potential yield was estimated to be 307 million tons, but the 1989 world marine catch was only 86.5 million tons. The major fraction, 196 million tons, of the estimated potential yeild was for the open ocean where technological constraints may prevent its full realization. Of the remaining 111 million tons of the potential, 18.0 million tons (16.2%) may come from estuaries and probably already is fully exploited. The potential catches from shelves, 68.5 million tons (61.6%), and upwelling areas, 24.8 million tons (22.2%), while considerably larger than those from estuaries, are lower in a relative sense (per unit area) than fisheries production and potential catch in estuarine zones. Relationships between fish production, fish harvest, and primary production were examined in specific estuaries. The developing role of aquaculture and its effect on estuarine fisheries are discussed.

Fisheries and the Evolution of Resource Management on the Lower Amazon Floodplain

Abstract: Traditionally, the ribeirinhoeconomy has been based on strategies of multiple resource use including agriculture, fishing, and small-scale stock raising. In the last two decades though, ribeirinhostrategies of resource management have undergone major changes due to the decline of jute production (the principal cash crop), and the intensification of the commercial fisheries. As a result of these trends, there has been a shift of ribeirinholabor from agriculture to commercial fishing. Today, the diversity which once characterized ribeirinhosubsistence strategies is disappearing, and fishing has become the primary economic activity for the great majority of varzeafamilies. As pressure on varzeafisheries has increased, ribeirinhocommunities have attempted to assert control over local varzealakes and exclude fishermen from outside the community. In a number of cases, ribeirinhocommunities have closed lakes to outsiders and established informal lake reserves under local community management. These lake reserves are a promising strategy for managing lake fisheries on a sustainable basis.

A Review of Recent Developments in the World Sea Cucumber Fisheries

Abstract: Sea cucumbers (Holothuridae and Stichopodidae) have been harvested commercially for at least 1,000 years. The world fisheries for sea cucumbers, however, are not well documented and in general are poorly managed. Depending upon the species exploited, there are two processing procedures for the sea cucumber product. Some species are eaten raw, while most commercial species are processed into a dry product called beche-de-mer or trepang. This dry product is exported to a central market such as Hong Kong and then re-exported to the consumers. In this review, recent statistics on the world sea cucumber fisheries, collected from different services, are detailed for each major fishing area. Case studies for each fishing area are also presented. Recent major changes in the Indo-Pacific fishery include the participation of new producer countries, the shift in the species being exploited, and an increase in the Chinese market. The expansion of the largely monospecific temperate North Pacific fisheries is also described. Statistics from Hong Kong, Singapore, Taiwan, and the Food and Agriculture Organization provide valuable information on the producer and importer countries. Particular attention is paid to the reciprocal trade of beche-de-mer between Hong Kong and Singapore. An evaluation of the world sea cucumber landings and beche-de-mer production is presented. Recent developments include an expansion of the Hong Kong market due to increased demand by China, the importance of Indonesia as a major world producer, and an increase in the fisheries of Tropical Pacific nations. This increase is best documented for New Caledonia and Fiji. Ways to improve the access and the reliability of the statistics for the sea cucumber fishery are discussed, as is the potential for management of artisanal fisheries.

An overview of the history, knowledge, recent and future research trends in Mediterranean fisheries *

Abstract: SUMMARY: The Mediterranean sea is an area which has a longlived oceanographic tradition Since the remote antiquity, it has been the object of observations and descriptions in which maritime activities and fishing ho Id a para­ mount place This paper presents a synthe tic view on the history of the fisheries research and its evolution in the area The very rich mediterranean fauna and the highly multispecific nature of the catches certainly favoured the fact that the first works were mainly oriented towards attempts of exhaustive descriptions of the vital cycles and biological param­ eters of a given species The passage from marine biology sensu-stricto to fisheries research is relatively recent in the Mediterranean; the first attempts to apply sorne mathematical population dynamics models to the exploited stocks were realized in France and Spain in the last sixties Most of these analyses used the "global production models" which come out to be quite disappointing when applied in the area Several mediterranean work programmes are now oriented towards the use of "direct evaluations" and "analytical" methods of modelling of the exploited stocks Quanti­ tatively, the mediterranean state of knowledge about fisheries is not far from what we can find in man y atlantic european fishing grounds A recent innovation in the research about mediterranean fishing is to take in account the activity of the "small-scale" fleets and their interactions with other types of fisheries Catch and effort statistics remain a weak point, as the official statistical data are still often very far from reflecting the reality To avoid this situation, the latest works in the area have consisted in perfecting sampling and assessment strategies There is also an increasingly generalized awareness of the socio-economic importance of fishing, and of the fact that the effects of the anthropic coastal activities should be taken into account, as at a mundiallevel there is a general tendency to redirect the target of the fisheries science from ressources to entire ecosystems equilibriums The success of this evolution will depend mostly on a new wave of investment in a multidisciplinary fundamental research which might lead to a new start in the evolutive dynamics of the finalised research depending on il So the growing interest in semi-industrial and small-scale fisheries which is expressed today at an international level can make mediterranean fisheries research a valuable model

Tangled Webs of History: Indians and the Law in Canada's Pacific Coast Fisheries

Abstract: Fishing rights are one of the major areas of dispute for aboriginals in Canada today. Dianne Newell explores this controversial issue and looks at the ways government regulatory policy and the law have affected Indian participation in the Pacific Coast fisheries.For centuries, the economies of Pacific Coast Indians were based on their fisheries. Marine resources, mainly salmon, were used for barter, trade, ceremony, and personal consumption. This pattern persisted after the arrival of European and Asian immigrants, even during the first phases of the non-Indian commercial fishing industry when Indian families were depended upon for their labour and expertise. But as the industrial fishery grew, changes in labour supply, markets, and technology rendered Pacific Coast Indians less central to the enterprise and the aboriginal fishery became legally defined as food fishing. By the late 1960s, rigid new licence limitation policies were introduced and regulations transformed the processing sector. The result was reduced participation for fishermen and shoreworkers and the opportunities for Indian men and women declined dramatically. Government programs to increase or even stabilize Indian participation ultimately failed. Newell concludes that the governments of Canada and BC have historically regarded the aboriginal fishery narrowly and unjustly as a privilege, not a right, and have in fact moved against any changes which might put Indians into competition with non-Indians. Recently, BC Indians won a Supreme Court victory in Sparrow (1990) that will make it easier to change federal fisheries policies but aboriginal fishing rights remain before the courts and under federal government investigation.Awarded the Canadian Historical Association's British Columbia and Yukon Certificate of Merit Award for 'Professor Newell's courageous critique of a history of mismanagement and misunderstanding in one of the region's key sectors should provide pause for thought to anyone with an interest in the workings of the modern state.'

Swimming speeds of marine fish in relation to fishing gears

Abstract: Swimming ability plays a vital role in the survival of fish in terms of catching a prey and escaping from a predator or a fishing gear. Knowledge of how fish swim and how well they can swim is very important in the design and operation of selective and energyconserving commercial fishing gears, and in fisheries resource assessment through better understanding of selectivity and efficiency of survey trawls. This paper summar­ izes recent findings of swimming performance in marine fishes and discusses how a change in swimming ability due to biological and environmental conditions and how a change in trawl operation can influence the size selectivity of a trawl. Special attention is paid to commercially important species, including mackerel ( Scom ber scom brus ), herring (Clupea harengus), cod (Gadus m orhua ), and saithe (Pollachius virens).

A Review of Interactions Between Hawaii's Fisheries and Protected Species

Abstract: Several fisheries in Hawaii are known to have interactions with protected cetaceans, seabirds, marine turtles, or seals. Handline fisheries for bottomfish, tuna, and mackerel scad lose bait and catch to bottlenose dolphins, rough-toothed dolphins, and Hawaiian monk seals. Troll fisheries for billfish lose live bait to bottlenose dolphins, rough-toothed dolphins, albatrosses, and boobies; these fisheries may also lose catch to false killer whales. A longline fishery for tuna and billfish has burgeoned in Hawaii since 1987, resulting in interactions with protected species; marine turtles, seabirds, and monk seals take bait and are known to become hooked, and false killer whales may take catch. Research on deterrents or alternative fishing methods has been limited, and interactions have been reduced primarily through management and regulatory actions. These include area closures and gear requirements. An observer program has also been established for the bottomfish and longline fisheries.

Tsunami Intensity and Disasters

Abstract: A tsunami intensity is defined as the logarithm of the local tsunami height to the base two. In terms of this tsunami intensity, important tsunami aspects are classified such as tsunami profiles near the shoreline, damage to individual houses made of wood, stone or reinforced concrete, damage percentage of wooden houses in a flooded area, damage percentage of fishing boats, damage to aquaculture rafts and effectiveness of tsunami control forests, based upon data from old documents of the past tsunamis.

The shark fisheries in the Maldives.

Abstract: A rotary piston internal combustion engine with applied ignition by means of a spark plug within an ignition pre-chamber, especially of trochoidal construction, which essentially consists of a casing housing and of a polygonal piston rotating within the same which slides along a multi-arched inner casing running surface and over the orifice of a firing channel whereby a straight line extending in a cross-direction to the casing housing intersects both the center longitudinal axis of the spark plug as also the center longitudinal axis of the firing channel in the ignition pre-chamber in front of the center electrode of the spark plug.

Fishing in contaminated waters: Knowledge and risk perception of hazards by fishermen in New York City

Abstract: Risk perception studies show that people may underestimate significant risks while overestimating others. Further, government agencies may assume the public becomes aware of risks when the agency has issued advisories, when in reality a segment of the population remains unaware of these warnings. This article reports on a survey of people fishing on the catchment basins of Jamaica Bay Wildlife Refuge in New York City. Of the 154 groups interviewed, only 19% believed the waters or fish were contaminated or unsafe, despite state warnings to the contrary. Fishermen made nearly five visits per month, and ate an average of three fish a week, (remaining fish were eaten by their families) and fish were usually fried. Most people believed the fish were safe to eat, or that they could recognize if one was spoiled. Thus, most people were ignoring the health advisories on consuming fish from these waters. We suggest that these fishermen are unaware of health advisories, or ignore them because the fishing situation is familiar, voluntary, pleasurable, and has not resulted in their illness. Since they believe they can determine if the fish are bad from smell and appearance, they have changed their own analysis from the unknown (chronic, delayed risks from toxics) to the known (immediate illness), lowering their perceived risk, but not the actual risk.

Plant uses in a Brazilian coastal fishing community (Buzios Island)

Abstract: ABSTRACf.-Buzios Island (southeast Brazil) is a fishing community in which agriculture played an important role in the past. Despite the increased importance of market-oriented fishing, decline of agriculture, and shift from traditional herbal toward modern medicine, wild and cultivated. plants still playa major role in the economics of the community. This study gives a general description of vegetation, cultivated. or collected. plants used for food, construction, handicrafts, and medicinal purposes. Local and scientific names are provided for 61 plants used for food, 53 plants used in medicine, and 32 species used. for house and canoe construction and handicrafts. On Btizios, older adults showed a better knowledge of medicinal plants than younger ones. Many medicinal plants are used for the treatment of worms, which are common among children. The medicinal plants used. on Btizios Island are widespread plants commonly used in other parts of Brazil. We found a high diversity of plants used on Btizios even compared to Amazonian communities.

Feeding Ecology of Deepwater Lutjanid Snappers at Penguin Bank, Hawaii

Abstract: Deepwater snappers are a valuable component of fisheries on slopes and banks in Hawaii and in much of the world's tropics. Their ecology and trophic relationships in these deepwater habitats are poorly known. Line fishing in this study simultaneously collected six of the seven lutjanid species that commonly occur in the major deepwater snapper fishery at Penguin Bank, Hawaii. The catch rate of each species showed diel variability; the patterns of some species were distinctly different. The depth distribution of feeding, as indicated by depth of capture, differed considerably among species; all species were taken within several meters of the bottom. Size (fork length) of the predator species did not appear to be stratified by time of capture (daylight versus darkness) or median capture depth. Regurgitation of gut contents seemed to be reduced when fish were retrieved at a rate that was slower than used in commercial practice but rapid enough to prevent death or morbidity while hooked. The food rem...

The Bermuda Fisheries a Tragedy of the Commons Averted

Abstract: (1993). The Bermuda Fisheries a Tragedy of the Commons Averted? Environment: Science and Policy for Sustainable Development: Vol. 35, No. 1, pp. 6-33.

Taking refuge from bycatch issues : red king crab (Paralithodes camtschaticus) and trawl fisheries in the eastern Bering Sea

Abstract: Concerns about possibly heavy impacts of bottom trawl fisheries on red king crab (Paralithodes camtschaticus) pot fisheries in the eastern Bering Sea led in 1987 to an emergency closure of trawling in an area of adult and juvenile crab habitat. We examine the effectiveness of this bycatch refuge in protecting and possibly enhancing the crab resource using three approaches. First, bycatch of crab in trawl fisheries is a small proportion of total estimated abundance throughout the southeastern Bering Sea but may be high relative to stock abundance within the closed area and relative to annual crab landings; recent regulations have diminished this apparent effect. Effects of direct bycatch on the stock are obscured by lack of evidence on indirect effects of trawling, including crushing of crab and degredation of juvenile habitat. Second, surveys inside and outside the refuge before and after closure show no significant changes in abundance of female and prerecruit male crab. Third, important breeding and hat...

Hawaii's Pelagic Fisheries

Abstract: Hawaii's diverse pelagic fisheries supply the bulk of the State's total catch. The largest Hawaii fishery is the recently expanded longline fishery, which now lands about 4,400 metric tons (t) of broadbill swordfish, Xiphias gladius; 1,500 t of bigeye tuna, Thunnus obesus, and 3,000 t of other pelagic species annually. The increased catch of these other species has raised concerns regarding the continued availability of yellowfin tuna, T. albacares; blue marlin, Makaira mazara; and mahimahi, Coryphaena hippurus, in the small-vessel troll and handline fisheries which target those species. Analysis of catch per unit effort (CPUE) statistics from Hawaii's fisheries did not provide strong evidence of recent declines in availability related to local fishery expansion. A more influential factor was variation in Pacific-wide CPUE, representing overall population abundance and catchability. Exogenous factors, including Pacific-wide fishing pressure, may overwhelm the influence of local fishing pressure on fish availability.

Marine Invertebrate Conservation: Evaluation of Fisheries Over-exploitation Concerns

Abstract: The nature of overfishing of marine invertebrates is complex, ranging from the perception of overfishing because of competition by user groups for a common property resource to extensive overfishing to near extinction because of poaching by either licensed or unlicensed fishers. As a group, marine invertebrates seem particularly resistant to overfishing, primarily because their relative immobility and scattered concentrations means refuge populations often exist. However, this distribution pattern also means a fishery is scattered over an often large geographical area with relatively small, frequent landings at any location. A minimum legal size regulation, enforceable anywhere before consumption, is the primary regulation applied by managers for many species to ensure against overfishing. Overfishing concerns arise primarily for those species where price is sufficiently high to encourage illegal fishing or where harvest by fishers is not easily monitored or controlled because of the nature of the fishing activity or because only part of the animal ( e.g. , the flesh) is harvested. Instances of overfishing by cause are discussed, and examples are presented to demonstrate how managers are dealing with or have dealt with different situations.

Salmon in the sea and new enhancement strategies

Abstract: Part 1 Salmon in the sea: overview: movement and migration of salmon at sea climatic changes in the North-Eastern Atlantic and their impact on salmonsmolts marine environmental factors and predators of salmon factors affecting marine survival sea survival the salmon at sea - oceanographic cycles decline of sea trout in the West of Ireland and the Northwest of Scotland an indicator of forthcoming marine problems for salmon? the effect of the 1984 commercial salmon fishery on wild and enhanced stocks entering Nepisiguit Bay evaluation of marine exploitation, North America evaluation of exploitation, Europe allocation of the resource Control of marine exploitation. Part 2 New enhancement strategies: government and private sector collaboration - the Quebec Salmon Economic Development Program new uses for kelts salmonid enhancement - impacts from the past and a role for the future the importance of genetic uniqueness river enhancement strategies on a time-shared river a kelt-supported angling fishery on a Merrimack River what's new in downstream fish passage? quota purchases. Part 3: Summing up.

Spatial Model for the Population Dynamics and Exploitation of the Western Australian Rock Lobster, Panulirus cygnus

Abstract: There is concern about whether long-standing regulatory measures (size and effort limits) are adequate to protect spawning stocks of the Western Australian rock lobster, Panulirus cygnus, and assure the highest average yields. Virtual population analysis and tagging studies indicate that exploitation rates are extremely high (possibly exceeding 70%/yr) on younger, mainly immature lobsters. To predict the efficacy of alternative regulatory schemes, it has been necessary to explicitly model the spatial and temporal dynamics of lobster abundance and fishing effort. Puerulus settlement (at age 9–11 mo) is mainly into shallow-water (< 40 m) areas, and at 3–5 yr of age in most areas, there is a migration into deeper water where the animals mature after a further 1–2 yr. The size at migration (70–90 mm carapace length) ensures that at least some animals will have a chance to reach the breeding grounds offshore, where fishing effort has historically been lower than inshore, before they reach the minimum legal size (76 mm carapace length). By explicitly modelling the effort distribution as well as lobster movement and stock distribution, we hope to anticipate some consequences of changes in management policy that could not be predicted from biological assessments alone.

External information search in marine recreational fishing.

Abstract: The purpose of this study was to examine external search by marine recreational anglers. Both prepurchase and ongoing external search were examined as a function of (a) the perceived importance of information to fishing success and (b) the perceived difficulty of information acquisition. In addition, the effects of previous experience, knowledge, and involvement on the perceived information importance and difficulty measures were examined. The results indicate that information importance is a significant determinant of both prepurchase and ongoing external search. Furthermore, ongoing external search and the balance of prepurchase to ongoing search activities are also influenced by enduring involvement and previous experience.

The fishery for white steenbras Lithognathus lithognathus off the Cape coast, South Africa, with some considerations for its management

Abstract: Aspects of the fishery for Lithognathus lithognathus around the Cape coast are described and information pertinent to management is presented. Prior to 1960, beach-seining was the most important source of fishing mortality, but angling catches have become increasingly important since then. Total annual catch for the period 1985–1990 is estimated at 30 000–35 000 fish, approximately 70% of which was taken by recreational anglers and 30% by commercial fishermen. In terms of mass, the catch was divided equally between the two fisheries. Long-term catch data indicate major declines. The reported mean annual commercial catch for the period 1983–1991 was only 14% of that for the years 1897–1906. The catch rate of recreational anglers has declined by 90% since the mid 1970s. Modelling of the responses of yield per recruit, spawner biomass per recruit and mean mass to altered fishing mortality (F) and age at recruitment into the catch (tc ) suggests that die stock is overexploited and that a substantial decrease ...

Values and behaviors of trout anglers, and their attitudes toward fishery management, relative to membership in fishing organizations: a Michigan case study.

Abstract: A controversial proposal to adopt catch-and-release regulations for a section of the Au Sable River near Grayling, Michigan, provided an opportunity to study differences in management preferences and related characteristics between members of fishing organizations and nonmembers. Two fishing organizations were prominent among the Au Sable River sample of anglers, Trout Unlimited (TU, 43%) and the Fly Fishing Federation (FFF, 14%). However, only 1.8% of a statewide sample of stream trout anglers belonged to TU and 0.3% were members of FFF. Members were more specialized, had more fishing experience, and participated in trout (brown trout Salmo trutta, brook trout Salvelinus fontinalis, and rainbow trout Oncorhynchus mykiss) fishing more intensely and frequently than nonmembers. In addition, a higher percentage of members than nonmembers favored the proposed catch-and-release regulation and had supporting attitudes for special regulations. However, members and nonmembers were similar regarding motiv...

More Than A Living: Fishing And The Social Order On A Polynesian Atoll

Abstract: Part 1 Researching traditional fishing: getting it done. Part 2 Traditional fishing activities: traditional fishing activities netting pole and line fishing weirs collecting trapping angling the ordering of constraints on fishing activity. Part 3 Changing contexts and the contexts of change: coping with a changing environment the Americans - institutionalizing differentiation and uncertainty. Part 4 How it was, how it is, and how it might be: stable premises in a changing world.