328,692 research outputs found
The politics of Bluefin tuna in Malta
No full textThis paper analyzes the politics of bluefin tuna in Malta within the first years of EU accession (2004-9). The paper concludes that despite making certain impacts, ENGOs were unsuccessful in creating a hegemonic formation to stop the fishing of bluefin tuna until stocks recover.peer-reviewe
A Demand Analysis of the UK Canned Tuna Market
No full textThis study provides an analysis of the retail level demand for canned tuna in the UK using four-weekly scanned data for the period 1995–99. The role of product medium is analysed, looking at the interactions between the traditional tuna in brine and oil and the more recent value added tuna in sauces. A system of demand equations is estimated using the dynamic almost ideal demand system (AIDS) model. All products are demonstrated to have negative and inelastic own price elasticities. Tuna in brine and sauce is shown to be a normal good, while tuna in oil was demonstrated to be a luxury good. Tuna in oil was indicated as being a substitute for tuna in sauce., Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Marketing, Q21.,
Tuna-Led Sustainable Developlment in the Pacific
No full textThe paper reviews the importance of tuna fisheries in the western and central Pacific Island Countries (PICs) and examines whether current and proposed economically focussed institutional mechanisms, that underpin tuna management, are sufficient to promote appropriate and long term tuna-led development. Substantial potential gains are shown to exist from co-operation in terms of tuna management, but it seems highly unlikely such benefits will be realised in the short or medium term despite the formation in 2004 of the Western and Central Pacific Fisheries Commission. Even if gains from co-operation were to be realised, without substantial improvements in the nstitutional quality and capacity of many PICs the tuna fisheries might still fail to sustain the region’s long-term development. The study’s implications are that the twin development priorities in the region should be support for social infrastructure, especially capacity building to increase the effectiveness of the public sector, and the promotion of co-operative approaches to ensure the sustainability and profitable use of the region’s shared fishery resources.
OPTIMAL MANAGEMENT OF THE NORTHERN ATLANTIC BLUEFIN TUNA
No full textThis paper analyzes the optimal management of the Northern Atlantic bluefin tuna, both eastern and western stocks. The analysis is based on a deterministic multi-gear and age-structured bioeconomic model. In order to assess the importance of the gear structure in this fishery, the model is optimized in two scenarios. In the first, the strategies are restricted to the gear mix of the base year, whereas in the second, the optimal gear mix is estimated. For both scenarios, optimal constant strategies are determined. The corresponding optimal use is then compared with an open-access scenario. Also, optimal non-constant strategies are explored. As expected, the gear structure of the fishery proved to be highly relevant in the optimal payoffs. In particular, the unrestricted strategies yield rents substantially higher than the restricted ones. Also, the optimal management of the bluefin tuna fishery, in both the East and West Atlantic, would imply significant reallocation of the gear shares.Resource /Energy Economics and Policy,
MAXIMIZING RESOURCE RENT FROM THE WESTERN AND CENTRAL PACIFIC TUNA FISHERIES
No full textRent generated by the tuna fisheries occurring in the waters of Pacific Islands Nations is estimated for various levels and combinations of purse-seine, pole-and-line, frozen tuna longline, and fresh tuna longline fishing effort, using a multi-species, multi-fleet bioeconomic model. The underlying population model integrates available information on the population dynamics of skipjack, yellowfin, bigeye, and Southern albacore tunas in the Pacific Ocean. The economic model utilizes the most recent data on fishing effort costs for the purse seine, pole-and-line, and longline fleets operating in the western and central Pacific Ocean, along with recent estimates of prices by species, method of capture and market, and estimates of demand elasticities. The results of the model indicate that fishery rent could be increased substantially above the current level by decreasing the size of all fleets, with the possible exception of the tuna longline fleet. The results also suggest that the countries of the region could benefit significantly by changing the level and structure of access fees levied as a percentage of total catch revenue.Resource /Energy Economics and Policy,
Biology of Albacore tuna (Thunnus alalunga, Bonnaterre 1788) off the South West Coast of South Africa
No full textAlbacore tuna (Thunnus alalunga) is a highly migratory species found in all of the worlds oceans. The origin of albacore south of Africa is in question. This species constituted 85% of catches of the South African commercial tuna fishing fleet from 2000-2009 and is an important species in supporting a large boat-based recreational fishery. Albacore were sampled at angling competitions, which offer a repeatable and cheap source of tuna, in the Western Cape of South Africa during 2012 and 2013. 119 Samples were used to determine a length-weight relationship and to provide conversion ratios of various body measurements to fork length when total length was not available. Visual examination of testes and ovaries indicated that albacore are not spawning off the coast of South Africa.A comparison between the ease of using sectioned sagittal otoliths and first dorsal spines indicated that otoliths were more precise for estimating the age of albacore. Von Bertalanffy growth parameters were estimated from 51 fish, ranging from 2-9 years old (L∞=1100.07 mm; K=0.238 y-1; t₀=-2.14). Stomach content analysis indicated that the mesopelagic squid Lycoteuthis lorigera is the most important prey item for South African albacore. δ13C and δ15N stable isotope analysis of albacore and yellowfin tuna (T. albacares) muscle tissue showed that they feed on prey that may depend on different primary producers but that the two species of tuna share the same niche in the southern Benguela food web. Trophic levels of 3.8 and 3.76 were assigned to albacore and yellowfin tuna respectively
The Economics of Allocation in Tuna Regional Fisheries Management Organizations (RFMOS)
No full textThe paper reviews existing allocation mechanisms in the five tuna regional fisheries management organizatins and shows that although they have adopted different approaches all have failed to prevent overcapacity and, or some stocks, overexploitation. As an alternative, it is proposed that each tuna regional fishing management organization establish total allowable catches by species and area, and then allocate non-transferable and permanent country shares (as a proportion of the total harvest) to member countries. Each country would be free to use or sell its annual allocation of fish that would be determined by the permanent country shares, but the sales could only be to fellow member countries. A two-tier allocation to countries of permanenet shares of a total allowable catch, and then annual harvest allocations to vessels of member countries, offers the promise of mitigating, and possibly overcoming, the twin problems of overcapacity and overexploitation in the highly migratory and high seas tuna fisheries.tuna, property rights, allocation
The East Atlantic Bluefin Tuna Fisheries: Stock Collapse or Recovery?
No full textA discrete time, multi-gear, and age structured bio-economic model is developed for the East Atlantic bluefin tuna fisheries, a paradigmatic example of the difficulties faced in managing highly migratory fish stocks. The model is used to analyse alternative management strategies for the Regional Fisheries Management Organisation (RFMO) managing this fishery, and to investigate some of the policy implications. For the various scenarios, the optimal stock level varies between 500–800,000 tonnes, which compares with a stock level of 150,000 tonnes in 1995. In other words, there is a very strong case for rebuilding the stock. Moreover, the sustainability of the stock is threatened unless a recovery programme is implemented; indeed, the alternative may be stock collapse. Second, to rebuild the stock, Draconian measures are called for: either outright moratoria over fairly lengthy periods, or possibly a more gradual approach to steady state given by a Total Allowable Catch (TAC) at a low level for an extended period of time. Third, the cost of inefficient gear structure is very high indeed.Bioeconomic model, bluefin tuna, optimal management., Resource /Energy Economics and Policy, Q22,
Establishing a weight-length baseline for evaluating changes in yellowfin tuna (Thunnus albacores) body condition in the Western Indian Ocean
No full textStandard weight (Ws) equations were established for yellowfin tuna (Thunnus albacares) in the Western Indian Ocean and used as a baseline for calculating relative weight (Wr) indices. Length-weight data for yellowfin tuna were obtained from the Indian Ocean Tuna Commission (IOTC) for 1984 to 1991 and 2003 to 2013. Four quadratic standard weight equations were established (based on mean, median, first and third quartile statistics for each length class) using log10-transformed weight (W, in grams) and fork length (FL, in mm) data. The median Ws equation (log10(W) = -3.903 + 2.425(FL) + 0.103(FL)2) was the preferred baseline for the Wr analysis. Relative weight estimates for individual fish ranged from 92 to 110. Annual and monthly Wr estimates ranged from 99 to 101 and 99.9 to 100.5 respectively. A GLM was fitted to separate the effects of year, month and sex on the response variable Wr. Year, month, sex and the interaction terms Year:Sex and Month:Sex all contributed significantly to the variability in Wr explained. Correlations between environmental variability and yellowfin tuna condition were observed. Concentrations of suitable prey in 2003 and 2004 correlated to above average condition, although 2005 and 2006 were below average condition during similar prey availability and environmental conditions. Relative weight followed an increasing trend from 2008 to 2013 despite lower biological enrichment. Mechanisms such as a shallower thermocline and reduced fishing pressure are proposed explanations. This study provided a reference study for body condition studies of yellowfin tuna in the Indian Ocean. It also provided support for the application of the Wr index to other tuna species in the Indian Ocean managed by the IOTC
MULTILATERAL GOVERNANCE OF FISHERIES: MANAGEMENT AND COOPERATION IN THE WESTERN AND CENTRAL PACIFIC TUNA FISHERIES
No full textThe tuna resources of the Western and Central Pacific are the world's largest and most valuable fisheries of their type and are of significant economic importance to the Pacific island countries through whose waters they migrate. Two major concerns exist with the current governance of this fishery. First, Pacific island countries receive only a small share of the resource rents from the tuna fisheries. Second, the current management structure of the fisheries will not ensure the long-term sustainability of the resources. This paper derives a model to show that the sustainability of the resource can be improved when a single policymaker acts as Stackelberg leader and sets a tax, or an equivalent quantity instrument, to maximize rents from the resource. A practical institutional mechanism is presented that mimics the model's rent maximization outcome and that offers substantial benefits to both Pacific island countries and distant water fishing nations.Resource /Energy Economics and Policy,
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