The following work was conducted on subprojects in 2002:

1a) Update biological parameters; and
1c) Update harvesting effort distribution parameters

Parameter updating was completed under the supervision of Dr John Hampton.

Age classes for all four tuna species are now by year quarter.
Natural mortality is now defined by quarterly age class.
Mean climate and fishery parameters were estimated using catch and effort data for 1997-2000.
Additional fleets have been included in the model for the Philippines and Indonesia. There are now 20 fleets.

1b) Modelling the effects of El Nino - Southern Oscillation (ENSO) events on tuna catches

The model has been run with climatological and environmental data for the period 1965-1994. Further work will be carried out by Dr Chris Reid to test the effect of ENSO events on harvests and rents.

1d) Revised harvesting costs and catch level functions
Initial work has been carried out by Dr John Hampton on re-estimating stock and effort exponents in the tuna harvesting functions utilising the MULTIFAN-CL model developed by the Oceanic Fisheries Program (OFP) at the Secretariat of the Pacific Community (SPC) and others.

1e) Update tuna prices and demand parameters

Professor Harry Campbell worked on demand and cost estimates with Dr Chris Reid as discussed at the February project meeting at SPC in Noumea. A paper containing extensive information on current tuna prices and fishing costs, together with up-dated demand elasticity estimates and a discussion of access fees was prepared and presented at the December project meeting at the SPC. This paper provides the necessary demand and cost data as input to the revised bioeconomic model and the new spatially aggregated model.

2a) Appraisal of effort and catch reduction systems

Professor Harry Campbell and Dr Chis Reid identified two charging systems for obtaining shares in the rents obtained by Distant Water Fleet Nations (DWFNs) in harvesting in the exclusive economic zones (EEZs) of the Pacific Island Nations (PINs), on grounds of feasibility and economic efficiency: a charge on catch, and a charge on effort applied. It was argued that it is less costly to monitor effort than catch, and that therefore alternative charge-on-effort schemes should be considered. The scheme that is favoured is based on effort for each gear type, measured by vessel gross registered tonnage multiplied by number of days in the EEZs of the PINs, summed across all vessels. The pros and cons of implementing such an aggregate effort quota system through an auctioning system are debated.

1f) Model extension for access fees charged to DWFNs; and
1g) Model extension for fleet capacity decisions

The original project proposal was based on the assumption that the model developed in the previous ACIAR project (ADP/1994/005, entitled A Bioeconomic Analysis of Tuna Purse Seining in the Pacific Islands Region) would be used for modelling the determination of bargaining between the DWFNs and the PINs over charges for access to the EEZs of the PINs. The feasibility of this was discussed at the February 2002 meeting at the SPC. Because of the high spatial resolution of the original model, it was suspected that solution times would be too long to solve the bargaining problems. Subsequent investigation proved this to be the case. It was decided that a smaller, spatially aggregated model should be developed for modelling bargaining, with parameters based on the larger model. The updated larger model would be important for gauging the degree of aggregation bias in the smaller model.

Year 2 (01/01/2003-31/12/2003)
An important model being used in the current project for modelling optimal harvesting decisions of the DWFNs is a bioeconomic model developed in a previous ACIAR project (ADP/1994/005: A bioeconomic analysis of tuna purse seining in the Pacific Islands region). In 2003 updating of technical and economic parameters continued as planned, and revised harvesting policies for different tuna species obtained. A technical paper on revised prices and costs, titled 'Tuna Prices and Fishing Costs for Bioeconomic Modelling of the Western and Central Pacific Tuna Fisheries' was released. A website was built to enable easy access to this and subsequent papers, and to present the aims of the project and the contact details of the project participants. The website has attracted overseas interest.
Solution times for the bioeconomic model are relatively long, for two reasons-the first is the detail in modelling the seasonal migration of tuna in the Western Central Pacific Ocean between 5 degree squares, and the second is the very basic algorithm used for obtaining optimal solutions. Because the algorithm simulating optimal negotiation requires many runs of the model, there is the need for a faster, albeit less detailed, model. As planned, work continued in 2003 to develop a smaller, more aggregated model using a different solution process. The large model will be necessary for calibrating parameters in the smaller model. Work also started on reprogramming the large model to obtain solutions with the new optimising routine.
The special problem of obtaining international agreement on efficient management of migratory fish has been recognised in the United Nations Fish Stocks Agreement. This has led to establishment of commissions to oversee the conservation and management of migratory stocks in various parts of the world's oceans. When the project proposal was written in 2001 it was expected that a commission would be set up for the management of the migratory tuna stocks in the Western and Central Pacific Ocean. After a series of annual preparatory conferences, held since 2000 and involving the PINs and DWFNs affected, the Commission is to be convened in December 2004. The formation of the Commission should focus attention on the benefits of coordinated action by the PINs to improve efficiency in managing stocks.
A key question remains: What measures should be introduced to reduce the overexploitation of yellowfin and bigeye tuna by purse seine and longline vessels? The updated bioeconomic model is being used to study this question.

Background:

The aim of the current project is to determine the economic negotiating positions of Pacific Island Nations (PINs) that have rights to stocks of migratory tuna passing through their economic fishing zones, and the Distant Water Fleet Nations (DWFNs) such as Japan, USA, South Korea, Taiwan and China that are interested in paying for access to the stocks. This relies on interactive modeling of the optimal access offers of the PINs and the optimal harvesting decisions of the DWFNs.

The special problems of obtaining international agreement on efficient management of migratory fish have been recognized in the United Nations Fish Stocks Agreement, which came into force in 2001. This has led to the setting up of commissions to oversee the conservation and management of migratory stocks in various parts of the world's oceans. The commission for the region which is the focus of the project (Commission For the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific) was installed in December 2004. The formation of the Commission is likely to focus attention on the benefits of coordinated action by the PINs to improve efficiency in managing stocks.

Subprojects carried out in 2004:

1) Translating the computer code of the disaggregated bioeconomic tuna model from C++ to Visual Basic.
This was in response to the need to be able to modify the model to experiment with different model assumptions, such as modelling year to year changes in stocks over a 15-year period under alternative effort levels of harvesting fleets; and to be able to experiment with a faster optimising routine.

2) Progress with the small highly aggregated bioeconomic model.
A basic version of the model was completed, incorporating an optimising routine. This is being developed to model decisions of DWFNs on catch effort within the EEZ's of the PINs in response to access charges set by the PINs. To ensure feasible computing times to obtain solutions, a small highly aggregated model is required, with parameters which can be calibrated from test results from the larger model.

3) Investigating data and methods for determining the cost of increasing fleet capacity over time as original capacity declines (In line with Subproject 1g, Model extension for fleet capacity decisions).
Data were collected and analysed on the distribution of ages, capacities and prices of Purse Seiner and Longline vessels from published reports and internet sites advertising asking prices for second-hand vessels. The results were documented in a working paper.

4) Colour mapping on Microsoft Excel spreadsheets of the aggregation of variables such as fishing effort and catch across the 5 degree squares of the Western and Central Pacific Ocean, with calculation of subtotals inside and outside the combined EEZ's of the PINs.
A spreadsheet program was written for display of the fishing effort data by fleet entered for the large disaggregated model in each 5 degree squares of the WCPO, differentiating squares by colour according to whether they were land, sea within the PIN's EEZs, and sea outside the PIN's EEZs. This is important for understanding the overall magnitude and distribution of the effort of different fleets in different runs of the model, and.for displaying data on catch and effort across recent years from the Oceanic Fisheries Program database. The percentage of total catch outside and inside the PIN's EEZs is calculated.

Background

The aim of the current project is to determine the economic negotiating positions of Pacific Island Nations (PINs) that have rights to stocks of migratory tuna passing through their economic fishing zones, and the Distant Water Fleet Nations (DWFNs) such as Japan, USA, South Korea, Taiwan and China that are interested in paying for access to the stocks. This relies on interactive modeling of the optimal access offers of the PINs and the optimal harvesting decisions of the DWFNs.

The Commission for the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific was installed in December 2004, under the auspices of the United Nations Fish Stocks Agreement, which came into force in 2001. The Commission is investigating alternative management measures for ensuring stocks will be effectively managed and that catches will be sustainable. The modelling resources developed in this project will enable estimates to be made of the producer rents flowing to different fishing fleets targeting different tuna species, inside and outside the exclusive economic zones of the PINs, from alternative regulatory measures.

Work carried out in 2005
Under Objective 1: Updating and extending the capability of the bioeconomic tuna model:
Extending modelled fleet coverage
Domestic fleets of the Philippines and Indonesia and the troll fleet targeting albacore operating in the Pacific were added to the model.

The range of purse seine fleets was increased from the original four (Japan, Korea, Taiwan and the US) to include fleets for the Pacific Islands, Western and Central Pacific Ocean, and Eastern Pacific Ocean.
Extending the area of modelled fishing effort
Previously the model decision variables were harvesting effort by each fleet within the region covered by the Forum Fisheries Agency (FFA). Fleet harvesting efforts outside the FFA region are now included as decision variables.
Updating biological parameters
Age classes for all four tuna species are by quarter (previously albacore was by year).

Natural mortality is specified by quarterly age class, instead of constant across all ages.

Changes were made to make the harvest function selectivity coefficients dependent only on gear type (purse-seine, pole and line, and longline), instead of on fleet and gear type.

Effort and stock exponents in the harvest functions used in the model had been set at one following widespread practice. Empirical estimation showed that WCPO purse seine stock exponents for skipjack were better set at 0.7, and for yellowfin at 0.3. Changes have been made accordingly in the updated model.

The match between modelled catches and observed catches was improved by estimating catchability coefficients for each fleet, this time allowing the coefficients to be different for harvesting effort inside and outside the FFA region.

Adjustments have been made to parameters determining recruitment of young fish stock to fisheries in the fishing areas of the Philippines and Indonesia. These were to correct for perceived modelled shortfalls in recruitment in these areas.
Under Objective 2: Analyse strategic policy options facing the nations of the FFA
The following analysis was conducted with the updated model:
i) Changes in purse seine effort on catch per unit effort (CPUE) and economic rents in the purse seine fishery
The previous model predicted a 10 per cent reduction in fishing effort would increase rents by 55 per cent. The updated model predicted an increase of only 40 per cent.
ii) Effect of an increase in purse seine catchability of yellowfin and bigeye on longline catches and fishery revenue
Repeating tests for increases in purse seine catchability of 50 per cent carried out with the previous model, the updated model confirmed that in the case of yellowfin the overall value of the fishery increased, but decreased for bigeye. The results from the updated model were more pronounced.
iii) Effect of effort reduction across all fisheries on catch and economic rents
Results from the updated model showed that reducing effort level across all fisheries by 30 per cent leads to substantial percentage increases in rents for all fisheries (purse seine, pole and line, frozen longline and fresh longline), inside and outside the FFA region, except in the case of the fresh longline fishery within the FFA region, for which the rent reduction was 2 per cent. Of particular interest is the distribution of gains across the fisheries. The frozen long-ine fishery gains to a much greater extent than the purse seine, pole and line and fresh longline fisheries.

Background
The aim of the current project is to determine the economic negotiating positions of Pacific Island Nations (PINs)
that have rights to stocks of migratory tuna passing through their economic fishing zones, and the Distant Water
Fleet Nations (DWFNs) such as Japan, USA, South Korea, Taiwan and China that are interested in paying for
access to the stocks. This relies on interactive modeling of the optimal access offers of the PINs and the optimal
harvesting decisions of the DWFNs.
The Commission for the Conservation and Management of Highly Migratory Fish Stocks in the Western and
Central Pacific was installed in December 2004, under the auspices of the United Nations Fish Stocks
Agreement, which came into force in 2001. The Commission is investigating alternative management measures
for ensuring stocks will be effectively managed and that catches will be sustainable. The modelling resources
developed in this project will enable estimates to be made of the producer rents flowing to different fishing fleets
targeting different tuna species, inside and outside the exclusive economic zones of the PINs, from alternative
regulatory measures.
Work carried out in 2006
Under Objective 1: Updating and extending the capability of the bioeconomic tuna model
Subproject 1e) Updating economic parameters
Chris Reid incorporated revised price elasticities of demand by fleet, species and gear type in the large scale
bioeconomic model. The determination of the revised elasticities is detailed in Project Technical Paper 1.
Under Objective 2: Analyse strategic policy options facing the nations of the FFA
Subproject 2a) Appraisal of effort and catch reduction systems
The following paper:
Reid, C., Bertignac, M., and Hampton, J. (2006), "Further development of, and analysis using, the
Western and Central Pacific Ocean Bioeconomic Tuna Model (WCPOBTM)", Technical Paper
No. 2, ACIAR Project No. FIS/2001/036: Maximising the Economic Benefits to Pacific Island
Nations from Management of Migratory Tuna Stocks, June, pp. 25.
was released as Technical Paper 2 downloadable on the Project website:
http://www.business.latrobe.edu.au/public/staffhp/jkennedy/index.htm
The paper details the structural updating to the population dynamics and the harvest model carried out in
2005, and changes to the revenue model carried out in 2006. The paper also contains an analysis of the
effect of effort and catch reductions conducted with the updated model which is compared with results
obtained with the previous model described by Bertignac et al. (2000)1.
The results of the analysis indicate that if an across the board effort reduction were implemented in the WCPO
the total level of rent generated the WCPO tuna fishery as a whole is likely to increase but that the net benefits
Page 3 of 9
gained are likely to be disproportionately borne by particular fisheries and jurisdictions. The purse seine fishery
within the waters of FFA members is likely to see the least proportionate gains, while the highseas frozen
longline fishery is likely to see the largest net benefits from such an action. Actual outcomes are likely to be
more detrimental to FFA member countries with a significant purse seine fishery in their waters than the analysis
indicates as the model does not take into consideration the benefits gained from processing activities or
employment associated with the purse seine fishery which are not associated with the highseas longline fishery.
The adoption of management measures by the WCPFC is likely to have substantially different economic
outcomes for different fleets and Commission members. To overcome the difficulties inherent in obtaining
agreement on implementing management measures members of the WCPFC will need to give serious
consideration to the possibility of the use of "negotiation facilitators" or "side-payments" in order to ensure that
the costs and benefits of any such management measures are borne equitably between members.
Other key activities during 2006
John Kennedy presented a paper at the International Institute of Fisheries Economics and Trade (IIFET) 2006
Conference at the University of Portsmouth in the UK on policy options for management of highly migratory
fish stocks in the Western and Central Pacific2. The goals of the recently established Western and Central Pacific
Fisheries Commission were outlined. Statements by the Commission suggest that in the longer run Convention
Area total allowable catches (or total allowable effort levels) are likely to be imposed in exclusive economic
zones and high-seas sub regions. The role of bioeconomic optimizing models in helping to determine these is
canvassed. They are important for indicating which harvesting parties gain and which lose from the introduction
of new measures, and are thus likely to be useful in the determination of Convention Area total allowable catch
allocations. The paper was presented in a special session "Management of High Seas Fisheries" chaired by
Professor Gordon Munro, a specialist in the area of the United Nations Fish Stocks Agreement on managing
migratory stocks.
Work continued on the translation the C++ program of the large scale bioeconomic model of WCP tuna to
Visual Basic, preparatory to incorporating a more efficient optimising routine. Work began on a paper for the
Australian Agricultural and Resource Economics Society Conference in February 2007.
References:
1 Bertignac, M., H. F. Campbell, J. Hampton and A. Hand (2000), "Maximising Resource Rent from the
Western and Central Pacific Tuna Fisheries", Marine Resource Economics 15, 151-177.
2 Kennedy, J. (2006), "Policy Options for Management of Highly Migratory Fish Stocks in the Western and Central
Pacific Ocean". In: Proceedings of the Thirteenth Biennial Conference of the International Institute of
Fisheries Economics & Trade, July 11-14, 2006, Portsmouth, UK: Rebuilding Fisheries in an Uncertain
Environment. Compiled by Ann L. Shriver. International Institute of Fisheries Economics & Trade, Corvallis,
Oregon, USA, 2006. CD ROM. ISBN 0-9763432-3-1. ISBN 0-9763432-3-1. (Downloadable as Technical
Paper 3 on the Project website)