Researchers assess economic productivity for Hawaii longline fishery

image1 (1) (1)PIFSC Socioeconomics Program researcher Dr. Minling Pan, in collaboration with Northeast Fisheries Science Center economist Dr. John Walden, recently published a study measuring productivity changes in the Hawaii longline fishery in the journal Marine Policy. Fisheries productivity is the result of many factors, including exogenous and endogenous elements, such as regulation and stock condition. Understanding changes in productivity and the factors affecting that change is important to fishery management and a sustainable fishing industry. This work represents the first study to measure productivity change in the Hawaii longline fishery, the largest fresh bigeye tuna and swordfish producer in the United States.

A biomass quantity index is constructed to disentangle biomass impacts in a pelagic environment in order to arrive at an “unbiased” productivity metric. This is particularly important in the Hawaii longline fishery where catches rely mostly on transboundary (shared) stocks with little control on the total amount of extraction. As resource depletion of the transboundary stocks occurs, productivity losses may follow if less output is obtained from the same input usage, or more inputs are used to extract the same catch level from the fishery.

Using a Lowe productivity index, productivity change in the Hawaii longline fleet between 2000 and 2012 is measured in this study.Overall, unadjusted (“biased”) productivity in the Hawaii longline fishery showed a declining trend since 2005. However, once biomass change was used to adjust the index values, the negative productivity change turned positive (Figure 1).

Figure 1. Unbiased and biased Lowe index for tuna trips 2002 to 2012 (base year = 2005)

Figure 1. Unbiased and biased Lowe index for tuna trips 2002 to 2012 (base year = 2005)

While bigeye tuna biomass has trended down in recent years, fishing productivity has improved, as the unbiased productivity index (the adjusted Lowe index) went up steadily from 0.84 in 2009 to 1.36 in 2012. During the study time period, especially since 2010, analytical results show that tuna fishing became more productive in terms of endogenous productivity (e.g., fishing technology). Such an improvement of endogenous productivity has offset the negative impact of the bigeye stock depletion and kept the fishery stable in terms of output to input ratio. Without such an improvement in productivity, the tuna fishery would have had much poorer performance due to the depletion of the shared fish resources. Finally, the study compares productivity change under different fishing technologies and finds evidence that tuna fishing seems to be more efficient compared to swordfish fishing.

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