Why Harvest Efficiency Appears to Fall Over Time in the Production Functions of Fisheries

I.F. Wallace, Robert K. Lindner and David D. Dole

No 136826, 1997 Conference (41st), January 22-24, 1997, Gold Coast, Australia from Australian Agricultural and Resource Economics Society

Abstract: Harvest efficiency in the production functions of fisheries should increase over time with the introduction of new technology and with increasing knowledge of the biology and behaviour of the target species. This implies that the estimated catchability coefficients of Gordon-Schaefer or Fox models should also increase over time. We estimated both models using annual catch and effort data for four lobster fisheries and compared the regression results for different time periods. We also estimated modified forms of the models with a time trend in the harvest equation. Both approaches show that the estimates of the catchability coefficients have decreased significantly over time in all four fisheries. We suggest that one important source of this anomaly is the use of annual aggregate catch and effort data. To test this hypothesis, we examined trends in the distribution of effort over the season, and their effect on annual catch per unit effort. The results show that methods based on aggregate annual catch and effort data can introduce spurious trends in annual catch per unit effort, and hence in catchability estimates. Estimation of production functions for bioeconomic modelling should use catch and effort data that is disaggregated both temporally and spatially.

Keywords: Livestock; Production/Industries (search for similar items in EconPapers)
Pages: 22
Date: 1997
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://ageconsearch.umn.edu/record/136826/files/fiche015-report124.pdf (application/pdf)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:ags:aare97:136826

DOI: 10.22004/ag.econ.136826

Access Statistics for this paper

More papers in 1997 Conference (41st), January 22-24, 1997, Gold Coast, Australia from Australian Agricultural and Resource Economics Society Contact information at EDIRC.
Bibliographic data for series maintained by AgEcon Search ().