A model to calculate energetic returns and an ecological footprint of an industrial fishery with a case study of the 1980s northwest Atlantic cod fishery.

摘要

This research project focused on developing a general energetic balance model that evaluates an industrial fishery. It was constructed by incorporating methodologies developed by Tyedmers (2000) and other energetic principles to give both a energetic return for a fishery and an evaluation of ecological efficiency for that fishery. The energetic measurement is a comparison of all energy inputs that are derived from net primary production (NPP), whether recent or ancient in the form of fossil fuels, and the energy received in the form of food from the fishery. The ecological efficiency in this study uses the metric of an Ecological Footprint (EF).;The case study results indicated that the energetically and ecologically most efficient cod fisheries by vessel class ranked in the following order: twenty-five to thirty four feet, thirty-five to forty-four feet, forty-five to sixty-four feet and finally less than twenty-five feet class. The trend observed in three of the four vessel classes saw the efficiencies diminishing with time, probably reflecting a decreasing cod stock. Industrial fisheries methods have effectively increased human reliance on ancient NPP to perform these fisheries. In the past, energy from wind and currents was used. The energy is now derived from the combustion of fossil fuels, ancient NPP.;This model was used then to compare the different fishery vessel length classes of the cod fishery for the period of 1982-1986 found in what is defined by the Northwest Atlantic Fisheries Organization as 3K and 3L. This region lies mainly off of the coast of Newfoundland, Canada. The model can be used as a comparative tool to compare different fisheries or different fishery methods for ecological efficiency. The utility of knowing which fishery method is more ecologically efficient could allow those in managerial roles within the fishery to select those fisheries with optimal return and reduced ecological impact. This would be beneficial as fisheries are often an important food resource.