Research Document - 2012/112

A science-based interpretation of ongoing productivity of commercial, recreational or Aboriginal fisheries

By R.G. Randall, M.J. Bradford, K.D. Clarke, and J.C. Rice

Abstract

Canada’s Fisheries Act, amended in 2012, refers to ‘sustainability and ongoing productivity of commercial, recreational or Aboriginal fisheries’. A conceptual framework for a science-based interpretation of ongoing productivity of fisheries is described. The productivity of a fish population is determined by vital rates (reproduction, growth and survival) and by life history traits (fecundity, age at maturity). The vital rates regulate population abundance, biomass and fish production. Fish production rate is the rate that biomass is accumulated per unit area per unit of time. Fisheries yield (landings) is a function of total fish production. Fisheries are often comprised of more than one population or species. Fisheries productivity, in the context of the Fisheries Protection Provisions (FPP), is interpreted as the sustained yield of all component populations and species, and their habitat, which support and contribute to a fishery in a specified area. Sustainability, biodiversity, and measurement uncertainty are key dimensions of ongoing productivity that need to be kept in mind within the conceptual framework. Population abundance is dynamic over time, but to be sustainable, the management of habitat-related physical impacts and other threats must be done such that populations can rebuild within a reasonable period of time if they become temporarily depleted. The new Provisions focus on a larger, functional spatial scale (landscape, population or fishery) than the localized project scale that was the case historically. Three categories of projects that vary in spatial scale and complexity were identified: small scale projects involving loss of habitat area, diffuse projects that impact vital rates through changes in habitat quality, and large projects that result in ecosystem transformation. To be operational and to measure impacts at a landscape scale, the appropriate surrogates of productivity will vary depending on the project category, ranging from habitat-based approaches, where ongoing fish productivity is inferred from the quantity and quality of habitat, to more direct measures of fisheries productivity (such as yield) for larger scale projects. Two pressing needs for implementation are a clear description of the operational tools available to measure productivity at the landscape scale, and a new precautionary framework to guide fishery protection to maintain productivity and ecosystem function.

Complete document (PDF, 426 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.