Research Document - 2012/153
Scientific Information in Support of Identifying Critical Habitat for SARA-listed White Sturgeon Populations in Canada: Nechako, Columbia, Kootenay and Upper Fraser (2009)
By T. Hatfield, T. Coopper, and S. McAdam
Abstract
This document reviews existing information relevant to the determination of critical habitat for white sturgeon in each of the four SARA-listed populations in Canada. The report introduces the concept of critical habitat (as distinguished from other habitats used by the species) and summarizes existing information about the location, extent, current status, and potential threats to freshwater habitat that is critical to survival or recovery of white sturgeon in Canada. The report documents sources of information, methods by which information was collected, reliability of the information, and provides a brief discussion of data gaps. Basic biological information on the primary life stages of white sturgeon is provided, including diets and habitat needs.
The legal definition of critical habitat is provided, along with the practical interpretation of this definition and the methods by which recommendations for critical habitat were determined for each population. In addition to recommendations for critical habitat, the recovery team has identified “important habitat,” which is defined as habitat that is suspected to contain critical habitat, but for which existing knowledge is inadequate to meet the burden of proof, as set by the Recovery Team, to designate critical habitat. The purpose of identifying important habitat in addition to critical habitat is to recognize that full recovery for white sturgeon requires management of a larger set of geographic locations than can be identified at this time, and more specifically to recognize geographic locations that are likely to be identified as critical in the light of future information.
Critical and important habitats of each life stage are discussed and identified, where possible. Threats to these habitats, data gaps and data sources are also presented. Maps of critical habitat areas are provided for each watershed, with each map indicating boundaries of the critical habitat units.
Critical habitats defined in this document, when combined with functioning recruitment in each population, should provide the initial basis for population recovery. Although there remains some uncertainty regarding factors such as the precise timing and spatial location of some specific critical habitats proposed here, the greater uncertainty is the cause of persistent recruitment failure and identification of a feasible means of restoration. This is reflected in the knowledge gaps identified in the recovery strategy, which provides a guide to future studies with a strong focus on recruitment failure diagnosis and restoration. While some studies conducted on the species biology and movement may provide further information on definition of particular critical habitats, such studies should not supersede investigations of recruitment failure and its restoration because doing so may not be in the best interest of the species.
Disclaimer: The advice provided in this document followed DFO guidance available at the time of the review (2009).
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