Research Document 2017/033
Monitoring fish habitat compensation in the Pacific region: lessons from the past 30 years
By Bradford, M.J., Macdonald, J.S., and Levings, C.D.
To offset the impacts of development projects on fish and fish habitat, compensation or offsetting works can be required as a condition of an Authorization issued under the Fisheries Act. However, the efficacy of these works is often unknown as follow-up monitoring is infrequently conducted. Here we review past habitat compensation and restoration monitoring activities in Canada’s Pacific Region. We first describe various types of monitoring schemes that differ in their objectives, the types of information collected, and required levels of expertise. We then review monitoring studies in the Region with a focus on four case histories. We found successful monitoring of biotic responses (fish or invertebrates) were few as the spatial and temporal scales of most programs were too limited to cope with natural and sampling variation. Few studies had pre-project baseline information, and subsequently sampling relied on comparisons of treatment sites against control or reference areas. A number of the most insightful studies sampled sequentially over time and identified decadal-scale changes in constructed habitats. Most monitoring programs were of insufficient scope to estimate the effect of restored or constructed habitats on fish population productivity. We conclude that when designing a monitoring program investigators carefully specify their objectives and determine whether those objectives can be met given available resources, time, and expertise.
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