White sturgeon were formerly abundant in the lower Fraser River of British Columbia, but have been dramatically reduced by overfishing and habitat loss. Significant efforts have been put into collecting baseline abundance and demographic data over the past decade. Here we fit an age-based model for white sturgeon to the available length-frequency data from slough and river habitats. Our analysis of the parameterized model indicates that the white sturgeon population in the lower Fraser River was declining through the 1980s and into the 1990s. We estimate a growth rate in the range of λ=0.90 to λ=0.96, which corresponds to a 4%−10% decrease in the population each year. Thus, we infer that improving juvenile survival in the slough habitats is key to conserving this white sturgeon population.

White sturgeon were formerly abundant in the lower Fraser River of British Columbia, but have been dramatically reduced by overfishing and habitat loss. Significant efforts have been put into collecting baseline abundance and demographic data over the past decade. Here we fit an age-based model for white sturgeon to the available length-frequency data from slough and river habitats. Our analysis of the parameterized model indicates that the white sturgeon population in the lower Fraser River was declining through the 1980s and into the 1990s. We estimate a growth rate in the range of λ=0.90 to λ=0.96, which corresponds to a 4%−10% decrease in the population each year. Thus, we infer that improving juvenile survival in the slough habitats is key to conserving this white sturgeon population.