Bottomfish Variability in the Proposed Marine Reserves of Skagit County, Washington.

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Bottomfish Variability in the Proposed Marine Reserves of Skagit County, Washington.

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Title: Bottomfish Variability in the Proposed Marine Reserves of Skagit County, Washington.
Author: Valz, JH; Dinnel, PA
Abstract: Among groundfishes, rockfishes (genus Sebastes) are some of the most over-fished species in the United States. Populations in Puget Sound have declined rapidly over the last century; some rockfish species have 10% or less of their historical reproductive output. This population decrease is paralleled by declines in physical size. To address this problem, the Skagit County Marine Resources Committee has proposed establishing one or more no-take marine reserves to protect rockfishes and other groundfishes. The majority of studies of groundfish populations in the northeast Pacific have focused on summer distributions. The goal of this study was to relate intra-annual dynamics of groundfish, especially rockfishes, to physical and biological factors to assess the suitability of individual sites as reserves. Twenty-four dives were performed over one year at six sites under consideration as Skagit County marine reserves. Each dive consisted of eight 25-m transects where fish number and size, plus bottom composition were measured. Initial results show that changes in season were associated with changes in densities of the most abundant groundfishes (copper rockfish, kelp greenling, and lingcod). Depth and site also had a significant effect on densities of copper rockfish, which was the most common rockfish observed. Because of the large seasonal trends and effects of physical factors, more diverse sampling regimes should be used rather than the common summer sampling schedules. Additionally, larger-sized and deeper reserves should be considered to compensate for the seasonal migration of groundfishes.
Description: American Academy of Underwater Sciences (http://www.aaus.org/)
URI: http://archive.rubicon-foundation.org/6986
Date: 2007

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