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COSEWIC Assessment and Status Report on the Rougheye Rockfish sp. type I and sp. type II in Canada

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COSEWIC
Assessment Summary

 

Assessment Summary – April 2007

Common name:

Rougheye Rockfish - type l

Scientific name:
Sebastes sp. type I

Status:
Special Concern

Reason for designation:
This species is a relatively large (reaching 90 cm length) rockfish species and among the longest-lived, estimated to approach 200 years. It is one of two sympatric species which have been identified within the described species Sebastes aleutianus. It ranges from northern Japan to southern California in depths 200 to 800+ m along the shelf break. In Canadian waters abundance information is derived from surveys and from the commercial fishery that has maintained a relatively constant reported catch of between 1000 and 2000 tonnes annually over the last 2 decades. Abundance indices and biomass estimates are uncertain, compromised by short time series and survey techniques not always appropriate for the species. No strong abundance trends are observed in the available indices. There is evidence of truncation of the age distribution over the last decade, suggesting that mortality from all sources may have doubled (4.5% y-1 to 9.1% y-1). Long-lived, low-fecundity Sebastes species are particularly susceptible to population collapse, and recovery may be compromised when the age- and size-distribution is truncated (i.e. when the number of spawners declines) through fishing. Difficulty in separating the two species increases the risk of potential impacts on one of the species going unnoticed.

Occurrence:
Pacific Ocean

Status history:
Designated Special Concern in April 2007. Assessment based on a new status report.

 

Assessment Summary – April 2007

Common name:

Rougheye Rockfish - type II

Scientific name:
Sebastes sp. type II

Status:
Special Concern

Reason for designation:
This species is a relatively large (reaching 90 cm length) rockfish species and among the longest-lived, estimated to approach 200 years. It is one of two sympatric species which have been identified within the described species Sebastes aleutianus. It ranges from northern Japan to southern California in depths 200 to 800+ m along the shelf break. In Canadian waters abundance information is derived from surveys and from the commercial fishery that has maintained a relatively constant reported catch of between 1000 and 2000 tonnes annually over the last 2 decades. Abundance indices and biomass estimates are uncertain, compromised by short time series and survey techniques not always appropriate for the species. No strong abundance trends are observed in the available indices. There is evidence of truncation of the age distribution over the last decade, suggesting that mortality from all sources may have doubled (4.5% y-1 to 9.1% y-1). Long-lived, low-fecundity Sebastes species are particularly susceptible to population collapse, and recovery may be compromised when the age- and size-distribution is truncated (i.e. when the number of spawners declines) through fishing. Difficulty in separating the two species increases the risk of potential impacts on one of the species going unnoticed.

Occurrence:
Pacific Ocean

Status history:
Designated Special Concern in April 2007. Assessment based on a new status report.