Last updated on 30 June 2017

SUMMARY

SUMMARY

IDENTIFICATION

SCIENTIFIC NAME(s)

Lepidopsetta polyxystra

SPECIES NAME(s)

Northern rock sole

Rock Sole (Lepidopsetta spp.) occur along the entire coast of British Columbia (BC), Canada, with abundance highest in Hecate Strait and Queen Charlotte Sound. The majority of Rock Sole catch is taken by the groundfish trawl fishery. Two species of Rock Sole occur in BC: Southern Rock Sole (L. bilineata) and Northern Rock Sole (L. polyxystra). Rock Sole encountered in BC fisheries and research surveys are almost exclusively Southern Rock Sole. Rock Sole stocks in BC are assessed and managed as five separate areas based on DFO Statistical Areas. This assessment provides harvest advice for Areas 5AB (Queen Charlotte Sound) and 5CD (Hecate Strait). Limited fishery and survey data from the other three management areas (3CD, 4B, 5E) preclude the provision of quantitative harvest advice. Summaries of available data for these areas are provided (Holt et al. 2016).


ANALYSIS

No related analysis

FISHSOURCE SCORES

Management Quality:

Management Strategy:

NOT YET SCORED

Managers Compliance:

NOT YET SCORED

Fishers Compliance:

NOT YET SCORED

Stock Health:

Current
Health:

NOT YET SCORED

Future Health:

NOT YET SCORED


FIPS

No related FIPs

CERTIFICATIONS

No related MSC fisheries

Fisheries

Within FishSource, the term "fishery" is used to indicate each unique combination of a flag country with a fishing gear, operating within a particular management unit, upon a resource. That resource may have a known biological stock structure and/or may be assessed at another level for practical or jurisdictional reasons. A fishery is the finest scale of resolution captured in FishSource profiles, as it is generally the scale at which sustainability can most fairly and practically be evaluated.

ASSESSMENT UNIT MANAGEMENT UNIT FLAG COUNTRY FISHING GEAR
British Columbia Canada British Columbia Canada Bottom trawls

Analysis

OVERVIEW

1.STOCK STATUS

STOCK ASSESSMENT
Canada British Columbia

Last updated on 30 August 2016

A female-only statistical catch-at-age model in a Bayesian estimation framework was used to assess Rock Sole in Areas 5AB and 5CD. The model was fit to catch data, two or more indices of abundance, and age composition data from commercial trawl fisheries and research surveys. Indices of abundance included fishery-dependent catch-per-unit effort time series as well as fishery-independent trawl survey indices (Holt et al. 2016). 

SCIENTIFIC ADVICE
Canada British Columbia

Last updated on 30 August 2016

Advice to management is presented in the form of decision tables using five-year projections for a range of constant catches. For each level of constant harvest, decision tables show the probability that projected stock status in each year will be greater than specified reference points.

Reference Points

Last updated on 30 Aug 2016

Stock status in Areas 5AB and 5CD is evaluated relative to two types of reference points: MSY-based and historical. 

The MSY-based reference points are consistent with the provisional reference points contained in the DFO Fishery Decision-making Framework Incorporating the Precautionary Approach. These include a limit reference point (LRP = 0.4BMSY, where BMSY is the female spawning biomass associated with maximum sustainable yield), an upper stock reference point (USR = 0.8BMSY), BMSY, and the harvest rate associated with MSY (uMSY). The historical reference points were previously developed and applied to BC Rock Sole stocks in 2006, and include a limit biomass (BLIM), a target biomass (BTAR), current biomass (B2014), and a target harvest rate (uTAR) (Holt et al. 2016).

CURRENT STATUS
Canada British Columbia

Last updated on 30 August 2016

Exploitation rates in 2013 are estimated to be below uTAR and uMSY in both management areas. In Area 5AB, the ratio of u2013 / uTAR is 0.59 (0.46-0.75) and the ratio of u2013 / uMSY is 0.46 (0.30-0.72). In 5CD, the ratio of u2013 / uTAR is 0.32 (0.24-0.42) and the ratio of u2013 / uMSY is 0.08 (0.04 -0.16). In both areas, there is a 100% percent probability that the exploitation rate in 2013 is less than uTAR and uMSY (Holt et al. 2016).

2.MANAGEMENT QUALITY

MANAGEMENT
Canada British Columbia

Last updated on 30 August 2016

Management of the BC Rock Sole fishery has used a range of tactics, including trip limits and annual quotas. There were no catch or trip limits for Rock Sole before 1982. A trip limit of 11 tonnes was introduced for management region 5CD in 1982. By 1986, trip limits of 14 tonnes were in place for each of Areas 5CD and 5AB. Trip limits continued to be applied until 1992, at which time area-specific management by Total Allowable Catch (TAC) was introduced for management areas 5AB and 5CD. These initial quota levels were set at 800 tonnes in 5AB and 1150 tonnes in 5CD based on a review of catch and effort trends. A TAC of 102 tonnes was introduced to region 3CD for the 1997/1998 fishing year and has remained at this level since then (Holt et al. 2016).

The TACs were reduced for areas 5AB and 5CD in the early 2000’s. Areas 4B and 5E have never been assigned TACs as they represent a minor component of total coastwide landings. There is no legal size limit for Rock Sole; however, an effective minimum size in the landings is driven by market preference. Typically a preferred fish is at least 33 cm total length to ensure a worthwhile fillet yield (Holt et al. 2016).

This effective size limit results in a fishery that is primarily made up of females, with the majority of males being below 33 cm. In addition to the trip limits and TACs, there have been other significant management tactics applied to the trawl fishery in the last decade that may affect fishery-dependent data (Holt et al. 2016).

3.ENVIRONMENT AND BIODIVERSITY

FishSource Scores

MANAGEMENT QUALITY

STOCK HEALTH:

No data available
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Fishery Improvement Projects (FIPs)

No related FIPs

Certifications

Marine Stewardship Council (MSC)

No related MSC certifications

Sources

Credits
  1. Wilderbuer, T. K., Walters, G. E., 2004. NPFMC Bering Sea and Aleutian Islands SAFE, Chapter 7: Northern Rock Sole, 50 p.http://www.afsc.noaa.gov/refm/docs/2004/BSAIrocksole.pdf

  2. Holt, K.R., Ackerman, B., Flemming, R., Forrest, R.E., Kronlund, A.R., Lacko, L., Olsen, N., Rutherford, K., Stanley, R.D., Taylor, N.G. and Workman, G., Canadian Technical Report of Fisheries and Aquatic Sciences 2016/009. http://www.dfo-mpo.gc.ca/csas-sccs/Publications/ResDocs-DocRech/2016/2016_009-eng.pdf

References

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