Science Advisory Report  2016/048

Update to the assessment framework for Goose Barnacles (CaɁinwa; Pollicipes polymerus) incorporating Local Ecological Knowledge and advancements in technology in Clayoquot Sound off the West Coast of Canada

Summary

• Five Nuu-chah-nulth-aht Nations (Ahousaht, Ehattesaht, Hesquiaht, Mowachaht/Muchalaht, and Tla-o-qui-aht) have led, in collaboration with Fisheries and Oceans Canada (DFO), the development of an updated assessment framework for Goose Barnacles. The updated assessment framework incorporates Local Ecological Knowledge (LEK) along with revised survey methodology and analytical procedures for estimating Goose Barnacle bed area using current GPS technologies and new analytical procedures to quantitatively estimate biomass. 
• LEK is used to estimate the harvestable biomass which takes into consideration size range for market, accessibility and the ability to harvest live animals. LEK harvestable biomass is compared to quantitative estimates of total biomass and is found to represent an average of 4.6% (range 0.8 – 15.1%) of the quantitatively estimated total biomass.
• Goose Barnacle biomass estimates by rock are presented as probability distributions and reported in a decision table to allow managers to choose appropriate risk levels. The presented probabilities are P10, 20, 30, 50,70% which represent the probabilities that the true biomass is smaller than the estimate.
• A novel approach was used in the development of reference points compliant with the Precautionary Approach (DFO, 2009a):
  • The use of estimated total potential habitat as a proxy for virgin biomass (B0) is recommended as an interim measure. This approach proposes provisional Limit Reference Points (LRP) and Upper Reference Points (URP) of 20% and 40% of estimated total potential habitat.
  • This approach is deemed appropriate in the unique case of Goose Barnacle in the Clayoquot Sound area due to the sessile nature of the organism, the data limitations associated with estimating population parameters, the small spatial scale on which it is being applied, and in recognition that the refugia are spatially integrated into the current harvest area meaning that larval connectivity is likely.
• The updated framework is proposed to be used specifically in Clayoquot Sound.  However, it is adaptable for application in other areas along the coast of British Columbia.

This Science Advisory Report is from the June 14 - 15, 2016 regional peer review on the Update to the assessment framework for Goose Barnacles (Pollicipes polymerus). Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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