Research Document - 2016/096

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

By Gagne, A., Picco, C., Rutherford, D., and Rogers, J.

Abstract

This Goose Barnacle Framework updates a general framework for Goose Barnacles (CaɁinwa;^{Footnote 1} Pollicipes polymerus) in waters off the West Coast of Canada developed by Lauzier in 1999. The update incorporates a revised survey methodology and analytical procedures for estimating goose barnacle bed area and biomass with the inclusion of Local Ecological Knowledge (LEK). Bed area can now be mapped and estimated using advances in Global Positioning System (GPS) technology and Google Earth Mapping Software. New analytical procedures using bootstrapping methodology and LEK are proposed for quantitatively estimating Goose Barnacle biomass. This paper explores the concept of using harvest area closures as an alternative to a biologically-based provisional Limit Reference Point (LRP) and an Upper Stock Reference (USR). The new methodologies are documented and results of recent surveys using the new methodologies are presented.

Goose Barnacle bed area for six rocks in Clayoquot Sound was surveyed using GPS. Replicate surveys were conducted and variability between surveyors averaged 12.3%. Goose Barnacle density data sampled from 19 rocks between 2000 and 2003 were used in the quantitative estimates of biomass for the six rocks with GPS derived bed areas. Densities ranged from 0 to 39 kg/m² and averaged 7 kg/m². Biomass estimates are presented along with probabilities in a decision table form.

Local Ecological Knowledge is incorporated into several aspects of the assessment framework. LEK is used to estimate the harvestable biomass which takes into consideration size range for market, accessibility and availability. LEK harvestable biomass was compared to quantitative estimates of total biomass. LEK harvestable biomass was found to represent 4.6% of the quantitatively estimated mean biomass for the six rocks surveyed using GPS.

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