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Evaluation of genetic structuring of California sea cucumber (Parastichopus californicus) across transfer zones in British Columbia



The introduction and transfer of fish and shellfish into and between facilities is regulated so that transfers do not adversely affect local aquatic species and habitats. This study aimed to assess a requirement for mitigation measures to minimize risks associated with transfer activities (e.g., egg disinfection, quarantine of stock) under s. 56 of the Fishery General Regulations.

In British Columbia, there are five distinct shellfish transfer zones (STZs) that span the Pacific Region. These zones are used to manage the movement of cultured shellfish to prevent gene flow between cultured and wild populations, and to manage the transfer of potential parasites/pathogens. Introducing or translocating cultured individuals can lead to gene flow with wild populations, and can result in a loss of genetic variation or adaptive genes found in the wild populations. Therefore, understanding the spatial scales at which shellfish populations are genetically distinct can help to optimize the boundaries of STZs to meet both ecological and socio-economic objectives.

Typically an Introductions and Transfers Licence is required both for between and within zone transfer activities of sea cucumbers in British Columbia. The present study assessed the genetic structure of the California sea cucumber (Parastichopus californicus), and compared the location of genetic discontinuities with the current STZ boundaries. More broadly, information on their genetic structure also contributed important spatial information for informing fisheries management and the design of Marine Protected Area (MPA) networks. The results of this project can contribute to science advice that can be used to enhance the scientific basis for shellfish transfer zones and the sustainable management of the shellfish aquaculture industry.


Overall, the study found evidence of population genetic structure for P. californicus that can inform the suitability of shellfish transfer zones (STZ) boundary locations in coastal British Columbia. At the largest spatial scale, clustering analyses revealed a genetic break between two distinct groups. Differentiation between these two clusters was driven by distance. Within regional groups there were further genetic breaks. Statistical analysis suggested that differentiation at a smaller spatial scale is not driven by distance.

Generally, the identified genetic clusters matched the location of STZ boundaries. In particular, STZs around Vancouver Island (West Coast Vancouver Island, Queen Charlotte Strait and Georgia Strait) matched the three identified clusters in the south region. However, results found it may be more appropriate for the west coast of Haida Gwaii to be managed as a distinct zone, while the north/east coasts could potentially be pooled together with the North and Central Coast STZ.


Xuereb, A., Fortin, M.-J., Bernatchez, L. and Curtis, J. 2017. Evaluation of genetic structuring of California Sea Cucumber (Parastichopus californicus) across Transfer Zones in BC.

Program Name

Program for Aquaculture Regulatory Research (PARR)


2015 - 2017

Principal Investigator(s)

Janelle Curtis
Research Scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region

Team Member(s)

Nicholas Duprey, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region

Chris Pearce, Research Scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region

Dan Curtis, Research Scientist, Fisheries and Oceans Canada, Pacific Biological Station, Pacific Region

Collaborative Partner(s)

Marie-Josée Fortin, University of Toronto

Amanda Xuereb, University of Toronto

Louis Bernatchez, Université Laval

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