Study of the impact of harvesting soft-shell clams using a hydraulic rake on the benthic community of the Malbaie barachois

Description

One way to increase the commercial productivity of shellfish beds is to develop soft-shell clam (Mya arenaria) culture, which essentially consists of seeding exclusive lots favourable to the growth of this species with juvenile clams and harvesting the clams once they have reached commercial size. At present, the recommended method for harvesting adult clams consists of dragging a hydraulic rake over seeded clam beds. Until now, few studies have been conducted on the impact of hydraulic rakes. The objectives of this study are to determine the impact of the use of hydraulic rakes to harvest soft-shell clams in the Malbaie barachois (Gaspé Peninsula) on the benthic community and on the soft-shell clam population and their habitat and to assess shellfish bed recovery time following raking. The impact will be evaluated in the spring and fall in order to explore two possible harvesting windows for industry. In each season, 5 sampling periods are planned: prior to the passage of the hydraulic rake, 1 day after, 1 month after, 3 months after and 12 months after. Biomass indices per species and size class for soft-shell clams as well as diversity indices, species richness indices and K dominance curves will be calculated to compare the various treatments and time periods, before and after harvesting.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)

Year(s)

2001 - 2005

Ecoregion(s)

Atlantic: Gulf of St. Lawrence, St. Lawrence Estuary

Principal Investigator(s)

Lizon Provencher
Email: Lizon.Provencher@dfo-mpo.gc.ca