Seaweed concern

Plan to harvest seaweed from Qualicum Bay beaches likely a bad idea

I am writing with some concern regarding the  experimental harvest of 1,000 tons of  seaweed from the shoreline between Deep Bay and Qualicum Bay.

The Seagrass Conservation Working Group feel there is a need  for further study, especially given that the actual licences are for five companies with a total of 5,000 tons annually.  Our concerns include the impact of removing massive amounts of organic matter from nearshore food webs, and other specific issues related to harvest methods.

Seaweed and other vegetation piled on the beach after storm events is called beach wrack. This wrack will stay for a time and then be carried by waves into off-shore food webs.  Recent studies have shown that decaying beach wrack exports substantial amounts of nutrients into nearshore  (and estuary) ecosystems. Nutrients are required for plant life and plankton to grow, which in turn feeds smaller organisms that feed commercially important marine life such as salmon and shellfish.

The beach wrack also has other important roles that keep our ocean ecosystem working for the benefit of fishermen, tourism industry, landowners and general community. These include maintaining the backshore; providing food for invertebrates, birds and animals on the beach; and fertilizing the intertidal and sub-tidal through nutrients carried to the groundwater by rain.

The harvesting methods involve the use of rakes and pitchforks which could potentially disturb Sand lance or Surf smelt, forage fish that spawn in the upper intertidal. These fish are key to many ocean food chains including salmon, herring,  whales, and marine birds.

Shaking a pitchfork is not a reliable approach to ensure they only collect the target species. Sorting is also not enforceable legally and so presents further potential for impacts.

And we have been made aware of some questions regarding the actual target species and for clarification purposes we would like see a specialized marine biologist review this information, so there is a shared understanding between all stakeholders.

Diane Sampson

 

Deep Bay