Research – Studying Drift Seaweed on Central Vancouver Island

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At the request of BC Ministry of Agriculture, the VIU Deep Bay Marine Field Station is documenting the ecological activities around the distribution of wrack and the harvest activities of the introduced algae Mazzaella japonica during the 2014/15 harvest season. This information will provide managers, community and harvesters with information that will help assess the local environmental effects of this activity.

Background For good summary about Mazzaella japonica (MJ) see this article by Dr. Michael Hawkes, Dept of Botany, University of BC.  As Dr. Hawkes points out, this species was first recognized in our marine flora about 10 years ago (although it may well have been here much longer than that) in the area from Deep Bay, at the south end of Baynes Sound, to Bowser on the east coast of Vancouver Island.  Presumably this species may have been introduced with shipments of oyster seed from Japan more than 80 years. ago and is now becoming abundant. 

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Mazzaella japonica as beach wrack decomposing on the beach – note the white ends as it decomposes and reacts with freshwater.

Kylee Pawluk, a Ph.D. student in the Dept. of Geography at the University of Victoria, has documented extensive subtidal beds of this species south of Baynes Sound. At the Salish Sea Conference in 2014 she presented some of her field work which showed that MJ appears to be out competing local species and may therefore be invasive.  The distinction between introduced and invasive is significant.  Biologists typically refer to an alien species as ‘introduced’ until it starts doing harm in the ecosystem at which point it is termed ‘invasive’.

Subtidal Mazzaella japonica - Vancouver Island

Thick subtidal beds of Mazzaella japonica off of Bowser taken by Kylee Pawluck – fall 2014

Winter storms break the seaweed off the bottom and it is washed ashore and becomes drift seaweed, known as “wrack”. Since 2007, the British Columbia Ministry of Agriculture (BCMoA) has been issuing licenses that permitted commercial operators to remove the wrack from beaches between Deep Bay and Bowser.  MJ is a valuable source of carrageenans widely used to gel, thicken and stabilize processed foods, cosmetics and pharmaceuticals. In 2011, investor interest increased, which led to an increase in licensed harvests. In 2012, the Ministry issued licences to commercially harvest up to 5,000 tonnes of from Vancouver Island.  An additional harvest of 600 tonnes near Bowser was approved for 2013 and 900 tonnes of quota over 3 licenses has been approved in 2014/15 under strict conditions of licence.

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Commercial harvest of Mazzaella japonica south of Deep Bay Fall 2014

In the last few years a group of local residents have voiced concern about the harvest citing environmental and social issues. Many others in the community seem to be neutral or in favour of the harvest for its economic benefits as long as it is sustainable. Drift seaweed can be an important part the intertidal ecosystem, supporting intertidal organisms and cycling nutrients from the ocean to the land and back. As well the physical activity of removing wrack from the beach could have negative impacts. To date information has largely been the result of literature reviews and discrete observations during the harvest. At the request of BCMoA, VIU Deep Bay Marine Field Station is documenting the ecological activities around the distribution of wrack and the harvest activities during the 2014/15 harvest season. This information will provide managers, community and harvesters with information that will help assess the local environmental effects of this activity.

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The core of our research team, right to left:  Jessica Holden (M.Sc. Student UVIC), Shaun MacNeil (Recent Grad VIU BA Natural Resource Management), and Dr. Sarah Dudas (Canada Research Chair).

Our Work to date: We have conducted a literature review of domestic and international wrack monitoring studies in order to establish an experimental design. Additionally we consulted experts in the field. A draft study design was completed and revised after preliminary testing within the study area.   A Stakeholder Advisory Committee was formed consisting of Chief Michael Recalma (Qualicum First Nation), Jason Rose (Stormy Shores Sea Products) and Ian Birtwell (Community representative nominated by Regional District of Nanaimo). Preliminary familiarization and field test sampling began during the week of October 20th and first data sampling occurred the following week.  As the wrack event and harvesting were well underway by the time of the contract approval we began sampling as soon as possible despite not having had time to fully resolve our techniques.  The sampling program is based on two approaches: 1) a large scale volume estimate of the entire beach area and; 2) a series of standard monitoring transects for ecological studies.

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With all the lowest tides in the night during the winter a lot of the work is happening in the middle of the night and is also utilizing student volunteers

Total wrack volume data is being collected once per week, with a total of 8 surveys completed to date. Surveys generally take place on Mondays (tide dependant) in order to ensure the most accurate data possible, as the wrack has been allowed to gather over the course of the weekend without the influence of the harvest.  The volume surveys entail a team of 2-3 people traversing the entirety of the 5km harvest area from the Buccaneer Beach access to the harvest area’s northern extent near the Deep Bay RV Park. Over the course of the walk, cross sections of the wrack bands are measured at randomly generated intervals  At each sample location GPS coordinates are recorded, photographs taken, wrack bands are characterized by qualitative decomposition class and width and depth measurements are taken so that volume can be estimated. Additional information is being collected during the walks including wildlife observed, evidence of harvest activity weather and sea state etc. A series of fixed volume weights are taken in order that volume can be converted into total tonnage estimated.

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Our weekly hike of the 5km study area

Weekly sampling of permanent transects running perpendicular to the water is being conducted at six different sites.is being conducted in order to meet the following project objectives

  • Collection of wrack samples to investigate invertebrate community composition
  • Quantification of relative algal species diversity and dry weight of wrack samples
  • Pre and post-harvest documentation of beach area

From these transects we have been taking measurements of wrack band widths, percent cover, depth, and temperature in addition to the collection of wrack samples. This data will allow us to investigate changes in wrack volume, age classes, algal species diversity and invertebrate community composition between harvested and un-harvested sites.

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Collecting data late at night – so far the crew has had everything from beautiful freezing clear nights to storm force winds and heavy rains

Media We have conducting the following communication activities during this project:

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Dr. Sarah Dudas speaking to CTV Vancouver Island Video Reporter Gord Kurbis from the wrack

Whats next? Sampling will continue through to February or until the wrack has disappeared from the beaches. We are processing the data we have been collecting now and our final report will be submitted to BCMoA by the end of March and then made available by BCMoA to the public.

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