Eelgrass forms a nearshore early warning system

  • Jul. 18, 2008 1:00 p.m.

Submitted by Ryan Duffy, Gwaii Haanas-At our ocean’s doorstep exist meadows that serve as an early warning system. Grazing upon information gathered from these meadows can help us understand how healthy our coastline is compared to others.Last week Parks Canada staff were making the most of July low tides while surveying seagrass meadows throughout the proposed Gwaii Haanas Marine Conservation Area Reserve. The monitoring program, now in its fifth year, provides information that can be compared to other national parks on the coast of British Columbia. Seagrass is not a seaweed (marine algae) or a true grass. Like its land dwelling relatives seagrass has green leaves, roots and flowers – however it chooses to reside below the tide. Seagrass occurs close to the coast, from the intertidal area to about 10 meters below the low tide. Parks Canada staff are particularly interested in a type of seagrass meadow – eelgrass (Zostera marina) – that occur in more sheltered locations such as protected bays on the east coast. As eelgrass occurs in nearshore waters, it is particularly vulnerable to the effects of human activities. This could include damage caused by boats anchoring at a popular location, to indirect human impacts such as excessive nutrients and sediments being washed into our oceans from land based activities. Monitoring eelgrass provides an early warning of coastal environment degradation, before it becomes too late to repair.Over 21 percent of Haida Gwaii’s coast is lined with eelgrass. Eelgrass meadows not only shelter an array of amazing creatures, such as the opalescent nudibranch, but are important spawning and nursery habitat used by juvenile herring, salmon, lingcod and rockfishes. Furthermore, other species such as great blue heron depend upon fish found within eelgrass meadows to rear their young.When Parks Canada staff visit eelgrass communities around Gwaii Haanas they observe and measure three things. Firstly, how much human disturbance an individual meadow has been exposed to (minimal in Gwaii Haanas). Second, how much material, such as algae, is growing on the seagrass leaves. Algal growth may make seagrass communities less productive and reflect abnormally high amounts of nutrients within the water. Finally, juvenile fish are caught using a seine net, identified, measured and released. Changes to fish populations or the numbers of species can also reflect changes within eelgrass communities.How does Gwaii Haanas compare against its Pacific coast cousins? Previous surveys suggest that Gwaii Haanas eelgrass meadows may be in better health than others monitored in the Gulf Islands and Pacific Rim. In Gwaii Haanas significantly more fish species have been caught, some meadows containing over 22 species, and less pollution has been detected. Although Gwaii Haanas eelgrass meadows are in good health at present, we need to continue monitoring if we are going to hear the alarm of this early warning system.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

BC Ferries reopens limited hot food service between Haida Gwaii, Prince Rupert

Release on July 8 says hot food will be served in packaging

VIDEO: Masset Dance Troupe presents beachfront ‘promenade performance’

Troupe performed ‘A Mid Summer Day’s Dream’ for family, friends on July 4 and 5

UPDATE: Masset anti-racism rally postponed

The Yahk’ii event, which means ‘truth’ in Haida, will be rescheduled at a later date

Haida matriarchs occupy ancient villages as fishing lodges reopen to visitors

‘Daughters of the rivers’ say occupation follows two fishing lodges reopening without Haida consent

Registration open for first-annual ‘NextIslandpreneur’ student business competition

Competition offers mentors, iPads, seed money, cash prizes to young entrepreneurs on Haida Gwaii

VIDEO: Masset Dance Troupe presents beachfront ‘promenade performance’

Troupe performed ‘A Mid Summer Day’s Dream’ for family, friends on July 4 and 5

Genetic detectives begin work to trace spread of COVID-19 in Canada

The kinds of genetic technology being used for this project did not exist when SARS hit Canada in 2003

Amber Alert for two Quebec girls cancelled after bodies found

Romy Carpentier, 6, Norah Carpentier, 11, and their father, Martin Carpentier, missing since Wednesday

Bringing support to Indigenous students and communities, while fulfilling a dream

Mitacs is a nonprofit organization that operates research and training programs

B.C. man prepares to be first to receive double-hand transplant in Canada

After the surgery, transplant patients face a long recovery

Grocers appear before MPs to explain decision to cut pandemic pay

Executives from three of Canada’s largest grocery chains have defended their decision to end temporary wage increases

Northern B.C. First Nations call for reversal of grizzly bear hunting ban

Growing grizzly populations have led to fewer ungulates and increased fear of attacks says Chad Day

RCMP ‘disappointed’ by talk that race a factor in quiet Rideau Hall arrest

Corey Hurren, who is from Manitoba, is facing 22 charges

NHL’s Canadian hubs offer little economic benefit, but morale boost is valuable: experts

Games are slated to start Aug. 1 with six Canadian teams qualifying for the 24-team resumption of play

Most Read