Meadows of the Sea

And no, I’m not bailing out from a flood (though the rain never lets up in this corner of the country!)  The doorstep in question is the Skeena River, one of BC’s largest and one of Canada’s healthiest “wild” rivers.   It is completely undammed and minimally impacted by industrial or agricultural water use.  The Skeena still supports viable runs of most salmon stocks, and supports both a commercial and recreational fishery.
The part where the river meets the sea is called the estuary, and it is key to the health of both upriver and marine ecosystems.  Those 20 million salmon spend several months to a year (depending on the species) hanging out in the estuary.   Why?  Because estuaries are basically great places to hang out – lots of food, relative protection from predators, a safe place to “cut your teeth” before heading out to the North Pacific.

Eelgrass meadow (c) Mike Ambach/WWF-Canada
An essential part of estuary habitat is eelgrass (Zostera marina).  Nothing to do with eels, this is a flowering plant that grows both underwater and within the tidal zone, forming meadows and providing habitat for all kinds of species: juvenile salmon, oolichan, crabs, marine snails and other invertebrates.   Readers of previous blogs (here or here) will know that WWF’s work in Northwest BC has focused on mapping eelgrass along with other foreshore habitat.  We’ve been able to gradually draw a better picture of the role played by eelgrass in this region, and the need for management measures that ensure its protection.
Most recently, we worked with local research contractors Ocean Ecology to carry out underwater video surveys of eelgrass beds around the Lucy Islands – a marine conservancy and Important Bird Area for rhinocerous auklet  (a diving seabird related to the puffin that feeds on fish and invertebrates using the estuary).  An overview of this work, including samples of the underwater video tows, can be viewed here).  Through the research, we were able to confirm healthy and abundant eelgrass areas that had not before been mapped, while also shedding some light on the factors most likely to influence eelgrass health (tidal currents, sediments distributed by the estuary, turbidity, etc.)  Results from this research will be presented by Ocean Ecology researcher Barb Faggetter at the BC Protected Areas Research Forum this December.

While Fisheries and Oceans Canada has a zero net loss policy for eelgrass (i.e. development that destroys eelgrass habitat has to restore / replant elsewhere), restoration has met with limited success in our region.  From a development perspective, the whole region has seen an increase in shipping and related infrastructure, so the more we know about the requirements and vulnerabilities of eelgrass, the better we’ll be able to mitigate against its loss and integrate its many ecosystem service values into planning.
There are plenty of resources to learn more about the critical role of these “Ocean Meadows”.  Try Seaweb’s November focus issue to get a more global perspective on seagrasses.  Or visit the Seagrass Conservation Working Group for a BC perspective.