Guest Contribution by Jen Graham
This post is a shout-out to coastal habitat. Salt marshes, estuaries, eel grass, mudflats, rocky shores- you are all awesome.
I could tell you why each of these habitats matters. After all, salt marshes are acre-for-acre the most productive places on the planet. However, the take-home message of this post is how coastal habitats are connected. Together, the various shallow water coastal habitats form a coastal ecosystem. The movement of species, the transfer of energy, nutrient exchange, and the flow of sediments connect this web.
Coastal ecosystems are not just connected they are interdependent. Gooey mudflats are the building blocks for new salt marshes. Existing salt marshes provide masses of decaying vegetable matter (called detritus) to nourish the mud-loving shrimps, clams, and other benthic invertebrates. This complex web linking rocky shores to eelgrass, and mudflats to marshes is the basis for the productivity of coastal waters, and the health of small-scale coastal fisheries. Let’s take a closer look at a few of the component pieces of the coastal web of life, and how they support inshore fisheries.
Salt marshes are sometimes called the “kidneys of the coast” because they trap sediment, filter pollutants, and improve coastal water quality. They are also excellent fish habitat. Many recreational and commercial fish species, like winter flounder and striped bass, spend at least part of their life cycle visiting marshes. As well, marsh detritus is flushed into bays and estuaries, the initial step in a “food web” that eventually feeds commercially important species. A Fisheries and Oceans Canada (DFO) website estimates that as much as 50% of the commercial catch of fish and shellfish use these organic materials directly or indirectly.
Mudflats also provide food. American Shad from every major river along the Eastern seaboard migrate to the Bay of Fundy to feed. Flocks of migratory shorebirds come to feed on the zooplankon produced in huge numbers on mudflats. It also feeds crabs, other invertebrates, and eventually nourishes larger creatures. This is why cod and haddock travel up the Bay of Fundy every summer, chasing herring and other species feeding on creatures that are feeding on the mudflats.
Other coastal habitats also support commercial fisheries. Young cod are sheltered in kelp or eelgrass beds. Juvenile pollock and herring are found in the rockweed habitat along rocky shores.
Until very recently in Canada, small-scale fisheries meant coastal fisheries. Fishermen still talk about the shallow bays and estuaries where juveniles were once found in abundance. They also speak of the damage that pollution, damming and diversion of rivers, run-off from land, and habitat-damaging gear like draggers have caused to coastal habitats along the Atlantic. And we have all seen the results; the systematic alteration and destruction of coastal ecosystems has certainly contributed to the depletion of our coastal fisheries.
Coastal habitats are often simpler to protect or restore than offshore areas. After all, we can more easily see and measure changes in habitat condition and species abundance. Removing tidal barriers can restore natural tidal flow to salt marshes and increase fish abundance. When leaking septic systems are repaired, water quality improves and closed clam harvesting areas can be re-opened. Studies show a clear correlation between restoring river habitat, rebounding herring, and subsequent rebounding haddock.
Many of the websites I referred to while preparing this post turned out to be recently archived DFO Habitat pages. That’s right: archived. Recent changes to the Fisheries Act mean that DFO will no longer manage coastal habitat if it does not directly benefit commercial fish species. This means DFO no longer has the mandate to educate people about coastal ecosystems and habitat, let alone to protect and restore them.
So this post began with a shout-out and ends with a plea. Our government no longer values and protects coastal habitat, or wants us to learn about how coastal ecosystems work. We may have to do the work ourselves. Check out these cool pages to learn about the myriad ways coastal habitats support small-scale fisheries. And please do your part to protect and manage these amazing places!
Jen Graham is the Coastal Coordinator at Ecology Action Centre. Since 2006, Jen has been using the “Have Fun; don’t mind the mud” approach to coastal conservation.