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On the Seashore

Subjects: science

Ever-changing Shorelines

All marine shorelines — beaches, dunes, estuaries, salt-marshes, mud-flats, and rocky tidal zones — have one thing in common: they are exposed to twice-daily tides. Combining land and sea, fresh and salt water, these transitional environments are in a constant state of change. The animals and plants that live here are adapted biologically to the harsh conditions that accompany constantly rising and falling water levels, salt spray from the ocean, frigid winter temperatures, and intense summer heat. But these challenges pale in comparison with the pressures inflicted on marine shorelines by oil spills, landfills, sewage, mining, damming, dredging, draining, urban and industrial expansion, recreation and tourism, erosion from farmlands, overharvesting of shellfish, and countless other human impacts.

A Sea of Troubles

Marine shorelines appeal not only to wildlife but also to humans. Beaches are among the most popular recreational spots. Whatever our reasons for visiting shorelines, these ecosystems often suffer: crabs and molluscs get over harvested, depriving predators of nourishment; barnacles and algae get squashed underfoot; all-terrain vehicles crush burrowing crustaceans and shorebird nests; and many animals are forced to move elsewhere when beaches become holiday resorts.

The future of many marine shorelines — and the wild species that depend on them — is seriously threatened by these additional human impacts:

  • Highways, railways, and causeways built across marshes hinder the life-sustaining ebb and flow of tides.
  • Oil spills leave kilometres of beaches blackened. Oil clings to the feathers of sea birds and waterfowl and kills numerous coastal animals, including fish.
  • The dumping of raw sewage overloads coastal wetlands with organic contaminants.
  • Run-off from farmlands containing pesticides kills crabs, shrimps, and raptors, while fertilizers, such as nitrates and phosphates, cause algal blooms, which deprive fish of oxygen.
  • The alteration of shorelines with dykes and dams has huge ecological consequences, including interference with spawning migrations.
  • Wetlands, drained and filled, make choice sites for shopping malls, airports, industries, and urban developments, but leave countless migratory waterfowl and other wildlife species in the lurch.

Turn the Tide

It is always a good time to start turning the tide for our marine shorelines. These suggestions will help get you started:

  • Celebrate Oceans Day and organize an ocean-related display or activity at school. Encourage your town council to declare the event. Spread the word among community service and faith groups.
  • Learn more about shoreline ecosystems and the problems facing them. Get to know a beach, dune, estuary, salt-marsh, mud flat, or rocky tidal zone.
  • Observe a “coastal code of conduct” when visiting shorelines: don’t drive or cycle on the beach; on rocky shores, avoid crushing barnacles or other species that live on the surface; leave seaweed and empty shells where they lie (shoreline creatures, like hermit crabs, need them for protection from predators); never move animals from one shore, beach, or tidal zone to another; leave the flora and fauna in tidal pools for viewing only (just dipping your hand in a pool can have a serious impact); avoid disturbing sea birds, especially when they’re nesting; and clean up all your trash (garbage attracts predators that eat eggs and nestlings).
  • Organize a beach sweep in your community. Invite a local business to sponsor the event by providing funding or supplies like rubber gloves and garbage bags. Then post “No Dumping” signs along the shoreline.
  • Help prevent unnecessary destruction to coastal shorelines by promoting conservation, wise stewardship, and pollution control. Inform your Member of Parliament about the urgent need to save these ecosystems.
  • A great way to restore beaches, dunes, and salt-marshes is to provide supplemental plantings.
  • Promote the establishment of a marine protected area (MPA) on a shoreline near you. Collaborate with others who have a stake in conserving ocean environments.
  • Report sightings of marine animals that are beached or entangled in debris and find out how to participate in a stranding network by contacting your local office of Fisheries and Oceans Canada.

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