Our Marine Environment
The Intertidal Environment
What
is the intertidal zone? Sometimes called the littoral zone,
the intertidal region is a zone of transition extending from
areas of high tide, that are routinely exposed to air and sunlight,
to areas of low tide that are rarely exposed. Plants and animals
that inhabit this area have adapted to the extreme variability
of conditions in and out of the water.
Vegetation
Marine
vegetation in the intertidal zone serves multiple functions for the
animals that live in the area. Marine vegetation is used as habitat
and refuge for many species and is a food source or birthing areas
for other species. Crabs creep along the bottom, fish hide in the thick
beds of grass and kelp, and snails slide their way up and down the
vegetation that grows on the ocean's floor. A complexity of organisms
rely on vegetation in the intertidal zone to live, feed and reproduce.
Shellfish
Shellfish
harvesting is a popular recreational activity here in the Pacific Northwest.
Manila clams, butter clams, littlenecks, geoducks, horse clams, and
oysters are all popular seafood fare and can be found at or below the
surface of a mud flat at low tide. These species of shellfish are also
important to the economy of the Northwest Straits as many are harvested
for commercial profit.
Fish
In
recent years, the state of salmon populations has become an important
issue in the Northwest Straits. The public attention given to the needs
of salmon, can sometimes overshadow the needs of other species of fish
which are equally important to the Northwest marine ecosystem. Such
species of fish are generally grouped into two categories, baitfish,
sometimes called forage fish, and groundfish or bottomfish. These species
of fish are important members of the marine food web.
Forage Fish
Ling Cod
Flounder & Sole
Rockfish
Pacific Sand Lance
Surf Smelt
Marine Mammals
Marine
mammals are often a favorite for people visiting the shoreline. Local
marine mammals include seals, sea lions, porpoises, dolphins and whales.
Such large animal species are easy to recognize and can be quite entertaining
to watch!
Marine Birds
Over
100 species of marine birds make Puget Sound their home during some
portion of the year. Waterfowl, seagulls, shorebirds, wading birds
and raptors are just a few of the types of birds we find near our local
waters.
Shrimp and Crab
Marine
crustaceans like shrimp and crab are common organisms in Puget
Sound. Dungeness crabs are the popular choice for recreational
and commercial harvesters in Puget Sound.
Substrate
Substrate
in the intertidal region provides a bed of sediment for marine vegetation
to grow in. It also provides a home for many marine invertebrates including
clams, oysters, crustaceans and marine worms that live within the sediment
or among the rocks.
Invasive Species in Puget Sound
Organisms that are not native to an area can become invasive species. Non-native species may be intentionally or accidentally introduced to an area. These species do not always survive in their new environments, but those that do survive and reproduce may change the ecosystem in a number of deleterious ways including:
- Introduction of new diseases
- Competition with native species for food, light, and living space
- Predation on native species
- Hybridization with native species
For more information about marine nuisance species visit these Washington Department of Fish and Wildlife (WDFW) links to:
Aquatic Nuisance Species
http://www.wa.gov/wdfw/fish/ans/ans1.htm
Washington State Aquatic Nuisance Species Management Plan http://www.wa.gov/wdfw/fish/nuisxsum.htm
Species of Concern http://www.wa.gov/wdfw/fish/ans/wa_speciesofconcern.htm
- Spartina
- European Green Crab
- Eurasian Water Milfoil
- Purple Loosestrife
- New Zealand Mudsnail
- Rusty Crayfish
- Red Swamp Crayfish
- Chinese Mitten Crab
- Zebra Mussel
- Purple Varnish Clam
Green Crab
http://www.wa.gov/wdfw/fish/ans/greencrab.htm