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Habitat Glossary

Where freshwater meets the ocean. Estuaries are the richest and most productive areas of the coastal environment.  Estuarine mudflats and eelgrass provide a home for tiny invertebrates, which support shellfish, fish, waterfowl, and other wildlife.  Estuarine habitat is especially important for juvenile salmon as they acclimate (smoltification) from freshwater to saltwater.  The length of time juvenile salmon spend  in the estuary varies by species.  Juvenile chinook, chum, and pink salmon can spend from a few days to as long as a month in the estuary, while other species like cutthroat trout generally spend several months before they emerge and enter the open ocean.  Returning adult salmon also use the estuary to reacclimate from saltwater to freshwater before returning upstream to spawn.

Historic dredging, filling, and shoreline modifications in the inner bay over the last 50+ years has seriously impacted the quantity and quality of estuary habitat associated with Squalicum Creek, Whatcom Creek and Padden Creek.  Consequently, restoration of  estuary habitat in inner Bellingham Bay is a priority. 

Eelgrass:  Eelgrass serves a variety of important functions and represents one of the most important marine habitats in the Northwest.  Eelgrass (Zostera marina) is an intertidal-shallow subtidal plant that is present throughout Puget Sound, Strait of Juan De Fuca and Strait of Georgia.  Because of its sensitivity to growing conditions, eelgrass typically grows in only selected shallow marine and estuarine areas. Most growth of eelgrass in the Pacific Northwest is by spreading roots, which eventually creates large colonies of beds (meadows).  Eelgrass grows on muddy, sandy bottoms in the shallow subtidal zone down to about 22 feet, especially in the estuaries and in areas without strong wave action.

Eelgrass provides shelter and protection from predators for many juvenile fish and crab species. Eelgrass leaves and meadows also provide a base for the complex nearshore food web.  Waterfowl, snails and urchins eat the leaves.  Bacteria, fungus and detritus (dead animal and plant matter) form a brown coating on the leaves, which then provides food for small invertebrates (like worms, sea stars and clams).  These invertebrates in turn provide food for fish, crabs and birds.  Eelgrass also provides valuable rearing habitat for many marine animal and plant species along the shoreline.   Herring are especially dependent on eelgrass for spawning (they lay eggs on eelgrass leaves) and protecting their young.  Herring is a major food source for salmon, seabirds, seals and other marine mammals.  When eelgrass leaves die, they provide an abundant food source for bacteria and fungi, helping to start the cycle over again.  Eelgrass is also an important food source for Brant, American Wigeon, Mallard and Northern Pintail.

Eelgrass (Zostera marina) habitat in inner Bellingham Bay have been substantially impacted (200 acres lost) over time as a result of shoreline modifications, historical dredging and filling activities. One of the priority objectives identified by the Habitat Action Team is to restore eelgrass (Zostera marina) habitat in inner Bellingham Bay to the extent possible.    The inner Bellingham Bay eelgrass beds would be restored to support a variety of species, species life history stages, and functions, likely to have been supported by the former eelgrass meadow provided that physical processes needed to sustain eelgrass meadows can occur.

Intertidal: The area between extreme high and extreme low tide levels.  The intertidal area is an interface between the land and water.  The alternate wetting and drying of this area by the tide cycles creates unique and challenging environmental conditions and habitats.  Forage fish species, such as herring, sand lance and surf smelt are small fish, usually nine inches or smaller that spawn in intertidal and subtidal beach gravel and vegetation.  These fish are an important part of the nearshore environment since they are a food source for a wide variety of organisms, including salmon.

A historical analysis of nearshore and intertidal habitat in the Bay indicates that historic filling and shoreline development has resulted in the loss of approximately 300+ acres of aquatic land in inner Bellingham Bay.

Migration corridors / Fish migration barriers or impediments:  Salmon begin their lives in fresh water streams, spend the majority of their lives in salt water, and return to the freshwater gravel beds of their birth to lay their eggs. Salmon spend 40-75% of their lives in the ocean traveling thousands of miles.  Juvenile pink, chum and chinook salmon depend on the shallow-water shorelines of Puget Sound as a migratory corridor where they can feed and find shelter from predators.  A number of shoreline characteristics can either hinder migration or reduce habitat use.  For many aquatic species such as juvenile salmonids, the water itself always provides a migration corridor.  However, the quality of the habitat function (e.g., feeding opportunities) is determined by the characteristics of the shoreline.  For example, steep armored shorelines that are covered by overwater piers provide relatively low quality rearing and refuge habitat. The Habitat Action Team considered means to improve the quality of existing degraded shallow water corridors and preserve higher quality corridors.

Overwater structures:  The lights and shadows from overwater structures such as large docks may scare fish such as herring away from traditional spawning areas.  When juvenile salmon encounter shadows they will leave the shallow-water shoreline to avoid them, making the juvenile salmon more vulnerable to predators in deeper water. Light reduction from overwater structures also impairs the growth of aquatic plants, such as eelgrass.  

Beach restoration: Beaches can be restored by replenishing the fine beach sand and gravel that has been lost over time.  Many of the best beaches and nearshore areas for forage fish spawning have been affected by the existence of manmade structures. Docks and jetties can interrupt the flow of sediments along the shore robbing some beaches of much-needed gravels.  Bulkheads change the way that waves hit the shore.  Instead of wave energy being dissipated as the waves roll up the beach, it hits the bulkhead, causing the wave to turn back on itself.  Over time, this action causes a scouring of the beach, as fine sand and gravels are pulled out with the waves.  The large rocks and hardpan beneath are not suitable for beach-spawning fish such as sand lance. Fine beach sand and gravel are needed by sand lance and surf smelt for spawning, while herring spawn in eelgrass. The loss of fine substrates can also result in the loss of eelgrass beds. 

Beach debris:  Beach debris includes manmade materials such as concrete construction debris, miscellaneous garbage, derelict boats, rogue creosote logs and lumber, auto bodies, metal materials and derelict building materials.

Inner Bay: The shoreline between the Cement Plant Pier and Post Point. 

In-water fills Dredging and filling of the inner Bellingham Bay nearshore area has resulted in the loss of approximately 332 acres of aquatic land.  Most of this loss has occurred within the Whatcom Creek, Squalicum Creek, and Padden Creek deltas.  The historical filling has resulted in net losses of intertidal and shallow subtidal lands within the inner bay.  These historic nearshore and intertidal habitats had physical (e.g., substrate type, elevation, slope, sediment quality, habitat edges) and biological (e.g., eelgrass, emergent marsh, marine/riparian buffer) attributes that supported a variety of fauna (e.g., epibenthos, benthic infauna, zooplankton, macrofauna, sedentary and mobile fish).  Some of these attributes can be restored through removing historic shoreline fills/landfills, remnant structures, treated timber piles, and through recontouring the shoreline. 

Shoreline riparian vegetation:  The riparian area, (the vegetation that borders the waterfront) provides shade near the water’s edge, keeping water temperatures cool for fish.  The vegetation and soil acts as a sponge, stabilizing flows and filtering contaminants.  Branches and leaves that fall from trees provide nutrients for the insects that become food for salmon.  Large pieces of woody debris provide salmon with places to hide from predators.  The roots of riparian vegetation stabilize the soil to prevent erosion.  Removal of this vegetation causes instability, increasing erosion and turbidity.  High turbidity can cause an increase in cloudiness of the water, interfering with the salmon’s vision and their ability to find food and hide from predators.  Suspended sediment can also damage the gills of fish. 

Substrate enhancement:  Substrate is a general term that refers to the surface on or within which organisms live.  Different kinds of substrate provide habitat for different kinds of marine life.  Larger materials such as cobble provide habitat for macroalgae and provide cover for fish and invertebrates; coarser grain sand and gravel can provide surf smelt and sand lance spawning areas; finer grained substrates can provide epibenthic habitat.  

Target species:  The Habitat Action Team identified the following target species with the acknowledgement that if habitat preservation and restoration opportunities are directed toward the needs of the target species, the preservation and restoration would also benefit the needs of other aquatic resources (e.g., epibenthic zooplankton, benthic infauna). 

This page last updated Friday May 27, 2011