Seaweeds & Sea Grasses

To follow are some of the species of seaweed that have been observed in Fishing Bay. 
 Look for future updates.

Green Seaweeds (phylum chlorophyta)

Sea Lettuce

(Ulva spp.)

     Look for:  Bright green
                        To 7"  long, broad 
                        Flat, thin single blades
                        Only 2 cells thick
                        Often with ruffled edges 
     Habitat:   On rocks, mid- to low intertidal
    Abundance:  Common, edible

Sea Hair

(Enteromorpha intestinalis)

     Look for:  Bright green to yellowish-white
                        Hollow tubes up to 8" long and 1/4" in diameter
                        Only 1 cell thick
     Habitat:   Dense mats on rocks or free floating clumps,
                         upper intertidal
    Abundance:  Common, edible

Brown Seaweeds (phylum phaeophyta)

Brown Bag

(Colpomenia bullosa)

     Look for:  Light brown
                        Globular form up to 4"
                        Smooth, dimpled, hollow sacs
     Habitat:   On rocks and other algae , mid- to low intertidal
     Abundance:  Common


(Fucus gardneri)

     Look for:  Olive green to yellow-brown
                        Blades to 1/2"  wide 
                        Flattened, forked blades 
                        Some terminal branches swollen and warty 
     Habitat:   On rocks, mid- to low intertidal
    Abundance:  Common


(Sargassum muticum)

     Look for:  Yellowish-brown
                        Flat, leaf-like growth 
                        Short stalk that branches repeatedly 
                        To 6-1/2' tall
     Habitat:   Attaches to rocks or shells, low intertidal 
    Abundance:  Common, non-native, introduced from Japan 

Sugar Kelp

(Laminaria saccharina)

     Look for:  Olive to light brown
                        Large single blades up to 10'
                        May have regular undulations or be smooth 
                        Attaches to substrate with branched holdfast
     Habitat:   On rocks,  low intertidal and subtidal
    Abundance:  Common 

Winged Kelp

(Alaria spp.)

     Look for:  Olive to light brown
                        Blade varies in length from 12" to 8' (most around 6')
                        Characteristic midrib along length 
                        Opposing rows of sporophylls along the stipe just 
                            below midrib forming "wings"
                        Branched holdfast
     Habitat:   On rocks,  low intertidal and subtidal
    Abundance:  Common 
    Comments:  A popular edible
                           Both blade and midrib can be eaten fresh, dried or 

Bull Kelp

(Nereocystis luetkeana)

     Look for:  A large kelp, can reach lengths of 98'
                        Attaches to rocks with holdfast
                        Holdfast supports a single, narrow, cylindrical stipe that
                            gradually increases in diameter along its length
                        A large hollow float (up to 5" in diameter) forms at end 
                            of stipe
                        Two clusters of blades from float
     Habitat:   Low intertidal and subtidal
    Abundance:  Common 
    Comments:  Forms large kelp forests
                            Incredibly fast-growin; reaches mature size in one 
                            Edible, stipe can be made into pickles or salsa, blades
                                can be dried

Red Seaweeds (phylum rhodophyta)

Turkish Towel

(Chondracanthus exasperatus)

     Look for:  Brownish-red to purple, iridescent when wet
                        One or more broad thick blade
                        Edges and flat surfaces can have stiff projections 
                        To 3' long, 12" wide
     Habitat:   On rocks, sub-tidal, often washes up on shore
    Abundance:  Common
                            One of the more common red algae on the Pacific Coast

Dead Man's Fingers

(Halosaccion glandiforme)

     Look for:  Yellowish-brown to deep red
                        Erect sacs standing from to 2-8" tall, 3/4" wide
                        Found in dense clusters, often in distinct bands
                        When sacs are squeezed, a jet of sea water shoots up
     Habitat:   On rocks, mid to low intertidal
    Comments: Often eaten by limpets, provides shelter to amphipods     

Red String Seaweed

(Sarcodiotheca gaudichaudii)

     Look for:  Yellowish-brown to deep red
                        Attaches to rocks with holdfast
                        Stringy round branches emerging from main stem or stipe
     Habitat:   Common in summertime on rocks within sandy- 
                        mud habitats; low intertidal and subtidal
    Comments: Can be eaten fresh in salads

Sea Grasses



Zostera is represented locally by two species,   Z. marina and Z. japonica. 
     Look for:  Dull green leaves flattened in cross-section
                        Usually wider than 1/4", and up to 4' long
                        Blades have 3-7 longitudinal veins
                        Z. japonica has a narrower blade than Z. marina
                        Perennial, overwintering as leafy shoots
     Habitat:   Wave-protected areas, rooted in mud
                        In Fishing Bay, Z. japonica dominates the inter-tidal 
                        region while Z. marina occupies the sub-tidal area
    Comments:   Z. marina  is a native species;  Z. japonica represents 
                        an accidental introduction, perhaps being introduced
                        as packing for Japanese oyster spat.  
Both species provide             
                        important habitat for a variety of  
organisms including 
                        fish and invertebrates.  
Eelgrass's tangled mat of rhizomes 
                        and roots 
stabilizes soft sea bottoms making it a valuable 
                        conservation plant.


Enteromorpha intestinalis

Colpomenia bullosa

Fucus gardneri

Sargassum muticum

Laminaria saccharina


Nereocystis luetkeana

Chondracanthus exasperatus

Halosaccion glandiforme

Sarcodiotheca gaudichaudii

Zostera japonica

Zostera japonica providing habitat for a small limpet