Sanctuary Integrated Monitoring Network
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Species Database

Laminaria setchellii - Setchell's kelp

Setchell's kelp image

Geographic range:

Aleutian Islands, Alaska to Baja California, Mexico

Key features:

It is a stipitate kelp with a large, broad blade that is very smooth but naturally splits into several ribbons. The blade has smooth edges.

Similar species:

Pterygophora californica -- Winged kelp
Eisenia arborea -- Southern sea palm
Pleurophycus gardneri -- Gardner's kelp


bay (rocky shore), exposed rocky shore, kelp forest, protected rocky shore

Primary common name:

Setchell's kelp

General grouping:

Brown seaweed/algae

ITIS code:


Geographic Range

Range Description:

Laminaria setchellii occurs on the Pacific coast from the Aleutian Islands to Baja California, Mexico.

Intertidal Height

Lowest intertidal height:

0 meters OR 0 feet

Highest intertidal height:

25 meters OR 83.25 feet

Intertidal height notes:

Laminaria setchellii can be found in the extreme low intertidal.

Subtidal Depth Range

Minimum depth:

0 meters OR 0 feet

Maximum depth:

25 meters OR 83.25 feet

Subtidal depth notes:

Laminaria setchellii can be found in the upper subtidal.


bay (rocky shore), exposed rocky shore, kelp forest, protected rocky shore

Habitat notes:

Laminaria setchellii lives on rocks in the low intertidal and subtidal. It has been reported to grow optimally between 10 and 15 degrees Celsius. When water temperatures increase to 17 degrees Celsius reproduction is limited.


Relative abundance:

Laminaria setchellii is common.

Species Description

General description:

Laminaria setchellii is a brown algae belonging to the Family Laminariaceae. It was previously known as Laminaria andersonii. It is an understory kelp usually encountered in bands or extended patches on exposed coasts.

Distinctive features:

Laminaria setchelliiís sporophyte is medium to dark brown. It has a thallus that is up to one meter tall and consists of a well branched holdfast of haptera that gives rise to a single, erect, unbranched and somewhat rigid stipe. The stipe supports a flat blade that is divided into several distinctive, narrow straps and is basally rounded to wedge-shaped. Laminaria setchellii is often misidentified as Laminaria dentigera.


Stipe can be up to 80 cm tall and 2-4 cm in diameter.

Natural History

General natural history:

The cross sections of Laminaria setchellii reveal concentric rings deposited annually that can be counted to determine both the ages of individuals and the population structure. Young individuals dominate at exposed populations due to the frequent removal of plants by storms; while more protected areas have evenly spread age classes. Individuals at exposed sites were also found to grow taller and have thicker stipes when compared to individuals of the same age at protected sites.


Herbivores feed on kelp such as Laminaria setchellii.


Laminaria setchellii is photosynthetic, converting the energy of light to the energy of carbohydrate molecules.

Feeding behavior


Feeding behavior notes:


April - September


North American kelps tend to reproduce in the spring and summer. Reproductive blades (sporophylls) are usually apparent during this time.

Monterey Bay National Marine Sanctuary:

None that we know of.
Click on an image below to view a larger version in the SIMoN Photo Library. You will also be able to view important information on each photo such as photographer, date, caption and more.
Mondragon, J. 2003. Seaweeds of the Pacific Coast: common marine algae from Alaska to Baja California. Sea Challengers, Monterey, CA. 97 p.
O'Clair, R.M. 2000. North Pacific Seaweeds. Plant Press, Auke Bay, Alaska. 162 p.