Giant Kelp (Macrocystis pyrifera)

Species · GBIF taxon 5422328

Giant Kelp

Macrocystis pyrifera

Also known as Bladder Kelp, Giant Bladder Kelp

Giant kelp grows at extraordinary speeds of up to two feet per day, anchoring to rocky ocean floors with specialized holdfasts and rising toward the surface on gas-filled bladders. These towering marine algae form dense underwater forests that shelter hundreds of marine species, from sea otters and fish to tiny invertebrates. Their massive fronds absorb vast amounts of dissolved carbon while buffering coastal ecosystems against wave energy.

MarineFast-GrowingKeystone Species

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Licensed reference"Giant kelp (Macrocystis pyrifera), Monterey Bay aquarium, California" by LT&C is licensed under CC BY 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/. · cc-by

—observations

—countries

—peak records

Not EvaluatedConservation status

Key facts

Diet & prey

Photosynthetic (sunlight and dissolved ocean nutrients)

Predators

Purple Sea Urchin
Red Sea Urchin
Kelp Snail

ThreatsOcean warming, marine heatwaves, sea urchin overgrazing, and severe storms

HabitatsSubtidal rocky reefs and cool temperate coastal waters

Life spanUp to 3 years (individual fronds live about 100 days)

Size / weightNot available

Classification

FamilyLaminariaceae
SpeciesMacrocystis pyrifera

Range & activity

Range data is not available yet.

Safe observation

Interaction riskLow

Low
Moderate
High
Very high

Why interaction risk is low: Safe to observe from boats or while diving; strong ocean currents present the primary hazard.

Responsible observation

Diving Etiquette: Avoid pulling on fronds or disturbing holdfasts anchored to rocky seafloors.
Boating Safety: Keep propellers clear of floating canopies to prevent entanglement and plant damage.

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