Eelgrass and Kelp Play Vital Role in Coastal Ecosystems, Communities—but Face Diverse Threats

Underwater vegetation that sustains marine life and reduces the effects of climate change needs protection 

See How At-Risk Vegetation Supports Coastal Ecosystems
The Pew Charitable Trusts

Eelgrass and kelp are crucial components of healthy and productive coastal ecosystems. They nurture commercially and recreationally important fish and shellfish, absorb climate-warming greenhouse gases, improve water quality, and help protect coastlines from increasingly frequent and severe storms.

But like other submerged aquatic vegetation, eelgrass and kelp are threatened by pollution, dredging, shoreline development, warming waters, and rising seas. For example, eelgrass in California’s Morro Bay has declined 90% since 2007. West Coast kelp forests also have been decimated by the loss of sea stars and a corresponding explosion in the number of purple sea urchins—a voracious kelp predator—in recent years.

The Pew Charitable Trust works with decision-makers, managers, Tribes, and ocean stakeholders to protect and restore eelgrass, kelp, and other submerged aquatic vegetation for the future of marine fisheries, wildlife, and the coastal economies that depend on them.

Eelgrass meadows are found in estuaries, bays, and shallow nearshore areas. They provide habitat for microorganisms such as plankton—an essential part of the ocean food web—and nursery areas for Pacific herring, Dungeness crab, and salmon.

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Eelgrass provides many benefits to coastal ecosystems and communities.

Eelgrass provides foraging, nursery, and spawning habitat for important marine and estuarine species, and the National Oceanic and Atmospheric Administration (NOAA) has designated it as “essential fish habitat” for species such as salmon and groundfish.

Eelgrass stabilizes shorelines, protects coasts from storms and floods, and helps clean water by filtering sediments.

Eelgrass sequesters climate-warming carbon from the water and air in its leaves, roots, and underlying soils, and reduces ocean acidification—which inhibits shellfish growth—in surrounding waters.

Eelgrass supports fish and shellfish that are vital first foods for Indigenous communities and are critical to commercial and recreational fishing.

Eelgrass faces threats related to human activity and changing ocean conditions.

Structures such as docks and piers block the sunlight that eelgrass needs to grow and thrive.

Excess nutrients, toxins, and sediment in runoff from wastewater and other sources smother eelgrass beds. Oil spills and other pollution kill marine life and harm nearshore ecosystems, including eelgrass.

Sea level rise, warming waters, increased sedimentation, and other impacts of climate change are causing eelgrass beds to decline.

Dredging for development and harbor maintenance, as well as shoreline armoring such as seawalls, prevents natural sediments from replenishing coastlines, and exacerbates the effects of sea level rise, all of which can damage eelgrass beds.

Eelgrass provides many benefits to coastal ecosystems and communities.

Eelgrass provides foraging, nursery, and spawning habitat for important marine and estuarine species, and the National Oceanic and Atmospheric Administration (NOAA) has designated it as “essential fish habitat” for species such as salmon and groundfish.

Eelgrass stabilizes shorelines, protects coasts from storms and floods, and helps clean water by filtering sediments.

Eelgrass sequesters climate-warming carbon from the water and air in its leaves, roots, and underlying soils, and reduces ocean acidification—which inhibits shellfish growth—in surrounding waters.

Eelgrass supports fish and shellfish that are vital first foods for Indigenous communities and are critical to commercial and recreational fishing.

Eelgrass faces threats related to human activity and changing ocean conditions.

Structures such as docks and piers block the sunlight that eelgrass needs to grow and thrive.

Excess nutrients, toxins, and sediment in runoff from wastewater and other sources smother eelgrass beds. Oil spills and other pollution kill marine life and harm nearshore ecosystems, including eelgrass.

Sea level rise, warming waters, increased sedimentation, and other impacts of climate change are causing eelgrass beds to decline.

Dredging for development and harbor maintenance, as well as shoreline armoring such as seawalls, prevents natural sediments from replenishing coastlines, and exacerbates the effects of sea level rise, all of which can damage eelgrass beds.

Eelgrass provides many benefits to coastal ecosystems and communities.

Eelgrass provides foraging, nursery, and spawning habitat for important marine and estuarine species, and the National Oceanic and Atmospheric Administration (NOAA) has designated it as “essential fish habitat” for species such as salmon and groundfish.

Eelgrass stabilizes shorelines, protects coasts from storms and floods, and helps clean water by filtering sediments.

Eelgrass sequesters climate-warming carbon from the water and air in its leaves, roots, and underlying soils, and reduces ocean acidification—which inhibits shellfish growth—in surrounding waters.

Eelgrass supports fish and shellfish that are vital first foods for Indigenous communities and are critical to commercial and recreational fishing.

Eelgrass faces threats related to human activity and changing ocean conditions.

Structures such as docks and piers block the sunlight that eelgrass needs to grow and thrive.

Excess nutrients, toxins, and sediment in runoff from wastewater and other sources smother eelgrass beds. Oil spills and other pollution kill marine life and harm nearshore ecosystems, including eelgrass.

Sea level rise, warming waters, increased sedimentation, and other impacts of climate change are causing eelgrass beds to decline.

Dredging for development and harbor maintenance, as well as shoreline armoring such as seawalls, prevents natural sediments from replenishing coastlines, and exacerbates the effects of sea level rise, all of which can damage eelgrass beds.

Kelp forests are one of the most productive marine ecosystems in the world. This canopy-forming algae can grow more than 2 feet a day, absorbing carbon dioxide as it grows and, in some cases, reducing the effects of ocean acidification in surrounding waters. It provides food, shelter, and nursery areas for an array of marine life, including otter, salmon, rockfish, shellfish, sea stars, and other invertebrates.

Kelp supports a healthy ocean and economy.

Kelp provides foraging, nursery, and spawning habitat for many important marine and estuarine species. NOAA has designated areas that contain kelp as critical habitat for several endangered and threatened species.

Nearshore kelp forests provide a valuable buffer against waves, particularly during severe West Coast storms, helping prevent coastal erosion. They also filter excess nutrients from the water.

Kelp forests absorb carbon dioxide from the water and store it over the long term in the ocean floor after the kelp dies. Kelp also produces oxygen and can help reduce ocean acidification in surrounding waters, providing a refuge for important shellfish species such as crab and oysters.

Kelp forests support fish and shellfish that are vital first foods for Indigenous communities and are critical to commercial and recreational fishing.

Kelp faces threats such as overfishing, pollution, and climate change.

Changes in the ocean food web caused by overfishing or climate change can lead to kelp die-offs. For example, the loss of sea stars and other predators in California has caused populations of purple sea urchins, which feed on kelp, to explode, decimating entire kelp forests.

Pollution and sediment from sewage, industrial disposal, and coastal runoff can hinder reproduction and slow growth rates of kelp forests.

Sea level rise, warming waters, increased storm activity, and other impacts of climate change are causing kelp to decline.

Overharvesting, as well as damage from boat propellers and fishing gear, diminishes kelp’s ability to support coastal economies and Indigenous ways of life.

Kelp supports a healthy ocean and economy.

Kelp provides foraging, nursery, and spawning habitat for many important marine and estuarine species. NOAA has designated areas that contain kelp as critical habitat for several endangered and threatened species.

Nearshore kelp forests provide a valuable buffer against waves, particularly during severe West Coast storms, helping prevent coastal erosion. They also filter excess nutrients from the water.

Kelp forests absorb carbon dioxide from the water and store it over the long term in the ocean floor after the kelp dies. Kelp also produces oxygen and can help reduce ocean acidification in surrounding waters, providing a refuge for important shellfish species such as crab and oysters.

Kelp forests support fish and shellfish that are vital first foods for Indigenous communities and are critical to commercial and recreational fishing.

Kelp faces threats such as overfishing, pollution, and climate change.

Changes in the ocean food web caused by overfishing or climate change can lead to kelp die-offs. For example, the loss of sea stars and other predators in California has caused populations of purple sea urchins, which feed on kelp, to explode, decimating entire kelp forests.

Pollution and sediment from sewage, industrial disposal, and coastal runoff can hinder reproduction and slow growth rates of kelp forests.

Sea level rise, warming waters, increased storm activity, and other impacts of climate change are causing kelp to decline.

Overharvesting, as well as damage from boat propellers and fishing gear, diminishes kelp’s ability to support coastal economies and Indigenous ways of life.

Kelp supports a healthy ocean and economy.

Kelp provides foraging, nursery, and spawning habitat for many important marine and estuarine species. NOAA has designated areas that contain kelp as critical habitat for several endangered and threatened species.

Nearshore kelp forests provide a valuable buffer against waves, particularly during severe West Coast storms, helping prevent coastal erosion. They also filter excess nutrients from the water.

Kelp forests absorb carbon dioxide from the water and store it over the long term in the ocean floor after the kelp dies. Kelp also produces oxygen and can help reduce ocean acidification in surrounding waters, providing a refuge for important shellfish species such as crab and oysters.

Kelp forests support fish and shellfish that are vital first foods for Indigenous communities and are critical to commercial and recreational fishing.

Kelp faces threats such as overfishing, pollution, and climate change.

Changes in the ocean food web caused by overfishing or climate change can lead to kelp die-offs. For example, the loss of sea stars and other predators in California has caused populations of purple sea urchins, which feed on kelp, to explode, decimating entire kelp forests.

Pollution and sediment from sewage, industrial disposal, and coastal runoff can hinder reproduction and slow growth rates of kelp forests.

Sea level rise, warming waters, increased storm activity, and other impacts of climate change are causing kelp to decline.

Overharvesting, as well as damage from boat propellers and fishing gear, diminishes kelp’s ability to support coastal economies and Indigenous ways of life.