Protect Ocean Habitats
Overview
Vibrant and beautiful corals, sponges, and other invertebrates create three-dimensional structures critical to supporting healthy fish populations by providing the habitat needed for fish to breed, feed, and grow. Some can take hundreds or even thousands of years to grow yet can be damaged or destroyed by a single pass of a trawl.
Oceana wins policy victories that protect these and other important and productive habitats — including seamounts (underwater mountains that rise from the seafloor), deep sea canyons, and rocky reefs — that are central to the health of fish and other marine animals.
Why Ocean Habitats Are Important
Campaign Victories
Campaigning by Oceana and our allies is reducing the impact of destructive fishing techniques on ocean habitats.
Deep-Sea Coral Gardens Protected in California
From polar seas to the tropics, diverse and productive ocean habitats create the foundation for countless marine species to thrive. Marine habitats provide space for marine life to grow, feed, reproduce, take shelter, and thrive. Coral reefs, for example, cover less than 1% of the world’s ocean, yet they are home to at least a quarter of all ocean species. Cold-water corals — similarly delicate, diverse, and colorful — grow thousands of feet below the surface, forming what scientists call coral gardens. Shallow coral reefs and deep-sea coral gardens are essential to the survival of fish, shrimp, crab, and other marine animals, providing critical areas for shelter, feeding, and breeding.
Other habitats play essential roles in supporting healthy ocean ecosystems and marine life:
- Kelp forests are towering structures used by fish, marine mammals, and other species.
- Sea sponges – similar to corals – are living animals on the seafloor that provide places for fish to feed or hide from predators.
- Arctic sea ice supports algae blooms that form the base of the ocean food web, supporting migratory animals like seabirds and gray whales, and the ice is critical habitat for large animals likes ice seals and polar bears.
- Undersea structures like rocky reefs, canyons, and seamounts also provide complex and important ocean habitat for numerous animals.
Some habitats are important to humans too. In addition to providing food, income, and coastal protection for some 500 million people, corals have emerged as a potential source of ingredients for new types of medication that fight diseases like cancer, HIV, Alzheimer’s, and chronic pain.
Kelp Forests
Kelp forests are one of the ocean’s most important ecosystems, home to thousands of species and vast biodiversity. Contrasted with coral, kelp can grow 18 inches a day in the right conditions. Anchored to the seabed, with dense canopies that reach as far as the water’s surface, kelp forests provide shelter for fish and marine mammals, including otters, seals, sea lions, and whales, as well as sea urchins and snails that feast on the fronds. Kelp forests also have a role to play in mitigating climate change, as they are capable of absorbing large amounts of carbon dioxide.
Threats to Ocean Habitats
Bottom Trawling in Alaska
Bottom trawls are large, weighted fishing nets that are dragged along the ocean floor, destroying creatures and habitat structures in their path. Bottom trawl fisheries keep the targeted commercial species and discard a large majority of everything else they catch, including nontargeted fish and animals — virtually all of them dead or dying.
When disturbed by bottom trawling, up to 90% of a coral colony dies, and up to two-thirds of sponges are damaged. Deep-sea corals and sponges, some of the oldest animals on Earth, grow at the rate of just a few millimeters each year, meaning even a single pass of a bottom trawl can flatten centuries of growth.
Deep-Sea Mining
Growing demand for rare metals is driving interest in mining the ocean floor. This destructive process involves using underwater vehicles to dredge the seabed, damaging habitats, and then pass mined materials to the surface, where the resulting sediment is dumped back into the water column to settle on bottom-dwelling sea life.
Climate Change
As a result of human-produced carbon-dioxide emissions, the oceans are now 30% more acidic than they were prior to the Industrial Revolution. That makes it harder for corals and other marine calcifiers — organisms that draw calcium carbonate from the surrounding seawater to build shells and skeletons — to build and maintain their rigid structures.
Recent studies on the growth rates of tropical corals have found that if concentrations of carbon dioxide reach 560 parts-per-million (twice pre-industrial levels), coral reefs and gardens around the world will stop growing and begin to erode. To put that in perspective, we are currently at around 420 parts per million, meaning we are more than halfway to this tipping point. Given the current rate of greenhouse gas emissions, we’ll reach this level of atmospheric carbon dioxide around the middle of this century.
Another climate change–driven threat to habitats is destruction by increasingly violent storms caused by higher ocean temperatures.
Take Action to Protect Precious Ocean Habitats
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Help Protect Corals in the Gulf of Alaska
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Save Our Oceans from Deep-Sea Mining
How We Can Protect Ocean Habitats
Oceana has developed a management approach that protects living seafloor habitat while maintaining vibrant fisheries for healthy, sustainable ocean ecosystems:
- Use all available scientific information to map existing habitats.
- Protect all areas not currently trawled to prevent expansion to new pristine areas.
- Identify important areas within any existing trawl areas and protect those special habitat areas.
- Identify seafloor structures where corals, sponges, and other invertebrates flourish, but where commercial take is low, and close these areas to trawling.
- Set limits on trawl bycatch of corals and sponges.
- Use seafloor mapping, research closures, regional onboard observers, and vessel monitoring systems to monitor the effectiveness of these protections.
- Identify potential habitat impacts from other fisheries like “midwater” trawling that may still contact the seafloor, and ensure those fisheries stay out of habitat protection areas.
Frequently Asked Questions
Q: What are corals?
A: Though some corals resemble plants, they’re actually animals. Broadly speaking, there are two types: hard corals are made up of jellyfish-like polyps that secrete calcium carbonate to form stony “skeletons” for support (reefs are accumulations of multiple hard corals); soft corals are flexible and plant-like, using tiny internal needles to cling to surfaces.
Both types can grow in shallow or deep water, and in warm or near-freezing temperatures. About two-thirds of all corals can be found in deep, cold water along continental margins, seamounts, undersea canyons, and ridges.
Q: How long can corals live?
A: Like California’s redwoods, deep-sea corals can live to be hundreds to thousands of years old.
Q: What is a sea sponge?
A: Sea sponges are plant-like animals that grow slowly (millimeters per year) and can live for hundreds of years. Sponges can be soft or hard. Soft sponges have an internal “skeleton” made of proteins, while hard sponges form a rigid skeleton using calcium carbonate (similar to hard corals) — or, in the case of “glass” sponges, silica — from the surrounding seawater. Sponges are often found growing alongside corals.
Q: Which fish species live in coral gardens?
A: In the cold waters of the Northeast Pacific, corals (and sponges) provide habitat for many types of animals like rockfish, flatfish, Atka mackerel, golden king crab, shrimp, Pacific cod, and sablefish. Other coral garden residents include sea stars, nudibranchs, octopuses, snails, crinoids, basket stars, and anemones.
Q: Where do corals grow?
A: There are thousands of species of coral distributed globally. Some corals grow in shallow tropical seas while others grow in the cold deep-sea far beyond the reaches of sunlight. Cold-water corals live at depths ranging from 30 feet to more than 10,000 feet in the Pacific and Arctic, from the Bering Sea to Southern California, and in the Atlantic Ocean from New England to the Gulf Coast and Caribbean. Shallow reef-forming corals prefer warm ocean waters between the Tropics of Cancer and Capricorn down to roughly 100 feet, however, some reef-building coral ecosystems can grow as deep as 500 feet.
Q: Why is bottom trawling bad?
A: Bottom trawling is a type of fishing where huge nets are dragged for miles along the seafloor to catch flatfish like flounder or sole. But trawl nets also destroy ancient corals and other important habitats, as they catch everything in their path. This habitat destruction has cascading impacts on fish and other sea life, ultimately threatening ocean ecosystems.
As a direct result of Oceana’s campaign efforts, more than 2.9 million square kilometers of ocean waters in the U.S. Pacific, Arctic, and Atlantic oceans are protected from destructive bottom trawling.
More About Fragile Ocean Habitats
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