Worth Saving

More Facts

Roundnose grenadier are not the only extraordinary inhabitants of the deep.


Deep-sea cold-water corals account for two-thirds of all coral species on Earth.

Less accessible and less obviously glamorous than their tropical cousins, they are arguably even more important, supporting up to 1,500 species of fish and providing hugely complex ecosystem services and habitats.

Some cold-water corals are between 5,000 and 8,000 years old and began growing before the great Pyramids of Egypt were built.

These corals began their life at a time when the world’s population was a mere 5—7 million people and agriculture was just beginning to spread its way across Europe.

Cold-water corals grow very slowly and are highly vulnerable. They are the first and most obvious casualties of bottom impact trawling, which literally smashes them to pieces with gear designed for precisely this purpose — levelling all obstructions to protect the nets from harm while harvesting the most fish possible.


Many deep-sea fish species are long-lived and slow to grow. This includes those actively sought by the bottom trawlers as having commercial value.

The orange roughy is a commercially sought species that typically reaches 150 years of age, when left to its own devices.

The oldest land animals don’t come close. The oldest spider recorded lived for 28 years, the oldest dog was 29, elephants will manage around 70 in the wild, the oldest cat was 38, the oldest bird 77. It’s only the giant tortoise that can beat an orange roughy.

The problem with being long-lived and slow to mature (orange roughy don’t reproduce until they’re 23) is that when fish are overfished, stocks are liable to collapse and very slow to recover.


There are more than 100,000 seamounts across the globe (marine mountains over 1,000m in height), which punctuate the deep ocean along with ridges and canyons.

Seamounts provide an important service within the ocean. Migratory species use them like highway service stations where they can stop and refuel. Other species use them as nursery and spawning grounds and they offer a unique habitat to the resident and highly diverse ecosystems that evolve around them.

Seamounts create highly productive islands under the sea, which can be made up of hydrothermal vents, cold-water corals, sponge beds and many other extraordinary marine habitats. They attract and enable such diverse ecosystems because of an upwelling of nutrients that occur around them and which support large swathes of ocean life.

Precisely because of the diversity they support, seamounts are deliberately targeted by bottom impact trawlers, which smash and scrape the sides of the mountain bare in their quest for fish.

Less than 0.001 percent of the world’s seamounts — the equivalent of just one — have been studied in any depth, so when we allow them to be destroyed we do so with no understanding of what will be lost.

All mountains over 1,000m high in England and Wales are protected as National Parks. Seamounts are not.


Marine protected areas (MPAs) are few and far between. For example, the surface area of the Mediterranean Sea is approximately 2,500,000 km2 but protected and managed areas account for a mere 97,410 km² — just 4 percent of the total.

The no-take area of the Mediterranean amounts to around 202 km², or 0.01 percent of the total surface, an area just twice the size of Paris.

Half of all MPAs are poorly managed, and over 75 percent of managers report high levels of illegal activities.

Fragile and unique deep-sea ecosystems are not being protected. The glass sponge Pheronema carpenteri plays a vital role in ocean ecosystems, promoting the abundance and richness of marine animals, but only 2 percent are protected.


Every year some 15 million square km of ocean is bottom trawled — that’s an area bigger than Canada, and one-and-a-half times the size of Europe.

A trawl scar can be 4km long — it would take you an hour to walk along its length, longer to swim it.

A single 1.8 km trawl has been shown to create a sediment plume up to 3—5 million metres cubed, which settles on anything left intact after the trawl is over.

The average trawl releases around 9 million metres cubed of silt — that is a volume of muck that would fill 3,500 Olympic-size swimming pools or the entire Empire State Building.