Can you fish without damaging life on the sea bed?

Play Tricky Trawling and learn how to become a sustainable fisher in Greenland!

Did you know that the deep seafloor of Greenland is home to the most amazing creatures? You have certainly heard of corals in the tropics, but in fact, there are also corals in the cold and dark waters of the Arctic! They share their home on and in the seafloor with feather stars, sea cucumbers, flatfish and skates, to only name a few!

In Greenland and many other places, humans catch valuable flat fish such as halibut, and other creatures like prawns that live on the seafloor. To do this we use bottom trawls – large nets with heavy “doors” (weights) that drag over the seafloor. This fishing practice can damage or displace delicate organisms which cannot escape.

Meet the scientists at ZSL

Find out how ZSL’s marine biologists explore the seafloor with their remote underwater cameras.

Our scientists travel to Greenland to find out about the animals living down on the seabed around 1000m below the sea surface and investigate the effects of the trawl fishery on them. Together with their colleagues from the Greenlandic Institute of Natural Resources they go on research vessels, deploying cameras to look at life in the deep sea. These cameras are placed inside strong underwater housings that can stand the high pressure and equipped with bright lights to capture animals in the darkness of the deep ocean.

Dr. Chris Yesson

Research fellow

Dr. Kirsty Kemp

Research fellow

Dr. Mona M. Fuhrmann

Postdoctoral researcher

Stephen Long

PhD candidate at UCL

Species facts


Umbellula seapens are commonly known as sea flowers due to their resemblance to flowers. They can grow more than a metre in hight and live more than 70 years. They can easily get tangled in fishing nets

Photo credit © NOAA Photo Library (2012) NOAA Okeanos Explorer Program.

View Project

Educational materials

Calling all teachers! Are you looking to inspire curiosity and awe in your students for deep-sea conservation?

The following manual was created to help guide you and your students through the main scientific messages found in the Tricky Trawling sustainable fishing video game. It contains key terms, more images, and even ten in-class activities to help bring benthic conservation to life in the classroom!
Our manual is free and entirely open source.
So if you want new and interactive ways of bringing deep-sea science to your students then click to explore below!

Fishing game glossary


The benthic zone (as opposite to the pelagic zone) is the the bottom zone of a lake or an ocean including the surface of rocks, boulders, sand or mud. The organisms that live in this zone (on, in or close to the seafloor) are called benthos.


The variability among living organisms (microorganisms, fungi, plants and animals) on this planet, and the ecosystems of which they are part. Scientists use the term ‘biodiversity’ to refer to the concepts of variation, ecosystems and the interconnectedness (how things are connected) of nature. High biodiversity basically means there are lot of different species in one area. These areas are worth protecting, because they maintain ecosystem function.


The unwanted fish (e.g. sharks) and other marine creatures (e.g. corals or sponges) trapped by commercial fishing nets during fishing for a certain species (e.g. halibut).


Conservation is the protection of animals, plants and natural areas (or entire ecosystems), especially from the damaging effects of human activity such as climate change.

Deep sea

Scientists usually refer to the deep sea as parts of the ocean beyond the continental shelf, others use the term for the marine world below 200 meters of depths, where there is no light left to penetrate the water column.

Demersal/Bottom trawls

These are the types of nets used in bottom fishery. They consist of a net, rockhopper gear (to stop the net being caught on stones), two trawl doors (which hold the net open). Demersal (bottom) trawls used in fishing halibut are very heavy. They are dragged along the seabed and can damage animals living there.


An ecosystem includes all of the living organisms (such as bacteria, plants and animals) in a given area, interacting with each other, and also with their non-living chemical and physical  environment (soil, water etc.).

Filter feeding

Many marine animals are filter feeding, meaning they have tentacles, feathery arms or other projections which can capture tiny plants or animals (plankton) or particles out of the water. In the sea this is possible because the current continuously supplies the animal with food, though in the deep sea there is less food flowing by. Seapens (below) are typical filter feeders.


The type of natural home or environment that the animal, plant, or other organism lives in.


A juvenile is a young person who is not yet old enough to be considered an adult. When we talk about juvenile fish we mean they have not yet reproduced, as opposed to mature fish, which can produce offspring.

Marine protected area

A marine protected area (MPA) may be established to protect animals and ecosystems or sustain fisheries production. Usually these are areas that have high biodiversity, have very rare species or are important breeding areas for some animals. They can vary in size and regulations (e.g. if fishery is restricted or forbidden) can differ between countries.

Floating trawl doors

Also called “semipelagic” trawl doors. These differ from normal trawl doors in the way that they float slightly above the seafloor. Floating trawl doors are better for wildlife as they don’t damage the sea bed as much as much as traditional trawl doors do.


are means by which many governments regulate fishing. The regulator (e.g. the government) sets a total allowable catch (TAC) for the commercial species, typically by weight and for a given time period. Then individual quota (or percentages) are distributed to each of the fishers participating. This is done to prevent overfishing and give the fish time to replenish. This keeps a fishery sustainable for the future.

Sorting mesh

Fishing nets can have selective mesh sizes so that juvenile fish can escape and grow up to adults.

Spawning ground

This is considered as the area where fish or other animals migrate to spawn, which means releasing their eggs.


Sustainable fishing means leaving enough fish in the ocean, respecting habitats and ensuring people who depend on fishing can maintain their livelihoods. A sustainable fishery will for example limit the number of fish that can be caught, leaving enough individuals which can reproduce and try to minimize the negative impacts on other species such as sharks and corals.


The term fish stock usually refers to a particular fish population that is more or less isolated from other stocks of the same species. They can be, but are not always, genetically different from other stocks.

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Photos used on this webpage © NOAA Photo Library