Pioneering ocean floor – new Greenlandic maps can make fishing more efficient and sustainable

Researchers area:

New seabed maps show what’s hidden on the ocean floor with an accuracy of 1 meter and help anglers avoid dangerous rocky cliffs.

Imagine a map that allows anglers to both maximize their fishing efforts and protect unique wildlife and ecosystems. It’s not just a wild dream.

In a new study, we show that we can now create 3D models and maps of the ocean floor in unprecedented detail over large regions, such as Disko Bay. This can ensure long-term sustainable use of Greenland’s valuable marine resources.

It is important for Greenlandic fishermen, our economy and the world. One of the United Nations Sustainable Development Goals – Life Below Water – aims for a healthy ocean where habitats and ecosystems are mapped and protected.

95% of Greenland’s export revenue comes from marine resources – and more than 2/3 of that revenue comes from halibut and shrimp fishing alone.

This is why a thorough knowledge of the seabed environment is crucial for decision-making and sustainable management.

Some facts about our research and our methods

First study: September 2018

Area: Disko Bay, west-central Greenland, 600 km2 (approx. 30 x 20 km)

Equipment: multibeam sonar, benthic video sled and fall camera, grappling hook

Data analyses: water depth, seabed relief, sedimentary environment, benthic megafauna

Data quality: gridded data on a 10×10 m resolution map

Results: Benthic habitat map showing the detailed distribution of two classes of muddy sediments, inhabited by shrimps and three classes of rocky sediments inhabited by attached fauna, such as sea anemones, sponges and corals (examples in picture 2-3)

Relevant literature: Krawczyk et al., 2021, Krawczyk et al., 2019, Krawczyk et al., 2019

What is hiding at the bottom of the sea?

Simply put, seabed habitats. They are crucial for understanding the dynamics of the marine ecosystem and its resources.

Seafloor habitats are distinct areas of the ocean floor that are associated with a particular species or group of species, often occurring together as a community.

These habitats include the natural environment in which the species live which can be described by a specific type of sediment, can be shallow or deep and have a characteristic landscape.

If you are an angler looking for shrimp or Greenland halibut, you know that these species are found in specific conditions, such as certain water depths and sediment types and at a certain distance from land, and these conditions are their habitats.

Every summer, I and other scientists at the Greenland Institute of Natural Resources slowly map Greenland’s seabed, to an accuracy of 1 meter, using our new multibeam sonar (top photo) and a underwater video.

So far we have mapped about five percent of the western shelf of Greenland’s seabed and by 2045 we expect this area to be mapped almost entirely!

Of course, we still have to consider system failures and data gaps, but fortunately these can be modeled and interpolated.

Like looking at the surface of the moon

Can you imagine watching a sudden drop of more than half a mile on your sonar screen in the middle of the night?

Steep cliffs submerged underwater are not only breathtaking, but can also damage bottom gear, and therefore be very risky for bottom trawling or fishing, so we track and map them as “ steep rocky slopes”.

These rocky slopes are also unique habitats for rich colonies of marine animals, such as corals, sponges, sea anemones and their relatives the zoanthids, which can be considered “vulnerable” to trawling (photos below ).

Rocky cliff habitat with sponges and sea anemones.

For me, mapping the seabed is like looking at the surface of the moon, except it’s full of life!

Rocky cliff habitat with zoanthid sponge community.

Rocky cliff habitat with zoanthid sponge community.

Our new detailed maps of the seabed and its inhabitants are intended to improve knowledge and regional development in Greenland. Such an effort is in line with the global sustainability trend towards “good environmental status” of marine resources.

Our new maps could benefit commercial fishing by maximizing fishing effort, while protecting unique areas of vulnerable wildlife and spawning grounds.

Are we ready to bring cutting-edge science to sustainable fishing in Greenland?

The references:

“First High-Resolution Benthic Habitat Map of the Greenland Shelf (Disko Bay Pilot Study)”, JGR Oceans (2021), DOI: 10.1029/2020JC017087

Profile of Diana Krawczyk in English (Pinngortitaleriffik – Greenland Institute of Natural Resources)

Profile of Diana Krawczyk in Danish (Pinngortitaleriffik – Greenland Institute of Natural Resources)

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