Antarctic – cruise ships: permanent traces in depth

They are considered the retreat for rare species as an untouched wilderness far from human influences: the icy waters around the Antarctic continent. About 4,000 species live here on the sea floor, many are unique. But a research team around the marine biologist Matthew Mulrennan has now documented how anchors and chains of ships damage the fragile ecosystem on the bottom of the sea – with deep furrows, destroyed habitats and almost extinct zones.

It was the first time that the effects of anchors and chains on the sea floor in antarctic waters were documented, Mulrennan said. “Although strict nature conservation requirements apply to activities in the Antarctic, the anchoring of ships has so far been almost unregulated.” The founder of the marine protection organization Kolossal was in 2022/2023 with a tourist ship in the region, actually looking for the rare Koloss-Kalmar. Instead, his camera provided the first underwater shots of documented anchor tracks in antarctic waters – now published in the journal »Frontiers in Conservation Science«.

The video recordings were created in 36 places along the Antarctic Peninsula and in front of the island of South Georgia. The researchers found particularly serious damage in the Yankee Harbor, a popular destination for expedition ships. There were deep scratches, shifted sediments, but hardly to see life on the sea floor. On the other hand, the marine ecosystem flourished just a few meters next to the destroyed areas: sponges, seafares, crabs, squids and fish species lived there close to each other. “The observed damage missed almost three huge volcanic sponges,” said Mulrennan. These can live up to 15,000 years old and are among the oldest known animals on earth.

“The anchoring of ships has so far been almost unregulated.”

Matthew Mulrennan Marine biologist

Anchors can be several meters wide and crush everything living on. But often the anchor does not do the greatest damage itself, but the heavy chain that connects it to the ship. It runs across the sea floor and grinds over sensitive habitats. Sally Watson, marine geophysicist at the New Zealand National Institute of Water and Atmospheric Research explains: “We know that the effects of anchors in tropical coral reefs can remain visible over a decade,” said the researcher. “In cold waters, organisms grow significantly slower than in warmer – so I assume that the recreational process will continue to be delayed with increasing geographical width.” She spoke of “the most underestimated environmental threats” for the sea floor – comparable to the damage caused by industrial basic towing networks.

There are no reliable figures-but in the Antarctic season 2022/23 at least 195 ships were spotted in anchorable depths. These included tourism and research ships, fishing boats and private yachts. Experts assume that further ships are traveling in the region without official approval.

Both Mulrennan and Watson demand to include the topic in the regulation of Antarctic trips. Because according to estimates Could quadruple the number of tourists to over 450,000 per year by 2033. Lisa Kelly, managing director of the leading advocacy of the Antarctic travel provider Iaato, told the Australian broadcaster “ABC” that the study was a “snapshot”, the results of which would be shared with responsible committees and working groups in order to further develop the “safe and environmentally responsible company”.

So -called “parking zones” could be considered as solutions for anchors so that all ships moor within defined areas – or alternatively firmly anchored moorings, to which ships can be securely attached. However, the latter would be exposed to extreme weather and driving ice mountains. Some ships are already avoiding anchoring today. Motors and GPS systems keep the ship in position without touching the sea floor.