I’m in the Southern Ocean on the Royal Research Ship James Cook. The weather has been amazingly calm for a week, very unusual for this part of the ocean. Last year we had a tremendous storm here with swells of 15m. It’s cold, and during winter the ocean freezes as up to 15 million km2 of winter sea ice forms around the continent of Antarctica. An extreme environment but one where marine life can appear to be abundant to the point of exuberance. Over the last few days we have been surrounded by groups of noisy chinstrap penguins braying to each other and investigating our underwater vehicle when it returns to the surface from the deep. Giant petrels, ranging from a dirty grey or brown to almost pure snow white are gathered around the ship. Delicate blue-grey prions speed around the vessel almost constantly.
Photograph Dr Alex Rogers/IPSO
Most spectacular have been the whales. Humpback whales have visited us several times, swimming around the ship. Sticking their heads out of the water to observe the curious thing on the surface of the oceans, behaviour called spy-hopping. Lolling on their backs and sticking their flukes in the air. The day before we had probably fifty fin whales and other species pass us, all storming south no doubt to rich feeding grounds brimming with pink krill, a small shrimp that forms a critical link in the food chain from microscopic plants (phytoplankton) to whales, penguins and seals. Smaller minke whales have also been seen with distinctive white markings on their flanks, lunging out of the water chasing krill or fish.
Here you can really get a hint of just how bountiful the ocean was in times past. Amazingly I looking at a system that man has severely disturbed in the past. The large whales of the Antarctic were almost all reduced by hunting in the 18th, 19th and 20th centuries to 5-10% of their pre-exploitation population sizes. Antarctic and sub-antarctic fur seals were hunted almost to extinction. Elephant seals were decimated with over 2 million taken from the Scotia Sea region alone. Even king penguins were killed for food and for their oil.
The exploitation did not stop there. In the 1960s and 1970s industrial fishing came to the Antarctic. The fisheries were not regulated and initial catches were huge, amounting to over 2 million tonnes by 1992 in the Atlantic sector of the Antarctic alone and about 3 million tonnes overall, not including fish taken by illegal fishing vessels after the establishment of the Convention for Conservation of Antarctic Marine Living Resources (CCAMLR). Over the initial period of fishing, which occurred during my lifetime, Sub-Antarctic and Antarctic fish stocks were serially depleted and have never recovered. The ecosystem-wide impacts of removal of these fish on their predators, animals like elephant seals, fur seals and penguins is only just now being recognised by scientists. It may be the case that such unrestrained removal of Sub-Antarctic and Antarctic fish stocks have moved these ecosystems into a less stable state where climate change is likely to have far more profound effects on these predators than it would have in a healthy ecosystem.
One other effect of these fisheries has been the by-catch of albatrosses by Sub-Antarctic and Antarctic long liners. The birds are attracted to the baited hooks deployed by fishing vessels and become snared and drowned. As a result of this and other human pressures all of the albatross species we have seen during our trip are in trouble, even though in areas of the Southern Ocean, fishers have adapted their fishing methods to prevent this wasteful slaughter. Scientists estimate the level of danger of extinction of an animal through the Red List, maintained by the International Union for the Conservation of Nature. Under this system wandering and grey-headed albatross are classified as Vulnerable, light mantled sooty albatross as Near Threatened and sooty and black-browed albatrosses as Endangered with extinction.
So, I can only stand here and marvel at the spectacular sites the Southern Ocean still has to offer. However, I do it in the full knowledge that 200-300 years ago this ocean hosted a spectacular abundance of life and is now a shadow of its former self. I cannot perceive what it must have been like, the baseline has truly shifted, the ecosystem has become less stable. What the future holds for Antarctica is uncertain yet this is still perceived by many people as a near-pristine environment in comparison to the oceans elsewhere. This is truly a concern, the oceans are part of the life-support system for the entire planet and we, like almost all other life, are dependent on them.
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