A New Explanation for Decreasing Penguin Populations

The Lenfest Ocean Program’s Research series has recently released a study which reexamines changes in Penguin populations. While previous studies showed how changes in ice melt have influenced shifts in penguin populations, this study looks at how penguin populations may also be influenced by the availability of their primary prey – krill. The combination of climate change, increased human fishing and rival krill predators significantly influence krill’s availability. Some studies show that on account of this combination of factors the southern ocean’s krill populations have decreased by nearly 80% since the turn of the 20th century. Krill being the penguins’ primary food source, it is necessary to study the link between the two species, in order to better predict the future of Antarctic penguin populations.

The study uses over thirty years of data, focusing on populations of both Adelie and Chinstrap penguin species. The two penguin species have declined by more than 50% in the South Shetland Islands region, over the course of the study. The study suggests that penguin populations more closely track patterns in krill abundance over time. Penguin populations are likely to continue their decline, so long as climate change and krill populations continue their course of change.

This is most alarming for Chinstrap penguins, which breed almost exclusively around the South Shetland Islands. Because they have such a limited range, the combination of diminishing ice due to climate change, and decreasing krill populations in the South Shetlands is especially concerning to Chinstraps, compared to other penguin species which aggregate in multiple regions.

Though humans are not the only factor that is removing krill from the Southern Ocean ecosystems, how we capture krill is one factor over which people do have some control. This speaks to the importance of creating more Marine Protected Areas (MPA) around the Antarctic. While it was a victory to declare the the Ross Sea an MPA, it is necessary that there be more. With more MPAs especially in areas of great krill aggregation, there would also be greater penguin protection.

Cool new pictures from the Ross Sea

Over at the Huffington Post, there's a gallery of pictures taken onboard a ship travelling throughout the Ross Sea as part of a research mission. It's a great reminder of how vibrant the seas around Antarctica are - and how much is going on, scientifically speaking, in a region that is pretty devoid of humans otherwise. Most of us won't ever get to see the Ross Sea in person. But it's still important, because the Ross Sea is the most intact marine ecosystem remaining on earth, according to a 2008 study (Halpern et al.). It's therefore an unparalleled marine laboratory, not to mention a haven for wildlife. There are some who want to take out about half of one of the top fish predators in the Ross Sea, changing the ecosystem forever. This may not wipe out the toothfish population, but it will have consequences. Others like us, however, say that we should set it aside as a marine park- the fish harvested from the Ross Sea is sold for $20 per pound, so no one will go hungry without it. Humanity would lose a lot, on the other hand, if the Ross Sea becomes subject to increasing human interference in the delicate balance of its ecosystem.

We have one last chance to protect one very special place in the ocean. Look at the slideshow and think about what you'd rather have - a few fish filets, or an amazing marine laboratory that can help us understand how to restore damaged marine ecosystems to health?

Creating a Network of Marine Reserves

One of the major issues facing the UN convention on Biodiversity (UNCBD) is the creation of an effective global network of marine reserves. As ASOC colleague Richard Page reported from the recent UNCBD meeting in Japan, while progress is being made in this arena it may not be fast enough to meet the convention’s 2012 deadline.

It is difficult to stress how important this network of marine reserves, or Marine Protected Areas (MPA), is. When the UNCBD comes to an agreement it will be a network of hot spots of great biodiversity, which serve as breeding ground for some of our oceans’ most important creatures and also as precious habitat for many juvenile fishes. The greatest worry is that these biological hot spots are faced with decimation due largely to overfishing. When a bottom trawl, as wide as half the length of a football field, scrapes the sea bottom in these areas, picking up or destroying everything in its path, that area remains scarred and barren of life. Thus it is most important that we stress that the UNCBD push forward and make significant progress in the coming weeks and beyond.

In order to preserve these precious ecosystems, including Antarctica’s Ross Sea, which still remains largely untouched, it is absolutely necessary that such international bodies significantly restrict where destructive fishing practices and other marine industries may be carried out. Beyond the UNCBD it will be interesting to see what progress the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) delegates will make with this issue during their ongoing talks in Hobart, this week and next.