Climate week – How can climate change affect cetaceans?

…Sea temperature rising

….Shifts in current patterns

….Changes in sea ice cover

What about the whales, dolphins and  porpoises??     

All living creatures are finely tuned to their environment, each species presenting unique adaptations which enable it to survive within the particular conditions of its habitat. Any shift in this habitat will force the animal to adapt and change. Some changes may take place immediately, and others will take generations to be observed.

The effect of climate change on cetaceans is a particularly tricky question for a number of reasons. Firstly, cetaceans are situated at the top of of the food chain. This means that they will not only be affected by environmental changes but also by changes that are affecting their prey, and those that affect their prey’s prey and so on… In addition to this, each cetacean species has a complex life history. Some species depend on the year-round presence of sea ice while other’s reproductive cycles are tuned into the amount of available food. Where some species will simply spread north (or south) towards cooler waters, others are stopped from doing so by land. When considering climate change and cetaceans, it rapidly becomes clear that to fully understand the impacts, one would need to consider each species individually.

In broad terms the potential impacts are as follows:

Sea temperature – most species have an optimal range of temperatures for their survival and will seek out water of within this temperature range. This could have impacts in terms of species distribution (and not just for cetaceans). What happens if cetacean species move out of the protected areas that have been established to protect them?

Prey availability – our oceans are going to get more acidic which will negatively impact some species of invertebrates. A decrease in these prey species could affect cetacean distribution and potentially reproductive success.

Sea ice and breathing holes - some species are dependent on the presence of sea ice to survive and some also rely on the presence of breathing holes in the ice. In the last few years, not only has the sea ice retreated but breathing holes have disappeared or moved meaning that animals have become trapped. What will happen if the sea ice retreats enough to allow shipping in these areas? Will these vulnerable species be exposed to the risk of boat strikes and increased noise pollution?

Pathogens and disease - an increase in water temperature may introduce new pathogens into the marine ecosystem. How will cetacean’s immune systems cope with these new diseases?

A lot of research is being conducted in an effort to quantify the impacts of climate change on whales, dolphins and porpoises. Models are being used to calculate how much cetacean’s ranges are going to change and when. As always, the problem is that we don’t know enough about these animals. They are slow to reproduce so we need data sets that span over decades to understand what could happen to them if their habitat was to change.

At Sea Watch, we maintain the National Sightings Database which contains sightings data going back to the 60s. This database is invaluable when considering the long term trends and distribution of whales, dolphins and porpoises. We can find out where they go, when they go there and sometimes what they were doing. Over the years, these data have been collected by all kinds of people ranging from scientists and boat operators to dog walkers on coastal paths around the UK. So join us by contributing your sightings or even setting up your own watch!! To find out how to collect your own sightings and contribute to this database go to our sightings page or click here to find out how sightings are used.

 Find out more about Climate Week go to the SWF Climate Week Page  or www.climateweek.com