Blue whales are a conservation dependent species that will easily be threatened by further mortalities. With current human activities posing new threats to this endangered species, the blue whale may not be able to evolve fast enough to keep up with the human changes.
Oceanographic Change: Prey Depletion
The blue whale diet consists primarily of krill, a shrimp-like creature, which thrives in icy waters. Due to anthropogenic climate change, ocean waters have experienced rising sea surface temperatures. Consequently this adversely affects the productivity of the ocean ecosystems, specifically to krill which are sensitive to environmental change. Warmer waters result in significant declines in krill populations. Without an abundance of krill to consume, many marine organisms including the blue whale are forced to change their migratory and distribution patterns in search of sufficient sources of food. In addition to being difficult to sustain without sources of food, changes in distribution affect the reproductive patterns of the blue whale complicating the replenishment of population levels.Habitat Degradation: Physical Injury
With increased human activity in the oceans, whales that approach the surface of the water to feed or for other purposes are vulnerable to physical injury by ship strikes or entanglement in man made objects. Disquieting discoveries of multiple blue whale carcasses found washed up near shores are reportedly becoming common where there is a concentrated amount of ship traffic. In Sri Lanka, six dead blue whales have already been uncovered this year, while some twenty other whale carcasses (including other species) had been discovered last year. Blue whales killed by ship strikes are usually found with severe and massive injuries, often wrapped around the bow of a container ship. Unfortunately marine ecosystems ideal for the survival of blue whales often overlap with areas used as routes for ships - Sri Lanka, a prime example, has one of the world's busiest shipping lanes. The rising threat of ship strikes is another complication, which impedes the recovery of the blue whale.
Habitat Degradation: Noise Pollution
The blue whale is reliant on hearing and projecting sonar calls in order to communicate with other individuals and to navigate through the large expanse of the ocean. There is growing evidence that man-made noise from sources such as high-tech sonar from ships, seismic surveys, and low frequency radio transmissions have a negative impact on the communication and behavioural patterns of blue whales. It is believed that millions of years of evolution of the hearing of blue whales is being undone in a relatively short period of time. Currently, many blue whales have can hear up to 160 kilometres. In contrast to their once acoustic range of 1600 kilometres, this is an alarming change. Scientists at the University of Zurich found that blue whales change their calling behaviour when exposed to the noise of seismic exploration. Their calls carried on for longer and were more frequently than usual. Noise pollution is an alarming detriment to the hearing abilities of the blue whale. Furthermore noise pollution adversely affects the blue whale communication patters, consequently confusing their mating behaviours.