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Climate change in Beluga whales

Submitted by kheredia on Tue, 10/29/2019 - 16:36

Climate change can create a cascade of effects throughout entire ecosystems. In marine life, communities that rely heavily on biotic and abiotic factors have experienced the effects of rising temperatures in the ocean. Warming of the sea can be detrimental to life in the future, especially for migrants like beluga whales whose habitat is surrounded by seasonally-ice covered waters. This is why researchers have conducted a study spanning over 30 years to collect data and determine if the ever changing sea ice has had an impact on their migrational behavior. From 1974-2014, scientists followed four traditional migratory routes in beluga whales between wintering and summer  areas of the Alaskan and Canadian arctic.

The methods used to monitor the population included genetic data and harvesting data from whale sightings. Tissue samples from a total of 978 whales were collected and DNA was extracted from each sample and screened. Ariel surveys were taken by native hunters and field biologists which determined the annual arrival times during migration. Lastly, ice conditions were examined through passive microwave-derived sea-ice concentration (SIC). Based on the reports, it was revealed that beluga whales migrated to the Chukchi Sea each summer with its peak population in June at Kotzebue Sound, located in the Arctic.

The results from the SIC demonstrated that the varying sea ice conditions, (5.2% in 1997 vs. 83.7% in 2006), did not affect the times that the distinct populations arrived. However, after the year 1983, the occurrence of beluga whales at this location diminished quite dramatically despite two exceptions in 1996 and 2007. Genetic analysis determined that at one point, in 2007, 90% of the whale migrants to Kotzebue sound had been males, thus, suggesting a link between sea ice conditions and migratory behavior which caused them to alter their course. This phenomena also suggests that changes in the ecosystem may affect gender differently. During the years where sea-ice levels were low, orca whales were able to easily maneuver themselves into the Chukchi Sea. This resulted in an increase in predation, which may have been a contributing factor for evasive shifts in beluga migratory patterns.

The data collected from this study indeed proposed a relationship between ice levels and beluga whale migration, though the research may have been flawed. There most definitely are variables that could have skewed the results that was determined. For example, relying on whale sightings alone does not seem to be a strong enough resource for tracking. There should have been another method used to monitor movement: like attaching a gps tracking device to the mammal. In addition to this, it can be difficult to consistently measure sea-ice conditions that vary considerably throughout the year especially if they are due to underlying factors, which may need more research in the future to eliminate these possibilities.

This study was specifically chosen because of its relation to climate change and as an effort to shine some light on future conservation efforts. If the ocean temperature continues to rise and potentially even affect prey availability for beluga whales, it can pose a huge threat for them in the future. Hopefully soon they receive the rightful attention and action will be taken to conserve, and protect this species.