Global climate change is and will continue to be one of the defining challenges of the twenty-first century. Human adaptation to changing conditions is difficult enough. However, all the other organisms on the planet will also have to adapt to changing conditions. It is therefore critical to fully understand the biology of these organisms to assure or at least manage their well-being.
Changes in Arctic Sea Ice
Can Beluga Whales and Other Circumpolar Animals Adapt?
Dr. Gregory O’Corry-Crowe of the Harbor Branch Oceanographic Institute at Florida Atlantic University is a global leader in understanding how threatened and endangered circumpolar animals are affected by changes in Arctic sea ice. One of the species his research focuses on is the beluga whale. Belugas are supremely adapted to life in the Arctic.
They are almost entirely white, which minimizes visual contrast against the ice. This has given rise to the alternative name “white” whale. They lack dorsal fins, which facilitates swimming under and pushing through sea ice. Their seasonal migrations may extend over 6,000 km, and recent genetic studies have revealed that migration routes are passed from parents to offspring. When their summer feeding sites are inundated with advancing ice during autumn, they move south to spend the winter in the open sea alongside the pack ice or in areas partially covered by ice.
Beluga Whale Social Organization and Behavior
Genetic Investigations for Insight to Environmental Adaptation
One interesting aspect of beluga behavior is that they are highly social. These Arctic whales can form herds that number in the thousands. Another is that different groups of whales can have very different migration patterns.
Recent satellite tracking of individual whales has revealed much about their seasonal movements and the locations of habitats that are critical to different populations and stocks. However, knowing the familial relationships within and between social groups is necessary to understand how migration patterns are passed between generations and how individuals retain these patterns. A deeper understanding of beluga whale social organization, including who associates and interacts with whom, is critical to understanding how social behaviors may influence their adaptation to a changing environment. In a changing Arctic, it is critical to know who are the animals that blaze new trails, how social learning can spread new behaviors, and what the roles of kinship in behavioral adaptation. Genetic investigations focused on individuals therefore have huge potential for resolving the relationships between behavior, environment, and demographic history.
Capillary Electrophoresis (CE) Analysis
Short Tandem Repeats Through PCR Amplification
The Concept of STR Typing Can Be Applied to Any Species
The standard method for the genetic identification of individuals and familial relationships is short tandem repeat (STR) analysis using capillary electrophoresis (CE). Briefly, this involves PCR amplification of microsatellite regions that contain highly variable numbers of nucleotide repeats. PCR amplification produces a series of differently sized fragments that can be resolved by CE. By analyzing fragments produced across different loci, a distinct genetic fingerprint can be obtained and used to identify individuals with high confidence. STR typing is instrumental in human paternity and forensic analyses, but the concept can be applied to any species that has a set of highly variable microsatellite sequences.
Scientific study of beluga whale behavior is enhanced through the use of Thermo Fisher Capillary Electrophoresis solutions
Applied Biosystems CE Instrumentation for DNA and STR Analysis
Dr. O’Corry-Crowe and his team have formed partnerships with Indigenous communities across the Arctic and sub-Arctic. They have used Applied Biosystems™ CE instrumentation for mitochondrial DNA and STR analysis to track relationships in groups of belugas for more than 15 years. His group has utilized a panel of eight microsatellite loci that are highly variable in belugas [1], and they have recently expanded the marker set to 22 loci. His team travels to areas where belugas migrate and congregate. They then collect biopsies from individual whales and analyze STR patterns to determine the relatedness of individuals within groups. The remote biopsy procedure causes momentary discomfort for a free-swimming whale. In return, the whale provides a tissue sample roughly the size of a pencil eraser, which is enough for a suite of genetic analyses.
Beluga Whale Behaviors Revealed
Extended Lineage Groups and Migratory Patterns
Groups Include Extended Family Links and Unrelated Individuals
Dr. O’Corry-Crowe’s team has made some important discoveries about the behavior of different groups of whales. Unlike other toothed whale species like killer whales, sperm whales, and pilot whales, beluga groups are not strictly matrilineal. There are more extended family links between group members, including paternal links, and links between unrelated individuals [2]. They have found that close relatives within a group do not always associate, but instead associate with another group nearby. In contrast, unrelated whales can spend long periods of time together and cover considerable distances. Sometimes they split up and get together at a later time. Dr. O’Corry-Crowe’s data shows that belugas tend to return to the summer feeding grounds where they are born. They also maintain their entire migratory circuits in regions where there are few geographic barriers to dispersal [3].
Migratory Behaviors and “Cultural” Tendencies
The most important implication of these studies is that beluga whales display cultural tendencies in their migratory behaviors. In other words, entire groups and individuals maintain their migratory patterns [4]. Beluga culture manifests as the development and perpetuation of migratory circuits and the use of traditional feeding areas that benefit all group members. Association between unrelated individuals suggests that culture is perpetuated through learning from others in the group rather than innate wiring at birth.
Can Beluga Whales Adapt Quickly Enough?
Implications of Changes to Ecosystem and Beluga Behavior
Slow Behavioral Adaptation Makes Beluga Whales Vulnerable
This observation has enormous implications for preserving beluga whale populations. The cultural conservatism of beluga whales raises concerns about their adaptability, particularly in times of rapid change. For example, the collective memory of established routes may slow or inhibit the colonization of new areas or the adoption of new behaviors. Local threats, such as the decline of a preferred food source or an increase in human activity, coupled with slow behavioral adaptation to ecological change make this species particularly vulnerable. Minor environmental and ecological shifts in the Arctic can thus have serious impacts on beluga whales. Declining Arctic sea ice is already having a major impact on the distribution of potential prey and predator species, and there has been a dramatic increase in killer whale sightings. The erratic nature of climate change may put belugas at a higher risk of ice entrapment, because seawater can freeze unpredictably and cut off their escape route to open water. As the annual ice cover decreases, humans are gaining access to new areas and disrupting existing beluga whale habitats. For example, the number of vessels used for gas and oil exploration, fishing, and commercial shipping in the Arctic is increasing. Continuance of this trend may increase the risk of injury and death for beluga whales. Coupled with the disruption of migratory patterns, this would be detrimental for entire whale populations.
Humans Also Pay a Price
Beluga Migratory Changes Will Impact Indigenous Communities
Indigenous human communities that depend on beluga whales for cultural and dietary sustenance may also be affected. Traditional hunting rites have been preserved in these communities, and they are sensitive to changes in the behavior and health of whale populations. The disruption of traditional whale migratory patterns will impact these communities as well.
The Power of Genetic Profiling
Capillary Electrophoresis Tools to Help Solve Planetary Problems
Dr. O’Corry-Crowe’s team has just begun to reveal the power of genetic profiling in their research on whales in some of the most remote places in the world. These studies would not have been possible without Applied Biosystems™ genetic analyzers. Gold-standard chemistries, the ease of using the instruments, and the precise nature of the data they generate are fundamental to their work. They have shown how using Applied Biosystems CE tools for genetic studies can help solve some of the most urgent problems related to whale conservation, ecosystem resilience, and the impacts of climate change on wild areas and indigenous communities.
Related: Got Questions? We’ve got answers – FAQs about the Applied Biosystems SeqStudio Genetic Analyzer
References
- Buchanan FC, Friesen MK, Littlejohn RP et al. (1996) Microsatellites from the beluga whale Dephinapterus leucas. Mol Ecol 5:571–575.
- O’Corry-Crowe G, Suydam R, Quakenbush L et al. (2020) Group structure and kinship in beluga whale societies. Sci Rep 10:11462, https://doi.org/10.1038/s41598-020-67314-w.
- O’Corry-Crowe G, Mahoney AR, Suydam R et al. (2016) Genetic profiling links changing sea-ice to shifting beluga whale migration patterns. Biol Lett 12:20160404, https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2016.0404.
- O’Corry-Crowe G, Suydam R, Quakenbush L et al. (2018) Migratory culture, population structure and stock identity in North Pacific beluga whales (Delphinapterus leucas). PLoS ONE 13(3):e0194201, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194201.
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