Genetics Research Initiative

The Genetics Research Initiative uses molecular techniques to advance knowledge of Hawaiian monk seal health, population dynamics and diet.

A recent analysis using DNA and skull morphology (shape, size, and structure) to compare all three monk seal species determined that both the Hawaiian monk seal and the extinct Caribbean monk seal were distinctive enough from the Mediterranean monk seal (Monachus monachus) to warrant them being assigned a new genus "Neomonachus" (New World monk seal). This is significant, as this means that Hawaiian monk seal (Neomonachus schauinslandi) is the sole surviving species in the Neomonachus genus, as the Caribbean monk seal (Neomonachus tropicalis) was last seen in 1952.

The Hawaiian Monk Seal Genetics Research Initiative is overseen by Stacie Robinson, PhD. Research is conducted at the Conservation Genetics/Genomics Laboratory at the American Museum of Natural History Center for Conservation Genetics in New York City.

Further Reading:

Scheel D-M, Slater G, Kolokotronis S-O, Potter C, Rotstein D, Tsangaras K, Greenwood A, Helgen KM
2014. Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology. ZooKeys 409 (2014): 1-33. DOI: 10.3897/zookeys.409.6244

Genetic Research on Hawaiian Monk Seal Health

Genetic differences account for much of the variation observed among individuals, populations, and species. This genetic diversity (or variation) provides the raw material upon which natural selection acts and is important to the health of individuals and population persistence. Species with a rich store of genetic variation are better able to face adversity, whereas those with low genetic diversity are less able to fend off disease and adapt to changes in their environment.

To assess genetic diversity of the Hawaiian monk seal, nearly every seal encountered during population assessment surveys between 1994 and 2007 was genetically profiled. This research found that the Hawaiian monk seal has lower genetic diversity than any other mammal tested to date, including the cheetah, the northern elephant seal and the North Atlantic right whale. The cause of such low diversity remains unknown. Genetic variation was certainly lost during commercial and subsistence hunting of the species in the 19th century, but the duration of this bottleneck was not sufficient to account for such extensive depletion. As a large, insular (island-based) carnivore, it is possible that the Hawaiian monk seal had never existed in large numbers, and thus has always had low genetic diversity. Alternatively, it is possible that the species had been exploited even prior to historical records of harvest.

Even with such low genetic diversity, the Hawaiian monk seal is not doomed to extinction. By the 1950s, the species previously recovered from near extinction in the late 19th century. It remains unknown whether the lack of genetic variation has contributed to the current decline, characterized by high juvenile mortality. Future research will determine whether genetic differences among individuals are linked to survival and reproductive success.

Further Reading:

Schultz JK, Baker JD, Toonen RJ, Bowen BW
2009. Extremely low genetic diversity in the endangered Hawaiian monk seal (Monachus schauinslandi). Journal of Heredity 100: 25-33. DOI: 10.1093/jhered/esn077
Schultz JK, Marshall AJ, Pfunder M
2010. Genome-wide loss of diversity in the critically endangered Hawaiian monk seal. Diversity 2: 863-880. DOI: 10.3390/d2060863

Genetic Research on Hawaiian Monk Seal Population Dynamics

Stock assessment is a valuable management tool that monitors trends in abundance of a species. One important aspect of stock assessment is defining a "stock", a group of potentially interbreeding individuals. To guide the management of the Hawaiian monk seal, it is important to know whether the species is comprised of a single or several stocks. That is, do seals mate only with individuals from their natal (birth) island, or do they interbreed throughout the Hawaiian Archipelago?

By examining the genetic profiles of seals born and tagged in the Northwestern Hawaiian Islands (French Frigate Shoals, Laysan Island, Lisianski Island, Pearl and Hermes Reef, Midway Atoll and Kure Atoll) and in the main Hawaiian Islands, it was determined that genetic differences among seals were not spatially partitioned. This means that seals born at Kure were not genetically distinct from seals in the main Hawaiian Islands or from anywhere in between. This lack of genetic "differentiation" indicates that the Hawaiian monk seal is comprised of a single stock across its entire range.

Such findings have several important management implications. Given these results, it appears that Hawaiian monk seals avoid inbreeding by moving throughout the islands to find unrelated mates. Because seals naturally travel among the islands, human-mediated movement of seals (i.e., translocations) is not likely to result in genetic or adaptive incompatibilities. However, because seals move and mate among islands, there is great potential for infectious diseases to quickly move throughout the entire species.

Further Reading:

Schultz JK
2011. Population Genetics of the Monk Seals (Genus Monachus): A Review. Aquatic Mammals 2011, 37(3), 227-235. DOI 10.1578/am.37.3.2011.227
Schultz JK, Baker JD, Toonen RK, Harting AL, Bowe BW
2011. Range-Wide Genetic Connectivity of the Hawaiian Monk Seal and Implications for Translocation. Conservation Biology, 25: 124–132. DOI: 10.1111/j.1523-1739.2010.01615.x
Schultz JK, Becker BL, Johanos TC, Lopez JU, Kashinsky L
2011. Dizygotic twinning in the Hawaiian monk seal. Journal of Mammalogy 92(2): 336-341. DOI: 10.1644/10-mamm-a-275.1

Genetic Research on Hawaiian Monk Seal Diet

To compliment studies conducted under the Foraging Research Initiative, methods are being developed to determine monk seal diet by identifying prey DNA in monk seal scat (feces). This method may improve the ability to detect prey whose hard parts don't survive the digestive process or are so eroded that identification would otherwise be impossible. Additionally, this method may also provide a finer level of prey identification to the species instead of family level, which in many cases is not possible when using the traditional prey hard parts analysis. Such knowledge will allow scientists to better assess how changes in the abundance of prey species will impact monk seal survival throughout the Hawaiian Archipelago.