Trans-oceanic kinship in the sperm whale (Physeter macrocephalus)

Area of Science:

• Marine Biology
• Population Genetics
• Evolutionary Biology

Background:

• Oceanic connectivity and dispersal shape marine species' evolution, speciation, and diversity patterns.
• Unlike terrestrial environments, natural dispersal barriers are less apparent in oceans, influenced by factors like oceanography and prey distribution.
• Cetacean species exhibit varied population structures, from highly structured to panmictic, highlighting the need for species-specific research.

Purpose of the Study:

• To investigate the dispersal patterns and potential range of the largest toothed whale species, the sperm whale (Physeter macrocephalus).
• To compare kinship within and among North Atlantic sperm whale populations.
• To utilize whole nuclear genome data to confirm genetic relatedness across geographically distant populations.

Main Methods:

• Comparative kinship analysis within and between North Atlantic sperm whale populations.
• Whole nuclear genome sequencing and analysis.
• Genetic comparison of individuals sampled from the North Sea and the Gulf of Mexico.

Main Results:

• Sperm whales exhibit weak population structure across the North Atlantic.
• Close kinship was confirmed between a male sperm whale from the North Sea and a female offspring pair from the Gulf of Mexico.
• Whole nuclear genome data supports long-distance dispersal and connectivity in this species.

Conclusions:

• The findings suggest extensive dispersal capabilities in sperm whales, potentially spanning the North Atlantic.
• This challenges previous notions of limited connectivity for species with weak population structure.
• Understanding sperm whale dispersal is crucial for effective conservation strategies and managing cryptic diversity.