Insights to the genetic structure of Calanus helgolandicus (Calanoida: Copepoda) from deep-sea specimens in the Balearic Sea
Calanus helgolandicus is widely distributed across the northeast Atlantic and Mediterranean, and also found in the Black Sea where it is referred to as Calanus euxinus. Previous genetic studies do not include deep-water specimens despite high abundances at bathypelagic and mesopelagic depths. Our objective is to compare the genetic structure of C. heloglandicus from the deep Balearic Sea to that of coastal populations in the Northeastern Atlantic Ocean, the Adriatic Sea, and the Black Sea defined from previous research. We use a portion of the mitochondrial gene cytochrome oxidase I from 41 individuals of C. helgolandicus collected at 2170 m depth in the Balearic Sea to estimate genetic differentiation between geographic regions and elucidate phylogeographic patterns. Results show that populations do not follow an isolation by distance model. Instead, the lowest genetic differentiation is between two distant basins, the deep Balearic Sea and the Black Sea. The results can be explained by the presence of two types of C. helgolandicus, a coastal, shallow water, type and an oceanic, deep water, type that diapauses at great depths. Genetic differentiation between coastal populations is maintained by oceanographic barriers, while differentiation in oceanic populations is lower due to dispersal by deep ocean currents.
Figueroa, D. F., Cartes, J. E., & Figueroa, N. J. (2019). Insights to the genetic structure of Calanus helgolandicus (Calanoida: Copepoda) from deep-sea specimens in the Balearic Sea. Crustacean Research, 48, 119–132. https://doi.org/10.18353/crustacea.48.0_119