Phylogeography and connectivity of thePseudocalanus(Copepoda: Calanoida) species complex in the eastern North Pacific and the Pacific Arctic Region.
The genusPseudocalanus(Copepoda, Calanoida) is among the most numerically dominant copepods in eastern North Pacific and Pacific-Arctic waters. We compared population connectivity and phylogeography based on DNA sequence variation for a portion of the mitochondrial cytochrome oxidase I gene for fourPseudocalanusspecies with differing biogeographical ranges within these ocean regions. Genetic analyses were linked to characterization of biological and physical environmental variables for each sampled region. Haplotype diversity was higher for the temperate species (Pseudocalanus mimusandPseudocalanus newmani) than for the Arctic species (Pseudocalanus acuspesandPseudocalanus minutus). Genetic differentiation among populations at regional scales was observed for all species, exceptP. minutus. The program Migrate-N tested the likelihood of alternative models of directional gene flow between sampled populations in relation to oceanographic features. Model results estimated predominantly northward gene flow from the Gulf of Alaska to the Beaufort Sea forP. newmani. Model scenarios that allowed bidirectional gene flow between sampled populations gave the best Bayesian predictions forP. acuspes,P. mimusandP. minutus. Under current warming trends, biogeographical boundaries and barriers forPseudocalanusspecies may shift, allowing habitat range expansion or contraction and resulting in altered population connectivity between Arctic and sub-Arctic populations.
Institute of Marine Science , University of Alaska Fairbanks , 905 N. Koyukuk Drive , 245 O'Neill Building , Fairbanks , AK 99775 , USA.
Jennifer Marie
JM
Questel
Bermuda Institute of Ocean Sciences-Zooplankton Ecology , St. George's , Bermuda.
Leocadio
L
Blanco-Bercial
Institute of Marine Science , University of Alaska Fairbanks , 905 N. Koyukuk Drive , 245 O'Neill Building , Fairbanks , AK 99775 , USA.
Russell R
RR
Hopcroft
Department of Marine Sciences, University of Connecticut , 1080 SHennecossett Road , Groton , CT 06340 , USA.
Ann
A
Bucklin
Arctic; Pseudocalanus; phylogeography; population connectivity; zooplankton