Doris pseudoargus
A European invader in the Gulf of Maine.
This project began with the discovery of an unfamiliar dorid nudibranch colony during a series of dives in 2017 on Paddock Rock. The site consists of a submerged granite pinnacle that is located southwest of Gloucester harbor, Cape Ann, Massachusetts. The top of the pinnacle begins at ≈5m depth and steeply descends to a depth of ≈24m. The nudibranchs were all found below the thermocline and eating Isodictya palmata sponges which used to be locally common prior to this colonization.
Shortly after the initial observations of the colony, I returned to the site with the assistance of Cape Ann Divers for the purposes of collecting live specimens. Our samples were transported to Larry Harris, invertebrate zoologist, at the University of New Hampshire where he was able to identify the specimens as Doris pseudoargus. The ID was subsequently confirmed via genomic testing. I spent the next 5 years documenting and cataloging each Doris observation I made in southern New England and eventually we published the paper linked in the button below.
Many thanks to Larry Harris, Alan Kuzirian, Terry Gosliner, Samantha Donodoo and the crew of Cape Ann Divers for their efforts on this.
Below are just some of the color morphs I’ve observed in the Cape Ann region throughout the years.
