Meeting Abstract
Invasive crustaceans, such as Carcinus maenas and Hemigrapsus sanguinaeus, have a significant and detrimental effect on coastal intertidal areas. We performed a 5 year monthly population analysis in a transect in southern Maine and found stable populations of both species, while similar studies in warmer areas report that H. sanguinaeus typically outcompetes and displaces C. maenas. In order to explain the coexistence of both species, the timing of larvae release, and the potential to settle in the intertidal area we performed nearshore plankton collections in close proximity of the intertidal transects. Conventional plankton tows are difficult in shallow nearshore waters, as boats can often not be used. Therefore, we designed a remote controlled boat with a plankton suction device that can be deployed in shallow waters. The plankton suction device is comprised of a 60 cm 4 inch acrylic pipe with a BlueRobotics T100 thruster, 200 µm plankton filter, and a General Oceanics mechanical flowmeter. 3D printed components were made to assemble the individual parts. The plankton suction device was then connected 30 cm underneath a remote controlled boat. This RC boat can be launched from the shore in shallow water and allows for collection of plankton samples in waters poorly accessible by boat based plankton nets. Samples collected with the RC boat-driven plankton sucker, as well as traditional boat deployed plankton nets were analyzed using a FlowCam particle imaging system. There were no differences between both sampling methods. The analysis of planktonic zoea larvae of C. maenas and H. sanguinaeus close to the 5 year transect site is ongoing. Supported by NSF grants MRI-1624984 and IUSE-1431955 to M.F.
