Point Sampling Data for Eelgrass (Zostera marina) and Seaweed Distribution and Abundance in Bays Adjacent to the Alaska Peninsula-Becharof National Wildlife Refuges, Alaska, 2010

We performed boat-based sampling at Chignik Lagoon from 15 to 23 June and in Mud Bay from 24 to 27 June in 2010. Survey points were distributed across each of these bays using a systematic random design and accessed by boat using a global positioning system (GPS) unit. We sampled points by snorkeling in dry suits during high tide. At each point, we measured water temperature and depth, salinity, substrate type and depth, and water clarity as determined with a 20 cm-diameter Secchi disk. We assessed percent cover of eelgrass and seaweeds within four, 0.25 m2 quadrats that were spaced approximately 5 m apart in cardinal directions around the point.

To determine annual aboveground biomass of eelgrass in each bay we collected shoots from 6–22 calibration quadrats taken at the entrance of the bays and across tide heights. We estimated percent cover (BB score; Braun-Blanquet 1972) and collected all eelgrass shoots within each quadrat, removed dead leaves and below-ground parts of the plant, and selected 3–10 representative shoots that were later measured for shoot length (meristem to tip of longest leaf) and leaf width (mm). We then dried entire samples to constant mass and weighed them to determine biomass per quadrat, which was scaled to grams per square meter.