Dataset: Sea star catch data: R/V Clifford A. Barnes cruise CB1038

Methodology:

A survey of SSWD was performed in Salish Sea waters 30 – 50m to determine the presence of Sea Star Wasting Disease (SSWD). Asteroids were frozen for later determination of viral prevalence and load of the sea star associated densovirus (SSaDV).  Chlorophyll a concentrations as measured by acetone extracted fluorometry.

Sampling and analytical procedures: 

Benthic dredge operations were performed on board the R/V Clifford A. Barnes during a 5-day cruise from Seattle to Bellingham, encompassing the range of the early (2013-2014) range of SSWD. Dredge operations comprised a 10-minute dredge following the 30 – 50m contour (determined using depth sounder). Dredge materials were emptied on deck, rinsed with flow-through seawater, and then quantified by species of sea star and presence or absence of SSWD. In addition, sympatric echinoderms (holothurians and echinoids) were also quantified. At each station, samples for chlorophyll a (2L surface seawater), virioplankton composition (20L), and sediments (5ml via Van Veen grab) were also taken. In addition, a 5-minute plankton tow (202um 1m net) was performed. After retrieval, asteroids were photographed to document overall size, and if >5 cm arm diameter dissected into constituent tissues (pyloric caeca, gonad, coelomic fluid and body wall). Animals that were < 5cm were frozen as whole animals. 

Chlorophyll a was determined using acetone-extracted fluorometry. Seawater (1L) was filtered over a 25mm diameter GF/A filter, which was then folded and placed into light-impermeable foil, and frozen prior to analysis. The filter was then extracted using 90% acetone (5ml) in 100x13mm borosilicate glass tubes overnight at -20oC. The extract was then quantified using a Turner Designs Aquafluor fluorometer.