Data Associated With Algal Toxin Testing of Common Murres (Uria aalge) and Forage Fish in Alaska, 2015–2017

Seabird Tissue Collection. During a large-scale die-off event of Common Murres in 2015–2016, we collected beach-cast carcasses from multiple locations across the Gulf of Alaska. As reference samples, we collected tissues from apparently healthy Common Murres and Black-legged Kittiwakes during the preceding and following summers. For seabird carcasses, we analyzed samples of breast muscle, liver, upper gastrointestinal contents (stomach contents and/or entire stomach and gizzard), and cloaca (entire cloaca and/or cloacal contents) for saxitoxin and domoic acid. From healthy, live-captured birds we analyzed feces and regurgitant (partially digested food stored in their proventriculi).

Forage Fish and Marine Invertebrate Collection. Forage fish and marine invertebrates were opportunistically collected during the summers of 2015–2017 in Cook Inlet and Prince William Sound to evaluate potential sources of saxitoxin and domoic acid in the food web relevant to marine consumers.

Saxitoxin Extraction from Tissues. Seabird tissues and whole forage fish and invertebrates were extracted for saxitoxin analysis using the procedure of Lawrence et al 2005 and stored at -20 ºC until ready for analysis. Optimally, 5 g of sample is recommended for the assay, but it was not always possible to obtain this much material from seabird and forage samples in this study.

Saxitoxin ELISA Assay. We used the Abraxis STX microtiter plate assay (Abraxis LLC, Warminster, PA) to test seabird, forage fish, and marine invertebrate samples for saxitoxin. We followed the manufacturer’s protocols with minor modifications. Extracts were diluted 1:250 instead of 1:1000 as recommended for shellfish samples. Final absorbance of the standard curve and samples were measured at 450 nm on either a ClarioStar spectrophotometer (BMG Labtech, Cary, NC) or an Emax Plus microplate reader (Molecular Devices, San Jose, CA).

Saxitoxin HPLC Assay. Samples estimated to contain >7 µg/100 g by ELISA were analyzed by HPLC using the standard method of Lawrence et al 2005. The standards/toxins analyzed were: dcGTX2,3; C1,2; dcSTX; GTX2,3; GTX5; STX; GTX1,4; and NEO.

Domoic Acid ELISA Assay. Samples were screened for the presence of DA using the commercially available ELISA kit manufactured by Biosense Laboratories (Bergen, Norway) or the DAK-36 Domoic Acid test kit (Mercury Science, Inc., Durham, NC) following the manufacturer’s protocol. Results were read at 450 nm on a spectrophotometer (Litaker et al 2008).