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Abstract DNA sequences were obtained from 32 blade-formingUlvaspecimens collected in 2018 and 2019 from four islands in the Galápagos Archipelago: Fernandina, Floreana, Isabela and San Cristóbal. The loci sequenced were nuclear encoded ITS and plastid encodedrbcL andtufA, all recognized as barcode markers for green algae. Four species were found,Ulva adhaerens,U. lactuca,U. ohnoiandU. tanneri, all of which have had their type specimens sequenced, ensuring the correct application of these names. Only one of these,U. lactuca, was reported historically from the archipelago.Ulva adhaerenswas the species most commonly collected and widely distributed, occurring on all four islands. Previously known only from Japan and Korea, this is the first report ofU. adhaerensfrom the southeast Pacific Ocean.Ulva ohnoiwas collected on three islands, Isabela, Floreana, and San Cristóbal, andU. lactucaonly on the last two.Ulva tanneriis a diminutive, 1–2 cm tall, high intertidal species that is easily overlooked, but likely far more common than the one specimen that was collected. This study of blade-formingUlvaspecies confirms that a concerted effort, using DNA sequencing, is needed to document the seaweed flora of the Galápagos Archipelago. 

A taxonomy delineates where trust can break down in a probabilistic machine learning workflow that informs critical decisions. 

Seafood mislabeling occurs when a market label is inaccurate, primarily in terms of species identity, but also regarding weight, geographic origin, or other characteristics. This widespread problem allows cheaper or illegally-caught species to be marketed as species desirable to consumers. Previous studies have identified red snapper (Lutjanus campechanus) as one of the most frequently mislabeled seafood species in the United States. To quantify how common mislabeling of red snapper is across North Carolina, the Seafood Forensics class at the University of North Carolina at Chapel Hill used DNA barcoding to analyze samples sold as “red snapper” from restaurants, seafood markets, and grocery stores purchased in ten counties. Of 43 samples successfully sequenced and identified, 90.7% were mislabeled. Only one grocery store chain (of four chains tested) accurately labeled red snapper. The mislabeling rate for restaurants and seafood markets was 100%. Vermilion snapper (Rhomboplites aurorubens) and tilapia (Oreochromis aureusandO. niloticus) were the species most frequently substituted for red snapper (13 of 39 mislabeled samples for both taxa, or 26 of 39 mislabeled total). This study builds on previous mislabeling research by collecting samples of a specific species in a confined geographic region, allowing local vendors and policy makers to better understand the scope of red snapper mislabeling in North Carolina. This methodology is also a model for other academic institutions to engage undergraduate researchers in mislabeling data collection, sample processing, and analysis.