A manager's guide to using eDNA metabarcoding in marine ecosystems.

Environmental DNA (eDNA) metabarcoding is a powerful tool that can enhance marine ecosystem/biodiversity monitoring programs. Here we outline five important steps managers and researchers should consider when developing eDNA monitoring program: (1) select genes and primers to target taxa; (2) assemble or develop comprehensive barcode reference databases; (3) apply rigorous site occupancy based decontamination pipelines; (4) conduct pilot studies to define spatial and temporal variance of eDNA; and (5) archive samples, extracts, and raw sequence data. We demonstrate the importance of each of these considerations using a case study of eDNA metabarcoding in the Ports of Los Angeles and Long Beach. eDNA metabarcoding approaches detected 94.1% (16/17) of species observed in paired trawl surveys while identifying an additional 55 native fishes, providing more comprehensive biodiversity inventories. Rigorous benchmarking of eDNA metabarcoding results improved ecological interpretation and confidence in species detections while providing archived genetic resources for future analyses. Well designed and validated eDNA metabarcoding approaches are ideally suited for biomonitoring applications that rely on the detection of species, including mapping invasive species fronts and endangered species habitats as well as tracking range shifts in response to climate change. Incorporating these considerations will enhance the utility and efficacy of eDNA metabarcoding for routine biomonitoring applications.

A new species of Alvinocaris (Crustacea: Decapoda: Caridea: Alvinocarididae) from Costa Rican methane seeps.

A new caridean shrimp, Alvinocaris costaricensis, is described from methane seeps in the eastern Pacific off Costa Rica. The new species is the 16th described species of the genus, and by molecular analysis appears closest to Alvinocaris komaii from the Lau Basin, southwestern Pacific, but shares certain morphological characters with A. lusca from the Galapagos Rift and A. muricola from the West Florida Escarpment, as well as with A. kexueae from the Manus Basin in the Southwest Pacific.

Status of Exosphaeromaamplicauda (Stimpson, 1857), E.aphrodita (Boone, 1923) and description of three new species (Crustacea, Isopoda, Sphaeromatidae) from the north-eastern Pacific.

Exosphaeromaamplicauda (Stimpson, 1857) from the west coast of North America is reviewed and redescribed and revealed to be a group of closely related species. A neotype is designated and the species redescribed based on the neotype and topotypic specimens. Exosphaeromaamplicauda is known only from the coast of California, at Marin, Sonoma and San Mateo Counties. Exosphaeromaaphrodita (Boone, 1923), type locality La Jolla, California and previously considered nomen dubium is taken out of synonymy and re-validated. A further three species: Exosphaeromapaydenae sp. n., Exosphaeromarussellhansoni sp. n., and Exosphaeromapentcheffi sp. n. are described herein. Sphaeromaoctonctum Richardson, 1899 is placed into junior synonymy with Exosphaeromaamplicauda. A key to the Pacific West Coast Exosphaeroma is provided.

Genetic utility of natural history museum specimens: endangered fairy shrimp (Branchiopoda, Anostraca).

We examined the potential utility of museum specimens as a source for genetic analysis of fairy shrimp. Because of loss of their vernal pool habitat, some fairy shrimp (including Branchinectasandiegonensis and Branchinectalynchi) are listed as threatened or endangered in Southern California by the United States Fish and Wildlife Service. Management of those species requires extensive population genetics studies and the resolution of important genetic complexity (e.g. possible hybridization between endangered and non-endangered species). Regulations mandating deposition of specimens of listed species have resulted in thousands of specimens accessioned into the Natural History Museum of Los Angeles County that have been preserved in a variety of solutions. We subsampled those specimens, as well as other Anostraca with known collection and preservation histories, to test their potential for genetic analysis by attempting DNA extraction and amplification for mt16SrDNA. Fixation and preservation in not denatured ethanol had a far greater sequencing success rate than other (and unknown) fixatives and preservatives. To maximize scientific value we recommend field preservation in 95% not denatured ethanol (or, if pure ethanol is unavailable, high-proof drinking spirits, e.g. Everclear™, or 151 proof white rum), followed by storage in 95% not denatured ethanol.