Cryptobenthic crab assemblages are more distinct across a 90 m depth gradient than 2500 km of shallow marine habitat in the Hawaiian archipelago.

Despite high biodiversity and the recognized importance of mesophotic habitats, most studies of coral reef community structure have focused on conspicuous taxa such as fishes and corals in shallow habitat <30 m. Here, we examined the variability of crab assemblages from Autonomous Reef Monitoring Structures deployed on shallow reefs across the Hawaiian Islands and a mesophotic depth gradient on O'ahu. We tested the effects of environmental, ecological, and anthropogenic factors on shallow (8-17 m) crab assemblages.

Plumbing the depths with environmental DNA (eDNA): Metabarcoding reveals biodiversity zonation at 45-60 m on mesophotic coral reefs.

Mesophotic coral ecosystems (MCEs) are tropical reefs found at depths of ~30-150 m, below the region most heavily impacted by heat stress and other disturbances. Hence, MCEs may serve as potential refugia for threatened shallow reefs, but they also harbour depth-endemic fauna distinct from shallow reefs. Previous studies have characterized biodiversity patterns along depth gradients, but focussed primarily on conspicuous taxa (fishes, corals, etc.

Genomic assessment of larval odyssey: self-recruitment and biased settlement in the Hawaiian surgeonfish Acanthurus triostegus sandvicensis.

The gap between spawning and settlement location of marine fishes, where the larvae occupy an oceanic phase, is a great mystery in both natural history and conservation. Recent genomic approaches provide some resolution, especially in linking parent to offspring with assays of nucleotide polymorphisms. Here, the authors applied this method to the endemic Hawaiian convict tang (Acanthurus triostegus sandvicensis), a surgeonfish with a long pelagic larval stage of c.

Skimming for barcodes: rapid production of mitochondrial genome and nuclear ribosomal repeat reference markers through shallow shotgun sequencing.

DNA barcoding is critical to conservation and biodiversity research, yet public reference databases are incomplete. Existing barcode databases are biased toward cytochrome oxidase subunit I (COI) and frequently lack associated voucher specimens or geospatial metadata, which can hinder reliable species assignments. The emergence of metabarcoding approaches such as environmental DNA (eDNA) has necessitated multiple marker techniques combined with barcode reference databases backed by voucher specimens.

Species Radiations in the Sea: What the Flock?

Species flocks are proliferations of closely-related species, usually after colonization of depauperate habitat. These radiations are abundant on oceanic islands and in ancient freshwater lakes, but rare in marine habitats. This contrast is well documented in the Hawaiian Archipelago, where terrestrial examples include the speciose silverswords (sunflower family Asteraceae), Drosophila fruit flies, and honeycreepers (passerine birds), all derived from one or a few ancestral lineages.