Hypoxia vulnerability in the salmon watersheds of Southeast Alaska.

The frequency of dissolved oxygen depletion events (hypoxia) in coastal aquatic ecosystems has risen dramatically since the late 20th century, yet the causes and consequences of hypoxia for some culturally and economically important species remain poorly understood. In rivers, oxygen depletion can be caused by high densities of spawning Pacific salmon (Oncorhynchus spp.) consuming oxygen faster than can be replaced by reaeration.

Pan-Arctic marine biodiversity and species co-occurrence patterns under recent climate.

The Arctic region is experiencing drastic climatic changes bringing about potential ecological shifts. Here, we explored marine biodiversity and potential species associations across eight Arctic marine areas between 2000 and 2019. We compiled species occurrences for a subset of 69 marine taxa (i.

Application of endocrine biomarkers to update information on reproductive physiology in gray whale (Eschrichtius robustus).

Most of our knowledge on reproductive biology of gray whales dates back to scientific research conducted during commercial whaling in the late 1950s and 1960s. The goal of the present study was to provide updated insights on reproductive physiology of gray whales, using progesterone and testosterone as biomarkers. We measured hormone concentrations using enzyme immunoassay (EIA) techniques in blubber biopsies collected from 106 individual whales from March to November over a span of 12 years (2004-2016) between California and Alaska.

Blubber endocrine profiles provide insights into reproductive biology in blue whales from the eastern North Pacific Ocean.

The goal of the present study was to complement existing data of testosterone and progesterone in blue whale (Balaenoptera musculus) blubber from the eastern North Pacific Ocean to evaluate effects of seasonality and location on these hormones and to better assess reproductive status of individuals. Physiological parameters regarding reproduction are fundamental for describing population dynamics, and hormones can be a valid tool to estimate those for wildlife populations. In this study, blubber tissue was validated for testosterone and progesterone assays.