Antarctic sea-ice low resonates in the ecophysiology of humpback whales.

The past six years have been marked by some of the most dramatic climatic events observed in the Antarctic region in recent history, commencing with the 2017 sea-ice extreme low. The Humpback Whale Sentinel Programme is a circum-polar biomonitoring program for long term surveillance of the Antarctic sea-ice ecosystem. It has previously signalled the extreme La Niña event of 2010/11, and it was therefore of interest to assess the capacity of existing biomonitoring measures under the program to detect the impacts of 2017 anomalous climatic events. Six ecophysiological markers of population adiposity, diet, and fecundity were targeted, as well as calf and juvenile mortality via stranding records. All indicators, with the exception of bulk stable isotope dietary tracers, indicated a negative trend in 2017, whilst C and N bulk stable isotopes appeared to indicate a lag phase resulting from the anomalous year. The collation of multiple biochemical, chemical, and observational lines of evidence via a single biomonitoring platform provides comprehensive information for evidence-led policy in the Antarctic and Southern Ocean region.

Mercury levels in humpback whales, and other Southern Ocean marine megafauna.

Mercury is a known potent neurotoxin. The biogeochemical cycle of mercury in the remote Antarctic region is still poorly understood, with Polar climate change contributing added complexity. Longitudinal biomonitoring of mercury accumulation in Antarctic marine megafauna can contribute top-down insight into the bio-physical drivers of wildlife exposure. The bioaccumulative nature of organic mercury renders high trophic predators at the greatest risk of elevated exposure. Humpback whales represent secondary consumers of the Antarctic sea-ice ecosystem and an ideal biomonitoring species for persistent and bioaccumulative compounds due to their extended life-spans. This study provides the first results of mercury accumulation in humpback whales, and places findings within the context of mercury accumulation in both prey, as well as six other species of Antarctic marine megafauna. Combined, these findings contribute new baseline information regarding mercury exposure to Antarctic wildlife, and highlights methodological prerequisites for routine mercury biomonitoring in wildlife via non-lethally biopsied superficial tissues.

First detection of short-chain chlorinated paraffins (SCCPs) in humpback whales (Megaptera novaeangliae) foraging in Antarctic waters.

Short-chain chlorinated paraffins (SCCPs) are particularly prone to environmental dispersal through long range atmospheric transport. Consequently, they have been detected in biota and environmental matrices at both the North Pole and South Pole. This study shows the first detection of SCCPs in southern hemisphere humpback whales feeding in Antarctic waters. Blubber of specimens stranded along the Australian coastline was analysed and SCCPs were detected in 7 out of 9 individuals. Levels of SCCPs detected in this study were generally low with concentrations up to only 46 ng/g lw. These results were significantly lower than those detected in Northern Hemisphere odontocetes from previous studies, although no reported burdens in northern hemisphere baleen whales are available for comparison. Both the highest level and lowest ( C13. Further investigation is needed in order to evaluate the presence and distribution of SCCPs in the remote Antarctica ecosystem, and delineate longer term environmental consequences of recent inclusion of SCCPs under Annex A of the Stockholm Convention, securing their phase out in ratifying nations.