G'day all, Just to introduce two new publications to come out of the NP lab in a bit of a flurry towards the end of the year. Feel free to contact any of the authors for further details, and for those of us who cannot attend the conference in San Francisco this year due to Antarctic fieldwork commitments, wishing you a Merry Xmas :) The first is not 'exclusively' marine mammal-focused, but utilizes hydrographic data collected by CTD-SRDL instrumented southern elephant seals to provide fine-scale three-dimensional habitat data for two other diving predators: A.D. Lowther, C. Lydersen, K.M. Kovacs. (2015). A sum greater than its parts: merging multi-predator tracking studies to increase ecological understanding. Ecosphere 6(12). Abstract. Understanding how animals find prey in heterogeneous environments is a central goal of ecology. Placing this process in an environmental context requires a lot of information regarding the characteristics of both the habitat selected by the animal and its surroundings. In high-latitude marine systems, information about subsurface habitats of marine predators is often very limited. Animal-borne oceanographic instruments have added a new modality to improve our understanding of marine predators and their habitats. While these instruments do not collect environmental information beyond that experienced by the animals carrying them, our study makes use of an oceanographic dataset collected by southern elephant seals (Mirounga leonina; N 1⁄4 15), to provide environmental context for two sympatrically foraging penguin species in the waters close to the subantarctic island of Bouvetøya. The seals collected 154 CTD profiles during the study period, averaging 4.9 (63.67 ) profiles per day, documenting the stratification of the upper water layer in terms of both seawater density and temperature. Using these data, we quantitatively describe the relationship between the diving behavior of the penguins (N 1⁄4 3,745 dives) and the hydrographic properties of the three-dimensional area in which they were foraging. Both penguin species appeared to favor water characterized by a shallow mixed layer. The chinstrap penguins (Pygoscelis antarctica) dove within a shallow, unstable body of water close to the colony, whereas macaroni penguins (Eudyptes chrysolophus) exploited the bottom of the surface mixed layer further offshore. The hydrographic properties preferred by the penguins match closely those that describe the highest densities of their preferred prey, krill (Euphausia superba), identified during a temporally and spatially concurrent study. We demonstrate how merging multiple telemetric data streams from animals can shed new light on aspects of foraging behavior beyond simply relating movements to two-dimensional, remotely sensed measurements of the environment. The second provides an empirical test of the accuracy of VHF telemetry data in determining the haulout behavior of Antarctic fur seals: Lowther, A.D., Ahonen, H., Hofmeyr, G., Oosthuizen, W.C., de Bruyn, P.J.N., Lydersen, C., Kovacs, K.M. (2015). Reliability of VHF telemetry data for measuring attendance patterns of marine predators: a comparison with time-depth recorder data. Marine Ecology Progress Series 538: 249-256. ABSTRACT: Very high frequency (VHF) radiotelemetry data has been used for over 30 yr to monitor the behavior patterns of otariid seals. These data have been used in a wide variety of ways, from characterizing the reproductive and foraging ecology of these species to inferring ecosystem changes based on variation in attendance patterns. Yet the accuracy of VHF data has never been appropriately evaluated. Our study compares VHF data collected on 16 lactating Antarctic fur seals to assess onshore attendance with concurrently collected time depth recorder (TDR) data used as the 'true' measurement of time spent onshore. Within the retrieved datasets, 25% of the VHF data could not be interpreted with any reliability. Additionally, there were significant differences in the number and duration of attendance bouts between the 2 instrument types, with VHF data overesti- mating attendance bout duration by approximately 8.9 h on average. Importantly, the magnitude and direction of errors between VHF and TDR measurements were not systematic, suggesting that VHF data is an inappropriate method for collecting attendance data. Modelling the raw VHF data in a state-space framework elicited mean attendance durations that were indistinguishable from TDR-derived measurements, suggesting this approach may provide a means to re-examine historic VHF data. However, given the evolution of electronic tags in terms of sophistication, miniaturization, longevity and decreasing cost over the last 30 yr, TDRs are a more appropriate means of collecting attendance data on centrally foraging marine mammals such as otariids.