Dear all, My colleagues and I are happy to share with the MARMAM Community our two companion papers on *Sperm whale (Physeter macrocephalus) acoustic ecology at Ocean Station PAPA in the Gulf of Alaska*, published online in Deep Sea Research Part I <https://www.sciencedirect.com/science/journal/09670637>. *- Part 1 investigates the seasonality in sperm whale occurrences* DIOGOU, N., PALACIOS, D. M., NIEUKIRK, S. L., NYSTUEN, J., PAPATHANASSIOU, E., KATSANEVAKIS, S., KLINCK, H., (2019). *Sperm whale (Physeter macrocephalus) acoustic ecology at Ocean Station PAPA in the Gulf of Alaska – Part 1: Detectability and seasonality.* doi: https://doi.org/10.1016/j.dsr.2019.05.007 *Abstract* Sperm whales *Physeter macrocephalus* produce loud, stereotypical click sequences and are an ideal species to be studied with passive acoustic techniques. To increase our limited knowledge of sperm whale occurrence patterns in remote and inaccessible locations of the North Pacific, we analyzed a five-year-long (June 2007–April 2012) acoustic data set recorded at Ocean Station PAPA (OSP; 50°N, 145°W) in the Gulf of Alaska (GOA). Firstly, we assessed the sperm whale detection performance of the Passive Aquatic Listener (PAL), and secondly, we investigated temporal patterns of sperm whale presence at OSP. The PAL proved highly efficient, with above 50% probability of detecting more than two sperm whales, a condition met for over 50% of the recordings. Results indicated that sperm whale clicks were recorded year-round, with a clear seasonal pattern. The number of detections during the summer months was approximately 70% higher compared to winter. An ambient noise analysis showed that differences in detection rates were likely not driven by seasonal changes in ambient noise levels. The average propagation range of sperm whale clicks ranged between 7 and 8 km between summer and winter, with slightly decreased detection distances observed in winter. Seasonal shifts in the intensity of the Alaska Current and the latitudinal oscillations of the North Pacific Transition Zone results in changes in water mixing, transport of nutrients and the concentration of prey such as squid, which likely drives sperm whale distribution. The manuscript is available for download at: https://www.sciencedirect.com/science/article/pii/S0967063718302577 *- Part 2 assesses and explains the sperm whale oceanographic preferences * DIOGOU, N., PALACIOS, D. M., NYSTUEN, J., PAPATHANASSIOU, E., KATSANEVAKIS, S., KLINCK, H., (2019). *Sperm whale (Physeter macrocephalus) acoustic ecology at Ocean Station PAPA in the Gulf of Alaska – Part 2: Oceanographic drivers of interannual variability*. doi: *https://doi.org/10.1016/j.dsr.2019.05.004 <https://doi.org/10.1016/j.dsr.2019.05.004>* *Abstract* Understanding top predator responses to environmental variability is key to assessing potential impacts of global warming on marine ecosystems. However, tracking environmental changes and their effects across multiple trophic levels up to predators can be difficult. Here, we related the interannual (2007–2012) acoustic occurrence of sperm whales (*Physeter macrocephalus*) at Ocean Station PAPA (OSP), in the offshore Gulf of Alaska (GOA), to environmental drivers within an explicit time-series modeling framework. In a model based on a combination of *in-situ* and remotely sensed variables, ocean heat content (HC), meridional current (V), eddy kinetic energy (EKE), strength of the permanent pycnocline (maxBVF), sea surface temperature (SST) and SST standard deviation (SSTsd) explained 51% of the variability in sperm whale presence, indicating a positive relationship between sperm whale occurrence and increased ocean heating, vertical stratification, and circulation. Sperm whale detections were anomalously high in summer 2010 and winter 2011, and anomalously low at the end of summer and winter 2008, and spring 2011. Results suggest these strongly anomalous detection events reflect a response to El Niño–Southern Oscillation (ENSO) events, with an 8-month lag. In the study area, El Niño leads to a stronger permanent pycnocline, a weakening of the Alaska Gyre, a northward expansion of the North Pacific Subarctic Frontal Zone, and a prevalence of offshore mesoscale eddies, likely favoring the abundance of squid and their predator, the sperm whale. The overall results are consistent with a scenario of increasing sperm whale occurrence at high latitudes under increased ocean warming. The manuscript is available for download at: https://www.sciencedirect.com/science/article/pii/S0967063718302589 Please do not hesitate to contact me (niki.diogou <https://lists.uvic.ca/mailman/listinfo/marmam> at gmail.com) with any comments or questions. Enjoy, Niki -- Niki Diogou, PhD *Acoustic Ecology* University of the Aegean, Department of Marine Sciences Oregon State University Research Collective for Applied Acoustics (ORCAA) Hellenic Center for Marine Research, Department of Oceanography *+593 996084868*