1. Predictive species distribution models (SDMs) have become powerful tools to determine habitat use patterns of mobile marine predators and their spatial overlap with potentially impacting anthropogenic activities.2. This study used SDMs to investigate fine-scale habitat use patterns of two poorly known and broadly sympatric coastal delphinids, Chilean dolphins (Cephalorhynchus eutropia) and Peale's dolphins (Lagenorhynchus australis), and their spatial interactions with intense aquaculture farming activities in the Chiloé archipelago, southern Chile. A long-term dataset (2002-2012) of boat-based dolphin sightings and concur-rently in situ collected environmental and anthropogenic variables was analysed using binomial Generalized Additive Models to investigate ecological drivers of each species' fine-scale distribution and to predict dolphin occurrence spatially.4. Chilean dolphins preferred shallow (<30 m deep), turbid waters, close to shore (<500 m) and river mouths which often placed them in sheltered bays and channels used intensively by shellfish farms. Peale's dolphins were also found in shallow waters but occurred over a wider range of conditions along more open or exposed coastlines. Both species had to navigate extensive salmon and shellfish farming sites to transit between areas of important habitat.5. Sightings and predicted occurrence maps showed a clear pattern of spatial habitat partitioning between species, which remained stable across the 11 year study period. The identification of important habitat for Chilean dolphins warrants the consideration of spatially explicit conservation measures to limit the potential effects of overlapping salmon and shellfish farming.6. The observed differences in ecological plasticity of the two sympatric species should be considered when evaluating and mitigating the effects of environmental change and ongoing anthropogenic pressures on their nearshore habitat. The estimated species-environment relationships could also be used to predict where dolphin habitat and anthropogenic activities are most likely to overlap in other parts of the species' ranges.

In this paper, evidence is provided that Chilean dolphins (Cephalorhynchus eutropia) produce ultrasonic echolocation clicks of the narrow-band high-frequency category. Echolocation clicks emitted during approaches of the hydrophones consisted only of narrow-band (rms-BW: 12.0 kHz) single pulses with mean centroid frequencies of about 126 kHz, peak frequencies of 126 kHz, and a 20 dB duration of 82.6 micros. The maximum received level measured exceeded 165 dB re 1 microPa. In addition, high repetition-rate buzzes were recorded during foraging behavior (click interval: 2 ms), but no whistles or calls with tonal components were detected.

Sediment samples from ODP Site 1085 were investigated in order to obtain more information on the initiation and development of the Benguela upwelling system during the middle and upper Miocene. In particular, our intent was to establish the causes of the upwelling as well as the response of the upwelling regime to the development of the Antarctic Circumpolar Current. Based on changes in the calcareous dinoflagellate cyst association, we found an initial increase of the dinoflagellate cyst productivity, probably related to the initiation of upwelling about 11.8 Ma ago. Two distinct increases in cyst productivity in conjunction with temperature decreases of the upper water masses reflect upwelling pulses off Namibia and occur at the end of the Miocene cooling events Mi5 (about 11.5 Ma) and Mi6 (about 10.5 Ma). Both cooling events are associated with an ice volume increase in Antarctica and are thought to have led to an increase in southeasterly winds, possibly causing these two upwelling pulses. We demonstrate a decrease in dinoflagellate cyst productivity and enhanced terrigenous input via the Orange River after the Mi5 event. At about 11.1 Ma, the dinoflagellate cyst productivity increases again. The polar cyst species Caracomia arctica occurs here for the first time. This implies an influence of subantarctic mode water and therefore a change in the quality of the upwelling water which allowed the Benguela upwelling to develop into modern conditions. From about 10.4 Ma, C. arctica forms a permanent part of the association, pointing to an establishment of the upwelling regime.

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