Hoiho tracking: 21 March 2019 – 20 April 2019
Creators: name: Mattern, Thomas
Publisher: name: figshare
Year: 2020
Subjects: subject: 60201 Behavioural Ecology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: Marine Biology
subject: 60205 Marine and Estuarine Ecology (incl. Marine Ichthyology)

description: As penguins all entered the moult phase, no logger deployments occurred in the past month; next deployments are scheduled for the first week of May. The downtime was used to run comprehensive analyses of the recorded data. The post-guard stage of the season 2018/19 started already in early December so that no chick-guard data could be obtained when field work commenced. The data outcome was very limited due to the problems with device recovery and damage as outlined in previous reports. GPS data was obtained for two penguins from the Catlins, one each from Te Rere and Penguin Bay. Foraging ranges between Te Rere and Penguin Bay differed (15.3 km vs 31.0 km) as did foraging trip durations (16.6 hrs vs 32.7 hrs). Dive data was recorded for three birds (2x Te Rere, 1x Penguin Bay). One of the Te Rere birds performed short, evening trips and showed high dive rates (no GPS data recorded); dive profiles suggest that foraged pelagically on 8 of its 9 trips. The other penguin fitted with a device at the same time left on one day trips (16.6 hrs) and foraged predominantly at the seafloor (70% of all dives benthic) which correlates with linear foraging observed (see January 2019 report). The Penguin Bay penguin predominantly foraged pelagically (65%) on its first trip while subsequent trips were characterized by benthic foraging again (see graphs on page 2). During the pre-moult, device deployments occurred at Otapahi, Otago Peninsula (2 birds) and Aramoana (5 birds); except for one of the Aramoana penguins which lost its device package, all loggers were successfully recovered and yielded GPS and dive data. Trip durations differed significantly with Aramoana birds staying at sea for 2-13 days (mean 4.7 days), whereas Otapahi penguins stayed at sea for no longer than three days at a time (mean 1.0 day). This also reflected in foraging ranges (mean foraging range; Aramoana: 33.6 km, Otapahi: 19.2 km). While the overall data outcome from Otapahi was too limited to draw general conclusions, the data sets of pre-moult movements of hoiho from Aramoana provided valuable, new insights. The combined GPS and dive data were used to model the penguins’ habitat use utilizing procedures developed for a comprehensive spatial analysis recently conducted for MPI. <br>Hoiho from Aramoana foraged predominantly over sandy sediment at water depths of &lt;70m (mean water depth: 35 m) between 5 and 30 km from the coast. A particularly frequent area lay 6-12 km off the coast of Karitane and Waikouaiti. Habitat use model indicate an area with a circumference of ca 200 km and an area of 1,750 km² ranging from the tip of the Otago Peninsula to the southern end of Barracouta Bay to be particularly suitable for hoiho foraging. Positions of set net operations between 2009 and 2012 available for this analysis shows a significant overlap with hoiho penguin habitat. Hence, the risk of interactions between fisheries and penguins is substantially higher north of the Otago Peninsula than in South Otago and the northern Catlins and comparable with that of the Foveaux Strait.