Knowledge about home ranges is essential for understanding the resources required by a species, identifying critical habitats, and revealing the overlap with anthropogenic impacts. Ranging behavior of Hector's dolphins (Cephalorhynchus hectori) was studied via coastal photo-ID surveys in the Banks Peninsula Marine Mammal Sanctuary (BPMMS) between 1985 and 2006. Univariate kernel density estimates of alongshore home range were calculated for 20 individuals with 15 sightings or more. For each individual, sighting locations were transformed into a univariate data set by projecting sightings onto a line drawn 1 km from the coast and measuring the distance along this line relative to an origin. Sightings were weighted by survey effort. Ninety-five percent (K 95 ) of the density estimate was used as a measure of alongshore home range, and 50% of the estimate (K 50 ) was used to reveal core portions of coastline where dolphins concentrated their activity. The mean estimates of K 95 and K 50 were 49.69 km (SE = 5.29) and 17.13 km (SE = 1.89), respectively. Four distinct hubs were apparent where the core areas of different individuals coincided. Three of the dolphins' alongshore ranges extended beyond the current northern boundary of the BPMMS, raising fresh concerns that the sanctuary is not large enough. Proposed changes to gill netting regulations, if enacted, will result in the alongshore ranges of all the dolphins in our study being protected.

The ability to measure and age individuals within a population has many important applications, for example, for examining growth and determining size class. We developed a simple photogrammetric system using two parallel lasers and a digital camera, in order to measure dorsal fin dimensions of free-ranging Hector's dolphins. Laser dots were projected onto the fin, providing scale, thus allowing measurement as well as simultaneous photo-ID of 34 individuals from fin nicks and other marks. Multiple measurements (≥5) were available for six individuals; these resulted in mean CVs of 3.71% for fin length and 3.76% for fin height. Errors due to variations in angle and measurement were quantified via photography of a fiberglass Hector's dolphin model. Allometric measurements and age data were collated from 233 autopsied Hector's dolphins. Using these data, fin length was found to be a better predictor of total length (females r 2 = 0.732, males r 2 = 0.678) than fin height. Gompertz age/length growth curves were fitted to these individuals. Linear regressions were used to estimate total length for 34 individuals from laser-metrically estimated fin base length. Individuals were then assigned one of three age categories. This system shows promise as a noninvasive way of measuring individuals, while allowing simultaneous photographic identification.

Aim To develop and validate a model for fine‐scale distribution of southern right whales (Eubalaena australis) on their calving grounds, accounting for breeding status. Location Port Ross, a harbour at the northern end of the sub‐Antarctic Auckland Islands, approximately 450 km south of mainland New Zealand. Methods Species–habitat surveys were conducted during annual winter expeditions to the Auckland Islands from 2010 to 2012. Presence locations for groups including calves (calf groups; n = 462) and not including calves (non‐calf groups; n = 313) were recorded during small‐boat surveys of Port Ross, and an equal number of pseudo‐absence locations were generated in a GIS analysis. Explanatory variables tested were water depth, seabed slope, distance to coast, distance to shelter from prevailing wind and average wave exposure (estimated from a custom‐built wave model). The occurrence of calf groups and non‐calf groups was separately related to explanatory variables using binomial generalized additive models, with best models chosen via the minimum Akaike information criterion score. Multi‐fold validation was conducted to assess model performance and temporal variation in distribution. Results The best models for calf groups were consistent, always including wave exposure, distance to shelter, depth and distance to the coastline. In contrast, the best non‐calf group models were more variable and explained only a small proportion of the variation in the data. Validation metrics indicated that the calf group models were useful predictors of distribution in Port Ross during winter, and that the calf group models performed better than the non‐calf models using the same suite of environmental variables. Main conclusions Breeding female southern right whales seek sheltered, nearshore waters during the early life‐stages of their calves and are more selective of these habitats than non‐calving whales. The results highlight the importance of sheltered habitat for taxa with vulnerable life‐history stages, and the need to account for reproductive status to refine species–habitat models.

Quantitatively describing the acoustic repertoire of a species is important for establishing effective passive acoustic monitoring programs and developing automated call detectors. This process is particularly important when the study site is remote and visual surveys are not cost effective. Little is known about the vocal behavior of southern right whales (Eubalaena australis) in New Zealand. The aim of this study was to describe and quantify their entire vocal repertoire on calving grounds in the sub-Antarctic Auckland Islands. Over three austral winters (2010-2012), 4349 calls were recorded, measured, and classified into 10 call types. The most frequently observed types were pulsive, upcall, and tonal low vocalizations. A long tonal low call (≤15.5 s duration) and a very high call (peak frequency ∼750 Hz) were described for the first time. Random Forest multivariate analysis of 28 measured variables was used to classify calls with a high degree of accuracy (82%). The most important variables for classification were maximum ceiling frequency, number of inflection points, duration, and the difference between the start and end frequency. This classification system proved to be a repeatable, fast, and objective method for categorising right whale calls and shows promise for other vocal taxa.

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