Browsing by Author "Fahlman, Andreas"

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Open Access
Extreme diving in mammals: first estimates of behavioural aerobic dive limits in Cuvier's beaked whales.
(J Exp Biol, 2020-09-23) Quick, Nicola J; Cioffi, William R; Shearer, Jeanne M; Fahlman, Andreas; Read, Andrew J
We analysed 3680 dives from 23 satellite-linked tags deployed on Cuvier's beaked whales to assess the relationship between long duration dives and inter-deep dive intervals and to estimate aerobic dive limit (ADL). The median duration of presumed foraging dives was 59 min and 5% of dives exceeded 77.7 min. We found no relationship between the longest 5% of dive durations and the following inter-deep dive interval nor any relationship with the ventilation period immediately prior to or following a long dive. We suggest that Cuvier's beaked whales have low metabolic rates, high oxygen storage capacities and a high acid-buffering capacity to deal with the by-products of both aerobic and anaerobic metabolism, which enables them to extend dive durations and exploit their bathypelagic foraging habitats.
Open Access
Predictive modeling of spinner dolphin (Stenella longirostris) resting habitat in the main Hawaiian Islands
(PLoS One, 2012-07) Thorne, LH; Johnston, DW; Urban, DL; Tyne, J; Bejder, L; Baird, RW; Yin, S; Rickards, SH; Deakos, MH; Mobley Jr, JR; Pack, AA; Chapla Hill, M
Predictive habitat models can provide critical information that is necessary in many conservation applications. Using Maximum Entropy modeling, we characterized habitat relationships and generated spatial predictions of spinner dolphin (Stenella longirostris) resting habitat in the main Hawaiian Islands. Spinner dolphins in Hawai'i exhibit predictable daily movements, using inshore bays as resting habitat during daylight hours and foraging in offshore waters at night. There are growing concerns regarding the effects of human activities on spinner dolphins resting in coastal areas. However, the environmental factors that define suitable resting habitat remain unclear and must be assessed and quantified in order to properly address interactions between humans and spinner dolphins. We used a series of dolphin sightings from recent surveys in the main Hawaiian Islands and a suite of environmental variables hypothesized as being important to resting habitat to model spinner dolphin resting habitat. The model performed well in predicting resting habitat and indicated that proximity to deep water foraging areas, depth, the proportion of bays with shallow depths, and rugosity were important predictors of spinner dolphin habitat. Predicted locations of suitable spinner dolphin resting habitat provided in this study indicate areas where future survey efforts should be focused and highlight potential areas of conflict with human activities. This study provides an example of a presence-only habitat model used to inform the management of a species for which patterns of habitat availability are poorly understood.