Knight, R. L. & Gutzwiller, K. J. Wildlife and Recreationists: Coexistence through Management and Research. The Journal of Wildlife Management (Island Press, 1995). https://doi.org/10.2307/3802624.

Clay TA, Mangel JC, Alfaro-Shigueto J, Hodgson DJ, Godley BJ. Distribution and habitat use of a cryptic small cetacean, the Burmeister’s porpoise, monitored from a small-scale fishery platform. Front Mar Sci. 2018;5:220. To explore if our results were heavily biased by tagging effects, we also exposed un-tagged porpoises monitored with a drone-mounted camera. Here, in the one successful exposure trial, a small group of un-tagged porpoises responded similarly to the tagged porpoises (Fig. 2f, Suppl. Video SV1). The focal porpoise swam away from the sound source at travel speeds (2.5 m s −1 during the 5-min period) comparable to or higher than those during exposure from the tagging study (1.4–2.5 m s −1, Fig. 2a–d). This suggests that the flight behaviour in response to AHDs is not a result of tagging-induced sensitisation. The focal porpoise had a calf and its sensitivity to disturbance might thus have been increased. On the other hand, in a study where drone-observed porpoises were exposed to pingers, an adult with a calf had similar responses and swimming speeds to a single adult porpoise 54. What is evident from both exposure of tagged and untagged animals is that every individual responded to the AHD. Moreover, these findings are overall in accordance with observations of porpoise deterrence due to AHDs 5, 6. Cox, T. M., Read, A. J., Solow, A. & Tregenza, N. Will harbour porpoises ( Phocoena phocoena) habituate to pingers?. J. Cetacean Res. Manage. 3(1), 81–86 (2001). Díaz-López B. Interactions between Mediterranean bottlenose dolphins ( Tursiops truncatus) and gillnets off Sardinia, Italy. ICES J Mar Sci. 2006;63: 946–951.

Discussion

Wild Harbour knows where every individual fish that they sell has come from: the time it was caught; the boat it was landed on; its ‘catch area’ (where it was caught). Honesty is a ‘top priority’. ‘Fish is something we need to be careful with and look after’ Dawson, S. M. C. and Communication: The behavioural and social contexts of Hector’s Dolphin vocalisations. Ethology 88, 265–276 (1991). Lyamin, O. I., Korneva, S. M., Rozhnov, V. V. & Mukhametov, L. M. Cardiorespiratory responses to acoustic noise in Belugas. In The Effects of Noise on Aquatic Life II (eds Popper, A. N. & Hawkins, A.) 665–672 (Springer New York, 2016). https://doi.org/10.1007/978-1-4939-2981-8_80. Ruxton, G. D. Testing for departure from uniformity and estimating mean direction for circular data. Biol. Let. 13(1), 20160756 (2017).

Olesiuk, P. F., Nichol, L. M., Sowden, M. J. & Ford, J. K. B. Effect of the sound generated by an acoustic harassment device on the relative abundance and distribution of harbor porpoises ( Phocoena phocoena) in Retreat Passage, British Columbia. Mar. Mammal Sci. 18, 843–862 (2002). The respiration rate was unchanged in two animals, while the four others changed respiration in different ways during exposure compared to the 15 min before exposure, ranging from a 15% decrease (HP4, from 3.9 to 3.3 min −1) to 31% increase (HP3, from 3.2 to 4.2 min −1) (Tables 2, S1). Received level and effect distances Higashisaka H, Matsuishi T, Akamatsu T. Presence and behavior of harbor porpoises ( Phocoena phocoena) around set nets revealed using passive acoustic monitoring. Fish Res. 2018;204: 269–274. Johnston, D. W. The effect of acoustic harassment devices on harbour porpoises ( Phocoena phocoena) in the Bay of Fundy, Canada. Biol. Conserv. 108, 113–118 (2002).

References

McDonald, B. I., Johnson, M. & Madsen, P. T. Dive heart rate in harbour porpoises is influenced by exercise and expectations. J. Exp. Biol. 221, jeb168740 (2018). Cotter, M. P., Maldini, D. & Jefferson, T. A. ‘Porpicide’ in California: Killing of harbor porpoises (Phocoena phocoena) by coastal bottlenose dolphins (Tursiops truncatus). Mar. Mammal Sci. 28, 1–15 (2012). Discussing the demise of Freight Books, Sinclair added: "We are sad to see Freight being wound up, and had hoped that a buyer would emerge over the past few months. That has not happened. It is sad to see a company disappear from the publishing landscape in Scotland and to see the effect it has had on all concerned. We put our efforts into helping Freight find a buyer and to help them with publishing issues as they emerged so it is a blow that they have not managed to do so, and that most of the authors will be without a home for their titles, in the short term at least.”