Acoustic interaction of humpback whales and whalewatching boats.

Acoustic interaction of humpback whales and whalewatching boats. (2000)

by W W L Au, M Green

Venue:

Marine Environmental Research

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Behavioural responses of humpback whales (Megaptera novaeangliae) to whalewatching boats near Isla de la

by Meike Scheidat , Cristina Castro , Janira Gonzalez , Rob Williams - Plata, Machalilla National , 2004

"... ABSTRACT Machalilla National Park, on the coast of mainland Ecuador, supports a growing whalewatching industry that focuses on Southern Hemisphere humpback whales, which spend the austral winter (June-September) in this area. This study was designed to measure short-term reactions of whales to the ..."

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ABSTRACT Machalilla National Park, on the coast of mainland Ecuador, supports a growing whalewatching industry that focuses on Southern Hemisphere humpback whales, which spend the austral winter (June-September) in this area. This study was designed to measure short-term reactions of whales to the whalewatching vessel activity typically seen in this area for two reasons: (1) to identify the nature of whales' avoidance response, if any, in order to draft whalewatching guidelines that help local mariners identify when they may be disturbing whales; and (2) to quantify the magnitude of any avoidance response, to examine how this relatively understudied population behaves around boats compared with whales in other whalewatching areas. A shore-based theodolite tracking team created a 'natural' experiment to observe relationships between whalewatching traffic and whale behaviour in 1998 and 1999. Swim speed and path directness of humpback whales were measured in the absence of boats, and how those parameters changed when boats arrived was recorded. When whales entered the study area accompanied by boats, a record was made of how their behaviour changed after the boats left. Humpback whales reacted to the approach of whalewatching boats by increasing swim speed significantly, and adopted a much more direct path after boats left. Future research is needed to determine whether responses vary with number, proximity or type of vessel. Similarly, future studies are recommended to determine whether different age-sex classes vary in vulnerability to disturbance. Meanwhile, this study enables provision of much-needed, practical advice to local operators who are concerned that they may be disturbing whales: one way that mariners can tell if they are causing disturbance is if they need to increase their vessel's speed to keep pace. The average behavioural responses measured were strong enough to recommend that Machalilla National Park adopt precautionary management procedures to limit number and proximity of vessels.

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i Cancho, editors

by Fm Smith, Rb Stephens, Mj Kennedy, Jv Reynolds - Proceedings of the 7th International Conference on the Evolution of Language (EVOLANG 7 , 2008

"... P53 abnormalities and outcomes in colorectal cancer: a systematic ..."

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P53 abnormalities and outcomes in colorectal cancer: a systematic

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Assessing sound exposure from shipping in coastal waters using a single hydrophone and Automatic

by Nathan D Merchant , Matthew J Witt , Philippe Blondel , Brendan J Godley , George H Smith - Identification System (AIS) data, Mar.pollut.bull

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An integrated and adaptive management model to address the long-term sustainability of tourist interactions with cetaceans. Environmental Conservation 35

by L Bejder, D. Lusseau , 2008

"... Rapid growth in demand for tourist interactions with cetaceans in the wild constitutes a challenge to management. Short-term animal behaviour changes can have long-term biological consequences for individual animals and populations. This paper reviews the whale-watching management context, describin ..."

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Rapid growth in demand for tourist interactions with cetaceans in the wild constitutes a challenge to management. Short-term animal behaviour changes can have long-term biological consequences for individual animals and populations. This paper reviews the whale-watching management context, describing the interplay of the macro (global), meso (national/regional) andmicro-level (local/site specific) policy, planning and management settings. Here, an integrated and adaptive management model based largely upon the delineation and monitoring of limits of acceptable change (LAC) parameters is proposed to address current shortcomings in the long-term sustainablemanagement of whale-watching activities. Although no integrated management framework cur-rently exists, a comprehensive management approach must be developed and applied in the interests of the long-term sustainable management of tourist interactions with cetaceans in the wild. The proposed management model highlights the importance of integrating multiple stakeholder perspectives in a way that is both research-informed and adaptive. Beyond tourist interactions with cetaceans, this management framework could be applied to a wide range of wildlife management contexts.

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Oceans of noise A WDCS Science report

by Mark Simmonds, Sarah Dolman, Lindy Weilgart, Mark Simmonds, Sarah Dolman, Lindy Weilgart, Sn Lj

"... WDCS is the global voice for the protection of cetaceans (whales, dolphins and porpoises) and their environment. ..."

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WDCS is the global voice for the protection of cetaceans (whales, dolphins and porpoises) and their environment.

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Behavioural Responses of Dusky Dolphin Groups (Lagenorhynchus obscurus) to Tour Vessels off Kaikoura, New Zealand

by David Lundquist, Neil J. Gemmell

"... Background: Commercial viewing and swimming with dusky dolphins (Lagenorhynchus obscurus) near Kaikoura, New Zealand began in the late 1980s and researchers have previously described changes in vocalisation, aerial behaviour, and group spacing in the presence of vessels. This study was conducted to ..."

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Background: Commercial viewing and swimming with dusky dolphins (Lagenorhynchus obscurus) near Kaikoura, New Zealand began in the late 1980s and researchers have previously described changes in vocalisation, aerial behaviour, and group spacing in the presence of vessels. This study was conducted to assess the current effects that tourism has on the activity budget of dusky dolphins to provide wildlife managers with information for current decision-making and facilitate development of quantitative criteria for management of this industry in the future. Methodology/Principal Findings: First-order time discrete Markov chain models were used to assess changes in the behavioural state of dusky dolphin pods targeted by tour vessels. Log-linear analysis was conducted on behavioural state transitions to determine whether the likelihood of dolphins moving from one behavioural state to another changed based on natural and anthropogenic factors. The best-fitting model determined by Akaike Information Criteria values included season, time of day, and vessel presence within 300 m. Interactions with vessels reduced the proportion of time dolphins spent resting in spring and summer and increased time spent milling in all seasons except autumn. Dolphins spent more time socialising in spring and summer, when conception occurs and calves are born, and the proportion of time spent resting was highest in summer. Resting decreased and traveling increased in the afternoon. Conclusions/Significance: Responses to tour vessel traffic are similar to those described for dusky dolphins elsewhere.

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Humpback Whale Song or Humpback Whale Sonar? A Reply to Au et al.

by Eduardo Mercado Iii, L. Neil Frazer

"... Abstract—Au and colleagues ’ arguments against the hypothesis that humpback whale songs function as long-range sonar are based on questionable assumptions rather than on empirical data. Like other echolocating mammals (e.g., bats), singing humpback whales: 1) localize targets in the absence of visua ..."

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Abstract—Au and colleagues ’ arguments against the hypothesis that humpback whale songs function as long-range sonar are based on questionable assumptions rather than on empirical data. Like other echolocating mammals (e.g., bats), singing humpback whales: 1) localize targets in the absence of visual information; 2) possess a highly innervated peripheral auditory system; and 3) modulate the temporal and spectral features of their sounds based on environmental conditions. The sonar equation is inadequate for determining whether humpback whale songs generate detectable echoes from other whales because it does not account for temporal variables that can strongly affect the detectability of echoes. In particular, the sonar equation ignores the fact that much of the noise encountered by singing humpback whales is spectrally and temporally predictable, and that audition in mammals is a dynamic and plastic process. Experiments are needed to test the hypothesis that singing humpback whales listen for and respond to echoes generated by their songs. Index Terms—Baleen whale, cetacean, environmentally-adaptive sonar, low-frequency sonar, mysticete.

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