Project BRAHSS: behavioural response of Australian humpback whales to seismic surveys.

BRAHSS is a major project aimed at understanding how humpback whales respond to noise, particularly from seismic air gun arrays. It also aims to infer the longer term biological significance of the responses from the results and knowledge of normal behaviour. The aim is to provide the information that will allow seismic surveys to be conducted efficiently with minimal impact on whales. It also includes a study of the response to ramp-up in sound level. Ramp-up is widely used at the start of operations as a mitigation measure intended to cause whales to move away, but there is little information to show that it is effective. BRAHSS involves four experiments with migrating humpback whales off the east and west coasts of Australia with noise exposures ranging from a single air gun to a full seismic array. Two major experiments have been completed off the east coast, the second involving 70 scientists. Whale movements were tracked using theodolites on two high points ashore and behavioural observations were made from these points and from three small vessels and the source vessel. Vocalising whales were tracked underwater with an array of hydrophones. These and other moored acoustic receivers recorded the sound field at several points throughout the area. Tags (DTAGs) were attached to whales with suction caps for periods of several hours. Observations and measurements during the experiments include the wide range of variables likely to affect whale response and sufficient acoustic measurements to characterise the sound field throughout the area. The remaining two experiments will be conducted further off shore off the west coast in 2013 and 2014

A study of the behavioural response of whales to the noise of seismic air guns: Design, methods and progress

The concern about the effects of the noise of human activities on marine mammals, particularly whales, has led to a substantial amount of research but there is still much that is not understood, particularly in terms of the behavioural responses to noise and the longer term biological consequences of these responses. There are many challenges in conducting experiments that adequately assess behavioural reactions of whales to noise. These include the need to obtain an adequate sample size with the necessary controls and to measure the range of variables likely to affect the observed response. Analysis is also complex. Well designed experiments are complex and logistically difficult, and thus expensive. This paper discusses the challenges involved and how these are being met in a major series of experiments in Australian waters on the response of humpback whales to the noise of seismic airgun arrays. The project is known as BRAHSS (Behavioural Response of Australian Humpback whales to Seismic Surveys) and aims to provide the information that will allow seismic surveys to be conducted efficiently with minimal impact on whales. It also includes a study of the response to ramp-up in sound level which is widely used at the start of operations, but for which there is little information to show that it is effective. BRAHSS also aims to infer the longer term biological significance of the responses from the results and the knowledge of normal behaviour. The results are expected to have relevance to other sources and species

ETAW: Exploring the thermal and technological limits of automatic whale detection

Thermographic imaging has been shown to reliably detect marine mammals, both day and night, for operational mitigation in polar and subpolar waters (Zitterbart et al., 2013), with encouraging findings having recently been reported for temperate waters (NOAA Southwest Fisheries Science Center, 2015). As thermographic imaging is based on thermal contrast between whale body or blow and the sea surface, thermographic discriminability is expected to wane with increasing sea surface temperatures. ETAW explored the upper sea surface temperature limit of this approach by deploying high-end thermal cameras on North Stradbroke Island, Queensland, Australia (subtropical conditions) and on both the North and South shore of Kauai, HI, USA (tropical conditions). The study design included both acquisition of thermographic video as well as concurrent visual sightings, including double-blind setups. Our findings show, that cues of humpback whales are thermally discriminable even under the highest sea surface temperatures encountered (26°C / 79°F). Thermal discriminability and performance of computer based automatic detection of cues, appear, as based on the (subjective) experience gained in the field, to be more dependent on covariates such as camera height, sea-state and glare than on sea surface temperature. While increasing sea surface temperatures appear to reduce the operational radius of thermographic images (yet not below typical mitigation radii of 1-3 km), they did not render cues entirely indistinguishable from the background image, while glare and increased sea states caused increased numbers of false alerts. Comparisons of different IR technologies (scanning LWIR 8 – 12µm, focal plane array LWIR 8.0 – 9.4µm, focal plane array MWIR 3.7 – 5.5µm) suggest that the broadband LWIR sensor produced the clearest image least affected by glare. Tests of polarization filters in different orientations revealed that glare is somewhat, but not significantly reduced, for horizontal polarization orientation, but that benefits are outweighed by image degeneration due to the additional optics, at least for the high temperature resolution required in this application

Project BRAHSS: behavioural response of humpback whales to seismic surveys

BRAHSS is a major project aimed at understanding how humpback whales respond to noise, particularly from seismic air gun arrays. It also aims to infer the longer term biological significance of the responses from the results and knowledge of normal behaviour. The aim is to provide the information that will allow seismic surveys to be conducted efficiently with minimal impact on whales. It also includes a study of the response to ramp-up in sound level. Ramp-up is widely used at the start of operations as a mitigation measure intended to cause whales to move away, but there is little information to show that it is effective. BRAHSS involves four experiments with migrating humpback whales off the east and west coasts of Australia with noise exposures ranging from a single air gun to a full seismic array. Two major experiments have been completed off the east coast, the second involving 70 scientists. Whale movements were tracked using theodolites on two high points ashore and behavioural observations were made from these points and from three small vessels and the source vessel. Vocalising whales were tracked underwater with an array of hydrophones. These and other moored acoustic receivers recorded the sound field at several points throughout the area. Tags (DTAGs) were attached to whales with suction caps for periods of several hours. Observations and measurements during the experiments include the wide range of variables likely to affect whale response and suf- ficient acoustic measurements to characterise the sound field throughout the area. The remaining two experiments will be conducted further off shore off the west coast in 2013 and 2014