Matthew K. Pine

Potential impacts of shipping noise on marine mammals in the western Canadian Arctic

As the Arctic warms and sea ice decreases, increased shipping will lead to higher ambient noise levels in the Arctic Ocean. Arctic marine mammals are vulnerable to increased noise because they use sound to survive and likely evolved in a relatively quiet soundscape. We model vessel noise propagation in the proposed western Canadian Arctic shipping corridor in order to examine impacts on marine mammals and marine protected areas (MPAs). Our model predicts that loud vessels are audible underwater when >100km away, could affect marine mammal behaviour when within 2km for icebreakers vessels, and as far as 52km for tankers. This vessel noise could have substantial impacts on marine mammals during migration and in MPAs. We suggest that locating the corridor farther north, use of marine mammal observers on vessels, and the reduction of vessel speed would help to reduce this impact.

The Source Parameters of Echolocation Clicks from Captive and Free-Ranging Yangtze Finless Porpoises (Neophocaena asiaeorientalis asiaeorientalis)

The clicks of Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis) from 7 individuals in the tank of Baiji aquarium, 2 individuals in a netted pen at Shishou Tian-e-zhou Reserve and 4 free-ranging individuals at Tianxingzhou were recorded using a broadband digital recording system with four element hydrophones. The peak-to-peak apparent source level (ASL_pp) of clicks from individuals at the Baiji aquarium was 167 dB re 1 μPa with mean center frequency of 133 kHz, -3dB bandwidth of 18 kHz and -10 dB duration of 58 μs. The ASL_pp of clicks from individuals at the Shishou Tian-e-zhou Reserve was 180 dB re 1 μPa with mean center frequency of 128 kHz, -3dB bandwidth of 20 kHz and -10 dB duration of 39 μs. The ASL_pp of clicks from individuals at Tianxingzhou was 176 dB re 1 μPa with mean center frequency of 129 kHz, -3dB bandwidth of 15 kHz and -10 dB duration of 48 μs. Differences between the source parameters of clicks among the three groups of finless porpoises suggest these animals adapt to their echolocation signals depending on their surroundings.

Sounds of Arctic cod (Boreogadus saida) in captivity: A preliminary description

Sounds produced by Arctic cod were recorded for the first time and suggest passive acoustic monitoring (PAM) can be an effective additional tool for the study and management of the species. Each of the 38 calls detected in three different aquatic facilities consisted of a single grunt with 6 to 12 pulses and a mean duration of 289 ms. Call frequency ranged between 59 and 234 Hz, with a mean peak frequency of 107 Hz. These preliminary data suggest Arctic cod can be distinguished from other gadids, but additional studies of sympatric species are needed before PAM can be confidently adopted.

Behavioral laterality in Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis)

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is a critically endangered species with less than 1000 individuals expected to be left in the wild. While many studies have been conducted on laterality among several cetacean species, no studies investigating the Yangtze finless porpoise have been conducted. Using event sampling methods, several behaviors such as flipper-body touching, object touching, barrel-rolls, side swimming, and swimming direction were recorded from six captive porpoises (three males and three females). Analyses of 360 observations recorded over two months revealed that, at group level, porpoises showed laterality in swimming behaviors. Porpoises swam preferentially with their right pectoral fin upward and their left pectoral fin downward with a clockwise swimming direction and also displayed a consistent bias for a counterclockwise barrel-roll direction. No significant differences were reported for flipper use either during the interaction with conspecifics or with objects. The results from the current study provide novel insight into the cerebral asymmetry in a species previously ignored within the literature, thus improving our understanding on the extent of laterality in cetaceans and on the evolutionary history of hemispheric laterality for vertebrates in general.

Monitoring rising ambient sound levels from vessels and impacts on Indo-Pacific humpback dolphin (Sousa chinensis) occurrences

Home to the worlds largest population of Indo-Pacific humpback dolphins, Sousa chinensis, the Pearl River Estuary in China is the one of the world’s busiest embayments for vessel traffic. Quantitative studies on the potential impact of rising ambient noise levels on the habitat use of dolphins in this estuary are lacking. We investigated the relationships between dolphins, vessel noise and fish choruses to better understand the potential influence that an increasing ambient noise floor from vessels may have on the occurrence of Indo-Pacific humpback dolphins within the estuary. Over 330 hours of recordings spanning 106 days were analyzed. Vessels were found to raise daily ambient noise floors, however such increases had no detectable influence on dolphin detection rates. Fish choruses and dolphin detection rates were linked, however, with higher average detection rates occurring at times of peak fish activity. These findings suggest that distributions of Indo-Pacific humpback dolphins within the PRE may ...

Assessing vessel slowdown as an option for reducing acoustic masking for Arctic cod in the western Canadian Arctic

Noise from this shipping traffic can lead to acoustic masking, reducing the ability of marine animals to detect and use biologically important sounds. Vessel-slow down may be an alternative mitigation option in regions where re-routing shipping corridors to avoid important habitat for fish and marine mammals is not possible. We investigated the potential relief in masking from a 10 knot speed reduction of container and cruise ships. Based on ambient sound measurements and real shipping data, the percentage reduction in the available listening space for fish as a container or cruise ship passes under varying speeds and ambient sound conditions was shown. The mitigation effects from slower vessels (travelling at 15 knots compared to 25 knots), in terms of auditory masking, was equal between ambient sound conditions, but not equal between the type of vessel. Slowing vessels led to a substantial decrease in the listening space reductions, with the amount of reduction varying by distance away from vessels. Vessel slowdown through sensitive habitat could be an effective mitigation strategy for reducing the extent of auditory masking.Noise from this shipping traffic can lead to acoustic masking, reducing the ability of marine animals to detect and use biologically important sounds. Vessel-slow down may be an alternative mitigation option in regions where re-routing shipping corridors to avoid important habitat for fish and marine mammals is not possible. We investigated the potential relief in masking from a 10 knot speed reduction of container and cruise ships. Based on ambient sound measurements and real shipping data, the percentage reduction in the available listening space for fish as a container or cruise ship passes under varying speeds and ambient sound conditions was shown. The mitigation effects from slower vessels (travelling at 15 knots compared to 25 knots), in terms of auditory masking, was equal between ambient sound conditions, but not equal between the type of vessel. Slowing vessels led to a substantial decrease in the listening space reductions, with the amount of reduction varying by distance away from vessels. Ves...

Glass sponge reef soundscapes

Many structured biogenic habitats are biodiversity hotspots and thus possess unique soundscapes largely driven by the biophony. To date, the vast majority of research has focused on shallow-water biogenic habitats such as coral or oyster reefs. Glass sponge reefs are a deep-water habitat analogous in many ways to shallow-water coral reefs. These reefs are built by three species of hexactinellid sponges which form complex 3-dimensional habitats that support diverse communities of animals. Many soniferous animals, including rockfish, are strongly associated with patches of live-sponge dominated habitat within the reef foot-print. Consequently, we hypothesized that glass sponge reefs and the communities they support would generate unique soundscapes. Beginning in September of 2016, we deployed a series of underwater acoustic recorders on sponge reefs throughout Canada’s Pacific continental shelf. Initial results show that recorders located on sponge reefs were significantly louder in the mid- and high-frequency bands (100–1000 Hz and 1–10 kHz, respectively). Additionally, many fish calls were detected in recordings from within sponge reefs, while few fish calls were observed at similar depths in off-reef habitats. We will discuss our understanding of the link between soundscapes and biodiversity in glass sponge reef habitats and the potential application of ecosystem-level monitoring.

A case of epimeletic behavior and associated acoustic records of Indo-Pacific humpback dolphins (Sousa chinensis)

Several cetacean species have demonstrated epimeletic behavior that relies on the tight social bonds between conspecifics. These behaviors and the corresponding vocalizations were recorded during a rare encounter with a group of Indo-Pacific humpback dolphins (Sousa chinensis) that included a presumed mother and deceased calf, in Sanniang Bay, China. The observed dolphins were divided into 2 apparent groups: 1) a central group with the presumed mother and her deceased calf, along with 1 to 6 other individuals swimming in synchrony with the presumed mother; and 2) a following group of several individuals, dispersed over varying distances from approximately 20 to > 300 m, that swam in the same direction as the central group. The mother was seen mostly supporting the calfs body using her back, anterior to the dorsal fin and posterior to the melon, while the other members of the central group exhibited standing-by behaviors (i.e., remaining close to the deceased calf but not providing aid). Whistles in this context were of a longer duration and a higher complexity in the frequency modulation compared to social contexts. Several whistle types were also repeated frequently. This paper provides a detailed description of epimeletic behavior and the whistles possibly associated with that behavior in an endangered population of Indo-Pacific humpback dolphins.

Investigating the spatiotemporal variation of fish choruses to help identify important foraging habitat for Indo-Pacific humpback dolphins, Sousa chinensis

Given the common physical overlapping between coastal developments and important marine mammal habitats, there is a need to identify potentially important foraging grounds for dolphins when informing marine spatial planning and management of underwater noise. Hydrophones were deployed at four locations either side of the mainland China-Hong Kong Special Administrative Region border to monitor the presence of soniferous fishes; a key prey item for Indo-Pacific humpback dolphins. Five distinct chorus-types were identified; each showing spatiotemporal variability. Each chorus-type was assumed to represent a separate species. Chorus-type diversity also differed between sites, with SP4 and SP5 types only being detected within Hong Kong waters where bottom trawling is illegal. Chorus-type SP1 was only detected at the recording sites in mainland Chinese waters. Call rates and chorus duration were highest during the spring and summer months. Given these dolphins show a predator-prey relationship, these data provide new information on the local fish communities at a much finer-scale than fish landing records and a baseline of fish activity in an environment that is challenging to explore. Overlaid with acoustic detections of foraging dolphins, these data form a basis for identifying potentially important foraging habitats that should be afforded the highest priority for protection.

The echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis)

While the transmission beam of odontocetes has been described in a number of studies, the majority of them that have measured the transmission beam in two dimensions were focused on captive animals. Within the current study, a dedicated cross hydrophone array with nine elements was used to investigate the echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins. A total of 265 on-axis clicks were analyzed, from which the apparent peak to peak source levels ranged between 168 to 207 dB (mean 184.5 dB ± 6.6 dB). The 3-dB beam width along the horizontal and vertical plane was 9.6° and 7.4°, respectively. Measured separately, the directivity index of the horizontal and vertical plane was 12.6 and 13.5 dB, respectively, and the overall directivity index (both planes combined) was 29.5 dB. The beam shape was slightly asymmetrical along the horizontal and vertical axis. Compared to other species, the characteristics of the transmitting beam of Indo-Pacific humpback dolphins were relatively close to the bottlenose dolphin (Tursiops truncatus), likely due to the similarity in the peak frequency and waveform of echolocation clicks and comparable body sizes of the two species.