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A Sound-Centered Species in Today's Noisy World

 

Belugas are highly gregarious, and the glue to their society is sound
Photo: Valeria Vergara

 

Belugas are one of the most acoustically active cetaceans, using sound to communicate, maintain contact, navigate and find food.  As such, noise pollution from a number of sources is a serious threat faced by the species across much of its pan-Arctic range.  The Vancouver Aquarium MMRP has conducted both in-situ and field studies of beluga whales for nearly two decades, with a strong focus on studies of acoustic communication in relation to underwater noise.

 

 

In the Beginning

 


Valeria Vergara conducting her earlier studies at the Vancouver Aquarium
Photo: Sylvie Gilman

Dr. Valeria Vergara’s earlier research identified what is likely the most critical call type in the extensive vocal repertoire of beluga whales: contact calls, used primarily for maintaining group cohesion and to regain or maintain contact between mothers and their dependent calves.  Her research also showed that calves initially make underdeveloped versions of this call type, with lower pulse repetition rates and little acoustic energy produced above 10 kHz. This makes masking by noise a particularly dire problem for dependent calves because the acoustic energy of vessel noise tends to be highest between 0.1 and 10 kHz, a range that overlaps that of neonate calls.

 

 

A Quiet Haven

 

Beluga calves were easily observed in Cunningham Inlet
Photo: Valeria Vergara


Valeria observes and records beluga whales from a research tower
Photo: Valeria Vergara

In the summers of 2014 and 2015 Valeria took her research to Cunningham Inlet, a pristine summering and nursery area for the Eastern High Arctic-Baffin Bay beluga population. The inlet is still unaffected by the increase in anthropogenic noise seen in other areas as a result of the accessibility brought about by the large decrease in Arctic ice cover.  Valeria hoped to establish a baseline on call usage in undisturbed areas, against which the effects of noise on communication can be measured in the future. Crucial mother-calf contact calls, identified in her previous studies at the Vancouver Aquarium, were at the center of this study: What is their rate of use? How is this correlated with the number of calves in a group?  Are contact calls individually distinct?

 

Valeria recorded and observed large herds of belugas both from a research tower which could be accessed at low tide, and directly from the shoreline.  She also targeted smaller groups that swam periodically up river channels, becoming temporarily from the larger herds. 

 

 

   
  Valeria records groups of beluga whales temporarily isolated in river channels
Photo: Natural Mystery Films
 

  

Click an this spectrogram to listen to an example of broadband contact calls recorded in Cunningham Inlet

Her findings? Valeria and her research assistant Marie-Ana Mikus continue to analyze hours of recordings and literally thousands of vocalizations. Preliminary findings are exciting: she confirmed the critical role of broadband contact calls in nursery areas and identified lower frequency calls associated with the presence of neonates.  These findings will help us understand the effects of underwater noise on beluga communication in busier waters, such as in Quebec’s St. Lawrence estuary, where beluga populations are in serious decline.

 

Listen to a recording of a large herd in Cunningham Inlet. Can you make out the distinct contact calls?

 

For a first-hand account of her Arctic field-work, read Valeria's Field Notes 

 

A Noisy World

 

The St. Lawrence Estuary beluga population is estimated to be at just over 800 individuals and was evaluated as “endangered” in December 2014 by the Committee on the Status of Endangered Wildlife in Canada. The population has been declining steadily since the early 2000s, a trend that may be accentuated by a recent unprecedented increase in calf mortality.  What explains this unusually high number of calf deaths? The answer continues to be a mystery. Various factors have been proposed to play a role: climate change, algal blooms, pollution, industrial developments and disturbance. An increase in underwater noise could be a contributing factor.  The St. Lawrence River is an increasingly crowded place. Shipping, ferries, recreational boats, and a growing whale watching fleet significantly affect the belugas’ soundscape in their critical habitat, especially during the summer months when females give birth.

 

Mom, Can you Hear Me?

 


Beluga newborn carcasses found in unprecedented numbers in the St. Lawerence and it shores
Photo: courtesy of GREMM

Is it possible that underwater noise from vessels masks the underdeveloped contact calls of calves, affecting the ability of mothers to hear them and increasing the risk of separation?  We are collaborating with the Group for Research and Education on Marine Mammals to answer this important question. The project builds on Valeria’s earlier work both in-situ and in Cunningham Inlet, which made it possible to reliably identify the contact calls of newborn calves.  Results of this study will contribute to developing sound mitigation efforts in critical beluga habitat. 

 


Valeria Vergara and Robert Michaud look for beluga whales from the research vessel Le Bleuvet
Photo: Suzanne Chisholm

A collaborative pilot study with our project partner and long-term collaborator Robert Michaud (GREMM), conducted along the Saguenay River in August 2015, was instrumental in developing practicable field protocols.  Pending funding, the kick-off of this project will be this summer (2016).

To learn more about this project visit The Nature of Things (CBC).

 

 

 

 

Sponsors

This research would not have been possible without the generous support of the following organizations and individuals: 

  • The Vancouver Aquarium Board of Directors
  • The W. Garfield Weston Foundation
  • The SeaWorld & Busch Gardens Conservation Fund
  • Quark Expeditions
  • The Arctic Watch Beluga Foundation
  • Natural Mystery Films
  • Rodney and Marie Neys

 

Photo: Valeria Vergara