” Social exploitation of extensive, ephemeral, environmentally managed prey spots by supergroups of rorqual whales” by David E. Cade, James A. Fahlbusch, William K. Oestreich, John Ryan, John Calambokidis, Ken P. Findlay, Ari S. Friedlaender, Elliott L. Hazen, S. Mduduzi Seakamela and Jeremy A. Goldbogen, 19 November 2021, Animal Behaviour.DOI: 10.1016/ j.anbehav.2021.09.013.
” Acoustic signature exposes blue whales tune life-history shifts to oceanographic conditions” by William K. Oestreich, Briana Abrahms, Megan F. McKenna, Jeremy A. Goldbogen, Larry B. Crowder and John P. Ryan, 3 February 2022, Functional Ecology.DOI: 10.1111/ 1365-2435.14013.
Using sound recordings from the heart of Monterey Bay National Marine Sanctuary, MBARI scientists and their partners have actually found new measurements of blue whales lives. The MBARI hydrophone is giving us new insights into not just blue whale habits, however what that habits can tell us about the prey conditions in Monterey Bay that are important for the entire environment,” stated Cade.
The research study group observed that rather than completing for food, blue whales called to other whales to indicate food was present. In 2020, Oestreich and a group of researchers from MBARI and Stanford University recorded distinct seasonal changes in blue whale vocalizations that expose when these gentle giants begin their annual migration. MBARI will expand these efforts in 2022 with the new Blue Whale Observatory.
The blue whale (Balaenoptera musculus) is the biggest animal that has actually ever lived on Earth, yet we still have many unanswered questions about its biology and ecology. New research leverages audio taped by an undersea microphone on MBARIs cabled observatory to better understand the behavior of these behemoths. Credit: © NOAA
An underwater microphone (hydrophone) on MBARIs cabled observatory has been an important tool for studying whales that collect seasonally in the fertile waters of Monterey Bay. The microphone records the calls of whales– acoustic information that use insight into the animals habits.
” Because whales and other marine mammals use noise in the essential life activities of communicating, foraging, browsing, socializing, and recreating, there is a wealth of expressed awareness in the ocean soundscape. We aim to tap that wealth to much better comprehend and protect ocean life,” stated John Ryan, a biological oceanographer at MBARI.
Previous research by Ryan and partners at Stanford University– consisting of inbound MBARI Postdoctoral Fellow William Oestreich– coupled the hydrophones extensive archive of acoustic data with field studies to better comprehend blue whale habits.
When blue whales dive out of sight underneath the oceans surface area, researchers rely on the whales thriving vocalizations to study their behavior. Credit: William Oestreich (NMFS Permit # 16111).
” Our previous research study efforts with partners from around Monterey Bay opened the door to understanding the behavioral context of patterns in the acoustic information collected on blue whales with MBARIs hydrophone. This context has actually set the stage for a series of research studies which take advantage of the incredible long-lasting view on behavior that this acoustic record supplies,” said Oestreich.
Now MBARIs acoustic data have actually contributed to two new research studies about blue whales led by graduate trainees at Stanford Universitys Hopkins Marine Station in Pacific Grove, California.
Cade was recently a postdoctoral researcher in Ari Friedlaenders Bio-Telemetry and Behavioral Ecology Lab at University of California, Santa Cruz, and is now a postdoctoral scientist in Jeremy Goldbogens lab at Hopkins Marine Station.
Leveraging biologging tags, acoustic victim mapping, hydrophone recordings of social hints, and remote sensing of ocean currents, the research study team, consisting of Oestreich and Ryan, investigated the environment dynamics underlying abnormally dense aggregations of blue whales– up to 40 of the giants within a one-kilometer radius area.
Krill are small shrimp-like shellfishes that are the primary food source of blue whales. Dense aggregations of krill occur seasonally in Monterey Bay, sustaining populations of lots of marine animals. Credit: © 2003 MBARI.
” We are only simply beginning to study the role of these giant, however ephemeral, krill patches that can feed a super-group of blue whales. These hotspots likely play a critical function in general in a blue whales ability to discover sufficient food prior to it swims south for the winter season. The MBARI hydrophone is providing us new insights into not only blue whale behavior, but what that behavior can inform us about the prey conditions in Monterey Bay that are important for the whole ecosystem,” said Cade.
The mix of oceanographic conditions and seafloor surface (bathymetry) focused great deals of shrimp-like crustaceans called krill, which are the main food of blue whales. The enormous size of the krill swarms permitted these “supergroups” of blue whales to forage together without exhausting the food supply.
Ryan and Oestreich were studying all types of blue whale vocalizations, consisting of one that is related to foraging.
” In the hours right away preceding these impressive aggregations of foraging blue whales, MBARIs hydrophone tape-recorded anomalously dense clusters of a specific blue whale call type. This exciting finding raised a number of hypotheses and concerns worrying the role that these vocalizations play in blue whales foraging and sharing of info,” remembered Oestreich.
By studying vocalizations from “supergroups” of blue whales while they feasted on krill in Monterey Bay, researchers observed that instead of keeping quiet about discovering an abundance of food, private whales contacted us to others to share in the feast. Credit: © Duke Marine Robotics and Remote Sensing (NMFS Permit # 16111).
The hydrophone recordings exposed that, counterintuitively, the whales displayed a social foraging method. The research team observed that instead of competing for food, blue whales called to other whales to signify food existed. The blues bellows welcomed others to sign up with the banquet.
Modeling of social interactions showed that using social details from other whales decreased the time needed for individual whales to find and exploit the thick spots of food that they need to make it through. The whales foraging ended up being more effective, with no apparent costs to the caller who first discovered the spot of food.
A 2nd research study, [2] led by Oestreich and published this month in Functional Ecology, also made use of MBARIs acoustic archive to acquire new insight into blue whale behavior.
In 2020, Oestreich and a team of researchers from MBARI and Stanford University documented distinct seasonal modifications in blue whale vocalizations that expose when these gentle giants begin their yearly migration. Throughout summer and early fall, blue whales sing more during the night.
Excerpt from a blue whale tune tape-recorded in Monterey Bay, California. To make the low-frequency sound more audible, playback speed is 10x initial. This spectrogram shows the “A,” “B,” and “C” calls of blue whales, coupled with audio of these same calls repeated at 10 times their initial speed to make them simpler to hear. This audio was tape-recorded from MBARIs hydrophone situated in the heart of Monterey Bay National Marine Sanctuary. The day/night pattern of “B calls” can be utilized as an indication of whether the whales are moving or feeding. Credit: © 2020 MBARI.
Now, Oestreich and his collaborators have utilized MBARI hydrophone information to comprehend how blue whales change the timing of their migration back to reproducing locations from year to year.
We have actually long known that whales time their migratory motions with natural cycles in their marine environment, specifically seasonal changes in productivity. How populations adjust the timing of their migrations in response to year-to-year ecological irregularity stayed uncertain.
The information, gathered from summertime 2015 through spring 2021, taped the shouting vocalizations of blue whales in the Monterey Bay region. Sound signified when whales stopped foraging on the local abundance of krill to start their southward breeding migration. To the teams surprise, the start of the whales migration might differ as much as 4 months from year to year.
Considering that the blue whale reproducing season itself covers only around 4 months, this big variation in the timing of migration was at first perplexing. Here, data about environment changes from year to year offered crucial hints.
Migration timing carefully followed conditions within the whales foraging habitat. Specifically, blue whales remained longer off central California when the ecosystem supplied more opportunity for them to build energy stores. A later shift from foraging to migration took place in years with an earlier start, later peak, and higher build-up of biological efficiency.
A blue whale surfaces in between foraging dives in Monterey Bay, California. Credit: William Oestreich (NMFS Permit # 16111).
These findings suggest that in years of the greatest and most consistent biological performance, blue whales wait to start their southward migration. Researchers think the whales do not just leave towards their southern breeding premises as quickly as sufficient energy reserves are built up. Rather, the whales delay their migration when food is plentiful to maximize their energy intake on their foraging grounds.
” We previously showed that blue whales use long-lasting memory to time their arrival on foraging premises based on when they anticipate food to be available due to the fact that they do not have advance info about what foraging conditions will be like when they get here. This allows these whales to be extremely flexible in when they initiate their southward migration to return to reproducing areas,” explained Briana Abrahms, an assistant professor in the Department of Biology at the University of Washington and a coauthor on the study on migration timing.
The usage of flexible cues– most likely including foraging conditions and long-distance acoustic signals– in timing a significant life history shift might be key to the persistence of this threatened population as it browses an environment that experiences big natural and anthropogenic changes.
” This research study suggests that blue whales are more versatile in their foraging and migratory behavior than previously recognized. Such flexibility is crucial for adjustment to a period of fast international change– whether this behavioral flexibility enables blue whales to adjust to long-lasting modifications in their foraging habitat stays to be seen,” stated Oestreich.
Open access to clinical information is a basic worth for MBARI and part of the institutes objective. As part of MBARIs dedication to open cooperation, the original audio recordings for the whole research study period are offered through the Pacific Ocean Sound Recordings task via the Registry of Open Data on the Amazon Web Services (AWS) cloud.
” Scientific discovery and progress need reproducibility, extensibility, and openness. Towards fulfilling these requirements, we share all of our audio recordings– 150 terabytes and growing– together with an analysis toolbox,” said Ryan. “Our newest confirmation of the worth of open data occurred recently, when a tenth grader from Canada contacted me to show me how he had actually extended research study from among our published research studies.”.
MBARI likewise streams live undersea audio to the Soundscape Listening Room to share the wonder and excitement of the ocean soundscape with the public. The live soundscape can be loaded with ocean “voices”– from the complex song compositions of humpback whales to the chatter of dolphin pods. The listening space also includes archived sounds for listening when the live stream is peaceful.
MBARI technology has actually proven important to researchers studying the habits of threatened blue whales. MBARI will broaden these efforts in 2022 with the new Blue Whale Observatory. This brand-new task– led by Oestreich and Ryan with marine ecologist Kelly Benoit-Bird and researcher Chad Waluk– will take a look at blue whale ecology in depth by incorporating interdisciplinary noticing of the whales, krill, and their ecosystem. The observatory will leverage an array of technologies to bring together the pieces of a complex, important, and beautiful puzzle.
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The blue whale (Balaenoptera musculus) is the largest animal to ever occupy our planet. Regardless of its giant size, lots of elements of its ecology, biology, and behavior still avoid us. This stunning mammal spends most of its time below the oceans surface, out of sight from researchers looking for to open its mysteries.
However even when we can not observe blue whales by sight, we can hear their effective vocalizations that take a trip hundreds of kilometers. Using sound recordings from the heart of Monterey Bay National Marine Sanctuary, MBARI researchers and their partners have found new measurements of blue whales lives. When to embark on their yearly long-distance migration for reproducing, we have actually found out how blue whales comply to forage and how they tune into the performance of their ecosystem to choose.
