Humpback Whales Feed in Different Ways Finds NOAA

SeaDiscovery.com
Thursday, September 26, 2013
Humpback with scraped nostril from bottom-feeding: Photo credit NOAA

New NOAA-led research on tagged humpback whales in Stellwagen Bank National Marine Sanctuary reveals a variety of previously unknown feeding techniques along the seafloor. Rather than a single bottom feeding behavior, the whales show three distinct feeding approaches: simple side-rolls, side-roll inversions, and repetitive scooping.

A recently published paper, in the journal Marine Mammal Science, indicates that bottom side-roll techniques are common in Stellwagen Bank National Marine Sanctuary and the Great South Channel study area, a deep-water passage between Nantucket, Mass. and Georges Bank-further southeast.The study further states that the observed feeding behavior also leads to vulnerability to entanglement in bottom set fishing gear, an issue which is a major mortality factor for the species. This finding reaffirms a NOAA Fisheries regulation that mandates the use of sinking line between fishing traps used in the lobster fishery as a way of reducing entanglements.

The new findings follow earlier NOAA-led studies detailing so-called "bubble net" feeding behaviors near and at the surface. Bubble net feeding is a behavior in which humpback whales corral and contain fish into a small area by trapping them in nets of air bubbles so they can more efficiently scoop them up in their large filter-feeding mouths.The behaviors are used by individual animals and as part of coordinated feeding behaviors involving two or more animals.
 
"Tagging technology is allowing us to observe whales underwater, much as land-based biologists study animal subjects in their specific environments," said David Wiley, sanctuary research coordinator and aco-author on the paper. "The data have allowed us to detect new feeding techniques as well as nuances in those behaviors. We have determined that bottom feeding is a much more commonly used technique than the more well known bubble net behaviors."
 
Bottom side-rolling feeding was previously hypothesized from observations of scars on the jaws of humpback whales and from earlier tagging projects. In the recent studies, researchers showed that this behavior happens for extensive periods of time at or near the seafloor, that it occurs in the presence of concentrations of sand lance (a preferred prey fish), and that the behavior is accompanied by the expansion of the animal's ventral (throat) pleats.
 
Information was collected through the use of DTAGs (synchronous motion and acoustic recording tags) and Crittercam™, National Geographic Society's underwater video and audio recording system.
 
"By visualizing the data with TrackPlot, we can actually see how the whale moves underwater and this enables us to discover different kinds of foraging behaviors," said lead author Colin Ware of the University of New Hampshire's Center for Coastal and Ocean Mapping. TrackPlot is a custom software tool for DTAG data that produces a ribbon-like image in three dimensions. "With these 3-D visualizations, we can follow the path of the whale from surface to seafloor along with all of the pitch, roll and heading changes while underway. By adding Crittercam video, we now get a more complete understanding of these various bottom feeding techniques," Ware said.

Designated in 1992, Stellwagen Bank National Marine Sanctuary encompasses 842 square miles of ocean, stretching between Cape Ann and Cape Cod offshore of Massachusetts. Renowned for its scenic beauty and remarkable productivity, the sanctuary supports a rich diversity of marine life including endangered great whales, seabirds, more than 60 species of fishes and hundreds of marine invertebrates. 

 

Maritime Reporter September 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Technology

Maritime Broadband Opens Office in Greece

Maritime Broadband has expanded its worldwide footprint by opening an office, Maritime Broadband Hellas, in Athens, Greece. The new office addresses the growing

Statoil: New Oil in the Grane Area

Statoil has together with PL169 partners proved new oil resources in the D-structure in the vicinity of the Grane field in the North Sea.   Well 25/8-18 S, drilled by the rig Transocean Leader,

New Standard for LNG Cargo Containment Systems

Wilhelmsen Technical Solutions (WTS) said it has successfully completing the gas trial for the first LNG carrier built to a Boil Off Rate (BOR) of 0.08% per day.

Marine Science

Mitsubishi Super Skiving System

Mitsubishi Heavy Industries, Ltd. (MHI) has completed development of the "Mitsubishi Super Skiving System" for machining internal gears with high speed and outstanding precision.

Ocean Power Technologies to Deploy PB40 PowerBuoy Off New Jersey

Ocean Power Technologies, Inc., announced today that the PB40 PowerBuoy(R) fabricated for the WavePort Project has shipped from Santander, Spain to Bayonne, NJ

Northrop Grumman Sponsors Maritime RobotX Challenge

Northrop Grumman Corporation is expanding its support for science, technology, engineering and math (STEM) education across the globe by sponsoring the Maritime RobotX Challenge in Singapore, Oct.

Ocean Observation

Salamander Energy Updates on SONA Transaction

Salamander Energy said it has submitted a draft shareholder circular to the Financial Conduct Authority in relation to previously stated plans to divest of an interest in the Greater Bualuang Area.

Sea Level Rise ‘Worst Case Scenario’

A paper published this week in Environmental Research Letters by NOC scientist Dr. Svetlana Jevrejeva provides new information about the probability of a sea-level rise reaching of 180cm by 2100.

El Niño Could Kick Off in 1-2 months

The El Niño weather phenomenon is favored to occur in the next 1-2 months and last into next spring in the Northern Hemisphere, the Climate Prediction Center (CPC),

 
 
Maritime Careers / Shipboard Positions Maritime Contracts Maritime Standards Navigation Offshore Oil Pod Propulsion Salvage Ship Electronics Shipbuilding / Vessel Construction Sonar
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1438 sec (7 req/sec)