Home  |  Top News  |  Most Popular  |  Video  |  Multimedia  |  News Feeds  |  Feedback
  Medicine  |  Nature & Earth  |  Biology  |  Technology & Engineering  |  Space & Planetary  |  Psychology  |  Physics & Chemistry  |  Economics  |  Archaeology
Top > Biology > Tracking Sperm Whales' Ecology Through… >

Tracking Sperm Whales' Ecology Through Stomach Contents

Published: April 4, 2014.
Released by University of Massachusetts at Amherst  

AMHERST, Mass. – In the largest regional study of its type to date, marine ecologist Michelle Staudinger and colleagues offer better understanding of the feeding ecologies of two very rare sperm whale species in waters off the southeast U.S. coast, adding baseline data they say are important as climate change, fishing and pollution alters the animals' environment and food sources.

"Understanding what resources support populations of these incredibly rare animals is important to conservation," Staudinger, adjunct assistant professor in environmental conservation at the University of Massachusetts Amherst, says of the pygmy and dwarf sperm whales she studied. "If there are changes in the environment or their prey, we can now hope to better anticipate the potential impacts. There had been quite a knowledge gap about these animals, but this work gives us an idea of their ecological niche and requirements in the current environment."

For the investigation, which used two complementary methods to characterize whale foraging ecology, Staudinger and colleagues at the University of North Carolina Wilmington (UNC) analyzed stomach contents collected by the marine mammal stranding network from 22 pygmy and nine dwarf sperm whales found dead on the mid-Atlantic coast between 1998 and 2011. Study results appear in the April issue of Marine Mammal Science.

These whales in the genus Kogia feed almost entirely on beaked squid, cephalopods whose bodies are digested in whale stomachs except for the hard beaks made of chitin, a fingernail-like substance. Staudinger explains, "All deceased stranded marine mammals are necropsied, and scientists save and evaluate the stomach contents. So the stranding network had a stockpile of stomachs collected over 13 years from two of the most commonly stranded whales along the southeast and mid-Atlantic coast."

She adds, "Here I have to confess that I have a kind of unusual ability I learned in earlier research: I can identify cephalopod species by their beaks, a characteristic similar to birds. So when I heard about this study, I jumped at the chance to study these whales."

Some cephalopod species she couldn't recognize from her own reference samples, the marine ecologist noted, "so I went to the Smithsonian Institution's collection, where there are hundreds of species in collections of whalers and fishermen dating back to the 1800s."

Specifically, Staudinger and colleagues hoped to identify differences, if any, in ecological niches occupied by pygmy and dwarf sperm whales. These smaller cousins of the sperm whale were once thought to be a single species until modern analyses showed they are genetically distinct.

Beak analysis from cephalopod remains showed the diet of pygmy sperm whales to be more diverse than that of the dwarf species, the researchers report, and prey sizes were slightly larger for the pygmy than for the dwarf, but not statistically significantly so.

In the second analysis, they evaluated ratios of carbon and nitrogen isotopes in whale muscle samples, an indicator providing information on which habitats the whales were feeding in. That is, the eco-zone (e.g., mesopelagic and bathypelagic) and approximate depths where whales were feeding and whether their diets contained prey high on the food chain such as fish, or lower such as small crustaceans. Staudinger says, "As far as we know this the first time the isotopic signatures have been published for dwarf sperm whales."

She adds that isotopic tracer data suggest these two rare species, while not exactly the same, showed no significant differences in foraging parameters. "We found the ecologic niche of the two species is very similar in U.S. Atlantic waters, which is consistent with other global studies," Staudinger summarizes. "The pygmy sperm whale consumes a greater diversity and size of prey, which means they may be diving deeper than dwarf sperm whales to feed, this makes sense because pygmy sperm whales grow to larger sizes than dwarf sperm whales, however, this could also be an artifact of small sample sizes."

This is important information, Staudinger says, because if these two species show no evidence of resource partitioning there are likely enough food resources to support both their populations in the region. Though if resources shifted or became limiting, pygmy sperm whales would likely have an advantage over dwarf sperm whales as they show evidence of being able to exploit a wider range of food resources and habitats.

In the future, Staudinger plans to expand her expertise in deep-sea squid ecology through additional studies of marine mammals with UNC Wilmington, and a new investigation of cephalopod biodiversity on the Bear Seamount in the North Atlantic with the Smithsonian Institution, and the National Marine Fisheries Service National Systematics Laboratory.




The above story is based on materials provided by University of Massachusetts at Amherst.

Translate this page: Chinese French German Italian Japanese Korean Portuguese Russian Spanish


comments powered by Disqus


Related »

Whale 
3/20/14 
Passive Acoustic Monitoring Reveals Clues to Minke Whale Calling Behavior And Movements
Scientists using passive acoustic monitoring to track minke whales in the Northwest Atlantic have found clues in the individual calling behaviors and movements of this species. These findings, recently …
Whale 
8/14/14 
Minke Whales Lunge 100 Times/Hour to Feed Under Sea Ice
Highly manoeuvrable and built like torpedoes, minke whales are the most common whales in Antarctic waters, yet the animals could be living on a knife edge as their sea-ice …
Antarctic 
3/8/12 
Genetic Survey of Endangered Antarctic Blue Whales Shows Surprising Diversity
More than 99 percent of Antarctic blue whales were killed by commercial whalers during the 20th century, but the first circumpolar genetic study of these critically endangered whales has …
Whales 
8/3/11 

Cape Cod Bay Holds Hidden Risk for Dining North Atlantic Right Whales
Whoi 
4/17/12 
★★★★ 
Study Amplifies Understanding of Hearing in Baleen Whales
For decades, scientists have known that dolphins and other toothed whales have specialized fats associated with their jaws, which efficiently convey sound waves from the ocean to their ears. …
Whales 
12/16/14 

Syracuse Biologist Reveals How Whales May 'Sing' for Their Supper
Whales 
8/30/13 
Whales Feel the (sun)burn!
Whales have been shown to increase the pigment in their skin in response to sunshine, just as we get a tan. Research published today in Nature journal, Scientific …
Sonar 
7/3/13 
Military Sonar Can Alter Blue Whale Behavior
DURHAM, N.C. -- Some blue whales off the coast of California change their behavior when exposed to the sort of underwater sounds used during U.S. military exercises. The whales …
Whales 
3/14/13 
Study Questions the Role of Kinship in Mass Strandings of Pilot Whales
NEWPORT, Ore. – Pilot whales that have died in mass strandings in New Zealand and Australia included many unrelated individuals at each event, a new study concludes, challenging a …
Gero 
5/13/11 
Dalhousie Biologists Interpret the Language of Sperm Whales
When they dive together, sperm whales make patterns of clicks to each other known as "codas". Recent findings suggest that, not only do different codas mean different things, but …
More » 
 
© Newsline Group  |  About  |  Privacy Policy  |  Feedback  |  Mobile