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New study may help free whales from fishing rope entanglement

By John Barrat

This four-year-old male right whale entangled in heavy fishing rope was spotted in February 16 2014, 40 miles east of Jacksonville, FL. Florida Fish and Wildlife biologists removed a large portion of the fishing rope and attached a satellite tracking buoy to the remaining rope so the whale could be relocated for further disentanglement the next day. (Florida Fish and Wildlife Conservation Commission image, taken under NOAA research permit #15488)

This four-year-old male right whale entangled in heavy fishing rope was spotted in February 2014, 40 miles east of Jacksonville, FL. Florida Fish and Wildlife biologists removed the fishing rope. (Florida Fish and Wildlife Conservation Commission image, taken under NOAA research permit #15488)

New data just published in the journal Marine Mammal Science may help save the whales, or at least a good many of them.

Using vertebrae and muscle measurements taken from dozens of whale skeletons in museums and research facilities around the country, a team of marine biologists has created a new chart estimating the maximum pulling force that different whale species can create with their tail flukes. Knowing these values may someday aid in designing fishing rope that whales can break or nets with built-in weak links that come apart when a whale becomes entangled.

“There is this idea that large whales are the strongest animals on the face of the earth and that nothing can stop them,” says William McLellan, a marine mammal expert at the University of North Carolina Wilmington and co-author of the paper. “While they have a lot of strength in their axial tail muscles, whales are not infinitely strong. There are actually some upper limits to their strength and the type of line they can break.”

“Critically endangered whale populations are struggling to recover and one of the things holding them back is entanglement in fishing gear,”  says Charles Potter, a whale expert at the Smithsonian. “It’s a very slow and painful death.”

 Representative vertebrae from several cetacean species, shown at the same scale and viewed from the cranial face. The vertebrae are denoted by the genus species abbreviated from Table 2

Representative vertebrae from several cetacean species, shown at the same scale and viewed from the cranial face.

One way to estimate the maximum force a muscle can produce is to simply measure its size. Starting with known values of force and thrust measured during trials with live bottlenose dolphins, the team used a cross section of a stranded bottlenose dolphin’s axial muscles (which power the tail flukes) taken near the dorsal fin and calculated the cross-sectional area of the dolphin’s muscle in this region of the vertebral column. With this known ratio between force and muscle area in bottlenose dolphins, the team next applied it to whales, taking measurements of museum whale vertebrae to get an estimate of a species’ average adult axial muscle size. With this measurement the scientists were able to estimate how much force the animal could produce.

For example, the study determined a 16.4-foot-long, short-finned pilot whale can produce a maximum force of roughly 1,131 pounds. A 12-foot whale of the same species can create a maximum force of 701 pounds.

Whale scientist Logan Arthur takes the measurements of a whale vertebrae.

Whale scientist Logan Arthur takes the measurements of a sperm whale vertebrae in the Smithsonian’s collection. (Photo by Ann Pabst)

“We started off with bottlenose dolphins and went up the size tree through to right whales, blue whales and sperm whales, estimating total force production. This is the first time we know of that this has been done,” says McLellan, who conducted the work with researchers from the University of North Carolina Wilmington, the Smithsonian’s National Museum of Natural History, the University of Maine and New River Kinematics.

To verify the accuracy of their estimates of axial muscle cross-sectional area in different whale species “we did a lot of dissections on stranded animals, so we had direct connection with the tissues of the large whales while we were on the beach,” McLellan says. Team members also took measurements from large whales that are on exhibit up and down the east coast, such as the right whale on exhibit at the New Bedford Whaling Museum.

Marine Mammal Collection

Staff from the Smithsonian’s National Museum of Natural History stand with a few whale specimens maintained by the museums Division of Mammals. (Photo by Don Hurlbert)

One surprising aspect of the study, according to principle author Logan Arthur, a recent graduate at UNC Wilmington, is that the force a whale produces begins to drop off in scale to its body size the larger it gets. In other words, “per unit body length, the larger whales were actually weaker than a dolphin,” Arthur says.

Another possible use for this data, McLellan says, is “we’ve been looking at the strength of the big offshore hooks used to catch bluefin tuna and swordfish and how much force a pilot whale would need to produce to be able to bend one of these hooks, straighten it and release itself.”

“It is fascinating to me,” Potter says, “that some whale specimens collected by the Smithsonian at the turn of the 19th century are being used to help with conservation issues that are confronting us today. In a sense museum specimens never stop giving. This is the kind of data that we biologists can produce and turn over to the fishing gear-tech folks to help create fishing gear that is safer for whales.”

 

 

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  • 301AndreaBordot

    Nice ideas ! BTW , if anyone requires a GBREB RA101 , my business partner filled a fillable version here http://goo.gl/nYBKMg

  • James W. Farr

    I have collected and curated Nassau County Dept. of Health’s Marine Polychaete collection kept in Mineola,N.Y. The importance of keeping specimens as long asyou can could lead to breakthroughs in keeping species from extinction.I also started the Tipulidae collection of Suffolk County, New York kept at the Tackapauscha preserve in Seaford.N.Y. Even local museums have huge importance in future research.I am very impressed by the Smithsonian scientists.

  • Mark Caponigro

    Charles Potter’s understated description of what happens to whales when they are entangled in the latest generation of fishing gear should be highlighted, for it’s morally the most important sentence in this article: “It’s a very slow and painful death.”

    “Painful” is a key word here, because it’s not just a matter of the whales’ being slowed down until they can’t feed themselves sufficiently; rather, the ropes cut ever deeper into the blubber, and this is excruciatingly painful.

  • 1GregDiDomenico

    Are you aware that conservation efforts and gear modifications in these fisheries has recovered humpback whales to a point where the NMFS is considering delisting them and right whale populations have been growing for 10 years?

    • Mark Caponigro

      This is not true. Recently designed fishing line now in use is harder than ever to cut, and digs deeper than ever into the blubber of an entangled whale. And the numbers of North Atlantic right whales have fluctuated somewhat, but there is not clearly a pattern indicating an increase in their population, nor are they at all “out of the woods.” They most certainly still need the protections they have, such as they are, and even more extensive ones. E.g., offshore activities related to exploration and drilling for oil reserves, off the US Atlantic coast, should not be permitted — for the sake not only of the right whales but of many other marine and coastal animals and ecosystems.

  • MaryFinelli

    Be a part of the solution NOW: Don’t eat aquatic animals. All of the nutrients derived from them -and all animals/animal products- can be obtained more healthfully, humanely, and environmentally responsibly from plant sources.

  • Teresa Wagner

    “Knowing these values may someday aid in designing fishing rope that
    whales can break or nets with built-in weak links that come apart when a
    whale becomes entangled.” This is fascinating and important work. But “someday” is too late. Worldwide laws are needed to both limit fishing and require ropes and nets that whales can from themselves from. And because that is a very very long way off and may never happen, if humans stopped raping the sea for fish and refused to eat food caught with these lethal nets, ropes and traps the whales, dolphins, seals, turtles, sharks and seabirds would have a chance.