A whale of a task: Restoring the right whale population

A North Atlantic right whale shows its fluke as it dives in the Bay of Fundy in 2009.
Bangor Daily News file photo by Bridget Brown
A North Atlantic right whale shows its fluke as it dives in the Bay of Fundy in 2009.
Posted Aug. 08, 2011, at 7:44 p.m.

Though it has been called “the urban whale,” little about the pace of modern life seems to apply to the North Atlantic right whale.

The species, one of the rarest and most endangered of all marine mammals, is often found in coastal shipping lanes and commercial fishing areas, which is how it got its relatively “urban” reputation. In the Gulf of Maine, researchers have found congregations of right whales in Jordan Basin and at Cashes Ledge.

Despite its proximity to the hustle and bustle of human marine activity, the whale is known for swimming at an estimated top speed of less than 6 mph and, in terms of the overall population, growing at an even more glacial rate of only 1 or 2 percent a year.

What it is most known for, however, is its critically low population estimates. It is so small — the latest estimate suggests there are between 450 and 470 — that scientists are concerned that the North Atlantic right whale could go extinct. The whales’ low population growth rate makes their situation especially dire, scientists have said.

The species is legally protected under the federal Endangered Species Act and Marine Mammal Protection Act, and because of those laws fishermen in Maine and elsewhere are facing restrictions on the gear they use to fish. Entanglements in such gear continues to cause the deaths of right whales, whale advocates say, and is believed to have caused scars on possibly more than three-quarters of all North Atlantic right whales.

In 2009, the federal National Marine Fisheries Service ordered lobster fishermen who set traps outside a distance roughly three miles from shore, including in the Gulf of Maine, to use expensive sinking ground lines between traps instead of vertically arcing loops of floating rope. The floating rope was cheaper and less likely to get caught on the rocky ocean bottom, but whale biologists said it posed more of an entanglement hazard for whales.

Ropes that connected traps to surface buoys were exempt from the 2009 law, but the National Marine Fisheries Service is in the midst of holding a series of public meetings along the East Coast to gather input about how to reduce the threat of entanglement in these ropes, also known as vertical lines.

Fishermen concerns

Lobstermen in Maine, who brought ashore a total of $313 million worth of lobster in 2010, have expressed frustration with the restrictions. The prices fishermen are getting for their lobster remain relatively low, many have said, while their expenses for fuel, bait and gear remain consistently high.

According to Maine Department of Marine Resources statistics, there are about 6,000 licensed commercial lobstermen in Maine.

“In the economic times we’re in now, jobs are at a premium and you’re asking us to make an extreme sacrifice,” Deer Isle fisherman Leroy Bridges told federal regulators at a July 12 meeting in Ellsworth about whale-safe gear restrictions. “We fished the way we fished because there was a need.”

One aspect about the prospects of additional restrictions that fishermen find confounding is that new mandates are being considered at the same time that the North Atlantic right whale population is increasing. According to official estimates, the number of right whales in the North Atlantic has increased from fewer than 300 two decades ago to around 450 now.

Why, some fishermen have asked, do they have to face more restrictions if the whale population is going up? Why is the chance of even one whale coming into contact with one of potentially several million traps in the water considered too high a statistical risk? How much longer will they have to abide by rules aimed at protecting a whale that many fishermen claim they have never seen?

“We’re still having [restrictions] thrown at us,” Bar Harbor lobsterman Jon Carter said at the same July 12 meeting. “[Our industry] is being driven by things that don’t care that we’re here.”

Population growth

According to a November 2010 National Marine Fisheries Service stock assessment of the North Atlantic right whale, the population is believed to have increased by more than 50 percent in the past 20 years. Fewer than 300 animals were estimated to exist in the 1990s, while the latest estimate is approximately 450.

The 1990s were a bad decade for right whale calf births. Twenty-two were born in 1996 and 20 more in 1997, but for each of the three years before 1996 and after 1997, fewer than 10 calves were born. In 2000, only one calf was born among the entire population.

Since 2001, however, the lowest number of calves born in any year was 17 in 2004. In 2009, 39 calves were born — the most in recent memory — while 19 were born in 2010 and 22 this year.”

According to the assessment, 297 calves were born from 1993 to 2009, more than twice as many that were born during the preceding 12 years. But 21 calves that were born from 1993 to 2009 are believed to have died later in their birth years, with a few more first-year deaths suspected for calves born in 2010 and 2011.

Scientists and others have expressed mild optimism that the population seems to be increasing. Still, because the species’ population remains so small, and because several whales are believed to die each year from fishing gear entanglements, ship strikes and natural causes, scientists believe the whales are not reproducing quickly enough to have long-term viability as a species. Even the premature death of one whale, especially a reproductive female, represents a significant setback to the right whales’ genetic diversity and future, according to advocates.

“That’s not a good rate of growth to recover a population,” Dr. Amy Knowlton, a researcher with New England Aquarium in Boston, said last week about the whales’ estimated 1 to 2 percent growth rate. “We’re only inching toward 500.”

Knowlton said two right whales died off the southeastern U.S. this past winter because of entanglements, and that as much as 82 percent of the North Atlantic whale population has been estimated to have scars from entanglements.

“It happens frequently,” she said. “It is not an insignificant problem.”

Other right whale populations

Knowlton compared the North Atlantic right whale population to the more numerous right whales in the southern hemisphere, which the London-based International Whaling Commission estimates to have a population of around 7,500. Despite their higher numbers, the commission has banned commercial hunting for southern right whales, as it has for all whale species.

Knowlton said it is not unusual for southern right whales to have 300 calves in any given year. She said the relative lack of human activity in areas of southern right whale habitat is thought to be a main reason why the number of southern hemisphere whales has increased more dramatically than that of their northern cousins.

“They don’t have the same density of fishing gear and they don’t have as intense shipping,” Knowlton said. “They don’t have as urban an ocean as we do up here.”

Southern right whales are considered a separate species from right whales in the North Atlantic or North Pacific, which likewise are considered separate species. The population of North Pacific right whales is thought to be similar to that of the North Atlantic species — measured in the hundreds rather than the thousands.

Because of the availability of food and their physiology, right whales do not swim past the equator in either direction, but southern right whales have the ability to swim among the southern Atlantic, Indian and Pacific oceans. Those in the north Atlantic and north Pacific oceans cannot swim north into other oceans because of the arctic polar ice cap.

Reproduction and mortality

According to David Laist, policy and program analyst for the federal Marine Mammal Commission, scientists aren’t sure why North Atlantic right whales started producing more calves in the 2000s. It could be related to climate change and may have been helped by regulations implemented in the mid-2000s that required large ships to reduce their speeds in known right whale habitat areas off Florida, Georgia and Massachusetts, he said.

Laist said there is no effective way to boost the whales numbers by other means, such as through artificial insemination or by breeding them in captivity.

“We don’t know exactly what it was,” Laist said recently about the increase in calves. “The only thing you can do for the right whales is reduce the known human-caused mortalities.

The reason this is difficult is because there are so few options.”

Though the increase is “encouraging,” Laist said, there is no guarantee that the low reproduction rate of the 1990s will not return.

Laist said he believes right whales have natural lifespans of 100 years or more but that deaths caused by ship strikes and entanglements are hampering the species’ reproductive success.

No one really knows how many whales die each year because those that do, especially as a result of entanglements, usually just “disappear” instead of being found by humans, he said.

Calves especially are vulnerable to dying in their first year, but experienced whale mothers are more successful than their younger counterparts at raising young, he added. If the whales generally live shorter lives, it likely impedes the number of chances cows have to successfully produce offspring.

“There’s no question the number of [premature] deaths is affecting population,” Laist said.

“The population is still very vulnerable.”

As for the ideal population size for the North Atlantic right whale, Laist said no one knows.

The question is academic because there is no scientific data about how many right whales there used to be before commercial whaling rendered them nearly extinct 100 years ago.

Endangered species listing

If the species can increase to “several thousand” animals, scientists and regulators likely would agree that its official status could be changed from “endangered” to “threatened,” a designation that means their situation is less dire. Barring any setbacks in the calving rate of the past decade, Laist said such downlisting likely would take “several decades” to accomplish. More specifically, he said he could see that happening in less than 100 years from now, but probably not less than 50.

“Everything about right whales is slow,” Laist said.

According to David Gouveia, marine mammal coordinator for the National Marine Fisheries Service, the agency’s revised recovery plan, which was drafted in the early 2000s, calls for the whales’ population to increase at a minimum rate of 2 percent a year over 35 years, which should result in the population doubling over that time. Only “about 300 individuals” were thought to exist at the time the plan was revised, the document indicates, which suggests that officials would like to see around 600 animals before 2040.

Gouveia indicated last week in an email that such a recovery could result in the whales’ status being changed to “threatened.” The plan does not set any benchmarks for removing right whales from the list altogether, he said. There are several variables that figure into right whale population projection models, he said, but the general sense among regulators and scientists is that it could take between 50 and 100 years to have a population of 1,000 whales or more.

“Decades of population growth likely would be required,” before the National Marine Fisheries Service would consider delisting right whales as either endangered or threatened, he said.

Lobstermen’s group: more research needed

Lobstermen, however, don’t want to wait that long to determine what kind of future their industry might have.

Patrice McCarron, executive director of Maine Lobstermen’s Association, said last week that lobstermen cannot stumble along indefinitely absorbing new restrictions based on theories. There needs to be scientific proof, not just anecdotal evidence, she said, that mandated lobster gear restrictions actually are making conditions safer for whales.

“I don’t think we should have to do something forever if we don’t know whether it’s working,” McCarron said.

Beyond doing research to examine the effectiveness of required gear changes, there should be more proactive research on whale behavior and other possible gear modifications, according to McCarron.

She has said co-occurrence models recently developed by the National Marine Fisheries Service, which show where whales and lobster fishing gear are most likely to come into contact with each other, represent an improvement in scientific data. A few years ago, during deliberations about the sinking ground line mandates, there were no probability models being used or considered by regulators, she said.

The models show that the areas in Maine where whales and lobster gear are most likely to overlap are off eastern Washington County and York County, though lobster buoys and whales can be found along the entire coast.

More specific research about interactions between whales and fishing gear would help determine how and where whales are getting entangled, McCarron said.

“The industry really needs to push for better information,” McCarron said. “If you don’t understand what’s happening, you’re in a position of not knowing what you’re trying to solve.”

Even though scientists have raised concerns about the high percentage of right whales that have apparent entanglement scars, McCarron said the marks suggest that whales can come into contact with fishing gear but then escape and remain healthy. If there is something that is helping whales swim away relatively uninjured from traps without ropes dangling off their bodies, it would help both fishermen and whales to find out what it is, she said.

“I think the fact that they’re swimming away happy — that’s huge,” she said.

If lobstermen can find a way to earn a living by catching lobsters without posing any threat to whales, she said, the industry will have a secure future.

“Even if the whales are still endangered, it doesn’t mean we would continue to be regulated,” McCarron said.

But for Knowlton, who comes to Lubec every summer with other New England Aquarium researchers to study right whales in the Bay of Fundy, how whales are affected by fishing gear should go beyond simple numbers.

Knowlton agreed that it could take 100 years or more for the right whale population to increase to a biologically viable level. In addition to boosting the species’ likelihood of survival, she said, humane treatment of the charismatic marine mammal should be considered a significant motivating factor for protections that are put in place.

The ideal approach is not just to make sure there are enough whales so that the species can survive entanglements and ship strikes, according to the scientist. The whales should be treated with empathy, she said, so that none has to suffer the agony of getting entangled and then suffering a slow, painful death that often involves starvation or drowning.

“They suffer a terrible ending to their lives,” Knowlton said.

Follow BDN reporter Bill Trotter on Twitter at @billtrotter.

http://bangordailynews.com/2011/08/08/environment/a-whale-of-a-task-restoring-the-right-whale-population/ printed on August 22, 2014