Right whales caught in fight for survival

THE RECENT discoveries of six dead North Atlantic right whales along the coast from New England to Florida are extremely troubling to the scientists who study them. However, the occasional news stories about a dead whale, when spread out over a year-long time frame, give little impression of the grave impact that the loss of these whales has on the future of their species. Right whales are dying faster than they are being saved.

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The tiny North Atlantic right whale population has hovered at around 300 for decades. Government biologists and regulators have determined that right whales are now so critically endangered that protecting every single animal is vital to the species' survival.

European and North American whalers hunted right whales to near extinction by the mid 18th century, and their recovery has been very slow since then. Possible genetic and environmental reasons are being explored, and a couple of especially important things have been learned.

The surviving animals exhibit an unexpectedly low and inconsistent reproductive rate, but that alone does not account for the stalled growth of the population. However, when mortality issues were also considered, more than half of all right whale deaths of known cause were found to be the result of human activities, primarily collisions with ships and entanglements in US and Canadian commercial fishing gear off the Atlantic coast. Since most of these whales die at sea, not on beaches where they can be fully investigated, the actual number of human-caused deaths should be assumed to be higher still.

Scientists at the New England Aquarium have reported that more than 72 percent of the 300 surviving right whales carry scars from encounters with ropes at sea and that up to 84 of these animals may become entangled every year.

Lethally entangled whales typically succumb to complications from their injuries or to starvation. Death can take months, and the whales may travel for thousands of miles dragging the gear with them. When last seen alive, these whales are often so emaciated that they would be expected to sink quickly upon death and are unlikely to be found. The number of deaths from entanglement cannot be known, but may be even higher than those caused by vessel collision, since entanglements are less likely to produce floating carcasses that can be counted.

Seventy years after right whales were protected by international agreement and more than 30 years after their protection was given the full weight of US law, it is evident that many right whale deaths are now the unintended consequences of the normal operations of legitimate, highly regulated marine industries. Humans are still their biggest threat.

Understanding that many more whales are killed than are reported, scientists find even the minimum mortality figures alarming. Three of the six dead right whales discovered during a 12 month period in 2004-05 were determined to have been victims of ship-strike. All three were also found to be adult females, each carrying a near-term fetus.

Let's try considering this from another perspective. It is often difficult to understand a biological phenomenon without examining it under a microscope. Perhaps if we placed right whale population numbers under a statistical microscope, the public perception of the issue of lethal human-whale interactions would be better addressed.

Under a 10-power, ''statistical microscope" the surviving 300 right whales would become 3,000, a number that still leaves them critically endangered. Since all relative proportions of the statistics are unchanged under our microscope, instead of the three recorded human-caused deaths we find that 30 dead pregnant right whales have now washed up on our beaches.

If we were actually fortunate enough to have 3,000 right whales today, the public response to 30 pregnant right whales killed along the US East Coast in a year would be significantly different than it was for only three. Nevertheless, the smaller number represents the identical ecological predicament for the whales. For humans, the difference is simply one of perception.

Bob Bowman studies whales off the New England coast and is a member of a federally authorized large whale disentanglement team.