Wednesday, June 13, 2007

What a pain in the neck...

Really fascinating story: a bowhead whale was found with a 19th century weapon embedded in its neck.

The whale was caught off the coast of Alaska, and apparently had escaped an earlier attempt at capture over a century ago. Judging from the age of the weapon (a fragment of a bomb lance, manufactured in New Bedford, Massachusetts), the whale's age is estimated to be about 115-130 years.

As the news article mentions, whales are thought to have extremely long lifespans, in some cases 200 years or more, but it is hard to determine exactly. The journalist makes a passing reference to the use of amino acids in the eye lenses. This was actually covered in a fascinating paper in a recent issue of the Journal of Mammalogy:

Garde, Eva, Heide-Jorgensen, Mads Peter, Hansen, Steen H., Nachman, Gosta, and Forchhammer, Mads C. 2007. Age-specific growth and remarkable longevity in narwhals (Monoceros monoceros) in Greenland as estimated by aspartic acid racemization. Journal of Mammalogy. 88(1): 49-58.

The abstract:
Eyes from 75 narwhals (Monodon monoceros) were collected in West Greenland in 1993 and 2004 for the purpose of age estimation. Age estimates were based on the racemization of l-aspartic acid to d-aspartic acid in the nucleus of the eye lens. The ratio of d- and l-enantiomers was measured using high-performance liquid chromatography. The aspartic acid racemization rate (kAsp) was estimated to be 0.001045/year ± 0.000069 SE by regression of d/l ratios on age estimated by length from 15 young narwhals (≤298 cm) and by earplug laminations from 13 fin whales (Balaenoptera physalus). The d/l ratio at age 0 ((d/l)0) was estimated to be 0.0288 by regression of d/l ratios against the estimated age of the 15 young narwhals. The intercept of the regression slope, providing twice the (d/l)0 value, was 0.05759 ± 0.00147 SE. The maximum estimated age was a 115-year-old (±10 SE) female. Asymptotic body length was estimated to be 396 cm for females and 457 cm for males, and asymptotic body mass was estimated to be 904 kg for females and 1,645 kg for males. Using the von Bertalanffy growth model, age at sexual maturity was estimated to be 6–7 years for females and 9 years for males.


At the time I thought this was an extremely fascinating article (the use of racemization might be the first time I was actually glad I'd taken organic chemistry!). The new bowhead find confirms that whales can live well over a century, sometimes even despite the efforts of armed humans.

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