Monday, January 19, 2009

Another great calving season

The right whale calving season started in December in the U.S. Southeast (primarily Florida and Georgia waters) and has been amazing with at least 22 calves born by the middle of January. Since 2001, the right whale population has been experiencing a baby boom with more than the average number of calves (~11) being born each year. The highest year was 2001 with at least 31 calves born, however, this is still below the biological potential for the population, i.e. there are still many females who are not having calves. It is quite possible this calving year might exceed the high in 2001. This is exacting what this population needs to recover to a more sustainable level. Right whales remain critically endangered with an estimated population of about 400.

Females typically space their calves by three years (unless their calf dies and then they may have a calf within two years), are on average ten when they have their first calf (youngest four, oldest twenty), and only have one calf at a time. Nursing a rapidly growing baby that weighs a ton at birth is very energy consuming, particularly when the females are fasting for the first few months. Female right whales need a resting year to regain weight before getting pregnant again.

Of our adoptable whales, so far:
  • Baldy, #1240 was seen with her eighth calf (last calf in 2005)
  • Calvin, #2223 was seen with her second calf (last calf in 2005)
  • #1503, daughter of Baldy, was seen with her fourth calf (last calf in 2006)
  • #2145, daughter of Grand Teton #1145 and Gemini #1150, was seen with her fourth calf (last calf in 2007 but calf died)
  • Couplet, #2123, grand-daughter of Kleenex #1142, was seen with her fourth calf (last calf in 2006). Her mother is Drippy-nose AKA Sonnet #1123
  • Shenandoah, #1266, mother of one of Baldy's grand-calves with son #2140, was seen with her seventh calf (last calf in 2004)
Another mother of note is Mavynne #1151. She was involved in the only known case of adoption in right whales in 1989 when she swapped her calf with the calf of Stumpy #1004. No one knows the circumstances, but presumably the two mothers gave birth close to each other and for whatever reasons, their calves ended up being exchanged. The association was discovered through genetic analysis of skin samples from the calves and comparison with their mothers. This is Mavynne's sixth calf. Unfortunately, Stumpy was struck and killed by a ship in 2004. She was missing the right fluke tip on her tail and hence her name.

The right whale catalogue is an invaluable source of information about individual right whales. It is maintained by the New England Aquarium's dedicated right whale team.

1 comment:

  1. The info is wonderful. It is greatly appreciated.