Good News in Whale Survey

Los Angeles-area whale watchers might want to mark the following dates on their 2007 calendars: January 15 and 18, then March 13 and 20.

Those dates were when sightings of southbound and northbound gray whales peaked during the 2005-06 migration period, according to the L.A. Chapter of the American Cetacean Society.

Also noted this week in the ACS/L.A.’s gray whale census and behavior project were fewer southbound but more northbound whales, and, for the fifth consecutive season, increased calf counts, indicative of a healthy population and evidence that more gray whales are giving birth en route to Baja California’s lagoons.

“Our high southbound calf percentages reflect evidence that up to half of calving probably occurs north of Carmel, rather than in Baja California as previously thought,” reported Alisa Schulman-Janiger, who heads the project.

The project, in its 26th year and active from dawn to dusk Dec. 1 through May 15 each season, is not intended to count California gray whales -- estimates range from 19,000 to 23,000 -- but to detect behavioral trends.

Volunteers recorded 529 southbound and 951 northbound gray whales in 2005-06. The previous season’s numbers were 622 and 929. Southbound tallies have been as high as 1,291 and northbound counts have reached 3,412.

Northbound counts are higher because cow-calf pairs stay close to shore while returning to their summer home in Arctic waters. Spotters tallied 38 southbound calves, up from 26 the previous season but well short of the 106 counted in 1997-98.

Schulman-Janiger noted that continuing ice reduction in Alaska’s Chuckchi Sea, “has provided six good feeding seasons, which improved the physical condition and reproductive success of gray whales, resulting in six seasons with very few strandings or emaciated whales and five seasons with higher calf counts.”

Delayed migrations caused by ice reduction may also be a factor in more births occurring during the 5,000-mile one-way trip.

Overall, the peak southbound days this year were Jan. 15 and 18, when 28 whales were spotted each day. On March 13 the northbound count was 35 and on March 20 it was 36. The official “turnaround date” was Feb. 26.

Also noted in the study were sightings of whales breaching, lunge-feeding, courting, nursing, rolling in kelp and just milling around. There were seven instances of harassment by private boaters.

“Reactions to nearly being run over,” the study concluded, “included going into stealth mode, abruptly changing direction and -- in the case of a nearshore cow-calf pair -- the mother threw herself out of the water in a breach right before the boat ran over them.”

*

pete.thomas@latimes.com