Tahlequah, the orca who carried her dead calf for 17 days, is pregnant again

August 12, 2020
Nature
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Image Source: https://www.seattletimes.com/

Tahlequah is pregnant again.

The mother orca raised worldwide concern when she carried her dead calf 17 days and more than 1,000 miles, almost exactly two years ago. Now, she has another chance at motherhood, scientists have learned.

Scientists John Durban, senior scientist of Southall Environmental Associates and Holly Fearnbach, marine mammal research director for the nonprofit SR3, recently finished recording drone images of the southern residents and discovered pregnancies amid the J, K and L pods. The recordings were done as part of a long-term study of the body condition of the endangered southern resident orcas that frequent Puget Sound. The photography is done non-invasively by a remote-activated drone flown more than 100 feet over the whales.

The pregnancies are not unusual, so the scientists don’t usually announce them. But Tahlequah’s pregnancy carries a special meaning for a region that grieved the loss of the calf.

The southern residents are struggling to survive, and most pregnancies for these embattled whales are not successful. Tahlequah’s baby was the first for the whales in three years. The southern residents have since had two more calves, in J pod and L pod. Both are still alive.

Tahlequah’s baby is still a long way away, and like all the orca moms-to-be, Tahlequah, or J-35, will need every chance to bring her baby into the world — and keep it alive. The gestation period for orcas is typically 18 months, and families stick together for life.

Everyone on the water all over the region can help, Fearnbach and Durban said. All boaters of every type should be careful to respect the whales’ space and give them the peace and quiet they need, they said.

Whales use sound to hunt, and boat disturbance and underwater vessel noise is one of the three main threats to their survival, in addition to lack of adequate, available salmon and pollution.

Just as important as the number of salmon in the sea — especially chinook, the southern resident orcas’ preferred food — is the salmon that southern residents can readily access in their traditional fishing areas.

“Just like human fisherman that don’t just go drop a hook in the ocean,” Durban said. “They have their favorite places.

“They are amazing societies that pass culture down from generation to generation. They are creatures of habit.”

However, right where orcas hunt — the west side of San Juan Island, Swiftsure Bank, and other salmon hot spots in the eastern end of the Strait of Juan de Fuca — right now are busy with boaters, commercial ships and fishermen.

Down to a population of just 72 whales, every baby counts for southern resident orcas. And their chances for successful pregnancies are not good. About two-thirds of all southern resident pregnancies are typically lost, researcher Sam Wasser of the Center for Conservation Biology at the University of Washington has found. Stress from hunger due to lack of salmon is linked to the whales’ poor reproductive success, according to his research.

Story Source: https://www.seattletimes.com/seattle-news/environment/tahlequah-the-orca-who-carried-her-dead-calf-for-17-days-is-pregnant-again/

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