#30: Mother lost her Calf

Gannet is a whale that we have been seeing throughout the season. She got her name from a white scar on the left side of her head that looks like a gannet in flight. Our survey team first saw Gannet in late December and then several times throughout January. We were very excited to sight Gannet with a calf on February 12.

Gannet with her Calf on Feb 12th. Notice the calf's fluke (enlarged below). Photo taken by Jonathan.
You can see more photos of Gannet on the North Atlantic Right Whale Catalog. Search for EG#2660.

This was an extremely busy day for the central Early Warning System (EWS) survey team. We saw 49 whales in our area, 22 separate sightings, including 15 mom calf pairs. It is always essential to cover the entire EWS area in order to get the whale alert positions out through the network. Other interesting species we saw that day were one humpback, two leatherbacks and five manta rays. We sighted Gannet with her new calf towards the end of the survey flight, at 2:20 p.m. Photographs serve a multitude of benefits in understanding the population as a whole, as well as keeping track of individuals for different reasons, such as monitoring health following the appearance of wounds. Gannet's scar first appeared in July 2000 as a large wound; it is not certain what caused it.

An enlarged view of the calf's fluke.
Photo taken by Jonathan.

Females are considered sexually reproductive when they reach 9 years of age; this is based on year of first calving being 10, assuming a one-year gestation period. Most females have their first calves at age ten to eleven. Age at first calving is highly variable in right whales, occurring as early as five, and as late as twenty-one years. Gannet was born in 1996, had her first calf at the age of 10, and it was therefore not a surprise to see her, as a potential mom down here in the calving grounds this season.

While downloading images from our initial sighting of Gannet with her newborn, we noticed that the calf was missing half of its fluke (See photo above). There was some speculation as to the reason for this. Was it a birth defect? Other species are born missing a digit, or with shortened limbs so it is a possibility. The edge where the fluke part was missing was not red raw, and no white scarring could be seen, but if it was a fresh cut, it may have been too early to see white scar tissue, and this also may have been hard to see from aerial photographs. Biopsy teams were on high alert, and ready to better document this calf from boat-based platforms in order to see better detail.

One of the last photos taken of Gannet with her calf.
Photo taken by Jonathan.

Unfortunately, the next sighting of Gannet was on the February 15, a day when we only flew short lines, partially covering our survey area, due to low lying clouds towards the end of our lines. However, we still were witness to two vessel whale interactions that day, communicating with vessels in order to avoid collisions. One of them involved Gannet, who was seen with a juvenile whale, but no calf. We circled on her for approximately half an hour, in order to be positive that there was not a calf with them, and also to ensure that the small fishing boat that had been on course for the whales, was not intending to harass them. It appears that Gannet had already been through a lot. We may never be 100 percent sure what happened to her calf, but we will continue to piece together the clues. Two days later, on February 17, the Florida Fish and Wildlife Conservtion Commission (FWC) aerial survey team found a calf carcass in their area. The pieces of the puzzle would appear to fit. She was first seen without her calf seven nautical miles (nm) northeast of St. Johns channel, Jacksonville. With the northeast winds that had been blowing around that time, it would make sense that the calf would show up to the south, 13 nm north-northeast of St. Augustine. It is also possible that this calf belonged to a different mom.

The carcass was towed in, but had been heavily scavenged upon by sharks, so it was missing all of the fluke, including most of the peduncle area too. The dead calf had a white belly, so we are now able to rule out all of the calves that we have seen since the February 17, and those with black bellies. A lot of important information can be gathered from the necropsy, which is why it is always so essential that we retrieve carcasses, and eventually the genetic sample will reveal who this calf belongs to. It is critical to determine the cause of death if we are to understand the various threats that this population faces.

Look out for the upcoming guest article from FWC on discovering the carcass.

-Jess

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