Saturday, July 14, 2012

Saturday July 14th

Another beautiful day on the water on Jeffreys Ledge. It was a little overcast in the morning and just a little wind refreshed us without making the seas too rough. The afternoon was a little sunnier and not a breath of wind, which meant it wasn't quite as cool, but still a lot more comfortable than the temperatures on land. In terms of the whales, we were able to get good looks at minkes, a humpback, and fin whales. 

In the morning, we were able to see Ebony again. We've been seeing this whale quite a bit on Jeffreys Ledge the past couple of days, but it does seem to be moving around a lot day to day in search of food. As far as large whales go, humpback whales are fairly slow swimmers, but they aren't the slowest, and in the search of food they might move several miles in just a couple of hours. Whales don't follow a set sleep pattern the way many other mammals (including us) do, and instead take short cat naps throughout the day and night. This means that sometimes whales are active and swimming all night long, so it is always a surprise where Ebony might show up the next day.

As mentioned below, Ebony was first seen in 1980 or 1981. She has had at least 10 calves since then, the first of which was recorded in 1983, and the most recent was recorded in 2007. If Ebony was at least 8 years old in 1983 (the average age of sexual maturity in humpback whales), then she could be over 37 today.

This is a color photo, but the skies were a little overcast this morning when we saw Ebony. You can see a nasty scar in front of Ebony's dorsal fin, and some less severe scuffing around the dorsal fin (which appears white).

Ebony going down on a deeper dive and lifting up her flukes. Notice some more scarring on Ebony's tail stock. You can also see all the barnacles hanging on for a ride on the corners of her tail.

As you can see Ebony has some nasty scars in the above photos. Unfortunately, these are probably the result of interactions with humans in one way or another. Two of the major risks to adult humpback health include ship strikes, and fishing gear entanglements. It is quite possible the scarring around Ebony's tail stock was the result of fishing lines cinching around her at some point in her life. Many humpback whales have some evidence of becoming entangled in fishing gear, and on occasion these animals are unable to extricate themselves and in extreme cases may be unable to swim or feed and may  drown or starve. Fortunately for Ebony, today she is entanglement free and appears healthy, though she will always bear some scars of some previous encounters.

Pictured below is one of the fin whales we encountered this afternoon. While we weren't immediately able to identify this individual on the boat, we did get some pictures and hope to match it up to the fin whale catalogue at a later time. It is possible this whale has not been seen before and its picture is not in the fin whale catalogue. In that case, today's sighting will go into the catalogue so that this whale can be recognized in the future if it returns to Jeffreys Ledge. Each year the Blue Ocean Society keeps track of all the fin whales indivi

In contrast to humpback whales, fin whales do not need to raise their tail above the water to take a deep dive. This is because while humpback whales tend to float when not swimming, fin whales are negatively buoyant and tend to sink. This whale is arching its back in order to glide down on a deeper dive.

This is a photo of the right side of a fin whale between the dorsal fin and the blow holes. This way is moving from left to right across the frame. The pattern of grays seen here on the right side of a fin whale comprise the blaze and chevron. These markers are unique to individual fin whales and can be used to identify them. This picture will allow this particular whale to be recognized in the future.

This is the same whale pictured above going down on a deeper dive. Pictured here is the dorsal fin, another key feature used to individually identify fin whales.

Finally we got some great looks of Minke whales throughout the day. Pictured below is one of those Minkes swimming right near the Isles of Shoals (only about 6 miles offshore from Rye, NH). In the background you can see Appledore Island with the flat top concrete tower on it as well as Star Island with the big white Oceanic Hotel on it. Minke whales are the smallest baleen whale we commonly see on whale watches in the Gulf of Maine.

A very large Minke whale would be about 30 feet and 10 tons. This is somewhere around the size of a large Killer whale. In fact, according to some reports Killer whales have been known to hunt Minke whales. In a paper published in 2006 in Marine Mammal Science, John Ford and the other authors hypothesize that Killer whales are just a bit slower than Minkes in a straight line. If it has a lot of wide open ocean a minke can escape from Killer whale pursuers. Killer whales may be more maneuverable than Minkes since they have longer flippers though, Ford continues, and researchers observed Killer whales successful in capturing Minke whales when the baleen whale runs out of ocean and hits land and must make a turn, or tries to seek refuge in a bay or other location. Fortunately for this Minke,  it probably doesn't have to worry about Killer whales today, as they are rarely seen so close to shore in the Gulf of Maine.

A Minke whale swimming near the Isles of Shoals

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