Whale Season
Feels like winter today. Overcast, showery, temperatures as low as 79. Bad day to work on re-bedding a section of toe rail. Good day to write a blog.
As I watch the constellations track across the elliptic at night, Orion reminds me that this is whale season. This is the second whale season I've missed since leaving Lahaina.
I miss those guys.
I last saw humpbacks in French Polynesia. These would be southern humpbacks, up from the Antarctic for their austral winter breeding season. I was alerted to the possibility of seeing them by postings detailing restrictions on approach to and maneuvering around them. I don't remember the details, but do recall that there were different, more restrictive regulations for mothers and calves. I also remember that you could approach a cow-calf pair to the same distance as males when approaching from the side the mother was on, but the approach distance was greater on the calf side.
I don't remember seeing any humpbacks in the Marquesas or Tuamotos. But I saw several in the Society Islands, in particular by Tahiti and Mo'orea.What I observed challenged what I have learned about breeding grounds, so I thought I'd bring it up for my whale nerds' consideration.
We have come to believe, and teach, that humpback breeding grounds world wide share certain characteristics, including a depth of less than 600 feet. The Maui Nui Basin is assumed to be an ideal locale for breeding and calving because of the particularly shallow depths between Maui and Lanai.
(I did come across a paper that cites evidence that cow-calf pairs tend to go from shallower depths to deeper depths with more rugged terrain from early sightings to late sightings in a season.)
In general, the Hawaiian Islands are surrounded by very deep water, with depths greater than 10,000 feet only a couple miles off shore, and often depths of greater than 1,000 feet only a quarter or half mile off shore. The Penguin Bank and Au Au Channel are notable exceptions. Humpbacks are observed throughout Hawai'i Nei, with clusters observed in a few distinct places, including O'ahu and Hawai'i, but especially Maui. Joe Mobley ran aerial transits, and plotted 'corridors' which corroborate the concentrations of sightings reported by other researchers and whale watchers.
The Society Islands in French Polynesia are 'high islands', i.e., they rise up to quite picturesque peaks hundreds or a couple thousand feet above sea level. They are older than the Hawaiian Islands, so they are not as high, and are also generally surrounded by outer reefs and lagoons. There are no shallow basins or banks between the islands. When you approach a channel through the reef, your depth sounder goes from --- 100 feet or so from one second to the next, and then shoals rapidly to 60 feet or less. The dropoff outside the reef is dramatically precipitous.
I saw a few individual humpbacks as I was approaching Tahiti from the east, and even saw a few individuals immediately outside the harbor breakwater at Pape'ete. If you were in the Lahaina Roadstead, and were immediately outside the harbor breakwater, the same immediately as the whales outside the Papeete breakwater, you'd be in 15 or 20 feet of water, about in between the number 4 and number 6 channel buoys. Off Pape'ete, the whales were in a couple hundred feet of water. I was 300 yard further out, in 600+ feet of water, beyond the range of my depth sounder.
I saw several humpbacks on my passage from Tahiti to Mo'orea, all in very deep water, and several more immediately outside the reef along the northern coast of Mo'orea, as I made my approach to Opunohu Bay. Again, very deep water. (Opunohu Bay was visited by Capt. James Cook and HMS Resolution and HMS Discovery, and also by Capt. William Bligh and HMS Bounty. Just for the record, Cook's Bay is not Opunohu Bay where Cook actually anchored. We anchored in Robinson Cove in Opunohu Bay. Just for the record, Robinson Cove is not named for Kirsten Robinson.)
I saw a couple more individuals on my passage from Mo'orea to Bora Bora, all in deep water.
In summary, I saw a few dozen humpbacks in Society Islands waters. While I saw a few that were close enough to each other to be 'associated' in some way, I saw no cow-calf pairs, no cow-calf-escort groups, no competitive groups. Yet, it was austral winter, it was breeding season for Southern Ocean humpbacks. Postings (in French) that I saw would lead me to expect to see calves, but I did not.
So, my question to my fellow nerds is this: what are they doing in Tahiti? Is it really a breeding ground? If so, why didn't I see calves? Are they birthing somewhere else (Tuamotu Islands? Austral Islands?), and then moseying on?
I don't have adequate internet resources to follow this rabbit down the hole, so I'm hoping this will pique someone's interest who may read this. Comments solicited. The best way to have a discussion with me on this is via one of the more old-fashioned modes of communication: email. I don't want to publish my email here, but there are still some among you that have it. If you don't know who to ask, you post a comment with your email address. I can't promise I'll see it right away. (After leaving Hawai'i the first time I was able to access the blog page and see comments was about six months after we settled into Majuro Atoll. Even with a reliable, for this part of the world, connection to the internet, I still have serious bandwidth limitations, so photos and video are problematic. Text only, please, and no group distributions. I can't afford to choke my only link to marine suppliers.)
Like I said, I miss them. I think about them a lot. It would be nice to talk some whale with some one.
As I watch the constellations track across the elliptic at night, Orion reminds me that this is whale season. This is the second whale season I've missed since leaving Lahaina.
I miss those guys.
I last saw humpbacks in French Polynesia. These would be southern humpbacks, up from the Antarctic for their austral winter breeding season. I was alerted to the possibility of seeing them by postings detailing restrictions on approach to and maneuvering around them. I don't remember the details, but do recall that there were different, more restrictive regulations for mothers and calves. I also remember that you could approach a cow-calf pair to the same distance as males when approaching from the side the mother was on, but the approach distance was greater on the calf side.
I don't remember seeing any humpbacks in the Marquesas or Tuamotos. But I saw several in the Society Islands, in particular by Tahiti and Mo'orea.What I observed challenged what I have learned about breeding grounds, so I thought I'd bring it up for my whale nerds' consideration.
We have come to believe, and teach, that humpback breeding grounds world wide share certain characteristics, including a depth of less than 600 feet. The Maui Nui Basin is assumed to be an ideal locale for breeding and calving because of the particularly shallow depths between Maui and Lanai.
(I did come across a paper that cites evidence that cow-calf pairs tend to go from shallower depths to deeper depths with more rugged terrain from early sightings to late sightings in a season.)
In general, the Hawaiian Islands are surrounded by very deep water, with depths greater than 10,000 feet only a couple miles off shore, and often depths of greater than 1,000 feet only a quarter or half mile off shore. The Penguin Bank and Au Au Channel are notable exceptions. Humpbacks are observed throughout Hawai'i Nei, with clusters observed in a few distinct places, including O'ahu and Hawai'i, but especially Maui. Joe Mobley ran aerial transits, and plotted 'corridors' which corroborate the concentrations of sightings reported by other researchers and whale watchers.
The Society Islands in French Polynesia are 'high islands', i.e., they rise up to quite picturesque peaks hundreds or a couple thousand feet above sea level. They are older than the Hawaiian Islands, so they are not as high, and are also generally surrounded by outer reefs and lagoons. There are no shallow basins or banks between the islands. When you approach a channel through the reef, your depth sounder goes from --- 100 feet or so from one second to the next, and then shoals rapidly to 60 feet or less. The dropoff outside the reef is dramatically precipitous.
I saw a few individual humpbacks as I was approaching Tahiti from the east, and even saw a few individuals immediately outside the harbor breakwater at Pape'ete. If you were in the Lahaina Roadstead, and were immediately outside the harbor breakwater, the same immediately as the whales outside the Papeete breakwater, you'd be in 15 or 20 feet of water, about in between the number 4 and number 6 channel buoys. Off Pape'ete, the whales were in a couple hundred feet of water. I was 300 yard further out, in 600+ feet of water, beyond the range of my depth sounder.
I saw several humpbacks on my passage from Tahiti to Mo'orea, all in very deep water, and several more immediately outside the reef along the northern coast of Mo'orea, as I made my approach to Opunohu Bay. Again, very deep water. (Opunohu Bay was visited by Capt. James Cook and HMS Resolution and HMS Discovery, and also by Capt. William Bligh and HMS Bounty. Just for the record, Cook's Bay is not Opunohu Bay where Cook actually anchored. We anchored in Robinson Cove in Opunohu Bay. Just for the record, Robinson Cove is not named for Kirsten Robinson.)
I saw a couple more individuals on my passage from Mo'orea to Bora Bora, all in deep water.
In summary, I saw a few dozen humpbacks in Society Islands waters. While I saw a few that were close enough to each other to be 'associated' in some way, I saw no cow-calf pairs, no cow-calf-escort groups, no competitive groups. Yet, it was austral winter, it was breeding season for Southern Ocean humpbacks. Postings (in French) that I saw would lead me to expect to see calves, but I did not.
So, my question to my fellow nerds is this: what are they doing in Tahiti? Is it really a breeding ground? If so, why didn't I see calves? Are they birthing somewhere else (Tuamotu Islands? Austral Islands?), and then moseying on?
I don't have adequate internet resources to follow this rabbit down the hole, so I'm hoping this will pique someone's interest who may read this. Comments solicited. The best way to have a discussion with me on this is via one of the more old-fashioned modes of communication: email. I don't want to publish my email here, but there are still some among you that have it. If you don't know who to ask, you post a comment with your email address. I can't promise I'll see it right away. (After leaving Hawai'i the first time I was able to access the blog page and see comments was about six months after we settled into Majuro Atoll. Even with a reliable, for this part of the world, connection to the internet, I still have serious bandwidth limitations, so photos and video are problematic. Text only, please, and no group distributions. I can't afford to choke my only link to marine suppliers.)
Like I said, I miss them. I think about them a lot. It would be nice to talk some whale with some one.
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