I'm still in a Polynesian frame of mind...
... and so I've been thinking about what I saw in Tahiti and French Polynesia quite a bit over the past couple of weeks.
While there, I saw lots of wildlife. Such as this anemonefish I found on Raiatea,
and black-tipped reef sharks...
... and while there's a fair bit of large fauna (I can't resist showing you this group of eagle rays that flew past us one afternoon),
I noticed that there were few mammals in the sea. Sure, I saw a few dolphins, and the islands are famous for their humpback whales. But no otters (which I didn't really expect), and very oddly, no seals or sea lions! I've seen seals in Hawai'i, but why nothing south of the Equator?
This leads to today's Challenge:
1. Is it true there are no seals or sea lions in Tahiti? If so why not? (Or did I just miss them?)
I'm used to seeing seals / sea lions just about everywhere. This is what I see locally in Northern California,
 |
| Harbor seals hauled out on a beach near Gulala, CA |
So why are none of these (apparently) in Tahiti?
2. (Extra credit) On board our ship I found this device. I'm not a big ship sailor, so I don't know what it is. Can you figure out what this is, and what it's used for on board?
As always, the real Challenge not just to find the answer, but to let us know HOW you did it. What searches did you do? Did you actually just ask someone? (That's a legitimate way to do SearchResearch Challenges!) Or did you just happen to know? (That's okay too--just let us know.)
Just tell us HOW... in the comments below.
Search on!
nice pics - giving the ec a spin…
ReplyDeletecapstan… as opposed to a windlass (which was my first thought…)
a specific brand, but shows basic principals
they draw press coverage
ReplyDeleteWotD: Pinnipeds - see: Distribution and habitat
Your shipboard device looks like a rachet-like winch (or capstan), around which rope is wound and pulled to pull up an anchor or trim sails. (It's what came to mind; a simple word search to confirm.)
ReplyDeleteWhy you didn't see seals or sea lions in Polynesia took a little more searching. Simple word searches [seal/sea lion in Tahiti/Polynesia] searches didn't find much -- although there was a 2016 sighting/capture of an ill/injured seal lion pup on a Tahitian island, which unfortunately died. (https://www.rnz.co.nz/international/pacific-news/311949/a-lone-baby-sea-lion-has-french-polynesia-guessing ... https://www.bbc.com/news/world-asia-37211718 )
But deeper in the results I saw "pinniped" ... and looked for [tropical pinnipeds] and found a 2017 book by that title ("Tropical Pinnipeds: Bio-Ecology, Threats and Conservation"
edited by Juan J. Alava), the 2nd chapter of which was "Overview on the Evolutionary History of Tropical Pinnipeds" by Carlos A. Vildoso Morales. Fortunately, it's included in the GoogleBooks preview (https://books.google.com/books?id=iFAsDwAAQBAJ&pg=PT24&lpg=PT24&dq=%22Overview+on+the+Evolutionary+History+of+Tropical+Pinnipeds%22+%22Carlos+A.+Vildoso+Morales)
"The evolutionary history of pinnipeds in tropical seas is complex," this chapter begins. "In a large portion of tropical areas (there are) scarce or no fossil remains of this group." The presence of pinnipeds in "the Indian Ocean Basin, Southeast Asia and the Central Pacific Ocean is exceptional, exclusively due to vagrants, dispersing very far out from their normal geographic ranges." Copying text is not enabled, but the gist of this chapter is that the species evolved with cold-water environments, except in a few exceptions, such a the Hawaiian Monk Seal. (The equatorial Galapagos pinnipeds, for example, take advantage of the cold Humboldt Current.)
I suspect that reading this chapter would satisfy one's curiosity about the paucity of pinnipeds in Polynesia. :-)
Nice job! (I'm impressed you knew about the winch/capstan off the top of your head!)
Delete[seals sea lions Tahiti]
ReplyDelete2016:A baby sea lion has made it all the way to French Polynesia Sadly, "Fox" died
*Sea lions are not common in the tropical waters of French Polynesia
[mammals of French Polynesia]
Wikipedia: List of mammals of French Polynesia French version is much better
French Polynesia, close to the center of the South Pacific Ocean
[Sea lions habitat]
DeleteSea Lion Habitat and Distribution Not Sea Lions in the Northern Atlantic Ocean
There are 7 species
[Sea Lions worldwide distribution map] still looking the results. With [sea lions habitat map]
Sea Lions
This thread is not about our Challenge. However it is interesting because it made me remember other Challenges by Dr. Russell and shows how much Mexico and Mexicans we need to work and how are we doing versus other years.
DeleteLink in Spanish. 2,863 USD in income. Mean is 860.65 per month per home
Just to share this interesting link (in Spanish) about maps, and The United States called Cuba. "La Carta Marina podría considerarse el primer mapa náutico impreso del mundo entero...Se trata de un enorme mapa hecho por el cartógrafo alemán Martin Waldseemüller en 1516." Map was saved by a miracle and now it is locate in LOC of The United States.
DeleteJust to share 2 articles about animals:
DeleteAncient parrot in New Zealand was 1m tall, study says
Raccoons are found on three continents, and warming could help their range expand northward.
The extra credit was easier.
ReplyDeleteA Bing visual search zooming in on the object immediately found this picture: http://svrainshadow.com/?p=342 - showing a Barient winch. Looking at your photo it's hard to be certain whether the name on top is Barient but it looks similar. So I think that's what it is. By the look of it, it's a self-tailing Barient Winch. Barient is no longer in business. Lewmar winches have taken over. There's also a Barlow make and a Barton marine winch but these look different.
The winch is used to "provide a mechanical advantage to help pull lines in or let them out" according to a glossary at http://northern-light-sf.com. Usage is described at http://northern-light-sf.com/procedures/basics.shtml which states that it is used pull in or loosen lines on the sails. (So you were on a sail boat - not really a ship unless it was a tall ship?)
Apparently front winches are the primary winches and the rear winches are the secondary winches. When sailing “to weather: the primary winch is used for the jib sheet (on the leeward side) and the secondary winch is used for the runner (on the windward side). When sailing to lee: the primary winch is used for the afterguy (on the windward side) the secondary winch is used for the spinnaker sheet (on the leeward side)”. (You do need to be a sailor to know what that's all about. I'm not!)
Now the second (harder) question. I did a number of searches: seal habitat, sea lion habitat, and similar to check where you find seals and sea lions. I also added in Polynesia / Tahiti and found this: https://www.rnz.co.nz/international/pacific-news/311949/a-lone-baby-sea-lion-has-french-polynesia-guessing - showing that sea lions are not part of the fauna in Polynesia. Sadly this sea lion didn't make it! https://www.independent.co.uk/news/world/australasia/baby-sea-lion-dies-mysterious-mile-journey-australasia-french-polynesia-a7216826.html
The question as to why is harder as seals and sea lions can be found in most of the world. A Wikipedia search showed the taxonomic name for both is Pinniped, so searches for this checks both. The Wikipedia page says sharks and killer whales are the main predators. As both are seem common in Tahiti (based on tour reports and ads for whale watching / shark swimming trips) the islands seem inhospitable to pinnipeds. Further most pinnipeds like cold water with coastal access.
Several Wikipedia links mentioned "The Pinnipeds: Seals, Sea Lions, and Walruses" by Marianne Riedman. This book has extracts on Google Books giving some idea of their habitat mentioning Hawaii, Guadalope and the Galapagos as habitats but not Polynesia.
A search for Tropical pinnipeds (as in the Riedman text) gave Tropical Pinnipeds: Bio-Ecology, Threats and Conservation edited by Juan J. Alava. This confirmed Pinniped geography with a map of their habitats in chapter 1.
https://www.seals-world.com/seal-habitat/ states that warm water seals depend on cold water currents to bring in an assortment of food to them. This is confirmed by https://www.jstor.org/stable/24871981?seq=1#page_scan_tab_contents - a paper by David K Cairns et al titled "Endothermy, ectothermy and the global structure of marine vertebrate communities". The abstract to this states that pinnipeds are ubiquitous in ocean waters with summer surface temperatures cooler than the low 20s C and are virtually absent from warmer regions. The authors suggest that warm water increases the difficulty of capturing fish prey and increases vulnerability to shark predation.
The Behaviour of Pinnipeds By D. Renouf (another Google book search) suggests distribution of female pinnipeds depends on food, parturition sites, coupled with lack of predation are the primary factors for island breeding pinnipeds.
So I think the answer you don't see them in Polynesia is linked to the risk of predation, plus water currents making food sources harder for them. This may change however with climate change or weather patterns such as El Niño.
That's really interesting... when I tried Bing image search, I couldn't find that link you showed. Could you try it again to see if it pops up for you still?
DeleteI've repeated it. The key is to zoom in / crop the image to the key bits. I had to scroll down a bit but this shows the search results.
Deletehttps://tinyurl.com/winch-searchresearch
Nicely done! I'll update the blog post in a bit with your observation.
DeleteI'll have the answer in a bitt.
ReplyDeleteLooks like a sailboat winch. Confirmed by Image Search. You sure have nifty days away. jon
ReplyDeleteI did find this one in almost as unlikely spot as Tahiti…
ReplyDeletesomewhere in upstate NY…
…hmmmm, look what ad turned up… along with some presidential seals…
ReplyDeleteThinkyman is thinking of cruises now… Goo helped… how did it know? (is Google genderless?)