SOFA - quod erat demonstrandum!

The SOFA: a humongous area in the NE Pacific where GWS disperse to forage.

Behold - and yes it is long!

Synopsis here - and yes this is impressive as hell.

And here's a nice, and short video about the technology - again, very impressive in terms of scope but also cost!

And now, re-read this.

See what I mean?

• The GWS are by no means "aggregating" but instead, they are actually dispersing in a huge area after having aggregated at the coast! I mean, seriously: watch the first video at 42.12: does that look like congregating to you?


• In the SOFA (which is the much better name than Café) they very much appear to be foraging and not mating: case in point, just listen to what Barb's got to say at 1:21ff of the first video where she explains how the data illustrate that those Sharks engaging in ROD are most likely targeting prey like Bigeye Tuna.


• Which obviously means that the GWS are mating in the known coastal aggregation spots like Domeier had postulated all along!


• And those infamous, and totally cockamamie hypotheses by Jorgensen and Chapple, respectively, that they may be lekking or, gasp, sniffing for female pheromones?
  Right...


• And oh yes that would very much be a q.e.d - just saying!
  And no this time I'm gonna be magnanimous and refrain from mentioning sniffing glue and the like! :)
  

But I'm digressing as usual.

Keep watching this website and also, keep watching this space.

To be continued no doubt!

Lupe - heavily pregnant GWS?

Have you seen Mauricio's video?

That's one fucking big Shark - and not very friendly!
Named Deep Blue, here she is again.

Wow.

But did I hear, heavily pregnant?

Were she a Bull, I would categorically state that she's big and bulky but certainly not pregnant - but not being a GWS connoisseur, who am I to say!

Looks like Mauricio and Skomal are of the camp  that asserts that the GWS mate at what they dub the GWS Café - but if so, how can those fresh scars indicate mating considering that pregnancy, let alone heavy pregnancy would only be discernible many months afterwards? Can't have it both ways!

Me, I'm obviously sticking with Domeier's theory (read it!) = that Lupe is the site of a GWS mating aggregation - meaning that the hypothesis that those are mating scars is totally plausible.

You GWS guys out there - opinions?

Anyway - what a magnificent animal!

PS - Michael here - not pregnant!

Not Lekking - Sniffing!

Gill Rakers with mating scars in Guadalupe - think they would still look like this is she had traveled all the way from the SOFA, and this weeks after the males? Source.

Oh for crying out loud!

It really gets curiouser and curiouser!

I always keep an eye on the crazies lest I get caught unawares by the latest stupidity out of left field - and bingo!

The bloviating fireman reports from a lecture by Taylor Chapple.

That would be the dude whose completely discredited GWS census has served as a basis for the failed push to list the NE Pacific GWS population under ESA. He's of course completely unrepentant, claiming that the whole fiasco was due to the fact that NOAA did only consider published data, and that, and I cite,

a big problem with the process and the peer review of the ESA application was a lack of paying attention to the supplemental. He said his supplemental carried a lot of key info but it seems like both NOAA as well as other researchers, when arguing points, seemed to not even have read the supplemental, or ignored the info in it. He says the supplemental really holds a significant portion of the weight of data and people need to make sure they read it prior to making judgment.

Indeed!

Because the supplemental data would have rectified his numbers and elevated them from his stated 3-400 to the best available science of between Burgess' 2,400 and NOAA's approx. 3,000?

Whatever - right?

And it gets even better!

Forget the lekking - this is what is really happening out there in the SOFA!

The movement at the CAFÉ was indicative of mating activity. 
The data showed that the males and females congregate at the CAFÉ at the same time, but while the females stay at more regular depth, the males shoot up and down rapidly. Males were going between the surface and 500 meters as many as 150 times per day. 

How does this indicate mating activity? 
Many sharks, including the Pelagics (open ocean), use pheromones to find mates. At the CAFÉ, the water currents are quite horizontal with little movement vertical. As a female releases her pheromones, it travels horizontally. The males shoot up and down in an attempt to “smell” the pheromones and follow them to the female. What the males are doing is fattening up at the coast to journey out to the CAFÉ and using their fat stores to make these up/down searches. Only the males that are fat enough and strong enough to endure this high-energy search pattern find the females to mate, ensuring the genetic top of the population reproduces. 

This is of course all data supported theory, not actually observed. But the data does seem to support it as a very legitimate theory. 

No not really!

To start with, it's not a theory but a hypothesis - and far from being legitimate, it is once again implausible to the point of being ludicrous! 

Don't worry, this time, I'm not gonna dwell, let alone make assertions of sniffing glue and the like. It's once again nothing more than the attempt at discrediting Domeier's research that postulates that the SOFA is, as the name indicates, a foraging area whereas mating takes place at the known aggregations sites on the coast. 

Read the paper and also my post, and you will discern that all the evidence points to Domeier being right and this being blatantly wrong - starting with the fattening paper that suggests that the Sharks go hungry for months whilst using up the fat stored in their livers! So how come everybody I've asked tells me that they are not emaciated when they get back to Guadalupe after months, and in the case of the females, years out at sea? And the postulated supporting data merely show ROD, whereas there is strong sexual segregation, and distances between individuals are enormous. Do we at least know that the male aggregation area is down-current from the female one? 

Because if not... 

And the lekking?
Welcome to the frothy Piranha tank! :)

Lekking GWS? Yeah, Right!

This is lekking.

These examples probably not as there is only one male.

But it's fascinating footage, so there.

So what is this all about?

A lek is a gathering of males, of certain animal species, for the purposes of competitive mating display. Leks assemble before and during the breeding season, on a daily basis. The same group of males meet at a traditional place and take up the same individual positions on an arena, each occupying and defending a small territory or court. Intermittently or continuously, they spar individually with their neighbors or put on extravagant visual or aural displays (mating "dances" or gymnastics, plumage displays, vocal challenges, etc.).

So this is an aggregation of males showing off in a competition, allowing females to compare and then choose what they consider to be the most attractive partner. Alternatively, weaker males may tire faster and the females may end up mating with those who endure the longest.

Often the result is that only a small percentage of the males will mate with a large percentage of females, thus eroding genetic diversity and resulting in the Lek Paradox, see the same Wikipedia link.

Sal Jorgensen believes that he has discovered lekking in GWS.

According to him, the GWS males aggregate in the SOFA and then engage in rapid oscillatory diving, or ROD in order to find and/or convince the females to mate with them.
Nice synopsis here.

I say this is total baloney, and this is why.

This is the map of where the ROD happens - yellow dots.

Right.

Correct me if I'm wrong - but this "aggregation" would be happening in an area measuring about 8-10 degrees (60x8 - 60x10 nautical miles) on each side, i.e., conservatively, an area of 230,000 square nautical miles!
Where I come from that is called dispersing, not aggregating!

And this would be comprising how many GWS?

The same Jorgensen has co-authored the paper stipulating that there are only 219 adults and juveniles in central California and approx double that in the whole of the the North-East Pacific including Guadalupe.
I believe it's crap - but let's take him at his word.

So there.
I think it's fair to assume a ratio of 4:1 of juveniles/sub-adults to sexually mature adults, meaning that there are only approx 88 adults of which let's assume 44 are males and 44 females. Let's further assume that all the males are always horny and are willing to travel for some hanky panky - makes one male every 5,200-odd square miles! I mean, seriously: does this correspond to a gathering as per the above definition?

And there's more than that: the females have a two-year cycle and thus the number of available females would be only approx 22!!!

Chances of  a female encountering a male?

And if so, chances that evolution would select for this astounding migration and according expenditure of energy only for mating?

Anybody who has perused Domeier's GWS book knows that the SOFA features several potential prey species, foremost of which Cephalopods.
For the pregnant females, it also constitutes a stepping stone for traveling further to Hawaii where  the warmer water may favor the development of the embryos - and where (that's me speculating) there used to be another readily available energy-rich food source in the form of the Hawaiian Monk Seal - now depleted but likely much more abundant when these migration patterns may have originated.

Sal's males are likely to be oscillating in order to catch some elusive Squid that aggregate in the SOFA, e.g. attacking the school of Squid from below, as they do, only to dive back down for a further attack (yes I'm of course speculating!) - as very much acknowledged in the weasely part where he does not make any strong statements but calls lekking merely a hypothesis warranting further testing!
Yeah, right - but shouldn't a hypothesis be at least plausible?

And Domeier?

He obviously assumes that mating occurs in the known hotspots Farallones and Guadalupe where both males and females aggregate (Chapter 16: A New Life-History Hypothesis for White Sharks, Carcharodon carcharias, in the Northeastern Pacific) - which considering the numbers makes much much more sense! That's what I call a gathering!

And maybe, there is lekking there - remember that the males often feature wounds that are being attributed to brawling, i.e. sparring individually with their neighbors!

Plus, there is this.

Gill Raker - source.

These would be fresh mating scars.

This is commonly observed on female GWS at Guadalupe and from my own experience, it is a strong indicator that mating has occurred in the proximate vicinity. Granted we haven't observed GWS - but we have now witnessed the near-miraculous healing of mating scars in Tigers, Bulls, Sicklefin Lemons and Grey Reefs, and the healing time has been 2 weeks, maximum!

How does that dovetail with the fact that the females leave the SOFA weeks to months after the males - or are we to believe that after having made their choice in the SOFA, the females recognize the successful suitor weeks later and mate with him in Lupe?

And there may be another clue.

Wheres some pelagic Rays like the Mantas and Eagle Rays mate on the fly in mid-water, all other Elasmobranchs I've witnessed (Shovelnose Guitarfish,  Scalloped HH and Reef Whitetip in person - Nurse, Zebra, Grey Reefie and Lemon on video) have a competitive mid water phase where several males try to latch on, after which the female stops struggling and sinks to the bottom with the successful male inserted. Copulation then happens on the bottom and lasts several graphic minutes.

Assuming this is the case in GWS - wouldn't copulating close to an island make much more sense than in the SOFA where the animals would sink forever? And is it possible for telemetry to detect that behavior?

Anyway.

I think Sal must have been sniffing glue when he came up with this - and shame on the reviewers for having approved of that ludicrous nonsense!

But of course this may not be merely about research.

Sal is very much one of the researchers "associated" with the Junior debacle - so may this be nothing more than another attempt to gnaw at Domeier's ankles?

Honi soit qui mal y pense!

About Great Whites

As usual, found by pure chance!

It is, I believe, a great piece about Great Whites, Shark research and Shark diving in the Farallone Islands - including some gruesome footage of finning, however totally without the usual unhelpful melodrama.
Very interesting to see McCosker explain his mistaken identity hypothesis - certainly plausible but not verifiable!

Enjoy!


QUEST on KQED Public Media.

Producer's notes here.

Great Whites: new Insights!

Unbelievably cool stuff!

I just got this synopsis of this year's International Great White Symposium in Hawaii.
It's a PdF document with the title Selected Highlights from the International White Shark Symposium February 7-10, 2010 that features no author, and I herewith apologize profusely for breaching any copyright and citing it verbatim in its entirety - but it's absolutely fascinating stuff and it would be a great shame if it remained reserved for the select few Shark scientists and not communicated to the many GW enthusiasts at large.

So without further ado: this is what we've learned about the life cycle of the Great White Shark.
Absolutely stunning!

In the past two decades, fish biologists have gained considerable knowledge about the great white shark, Carcharodon charcharias.
Many more investigations, however, are still necessary in order to understand the comprehensive biology and life history of this ecologically important and charismatic apex predator. Below are the some of the information presented as new or reviewed at the symposium:

A. White Shark population in the NE Pacific region:

1. Adult population size estimated to be between 200 to 300 individuals in the NE Pacific. Worldwide population is still not known

2. Females give birth (live birth) near shore in the Southern California coastal region; between Malibu, California and Vizcaino Bay, Baja California

3. White sharks copulate, have internal fertilization, the gestation period is about 18 months, and the pups at birth are about 4.5 to 5 ft long

4. White sharks are warm blooded and the young tend to congregate in near shore warmer waters: theoretically, the smaller size sharks need warmer water to assist in thermoregulation

5. Young white sharks feed primarily on fish, ignoring humans and other mammals near the coast

6. Young white sharks migrate 1000 km between the Malibu Coast and Vizcaino Bay. They are protected in Baja (like California), but the Mexican government does not enforce conservation. Thus, many of the young sharks in Mexico are being poached for food to feed the indigenous people while their fins are sold off lucratively. Scientists are analyzing the effect on the NE Pacific population resulting from this practice.

7. When the young sharks grow to about 9 to 10 feet long, they begin to feed on marine mammals plus other larger prey and start to migrate to the northern and colder regions of the Pacific. At this size, their thermoregulatory mechanism is well developed.

8. Genetic studies (using mitochondrial DNA) demonstrated that the NE Pacific white shark population is derived from the population in Australia/New Zealand. This NE Pacific group split off tens of thousands years ago.

B. Great White Shark Café:

1. The Café encompasses a region in the NE Pacific primarily between ...W to ...W and ...N to ...N where the adult white sharks migrate from the US west coast during winter to aggregate.

2. Some of these sharks, mainly males, go as far SW as the Big Island and as far NW as Midway Island. White Sharks have been tracked throughout the Hawaiian Islands

3. Great debate regarding the ‘purpose’ of the Café: food or sex or both?? One scientific group favors the view that the animals go there to feed and another sees it as an area for mating. Only circumstantial evidence is available to support either role.

4. Females and males appear to segregate at the Café. Each sex has its own preferred section. Males to the W-NW and females to the SE

5. Studies showed that the white sharks swim on the surface non stop between the US west coast the Café, crossing > a thousand miles of ocean (Adult white sharks have been found to be able to travel up to ~5,000 miles.)

6. Upon arrival at the Café, white sharks dive down and come up again continuously. They go from the surface and straight down to as deep as 800-1,200 meters, from 25 degrees C at the surface to 4 degrees C at depth. Again, this seems to be a non-stop, 24/7 activity.

7. Other marine life found at the Café: sperm whale aggregation and 3 species of squid, including the giant squid. Reproduction of all squid species has been observed here.

8. Although no similar Café has been described in detail as for the NE Pacific region, similarly tropical migrations during the winter have been found for the South Africa, Australia and New Zealand, and West Atlantic populations:
a) The New Zealand adult white sharks migrate to the New Caledonia region
b) The South African adult sharks migrate to the Mozambique coast and west Seychelles area
c) Australian white sharks migrate between S of the Sydney area in New South Wales up to tropical Queensland region
d) N Atlantic white sharks migrate from the Maritime Province area to Florida. These are known to have fed primarily on whale carcasses before conservation practices. Now that the gray seal population has bounced back near Cape Cod, after conservation is enforced after the enactment of Marine Mammal Protection Act in the 1970s, white sharks have begun preying on the seals in this region.

C. Other interesting information:

1. Scientists have not yet been able to witness the white shark mating/copulation act, not for the lack of trying. Must be an impressive sight as the scar patterns on head region of the adult females would indicate

2. Male adult white sharks (NOT female adults) appear to have a strong propensity to feed on newborn white shark pups. This could be the reason why male and female adult white sharks have different migration routes to the tropics

3. Intrauterine cannibalism of younger embryos by older ones has been documented for the white shark

4. Largest white shark caught and measured is > 7,000 lbs with its liver weight at 1,000 lbs.

5. Controversy over the evolutionary origin of the white shark: Megaladon (extinct ancient shark species) versus a Mako shark lineage.

6. Many of the studies that acquired the above information utilize dorsal fin tags that transmit data to satellites either when the sharks are at the surface or after timed-release of the tags

Is this cool, or what?

The question is, is there really a need to deploy more tags, especially those cruel SPOT, in the Pacific? How about taking that money and sending a ROV into the Café instead?

And who's gonna finance the same effort in the Mediterranean?

Always stirring the pot, am I...