Could a whale cause this?

[Don C L]

Originally Posted by bvisailing32

A huge sea beast, about 30 feet or so in length, narrower body than a whale, dorsal fin, but not long like an orca, very dark , dark blue and a swimming motion like a shark.


Probably a whale of some type since dana point and our socal coast is known for them, but it had a small dorsal fin, and swam like a shark.


Oh well, we will probably never know, but it makes for a good sea story when these subjects arise.

Hmm, I love a good puzzle... Basking shark? we have them around.. but it has a big dorsal fin.
It only had one distinct dorsal fin or did it stretch along the length of the body?

If it DEFINITELY swam like a shark then I guess we'll have to rule out whales though there are a number of good possibilities.

OK, I vote for Oarfish. We have big ones off Calif. coast.
https://en.wikipedia.org/wiki/Giant_...nt_Oarfish.jpg

https://www.youtube.com/watch?v=CZSv_SOw0_U

though your description doesn't account for that either.
Take pictures next time!

[bvisailing32]

Thank you all....

We are familiar with the Oar Fish, there was another photo, might not have been the same Oar fish, with three people holding it with their arms extended to the front and the long fish laying on the tops of their arms. That event was on the beach at Two Harbors, Isthmus Cove, West End, Catalina Island.

The fun mystery continues.

With our speed heading north and its speed heading south, we passed each other fairly quickly, and I did not even think about taking a photo.
The camera was down below secured in Erica's sailing bag.

Wish it would have been up topside.

Amazing the things that all of us have experienced at sea.....

You all might remember the world cruisers who witnessed that island being born and rising up out of the sea . I cannot remember the location but they video'd the sequence and aftermath. That would have been amazing .

[Peregrine1983]

Originally Posted by Exile

Manatee?

Hah! Yes, a manatee.

[hpeer]

I once was in a group of porposi, the individual pods were of 6-7 animals and maybe 100 yards apart. I estimated it to be 3 miles wide by 3 miles long. They were all moving rather briskly in the same direction. No playing around. They might swing by for a look just in passing. George’s Banks area.

[JohnT]

Originally Posted by Naughty Cat

We put out from Imperia (Liguria, Italy) a few weeks ago to head up the coast with an ok breeze, and a frustrating current from the north. A few miles offshore the depth sounder showed we were over the shelf at 200m+. The charts, as you would expect showed no rocks, obstacles etc..



Then the depth gauge showed 6.5m. Then blank, then 5.8m, blank, 6.5m etc and so on between 5.8 and 6.5m for 20 minutes or so. Eventually we tacked and it did the same at around 10m for about 5 minutes and then went blank again. There were no further anomalous readings that trip. I checked the depth sounder that night and it was clean.



Imperia is well known for whale sightings. We did not see any but it got us wondering whether we had something under us. Anybody else experienced something similar. Are we just wishful thinking?

You mention two relevant bits of info 1. The drop-off of the shelf and 2. The strong current. This is normally where you experience upwelling and that often brings up water full of silt. Most depth sounders cannot get a fixed depth due to this and especially where the depth is more than 200m. The same occurs off the southern west coast of Africa as well as the northern coast of South America in the region of French Guyana up to Guyana. It can be quite disturbing if the upwelling is very strong and the sea frothing - makes the mind work overtime trying to figure out what the hell is going on!
John.

[seasick]

Hpeer and jd1 are most likely correct. Thermocline and or depth beyond range.

[fuentes]

Originally Posted by Peregrine1983

This happens with our depth finder occasionally. Kelp, fish, whales, dolphins... who knows.

We recently had a humpback swim right under our boat just off Brooklyn, but as you might imagine I wasn't focused on the depth finder. The fat mammals have come back and it's pretty awesome!

Please excuse my cussing... we've seen plenty of dolphins, but we'd never seen an urban humpback. I cut the video short as my cussing gets a bit out of hand and the whale disappears under the boat.

We have had as many as 7 whales swimming along with us in the Sea of Cortez. My reaction and "expressions" were a little stronger than yours. I kept repeating. SOB, I hope it is not related to Moby Dick. One of them breached aboat 200 ftl from us. It rocked the boat, but that was it. What an experience. Just like in that insurance ad.

[nicholasd97330]

We've had this same thing happen and then the dolphins popped up.

[Peregrine1983]

Originally Posted by fuentes

We have had as many as 7 whales swimming along with us in the Sea of Cortez. My reaction and "expressions" were a little stronger than yours. I kept repeating. SOB, I hope it is not related to Moby Dick. One of them breached aboat 200 ftl from us. It rocked the boat, but that was it. What an experience. Just like in that insurance ad.

Hah! That’s fantastic. The Sea of Cortez is on my bucket list for sure...

[sv.antea]

in 1984, coming back from Europe, somewhere half way between Canaries and the Carribean, a lull in trade winds, very calm seas. We were motoring at night, on autopilot and I went below to take my 20 minute nap. Before I could fall asleep, the boat came suddenly to a full stop, pitching gently forward, that accompanied by scraping sound. Just like we ran aground on a sand bank. Did I screw up my celestial and did we hit some shoal near Cape Verdies? Unlikely, since all I did was multiple star sights and they are self confirming. I grabbed a flashlight and flew up on deck. Meanwhile, the prop was digging in and the boat accelerated back to our stately 5 knots. Nothing to see, same calm water around us. Did we hit a sleeping whale?
Within a mile of St. Thomas, it was another calm day, we took turns going for a swim. I put on a mask and dove under the boat and immediately saw scrapes in the bottom paint, pretty much as if someone took a rake to the bottom, scraping it from the waterline in the bow all the way down the bottom of the fin keel. Several grooves, I assumed from barnacles on the back of a whale.

[Baba Buoy]

My depth meter goes haywire like this when the water depth exceeds the range capability of the meter.

[Don C L]

Originally Posted by bvisailing32

With our speed heading north and its speed heading south, we passed each other fairly quickly, and I did not even think about taking a photo.
The camera was down below secured in Erica's sailing bag.

Wish it would have been up topside.

Yeah, don't we all Those things never give us any time to prep. Last time out half way across the channel we had a big shark appear and slide ride along the waterline under my son's dangling feet. He was going one way and we were going the other. It was a quick glancing blow, but given its appearance it was most likely a juvenile great white. But no way to take a photo and I HAD my phone in my hand! My son's not too interested in dangling his feet anymore.

[Don C L]

Originally Posted by sv.antea

in 1984, coming back from Europe, somewhere half way between Canaries and the Carribean, a lull in trade winds, very calm seas. We were motoring at night, on autopilot and I went below to take my 20 minute nap. Before I could fall asleep, the boat came suddenly to a full stop, pitching gently forward, that accompanied by scraping sound. Just like we ran aground on a sand bank. Did I screw up my celestial and did we hit some shoal near Cape Verdies? Unlikely, since all I did was multiple star sights and they are self confirming. I grabbed a flashlight and flew up on deck. Meanwhile, the prop was digging in and the boat accelerated back to our stately 5 knots. Nothing to see, same calm water around us. Did we hit a sleeping whale?
Within a mile of St. Thomas, it was another calm day, we took turns going for a swim. I put on a mask and dove under the boat and immediately saw scrapes in the bottom paint, pretty much as if someone took a rake to the bottom, scraping it from the waterline in the bow all the way down the bottom of the fin keel. Several grooves, I assumed from barnacles on the back of a whale.

...or a giant squid? Did the scratches on the keel look like the ones on the head of this Sperm Whale? "Rake" sounds more like the evenly spaced hooks on their tentacles.
http://squid.tepapa.govt.nz/anatomy/...-and-tentacles

[Naughty Cat]

The depth range appears to be 170m+. I am not on the boat at present to check but I have only seen 170m before it goes off scale '---'. It has never shown that behaviour before or since off scale hence I discounted instrument issues per se and noted the reading as exaordinary. The boat is a catamaran. The current was about 3knots and about 25 degrees N, compared to about 45 degrees north for the shelf. I have since found this excellent article studying the Genoa Canyon's influence on whales in the region and it highlights two things: https://www.omicsonline.org/open-acc....php?aid=77154

The first is the characteristic of down welling on the edges of the canyon, not up welling,
The second is best served by a quote: Physical oceanographic conditions inside canyons, such as accelerated currents, upwelling and dense-water cascades, are often caused by topographic and climate forcing. These phenomena can be responsible for increasing suspended particulate matter concentrations and transport of organic matter from coastal zones to the deep ocean, enhancing both pelagic and benthic productivity inside canyon habitats.

The interesting characteristic was that the depth changed from off scale to 5.8-6.5 suggesting the phenomenon was not consistent, potentially ruling out a thermocline, and, similarly suggesting a shoal of fish was not the cause as this would give more variety in depth readings. But, it could have been a bloom of some sort.

The boat is now moored just up the coast in Loano so we will sail the region further and I now have more ideas as to what to look out for, including sea temperatures.

[Scotty Kiwi]

Jellyfish?

Their "schools" can spread 10's of miles. Thickly.