Welcome, Guest. Please login or register.
November 24, 2017, 07:48:27 PM

Login with username, password and session length

Recent Topics

[Today at 07:41:45 PM]

[Today at 07:22:45 PM]

[Today at 07:17:47 PM]

[Today at 06:28:09 PM]

[Today at 06:15:08 PM]

[Today at 05:15:33 PM]

[Today at 05:12:46 PM]

[Today at 04:25:45 PM]

[Today at 04:22:35 PM]

[Today at 03:59:42 PM]

[Today at 03:43:26 PM]

by achu
[Today at 03:35:44 PM]

[Today at 03:10:54 PM]

[Today at 02:31:46 PM]

[Today at 01:26:35 PM]

[Today at 01:19:50 PM]

[Today at 01:02:12 PM]

[Today at 10:57:21 AM]

[Today at 10:28:29 AM]

by tiny
[Today at 07:26:10 AM]

[November 23, 2017, 08:14:06 PM]

[November 23, 2017, 04:28:15 PM]

[November 23, 2017, 04:27:40 PM]

[November 23, 2017, 04:26:00 PM]

[November 23, 2017, 04:11:01 PM]

[November 23, 2017, 12:41:54 PM]

[November 23, 2017, 12:19:43 PM]

[November 23, 2017, 12:17:43 PM]

[November 23, 2017, 11:13:59 AM]

by SOMA
[November 23, 2017, 10:32:51 AM]

Support NCKA

Support the site by making a donation.

2017 AOTY/DOTY Entry

Topic: Official GWS Thread  (Read 90002 times)

0 Members and 1 Guest are viewing this topic.

Bill

  • Sea Lion
  • ****
  • My Brother
  • View Profile BlazingB Studios
  • Location: San Jose,CA
  • Date Registered: Dec 2004
  • Posts: 4331
Bummer it does not say what type of shark it is. Some (maybe all?) sharks can get pretty territorial during breeding season. Bull sharks are notorious for persistent attacks against large inanimate objects that get into there territory. I have not seen much research into this from a GWS perspective though.


jmairey

  • Sea Lion
  • ****
  • 35" and ~25lbs of halibut
  • View Profile
  • Location: mountain view
  • Date Registered: Jul 2005
  • Posts: 3761
that kind of 'attack' is interesting. it's not trying to eat the boat, it just
plain don't like it and wants it to leave. some boats that come near
floating whale carcasses are encouraged to leave:



also, on the pelagic site, you see photos of females with scars over the gills.
(this one is a 19 footer, so I guess it's body is over 6 feet tall, fins not included?)

mating marks, it is assumed.



maybe art's fears of an amorous GW aren't too far off.  :smt010

here's a story of a white shark taking exception to a white bottomed dory and sinking it:
http://www.sharkresearchcommittee.com/inanimate.htm

the bottom line seems to remain that a white shark is not going to attack your boat,
knock you off and eat you. it might do one of those things, but not all in a nice
sequence like in jaws.  :smt004




john m. airey


mooch

  • 2006 Angler of the Year
  • Manatee
  • *****
  • Cancer Fighter
  • View Profile
  • Location: Half Moon Bay
  • Date Registered: Dec 2004
  • Posts: 15628
that first photo gives me the heebee gee bees  :smt118 imagine seeing that while your casually pulling up your struggling bloody halibut on deck  :smt009


jmairey

  • Sea Lion
  • ****
  • 35" and ~25lbs of halibut
  • View Profile
  • Location: mountain view
  • Date Registered: Jul 2005
  • Posts: 3761

does this count for lunch @ onno grill?

http://www.fishingkites.co.nz/newsletters/newsletter101.htm

Kayak Fisherman Harassed by Shark

I got a phone call from a very shaken kayak fisherman who was recently harassed by a very large shark while fishing around 800 meters offshore on the east coast of Northland.

The shark started it's relentless harassment of the kayak while the fisherman was hauling in a boat longline (yes it was one of ours) with fish on. The shark was taking or mauling the fish on the longline right under the kayak as the line was being hauled in.

In a bit of a panic and keen to put some distance between himself and the agressive shark, the fisherman quickly cut away the longline and accidentally sliced himself deeply above the knee in the process, this cut bled profusely.

The fisherman, obviously shocked by all this, then paddled very slowly away from the longline. Unfortunately, once the line was cut the shark shifted all of it's attention onto the kayak, it started by circling, and then bumping against the kayak. Occasionaly the shark would submerge only to come up from the depths and bump into the kayak from below.

The fisherman then put all of his remaining bait and burley into a plastic bag and tossed it well away from the kayak in the hope that this would divert the sharks attention, it almost worked as the shark went over to investigate the cause of the splash where the bait bag had landed, but to his horror it returned seconds later.

During the worst parts of the harrassment the fisherman was nearly knocked out of the kayak by the shark several times and had to put his legs over the side and into the water to regain balance.

He also vomited several times during the attack, probably due to the shock of being exposed to a serious and life threating situation for such an extended period of time.

In all the shark hit the kayak between 15 and 20 times with different parts of it's anatomy including the body, dorsal fin and tail.

When the fisherman was only 150 to 200 meters offshore the back of the kayak was hit violently and the stern momentarily went under. As soon as he had regained balance the fisherman poured on the power with the paddle and, as he reached the shallow weed line near the rocks, he glanced over his shoulder to see the shark close behind, but veering away to avoid the reef.

How Big Was the Shark

The shark was huge, on one pass at right angles and just under the center of the kayak the fisherman noted the width of the head was greater than the distance from the back of his seat to the front of his foot rests, his estimate is a meter or more between the eyes. On this pass the dorsal fin hit the kayak amidships and almost capsized it.

As for the length he noted that the shark tail extended "five to six feet" behind the stern of the kayak when the head of the shark was level with the front. He said the kayak is "twelve and a half feet long" so the shark must have been between 17' 6" to 18' 6' long or 5.33 to 5.64 meters!

What Sort of Shark was it

The fisherman describes the shark as having a shiny, almost jet black top and very white undersides. He mentioned the pectoral fins and tail were huge and he was adamant the tail was positioned vertically on the shark (which rules out a killer whale or other dolphin). He said the dorsal fin never rose higher than 300 to 400mm above the water although, as the back of the huge fish never broke the surface, it could have been longer.

He also noted the front of the head was flat and not pointed, this may rule out a white pointer, otherwise a great white would fit the rest of the description perfectly.

Why Did the Shark Attack the Kayak

Struggling hooked fish is probably the most powerful shark attractant available.

Sharks can pick up vibrations from struggling fish from kilometers away almost instantly, and this is probably what brought the shark to the boat in the first place.

When the shark arrived it took some fish from the longline which likely put it into a feeding mode, the added smell of blood in the water from the fish it had mauled would have probably kept in interested in the area.

Blood from the bait and burley thrown overboard, and any that was being washed off the deck of the kayak, plus the vomit and bleeding from the badly cut knee would have all added to the sharks curiousity in the kayak.

How to Minimize Risk

If you are setting a longline from a kayak, I would suggest baiting the line on shore, or at least have the bait cut up and in a waterproof container on the kayak, so that line setting times and bloody mess are minimised.

When hauling the line, do it as quickly as possible and iki or kill the fish as soon as they are landed, as the vibrations of a dying fish on deck will be amplifed by the hull.

Keep all fish and bait as well as any burley in leak proof containers. Doing this will make any blood and offal less likely to leak or wash over the side and possibly set up a burley trail leading straight to the kayak.

Witnesses

The massive shark stayed in the bay for a considerable time after the incident. The hapless fisherman watched the shark, along with about 40 other locals and holiday makers, from a nearby hill top. One of the visitors video taped the shark still circling the area where the incident occurred. If anyone has photos or video we would appreciate a copy to go with this article.

john m. airey


jmairey

  • Sea Lion
  • ****
  • 35" and ~25lbs of halibut
  • View Profile
  • Location: mountain view
  • Date Registered: Jul 2005
  • Posts: 3761

here's a another good one:

http://seakayaker.tripod.com/sharks1.htm

Paddling off Tomales Point one calm and balmy evening in early October, I heard a swishing noise. Looking over my shoulder, I saw a shark’s dorsal fin break the surface heading straight for me.

I paddled furiously, but the shark kept gaining on me. I paddled evasively on the right side only and the shark followed. I paddled evasively on the left side only and the shark followed.

I caught up to Don Fleming and yelled "Help! There's a shark following me!" I don't think Don appreciated my new-found friend; he started paddling toward the Bay. Don and I set a new world record paddling speed on the scrupper-pros. Luckily the shark lost interest and disappeared.

After blindly following basic instinct to avoid a charging animal, my first rational thought was to grab the camera and get a picture. My second thought was maybe I shouldn't run, that might only encourage a chase.

Lucky for me I followed my instincts and paddled evasively. If I had stopped, I think the shark would have hit the kayak and possibly knocked me in the sea. I always thought if attacked by a shark that it would be from underneath and I wouldn't see the shark until the last moment. I think I only saw him because the shark had to deal with a moving target. Don says it was a 10 foot or smaller shark, but it looked like a 35 footer from my deck.

Later I reported this incident online to the Shark Research Committee. Their definitions are informative:
Shark Encounter "A human is approached by a shark which leisurely circles and/or slowly swims past the subject without any aggressive behavior exhibited by the shark"
Shark Attack "If an impending attack is only avoided by evasive maneuver, this too shall be classified as an unprovoked shark attack"

Many thanks to Ralph Collier of the Shark Research Committee for the shark encounter definitions. Please report all shark encounters to http://sharkresearechcommittee.com They hope to eventually be able to determine cause and effect for kayakers.
 
 


Conditions:
Date of encounter: October 7, 2002, about 6pm
Conditions: calm winds and flat seas of 2-4 feet
Weather: sunny and warm, air temps in the 70s
It was a beautiful evening for sea kayaking; unfortunately, I have learned that sharks also like these conditions. It makes sense to me that a large fish would not like rough conditions.



john m. airey


Bill

  • Sea Lion
  • ****
  • My Brother
  • View Profile BlazingB Studios
  • Location: San Jose,CA
  • Date Registered: Dec 2004
  • Posts: 4331
Sorry John it was for that point forward and if you will allow me a little leeway I was thinking Nor-Cal only. I did not make that clear though so I will yeild to world wide but only GWS.


jmairey

  • Sea Lion
  • ****
  • 35" and ~25lbs of halibut
  • View Profile
  • Location: mountain view
  • Date Registered: Jul 2005
  • Posts: 3761

good, that would have taken some of the suspense out of things.  :smt004
john m. airey


Gowen4bigfish

  • Guest
Some unsolicited score keeping:  Jmairey The guy off the cost of Northland wouldn't count in the bet. Bill In reply #12 said no provoked attacks count.
 
The shark research committee considers chumming as provoking an attack.
 
So even though I sure the guy hadn't set off with cut bait fish on his kayak to chum a shark, he was still chumming none the less.
I keep tying to tell my wife pay attention to what you are doing and whats going on around you. I guess dude from Northland got a wake-up call.:smt078
 
 I guess the guy out at Tomales Point has reaffirmed you don't have to out paddle the shark
 you just have to out paddle your friend.  :yak   :yak       

It was seeming to me like Bill needs some help if he's going to make it 5 yrs.
« Last Edit: December 21, 2005, 07:16:53 PM by Gowen4bigfish »


Bill

  • Sea Lion
  • ****
  • My Brother
  • View Profile BlazingB Studios
  • Location: San Jose,CA
  • Date Registered: Dec 2004
  • Posts: 4331


Malibu_Two

  • Sea Lion
  • ****
  • View Profile
  • Location: San Francisco
  • Date Registered: Jul 2005
  • Posts: 2128
that kind of 'attack' is interesting. it's not trying to eat the boat, it just
plain don't like it and wants it to leave. some boats that come near
floating whale carcasses are encouraged to leave:




Actually, from what I've heard, some parts of boats give off electromagnetic waves, which makes the shark "mouth" the boat...
May the fish be mighty and the seas be meek...


Gowen4bigfish

  • Guest
Sure hope it's not the fish-finder's transducer or a GPS that causes that!  :smt107

Man that is one big shark :pale:


jmairey

  • Sea Lion
  • ****
  • 35" and ~25lbs of halibut
  • View Profile
  • Location: mountain view
  • Date Registered: Jul 2005
  • Posts: 3761
that photo is from www.pelagic.com. it says that they got too close to a feeding shark and
the shark attacked the boat:

Quote from: www.pelagic.com
A large white shark bites down on the outdrive of our research boat after encroaching on a feeding event near Ano Nuevo Island. winter 1995-96.

the bit about outdrives being electrical attractors of some sort is quite possibly apocryphal, urban myth, aka B.S.

If anybody can post a reference to this theory, please do so.
john m. airey


jmairey

  • Sea Lion
  • ****
  • 35" and ~25lbs of halibut
  • View Profile
  • Location: mountain view
  • Date Registered: Jul 2005
  • Posts: 3761
navigation aside (for which sight is only so useful), the theory seems to be that sight
is the main sense used by a GWS for predation:

http://www.sharkresearchcommittee.com/predation.htm

so I would not really worry about this electromagnetic thing, blue and my comments on ff notwithstanding,  :smt003.

as p-spark pointed out, this link also confirms that a GWS sees well in the day, not so good
at night and has good color vision, due to a ratio of cones (color, hi-res, non-movement)
and rods (black and white,  low light, movement oriented) receptors in the retina that
is similar to humans.

for comparison, dogs don't have much in the way of cones, they see color poorly, see in lower light
conditions well and probably detect movement better than humans.

Here's something I don't know (beside the details of that 1989 malibu kayak death...).

I saw a reference that a shortfin Mako is warm-blooded (well, almost)

http://www.elasmo-research.org/education/topics/p_warm_bodied.htm


Is a GWS warm-blooded?

I always assumed that fish are cold-blooded. their muscles will generate some heat
from swimming around, a really big fish like a GWS would have low surface to volume
and that heat would be retained well, but does it actually have some kind of thermo-regulation?
This would affect how often a single shark feeds. If you've ever had a pet snake, you
know they can go months in between eating. But a pet mouse eats every day.
It's partially due to this question of warm vs cold blooded, it takes way more energy to
regulate body temp.  If you are warm-blooded, you have to eat more often.

typically also, a warm-blooded animal can reproduce a lot quicker than a cold blooded animal can.

normally, the argument is that sharks reproduce very slowly and this is one reason for the protection.
But maybe GWS are pumping out 5 foot long babies at a high clip?  :smt006
john m. airey


Bill

  • Sea Lion
  • ****
  • My Brother
  • View Profile BlazingB Studios
  • Location: San Jose,CA
  • Date Registered: Dec 2004
  • Posts: 4331
Don't know about GWS but I saw that Salmon Sharks, which apperance wise seem related to Makos, are warm blooded. This enables to hunt Salmon in the cold Arctic waters.

Salmon Shark referrence - http://www.nsf.gov/news/news_summ.jsp?cntn_id=104543&org=NSF&from=news

It contains this interesting quote

"Salmon sharks are lamnids, a group of sharks that also includes the mako and great white."


promethean_spark

  • Sea Lion
  • ****
  • View Profile
  • Location: Sunol
  • Date Registered: Dec 2004
  • Posts: 2410
Their electrical sense is limited to 6-10ft only, they mainly use it in the last lunge when they roll their eyes back and open their mouth.  So an electrical thing wouldn't bring one in from any distance, but they may mouth something that gives off a tasty electrical signal if they happen to sense it cruising by.  The ff electrode is fully insulated inside the kayak, so I doubt they'd even notice it.  The FF transducer wires I've examined were also shielded, so it shouldn't give off any electric fields to speak of either.
The legend lives on from the Chippewa on down
Of the big lake they call Gitche Gumee
Superior, they said, never gives up her dead
When the gales of November come early.


 

anything