Identifying
Free Swimming Sharks
north of Cape Cod |
Don't
go by color! Some blue sharks are much darker
than other blue sharks, and some makos in warm water have a blue color not unlike a blue
shark, where as in the cooler water north of Cape Cod, the makos appear almost
black. So color is not generally a good guide. (The color exception is
for a white or a basking shark, they are much lighter in color than the others, more of a
brownish gray)
Go more by physical characteristics, such as body shape, fin structure, and by swimming
characteristics. In many instances, the identification of a swimming shark has to be
made in a matter of seconds. |
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A defined shape of a
white is easier to make out in the water than that of the basking shark. A white
swims in a determined fashion. Both the whites and baskers are lighter in color than the
blues, makos, porbeagles and threshers. Whites have a gray /brown coloration. Baskers
are slow swimmers. In deep water, "Baskers" look like a sand bar
slowly approaching the boat. It is hard to see a defined shape of a basking
shark in the water. That's because the skin is mottled, they distort their heads
while feeding, and the gill openings on a basker will almost encircle the whole head, with
just a short gap at the top.
Baskers are curious and often come to the boat. Baskers will also
swim along beaches in five feet of water.
Although a baskers dorsal and tail fin will appear black or dark
brown, protruding out of the
water, when a Basker goes under the boat the black or brown will not be that
noticeable. A baskers dorsal is well behind the pectorals, a
white's dorsal is closer to the pectorals. Baskers won't show much white on
their bottom as will a white.
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| White
Shark Dorsal
courtesy of
Pelagic Shark Research
Foundation/D. Casper
|
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Basking Shark
Dorsal
Courtesy of
Bob Jenkins |
OK lets do it!!
Put the polaroids on - get as high up on the boat as you safely
can, and look constantly at and into the water around the boat. Obviously
boats with towers and/or fly bridges have a big advantage over the other lower profile
boats. Eternal vigilance is the price of spotting a mako, porbeagle or
thresher. They won't hang around like the blue sharks. You must pay
attention. |
When You See a Shark
| Remember this method is for identifying free swimming sharks in
New England, north of Cape Cod. Look first directly at the tail
section of the shark! That's right, the tail section!
The tendency of most people when they see a shark is to look it over to get an idea
of its size. Or to try to make eye contact. Don't waste your time doing
that. It's more important to identify the species by looking for
characteristics. Discipline yourself to focus on the body section just as it joins
the tail. (caudal peduncle in shark speak) |
You will see one of three conditions north of Cape
Cod:
1. If you
see an extraordinarily long tail: Case closed. It's a Thresher
shark. (a rare sight on the north side of Cape Cod..)
Capt. Bill Brown photo |
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| 2. If
you see the body gradually tapers into the tail tapers into the tail,
and it has a normal shark tail; it's a Blue
shark, Prionace glauca. A look at the dorsal fin will
show it is set back well behind the pectorals. You can see in the photo, that the
upper sharks body section tapers into the tail. Also notice in these two blue
sharks the long swept back pectoral fins. |
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I took this photo of a flyrodder
awaiting a pickup in Mass. Bay. |
Fishermen on the south side of Cape Cod have more of an ID
problem than those of us north of Cape Cod, since the Tiger, Dusky and Sandbar (brown)
shark's body also tapers into the tail. Those 3 species won't be in Mass. Bay and
northward to New Hampshire and Maine.) |
| 3. If
you see a flared out body section just before the tail, it may be a Mako, a Porbeagle or a rare White. Look
quickly at the back bottom edge of the dorsal fin! If you see a white area, it's a Porbeagle,
Lamna nasus
It's a porbeagle in the photo! Notice the white
area on the back bottom of the dorsal fin.
NMFS Photo |
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On some porbeagles the white area on
the back of the dorsal fin is so noticeable in the water, it screams at you.
It looks as if it was painted gloss white. The size of the white area varies on each
porbeagle. On some it is an unmistakable good sized patch, on others just a
sliver of white. |
If you saw the bulged out section entering the
tail and got a good look at the back bottom of the dorsal fin and did not see a white
area; its a shortfin mako, Isurus
oxyrinchus. (Whites are rare)
If in doubt about the identification, assume it is a shortfin mako. Treat all unknown sharks as makos. No other fish is likely to jump
and land in the boat as makos have done. Makos don't have to be hooked to
jump. They regularly free jump.(as will threshers) A
mako is far more dangerous to an angler than any other fish you will encounter including
whites, bulls and tigers. Makos have jumped into, and wrecked more cockpits than any
other fish. |
If the shark stays in view, a positive
identification of a mako is easier.
The makos’ color in cool water is dark, almost a bluish black. (Lighter and bluer on the south side of Cape Cod.)
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Photo -Capt. Jack Tassinari If you can see its jaws; a mako’s teeth are always a mako’s teeth are always visible,
especially the protruding curved teeth in the lower front jaw.
The mako’s snout is acutely pointed, and is as
hard as a rock.
They have solid black eyes. Makos will often stare
at you as they go by the boat.
Makos rely more on sight than chum smell when they get close to your boat.
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Since makos regularly attack and kill blue sharks, blues usually show
respect for an arriving mako by moving out of sight; especially if the mako is good sized.
(300 lbs. or more) This does not happen all the time, and you may see a
mako swimming amongst the blue sharks, with a noticeably different swimming pattern.
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Notice the surface tracks from this
hammerhead swimming just below the surface.
Don't expect to see a hammerhead north of Cape Cod. Hammerheads
have been taken on the south side of Martha's Vineyard off Block
Island, and out in the offshore canyons.
When not chasing something, blue sharks swim in a
relaxed serpentine manner. A blueshark can swim inches below the surface and not
leave surface tracks. When close to the surface on flat calm days, makos may make
noticeable swirls in the water while changing direction. This is noticeable if makos
zigzag by a float, or around a shallow set bait.
Hammerhead photo courtesy ens-news.com
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Makos swim in an aggressive militaristic manner.
They are always on the move, looking , pacing and dominating the slick. Makos are
bullies, and you can instinctively sense it. They are always on a mission, and it is
reflected in their swimming pattern. They are not happy campers.
A blue will follow its nose right to the chum cage tied alongside the
boat, and often bite the cage; but once a mako, which is primarily a sight
feeder, sees the boat, it will usually change direction and start surveying the
area under and around the boat. Inexperienced people often think they are seeing two
different makos around the boat because the mako can move to a new location so
quickly. Blue sharks will hang around the chum cage for hours, but makos, porbeagles
and threshers are restless, and they will not stay very long.
JUMPERS
Minke whales, threshers , makos, and surprisingly basking sharks, while free swimming will occasionally jump out
of the water. Whales have horizontal tails and show a lot of black. The mako
will have a snow white bottom, and a fish's typical vertical
tail. Look for the long tail on the thresher. |
| The snow white belly
of a hooked mako, making repetitive jumps off the corner of our boat. |
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| A sunfish, Mola mola is very common in this area,
and will often have its dorsal fin protruding from the water . This dorsal fin is
often mistaken for that of a sharks dorsal fin. If you watch the motion of the
sunfish dorsal it is usual slightly tilted and swaying back and forth. Sunfish
are capable of free jumping completely out of the water, and I have witnessed this. |
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For more shark IDs around the world try this new
page I have added some of these sharks will not be in our New
England area, and of course some will be here.
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Updated March 20, 2008 -
Scituate, Massachusetts
