info on barracuda??!
spater at cellmate.cb.uga.edu
Fri Jan 12 17:47:02 EST 1996
On Mon, 8 Jan 1996, Piz Zart wrote:
> In article <Plmate.cb.uga.edu> you wrote:
> : I am studying behavioral ecology of great barracuda (Sphyraena barracuda)
> : - there are 19 or so other species, most of which have never been studied
> : in detail. I can have a go at any specific questions you want to throw
> : my way.
> : Shane
> Thanks - I do have some specifics. I'm doing a report for high school
> marine bio. Here they are:
Most of my comments are about the great barracuda, not the other species
(about which, for the most part, even LESS is known)...
Better than that...this might be overkill, but here's the whole taxonomy...
Species 20 species recognized by DeSylva
> Food they eat?
Great barracuda are highly opportunistic - pretty much whatever they
want...everything from lobsters
to both slow- and fast-swimming fishes. Not very gape-limited in the
size of prey they can take, since their jaws allow "chopping" to pieces -
they will often take the tail off larger prey, leaving it helpless, and
consume at leisure...or they'll chop the fish in half (even big ones,
like margate, are not much trouble for this beastie).
About 20 barracuda species - all in the same genus. I believe the
"nearest relative" changed over the past couple of years. If I remember
rightly, it was or is the mackerel Family (Scombridae) or mullet Family
(Mugilidae), but I'm not sure it's been resolved yet. No close relatives
- if you look at the classification scheme above, the barracuda are the
only members of their Family and Suborder - and are all in the same genus.
Some members of the mackerels, such as New Zeland's "barracouta" (I think
the specific name is _Thyrsites thunnus_, though if you need that I can
look it up to make sure) look very similar - they've converged on the same
general body plan. Pike, gar and a few other freshwater fishes have done
the same...they look similar because they have similar ecological "roles".
Barracuda - various species thereof - are sometimes called "sea-pike", and
for a while the great barracuda was considered to BE a marine pike.
> How they move around?
Quickly :-) They swim...some species move in schools, typically,
while others tend to be solitary (but not entirely). The great barracuda
(largest and most cosmopolitan species) can move very slowly, with
imperceptible fin movements - so it looks as if it is not moving at all
(handy for a predator) - but can also put on phenomenally fast bursts of
speed from a standstill.
> > How they get food?
As mentioned above, they can prey by means of stalking, ambushing, or
(and this has not been documented yet in scientific literature for adult
barracuda) acting togetehr, in groups. Their attack is blindingly fast
and their jaws are extremely powerful, with a smaller cross section than
a shark's, resulting in a blow similar to that a cleaver would inflict.
> > Who are their predators?
Larger ones can eat smaller ones, but not much preys on the adult great
barracuda - they've been found in the stomachs of tuna and dolphins
(mammal) and some sharks may be swift enough to catch one. Otherwise
it's fisher-people - many sport fishng types catch and release barracuda,
but their mortality once released is probably pretty high, since large
adults are highly sensitive to handling.
> > How do they protect themselves?
For the most part, they probably don't need to worry too much about
predation due to their speed, size, and impressive dental work.
Barracuda will bite or charge other barracuda. They also have impressive
camouflage ability which could act in dual roles - concealment for
predation and concealment against other predators. Young barracuda often
camouflage themselves to match their seagrass or mangrove habitat, and
Donald DeSylva (a professor at the University of Miami who wrote a paper in
1963 on barracuda) noted that they will sometimes stand on end in
seagrass to blend in better with the grass blades. Just as adult
barracuda are a top predator on reef and other areas, juveniles are
probably the top predator in extremely shallow water, where they are safe
from pretty much all predators other than wading birds.
Great barracuda found in all tropical/subtropical seas except the eastern
Pacific (coast of the Americas). Usually associated more with shallow,
nearshore waters - reefs, seagrass flats, sand flats, mangroves. Other
species more restricted in range, with the greatest diversity of
barracuda (everything, for that matter) in the Indo-Pacific.
Superbly adapted as a predator - flexible in behavior, able to change
color to blend in with varied backgrounds, including open water, and has
morphology which enables it to accelerate quickly, cruise, or sneak,
alowing the great barracuda to prey by ambush, hit-and-run, and other modes.
> > Important to humans?
Implicated in some attacks, mostly on swimmers in murky or similarly poor
conditions. Important in subsistence fisheries (where threat of
*cigutera* poisoning, the barracuda's greatest threat to human welfare,
is low) and soem commercial fisheries, as well as sport fishing. Popular
with divers/snorkelers/underwater photographers. California barracuda
(S. argentea) has been an important commercial fishery.
> > Any cool facts?
Too many. Working on finding out more. There has never been a detailed
study of barracuda behavior, and that's what I'm working on now. They
are very "plastic" (flexible) in their behavior - whether it relates to
interactions with other barracuda (joining groups or territoriality), the
mode they select for hunting (and the prey they select, which is related
to mode choice), their "boldness" toward divers and snorkelers...etc. I
suspect their social life is more intricate than we seem to have thought,
and that they may communicate partially through varying their colors,
shading, and markings. They also gape widely - showing off their teeth -
which is probably an intermediate-level threat display or, at least, a
"hello, I'm a barracuda and I could bite your hand off if I wanted to"
display. The usual maximum size given for great barracuda is 6-1/2 feet
in length. You'll often hear people talk about much larger ones, but it
should be borne in mind that SCUBA/snorkeling masks (the water, actually)
magnify things by an average of 25%, so a 6' barracuda is going to look
like it's 7-1/2 feet long...factor in the "terror factor" (large 'cuda
ARE very intimidating in appearance) and you've got someone thinking
they're looking at a 9' barracuda. However, it's possible they grow
larger - maybe even up to 10' in length, or that they have in the past,
before humans started having a great impact on their environment...the
reason I think that's possible is that (apart from the fact that almost
ANYTHING is possible) a scientist who does underwater fish census work
all over the world, who is very skilled at estimating sizes underwater,
swears he has seen an eight footer. The largest I've seen yet, and I
believe my size estimate is accurate (perhaps even an underestimate,
though not by much, if at all) were all in the 5-1/2 foot range. Pere
Labat, a French missionary/explorer in the caribbean in the 1700s,
brought back tales of barracuda which were 18-20 feet long, which ate
horses (and their riders) and were bloodthirsty in the extreme. Labal
also said that, if faced with the choice of a Frenchman and an Englishman
in the water, the 'cuda would eat the Englishman because English people
exude more "corpuscles"...i.e. they smell worse... :-) ...he reasoned
that English people tended to eat heavy, "beefy" foods, while Frenchmen
were more dainty and refined in their dining habits and don't smell as
bad...and he backed up this assertion by quoting Carib trackers who said
it was easier to track Englishmen through jungle than Frenchmen and,
further, that English flesh was a lot tastier than French...I think Labat
was a little biased in his opinions, though.
> > Lifespan?
DeSylva looked at scales (the annual rings can be counted like you would
for a tree, to give an estimate of age) and the oldest he found was 14
years old. They may grow a lot older than that, though - DeSylva noted
that the largest barracuda he looked at was only a quarter of the size
(by weight) of the largest barracuda then on record (which was 106 pounds).
> How do you tell the sex?
I wish I knew - beyond killing them and looking at the gonads, I know of
no way to do that. Sexes are (to our human perception) monomorphic.
Females are larger than males, but that is very relative.
> Sorry if this is alot of questions. I really aprreciate the help!!!
No problem...sorry it took so long (been really busy this past week due
to an accumulation of deadlines and bureaucracy). Good luck with the
paper and the class - I hope you're enjoying it. It's a great subject
(though I'm kinda biased).
See ya...just let me know if you have any other questions and I'll do my
best to answer them before your paper's due.
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