It was a perfect night for fishing the rip.
Pitch black and windless. There were large shoals of smelt in the water.
Plenty of trout feeding too.Their splashing testifying to what we could
not see.
Five or more of us, (seeing more than a man away was impossible), were
flinging flies in the general direction of the sounds but none of us could achieve a
hook-up. For about the fifth time in an hour I felt a pluck on the line
– I struck – but nothing. Again I stripped in the line to check
the fly, a soft silicone number. For the fifth time I needed to
replace it – the tail section gone again – the body
section serrated by teeth marks.
"Damn pluckers," I hissed to the night.
"Yea," answered one of my shadowy companions,
" they are just nipping at the flies."
General agreement rolled along the line of anglers.
The night continued that way. The casting irregularly
interrupted by a "damn" or stronger, as the ‘nippers’
and ‘pluckers’ toyed with us.
I fished on, thinking about a couple of articles
I had read. One in an English trout fishing magazine about a year
before, and one in a New Zealand fishing and hunting magazine
just a month or two before.
The English article was written by one a doyen of
the U.K. fishing scene. A proper fishing gent he is too –
from the tweed coat to the tie he wears – while fishing! The tone
of the article closely matched this gentleman’s appearance
– patronising to a nauseating extreme.
The article commenced with this; "When I am
fishing and I hear fellow anglers saying how hard it is to hook-up
because they are just plucking at the tail of the fly, I smile
and think to myself how little they know."
The writer went on for 2500 words to explain that
trout do not ‘pluck at the tail’ because that is not
the way they feed. The New Zealand article written by a well known
and respected fishermen and writer, postulated the same thing.
Both writers theorised that trout engulf their prey.
That is, trout approach their prey, open their mouths and flare
their gills, and the prey is sucked in to the mouth.
O.K. so for the moment we accept this theory, but
if it is true how do they explain the ‘nipping’ and
‘plucking.’ Both writers agreed that this occurred because
the fly is attached to a line and many times while being retrieved
the line is relatively taunt to the fly. So when the trout approaches,
opens its mouth and flares its gills the fly cannot be drawn into
the mouth. So it only briefly catches the lip.
When I first read the English version of this theory
my first reaction was – ‘bollocks!.’ That reaction may well have been
an adverse reaction to the patronising – "I know better than you" – tone of
the article. When I read the New Zealand article again my initial reaction
was ‘hello, hello the writer read the English article’,
but this was almost certainly unkind and totally unfounded. However, even
after reading both articles again I remained unconvinced of the
theory.
My scepticism was based on my own observations.
But then, so was much of both the original articles. The English
writer making much of observation of trout feeding habits in hatcheries.
So how do trout feed? I delved into my own fishing
book library, the public library, and searched the Internet. How
much information did I get? Very little indeed. There are literally
thousands of books on what, where and when trout feed, but very
little that I could find on how trout feed.
What information I could find confirmed that trout
do feed by ‘engulfing’ their prey, but not as our two
theorists would have it, exclusively.
When trout are feeding on drifting or very slow
moving prey, nymphs, shrimps, very small fish, and flies on the
surface, engulfing is used almost exclusively. The prey is approached
or carried by the current in front of the trout which opens its
mouth, flaring its gills and so sucking the prey into the mouth.
The prey is trapped by the tongue against the roof of the mouth
to ‘test’ the food, and then either swallowed or expelled.
This whole process takes place very quickly, almost in the blink
of a figurative eye.
Feeding this way is not exclusive to trout. Many
saltwater predator fish use similar techniques. For instance snapper, kingfish,
bass and hapuku (groper) feed this way as well. But
again not exclusively.
Some prey is not engulfed. To do so would pose a
life-threat to the fish. Freshwater crayfish must be grasped and
turned tail-first toward the throat and then swallowed, otherwise
the spikes and spines could catch in the throat and choke the
fish. This is also true of larger-fish prey with spikes and spines.
This grasping feeding system is confirmed by the
fact that trout have small, sharp grasping teeth. Nature simply
does not equip animals with appendages they do not need.
So what about the observation evidence of the hatcheries.
Fill a tank with hundreds of small trout and throw in some feed
pellets and a frenzy occurs. These fish dash about engulfing everything
that falls through the water. Let these fish grow on, and release
them into a lake and what happens? Very interesting. The English
stocked stillwater fisheries provide interesting trends.
In this scene a fixed number of fish are released
every evening after fishing has closed for the day. Next day fishermen
pay to fish for them. In most water using fish feed pellets imitations
is not allowed.
The operators of these fisheries work on the basis
that over ninety percent of the fish released the night before
will be caught the next day. Despite the fact that no pellet imitations
can be used. Seems that just about anything that falls through
the water will be eaten by the trout. Conditioned behaviour is
the word, (actually ‘words’ as you have already observed).
The primary point here is that observation of hatchery
fish feeding behaviour will not and cannot provide any real basis
for a hypothesis on those fishes’ natural behaviour in the
wild. In a hatchery there is only one source of food. That source
of food is delivered in the same way every day, usually at the
same time. Competition for that food is intense.
So observation in the wild should provide the most
telling clues. Here is what I have observed.
Trout will delicately pluck nymphs from weed in
lakes, even in heavily weeded lakes. I have observed them swimming
along the edges of weed banks nipping nymphs off the weed as they
go. As some kind of proof that these fish are not engulfing the
prey is the fact that any of these fish that I have caught, have
little or no weed in their stomachs.
In deeper water, trout chasing smelt
regularly ‘ball up’ small schools of smelt then swim
around it picking off one at a time. Sometimes when this is happening
on the surface, fish can be observed with prey in their jaws.
In shallow water around lake edges I have seen trout
move onto a smelt imitation fly and ‘nip’ at it and
immediately let go. I have learnt that sometimes if the retrieve
is stopped immediately this happens the trout will move forward
and pick up the fly as is drops.
Then there is the evidence that started this story
– the silicone flies with missing tails and teeth cuts on the
body. The engulf, swallow or expel theory does not cover this.
These flies have been bitten.
There was one fisherman who caught fish that night,
and he was using silicone flies. We stopped fishing at the same
time and as we walked out of the water I asked him what he was
doing. Seemed his technique involved not striking if the fly was
nipped or plucked. Instead he dropped the rod tip and immediately
flicked some slack into the water. This allowed the fly to sink.
Often he got a hook-up almost immediately. In addition every time
this technique worked, when he landed the fish the fly was always
without its tail.
I could have left it at that, but I noticed as we
walked up the bank and into the light that the silicone fly he
was using was very big by usual standards, perhaps 50 to 60 mm
long, compared to the more usual 30 to 40 mm long.
There appear to be two main types of smelt in Lake
Taupo, one of which is much larger than the other. It seems to
me that when I observe shoals of the larger smelt in the water,
nipping and plucking becomes more of a problem. Maybe the feeding
technique is different depending on the size of the prey.
Then a few weeks ago I saw a brown trout chasing
a small rainbow in the shallows and I got my final clue. The brown
did not try to engulf the rainbow, instead it seemed to try and
get just alongside the rear of the fish, and then with a rapid
swing of its head, it snapped its jaws. After two misses it finally
caught the rainbow.
So I started to watch rainbows in shallow clear-water
chasing my flies. Same thing. The rainbows swam slightly to one
side of the fly, and then swung its head across and grasped the
fly. This, in a bay where larger smelt seem to predominate.
On a couple of occasions I have been lucky enough
to observe a rainbow at close quarters in clear shallow water
harrying a shoal of smelt. On both occasions the trout slashed
around and through the shoal snapping and nipping at fish. When
the shoal broke up the trout leisurely swam back through the area
picking up wounded fish.
Why do they appear to behave this way? Very simple
really. Trout like many other predator fish cannot see what is
directly in front and close to its snout. When their mouth is
open this becomes even more true. So for larger stronger prey
that may well be able to resist a trout’s limited engulfying
ability in still water, the biting tactic may be required.
Trout have existed on this planet for millenia,
and like sharks they have not changed very much over that period.
Lack of change in nature usually means one thing, that an animal
is ideally suited to its environment. Trout will feed on a variety
of prey, in a variety of water during its life span. I contend
that they do not use one method of feeding, and while it may be
true that trout mostly engulf their prey, there are times when
they bite and grasp, before swallowing, especially in lakes.
So the next time you feel a nip or pluck, ignore
the smarmy, patronising smile of the English writer, and disregard what he would have
you believe he knows, and immediately stop your retrieve and let
the fly sink. If you hook up then it may not prove the engulfing
theorists wrong and me right, but hey, it may well get you the
fish.