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According to the book, The Essential GEM Skues, Skues first used
a marrow spoon to investigate the contents of a trout's stomach
in 1921. In Side-Lines, Side-Lights and Reflections, Skues wrote:
"It was some time later that I found on my home breakfast table
some huge marrow bones with a long marrow spoon with two ends, one
containing a long bowl of about five eighths of an inch wide and
the other an equally long bowl of about three eighths of an inch
in width. There is no obvious connection between marrow spoons and
trout, but my mind, to the lasting regrets of my women kind, runs
very much on trout, and it struck me immediately, 'Here is the ideal
means of extracting the contents of a trout's stomach without the
nasty mess of an autopsy.'." The idea of eating the marrow
from beef bones in the BSE-ridden days will, I am sure, excite some
people!
Skues recommended that you wet spoon, insert it into the trout's
stomach, turn it and extract it, all being well full of what the
trout had for breakfast - or lunch. Because food that has been in
a fish's stomach for some time can be quite compacted as it is being
digested, you may have to push your spoon into the fish quite firmly
as well as twisting your spoon. Food swallowed most recently will
probably be found quickly and easily.
It is worth remembering that not every trout that you catch will
have a full stomach or even anything very much in it. It may have
not been feeding very much or even just had a crap before it was
caught! Some fish that you catch will, in complete contrast, be
absolutely stuffed full of food.
Another device to consider is a stomach pump which can be made from
a syringe and length of soft plastic tube or a rubber ball valve
and length of tubing, if you do not want to buy one. As well as
your device of choice for relieving a trout of the contents of its
stomach, you will need a small, white dish or plastic container
into which you can put water and then empty the contents of your
pump or syringe into it.
The best way to hold a live fish - always with wet hands - is upside
down on its back which seems to keep them still and quiet. Do hold
your fish in the water - the right way up - and make sure that it
has recovered from everything that you have done to if before release.
While researching this article, I came across an illustration of
a syringe used by Charles Jardine in his book, Dark Pools, The Dry
Fly And The Nymph. As this looked interesting, I got in contact
with him. He told me that "The original was fashioned from,
believe or not, a snake bite kit that I somehow begged, borrowed
or stole from a visiting American angler way back in 1979. Before
that there was in fact a version manufactured in this country called
the Aymidge Stomach Pump.
"The problem with the original version (Aymidge) was that it
worked on a type of pipette system with a very small aperture that
did not - well at least I didn't think so - have enough "suck"
to vacuum up the foodstuffs. Anyway, after much experimenting the
best material I found, as the link between syringe and the trout's
maw was wine makers' flexible tube. I also found by heating the
ends, they could be softened to fit any aperture and almost shrink
fit around a nozzle, whilst at the other end, be burred over order
to soften any sharp edges which might damage the insides of a trout.
Oddly, it seemed to work. (Very soft silicon tubing is also available
from some model shops - it probably used for fuel lines on model
cars and aircraft.)
"There were and indeed are, huge benefits over the standard
marrow spoons and other concoctions. One main disadvantage with
standard issue marrow spoon is that the fish has to be killed to
be "sampled". With care, a great deal of care - and water
in the syringe tube prior to inserting it into the mouth - it is
possible to extract the last meal of bugs, whilst returning the
quarry. It goes without saying that the fish really should be held
in water throughout this episode.
"Of course the pump works every bit as well if your subject
is deceased! There are though, no perfect solutions to everything
and the pump does have its share of shortcomings. To be fair these
centre entirely on the size of the quarry's prey, much above a mayfly
(E. danica) nymph and your snookered. Fry do not fit, but you can
get telling clues by other means when they are eating stuff that
big - the trout's mouth is generally stuffed!
"The pump I now use has some nefarious use in hospitals which
I simply do not want to know anything about, let alone experience!
It is the biggest I can find for maximum suction. Even so they are
gentle on their subject but as with all things care must be taken.
One senseless trout death is just not worth it. However I would
say this: in all the time of using the pump I cannot recall any
trout death directly attributable to its use. It is also the most
efficient extractor of samples that I know.
"Just think, all that from a snake bite outfit."
In an endeavour to make my own pump, having failed, so far, to track-down
an old syringe, I came across a kitchen baster in a cookery shop.
This has a rubber bulb which provides the suck and a clear plastic
"body". To use it on live fish will require some modification
- shortening it as it is rather too long and fixing a piece of soft
tubing to the end. I have tried it on dead fish with mixed results.
One fish did not yield that much food to the pump but there were
plenty of partly digested nymphs etc packed fairly firmly at the
far end of its stomach when I cut it open. As Charles Jardine suggests,
a pump or syringe will probably extract only those items swallowed
most recently.
When you have emptied the contents of your spoon or pump into a
vessel of water you can stir them about gently so separating everything.
You can then start to look closely and see what you have found.
A small magnifying glass can be useful for identifying smaller food
items or checking the difference between seemingly similar nymphs
or olives.
Match the most prolific items that you find. If there does not seem
to a dun, spinner or nymph that is dominant, I would suggest that
you match the size, colour and type of the most popular item, whether
it is a nymph, buzzer, dun, shrimp etc.
I must end this article with a strong warning to anyone who is tempted
to have a go at stomach pumping a live trout. If you are not extremely
careful you risk ending up with a dead fish. Do practice on a dead
fish first although that will not be the same as trying to hold
a live fish and inserting your pump. Maybe get a fishing companion
to help you the first few times. If in doubt, don't.
Terry Lawton is a passionate nymph fisherman who caught his biggest
wild brown trout (in the UK) - 4lb 2oz - on a home-tied variant
of a goldhead, Sawyer-style pheasant tail nymph.
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Before acquiring a disposable syringe from
my vet, I came across this kitchen baster. Although it has fair
amount of suck, it did not extract that much from the stomach of
this trout. It is too big to use on a live fish.
A marrow spoon, which can only be used on
dead fish, is a good way of extracting the contents of a fish's
stomach which can be suprisingly well compressed.
Some of the insects extracted with the marrow
spoon. The fish was caught on a pale olive nymph which was a good
match for some of the nymphs that I found.
Live fish are best held upside down. This
seems to keep them calm and stop them struggling, which is essential
if you are trying to use a stomach pump on them.
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Say
"Aargh" - spooning fish