WHAT DO WE HOPE TO ACHIEVE
Before
answering this question let us look at some of the questions which have been
passed to us!
1. Where do our Sharks go?
2. Who else catches them?
3. How much do they grow?
4. Where do they breed?
5. What is their main 'Non Natural Predation'?
6. Do we catch the same Tope season after season?
7. Why do we need to have tagging?
Not a bad list and hopefully by running the UK Shark Tagging Programme we
will be able to answer some of the questions, even if only on a limited basis.
Let us try and answer some of these questions, even though they may not be
in the order asked.
7 Why do we need tagging?
Simply to answer questions 1 to 6 and to highlight that we do not have a never
ending supply of stock, which anglers, and indeed commercial fishermen can
keep going back to. No stock is infinite and should always be treated as finite.
In particular with shark species they are very slow to reach maturity, and
hence this leads to them breeding, comparatively speaking, late in life. They
also produce a small number of young which in Nature itself are predated upon
by higher Predators. By the continual slaughter of stock by anglers and commercial
fishermen we are hastening their demise, as in the case of Tope, a highly
sought after Sport Fish.
1. Where do our Sharks go?
Hopefully by use of the tagging programme this will tell us. What happens
is that the Shark is tagged and when that fish is subsequently recaptured
we know where it has been. As we have said in the introduction to the UK Shark
Tagging Programme, if another angler catches a tagged Shark, not to remove
the tag, but record the data and let us know and then on final recapture (presumably
by a commercial fisherman) we will be able to plot a small migration path
for that one fish. If a number of anglers catch that same Shark and let us
have the data, then we will be able to produce a more definitive migration
route.
2. Who else catches them?
Again this is only something that tagging can answer.
3. How much do they grow?
One of the questions asked on the return data form is a weight (whether estimated
or actual) of the Shark. Upon subsequent recaptures if this is noted we should
be able to answer this question, over a limited period of time.
4. Where do they breed?
Tagging may well be able to answer this question for us. If an angler catches
a non gravid female Shark, which is later reported recaptured by another angler
(or commercial fisherman) as being gravid, we will know that between the point
of tag and capture she has at least mated. The area of final recapture on
being gravid could be the breeding area. This could be borne out if there
are large numbers of 'just pupped size' Sharks in that particular area.
5 What is their main 'Non Natural Predation'
This is the question that only tagging can answer, but from the tag returns
which we have receved to-dateit would appear to be commercial fishing enterprises.
6 Do we catch the same Sharks season after season?
Again tagging will tell us, as January 2004, the programme having been running
for 3 years and we now have angler re-capture of sharks previously tagged
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