If you or your crew find a tagged
tuna or hear of anyone who has, please
sms, WhatsApp, or phone
+27 63 634 2503. This is a dedicated
line for reporting tag recaptures. After
providing information about the code
number of the tag, the length and the
area or exact location where the fish
was caught, the tag finders will receive
AOTTP T-shirts or caps and also a cash
reward of R140. The rest of the crew
will also receive T-shirts. If you give
permission, your name and the name of
your boat will also be published in a
monthly pamphlet that is being distrib-
uted at local boat and ski-boat clubs and
at launching and landing sites.
Fish tagged with red spaghetti tags
are bought from the fishermen at mar-
ket prices and biological samples are
harvested from those fish. In the case
of a recreational angler recovering a
fish with a red tag, that individual need
not be concerned with the legality of
receiving a reward for the return of his
fish as the fish is being used for scientif-
ic research. In many cases it is the fish
that have been chemically tagged that
are recovered and that chemical tag is
applicable to ageing studies.
VERY IMPORTANT
Please note that all fish tagged with red
spaghetti tags on the left hand side adja-
cent to the dorsal fin will also be tagged
with chemical or electronic tags. We
therefore need the whole fish back in
order to get the full spectrum of biolog-
ical data.SKIPJACK ARE THE WANDERERS
In the equatorial areas of the eastern
Atlantic tagging operations have been
taking place since June 2016. Data
from the first seven months of the pro-
gram has been collected from over
4 500 tag recoveries. After being
analysed and interpreted by ICCAT, this
data has revealed some interesting pre-
liminary trends in tuna migrations and
population dynamics.
During this period over 30 000 tags
were deployed, of which 15% of the
tags were recovered by commercial,
artisanal and recreational fishermen in
Senegal, the Ivory Coast and Ghana. It
is anticipated that the AOTTP will
improve our understanding of skipjack,
yellowfin and bigeye tuna and, in partic-
ular, their population sizes, growth and
mortality rates and movement patterns,
which will lead to better management
of these Atlantic Ocean resources.
So far the tagging data showed that
bigeye tuna travelled over twice the dis-
tance per month than previously found,
and skipjack almost three times the dis-
tance previously noted, with these
species averaging approximately 1 200
and 1 500 nautical miles per month,
respectively. Yellowfin tuna did not
travel as extensively compared to previ-ous findings. They averaged approxi-
mately 800 nautical miles per month,
which was only half the distance that
they were expected to travel.APPLYING THE KNOWLEDGE
I was fortunate to be invited to present
at an Otolith Ageing Experts Workshop
at the Centre de Recherches Ocean-
ologiques, Abidjan, Côte d’Ivoire, at the
beginning of March2017. Also in atten-
dance were representatives from the
South Pacific Commission (SPC) and
the Commonwealth Scientific and
Industrial Research Organisation
(CSIRO) who were there to share their
knowledge and techniques for ageing
yellowfin, bigeye and skipjack tuna.
The aim of the workshop was to
bring together the best tuna ageing
tools in order to develop a standardised
ageing protocol for the AOTTP and
share experience with developing labo-
ratories. This goal was achieved and
will help to ensure harmonised and
comparable ageing studies across the
Atlantic Ocean. Ageing studies have
now started in Senegal and the Ivory
Coast and once we have tag recoveries
from South Africa it will begin here too.
For more information on this pro-
ject visit <www.iccat.int/AOTTP/en/>,
email <[email protected]>,
phone 063 634 2503 or follow our
Facebook page: South African tuna tag-
ging program.42 • SKI-BOAT May/June 2017