Interested
in this project?
Dr Karen Diele
The project hosts workshops for local fishermen
Karen from the School of Applied
Sciences has been working with
the crabs and the fishermen for
a number of years to establish
the species’ breeding pattern.
With her Brazilian colleagues,
she has worked out that the crabs
always mate at either full or new
moon, and sometimes both.
As a result, capture bans are
currently in place at both full and
new moon times.
“That’s policy today. At these times,
the crabs are chasing mates outside
their burrows and it’s really easy to
catch them. Therefore there’s a risk
of overfishing. The fishermen are
furious because mostly the ban is
wrong at one moon and they’re not
allowed to catch them even though
they don’t mate. So the fishermen
lose income for no good reason.
We are trying to change this.”
“It’s a complicated cycle
but these little creatures
have worked it out.”
School of
Applied Sciences
To improve the placement of the
capture bans and change policy, Karen
and her colleague Dr Schmidt have
founded a network joining partners
of nine sites along the Brazilian
coastline (the REMAR network).
The partners are working together
with local fishermen to find out
what determines the breeding
patterns of these crabs.
“These crabs are really clever. They
pick days with big tides that are due
when the sun and the moon are in
a straight line. There is another cycle
when the moon is closest to the
earth. If that happens at new moon
then the new moon tides are bigger
than the ones at full moon. It’s a
complicated cycle but these little
creatures have worked it out since
the survival of their larvae depends
on these big tides. We are pretty sure
we can now predict for years to come
whether these crabs will breed at new
or at full moon, in any given year.”
Karen and partners are now
expanding the REMAR surveys to
include fishermen from other areas.
Built by a student from the School
of Computing at Edinburgh Napier,
a new mobile app allows fishermen
15
[email protected]
to record where and when they’ve
seen the crabs mating. All this citizen-
science data is then sent to a server
at the University, which is accessible
to the REMAR network.
“The app is a great tool for citizen
science. And the more people use
the app and provide data, the easier
it will be to change policy.
“We continue to work with partners
and host workshops in Brazil. When
we ask the fishermen what the
most important problem of their
crab fishery is, they say: ‘We are not
allowed to fish when the crabs make
love. This is fine, but we want to
be allowed to catch them when they
are not loving.’”
Get the whole story at
www.napier.ac.uk/impact