Timescales of reserve benefits
Callum Roberts
cr10 at york.ac.uk
Thu Feb 6 04:24:50 EST 1997
CEMRINO wrote:
"Marine reserves are well-known for allowing the recovery of fish
stocks within the reserve, which can lead to 1. some fish wandering
outside the preserve and getting caught, thus increasing total fish
catches. 2. Increased maximum fish size leading to greatly
increased egg & larvae production to re-seed other overfished areas
by dispersal. 3. Increased fish size and density necessary for dive
tourism. Bohnsack (1994) has argued eloquently for point 2. But I
would like to propose that point 1 is actually the most critical in the
short term. This is because developing countries like the Philippines
have little or no capacity for enforcement of regulations. IF
FISHERMEN FIND THEIR CATCHES INCREASING AFTER THE
ESTABLISHMENT OF A MARINE RESERVE, THEY WILL BECOME ITS
STRONGEST DEFENDERS.
A response to the interesting and very encouraging posting by
CEMRINO, relating particularly to point 1 above. Overspill from
reserves is clearly one important mechanism by which they can
benefit fishers. However, I doubt that the timescale over which such a
benefit will occur will be much faster than that over which benefits
from increased egg production accrue. Fish densities need to build
up in reserves before significant export of juveniles and adults will
occur. By this time, reserves should also be acting as an egg source
for replenishment of fishing grounds. In the short term (2-3 years) it is
likely that reserves will impose a cost on fishers. In the longer term,
the benefits from reserves are likely to greatly outweigh the start-up
costs. Garry Russ has shown empirically a delayed overspill from a
Philippine reserve, taking approximately nine years befored he could
detect enhanced abundance of fish adjacent to the reserve. Joshua
Nowlis and I have done some modelling work to look a timescales
and magnitudes of costs and benefits of reserve creation. If you
would like a copy of the paper email Josh (jnowlis at uvi.edu) or me.
Overcoming short-term costs of reserve establishment may be a
difficult hurdle for poor fishers who are already struggling hard to
make a living. There is a very good case for development projects
seeking to establish reserves to help people over this hump with
some form of subsidy, compensation or alternative livelihood
provision. That would give reserves a better fighting chance of
getting to the stage where they begin pouring benefits back directly to
the fishing community, and they attract the support of fishers on their
own merits.
Best wishes,
Callum Roberts
Nowlis, J.S. and C.M. Roberts (in press) You can have your fish and
eat it too: theoretical approaches to marine reserve design. Proc. 8th
Int. Coral Reef Symposium, Panama.
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Dr Callum Roberts
Dept of Environmental Economics and Environmental Management
University of York
York, YO1 5DD
UK
Tel: +44 (0)1904 434066; Fax: +44 (0)1904 432998; email
cr10 at york.ac.uk
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