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Biodiversity and
Fisheries Management
Daniel Pauly
Fisheries Centre,
University of British Columbia
Vancouver, Canada
United Nations Fisheries Training Programme
Marine Research Institure,
December 17, 2002, Reykjavik, Iceland
Frankly it is not obvious how ‘biodiversity’ can
be included into fisheries management, even if
the latter becomes ecosystem-based. However:
• Most of the world’s countries have signed
on the Convention on Biological Diversity,
and similar agreements and treaties, and
these require considering biodiversity
when managing fisheries; and
• Even without this formal reason, we
should in any case attempt not to lose
species and other genetic resources.
For example, we would not want to lose any of the
species of the Icelandic marine ecosystem
Through this presentation, I will therefore suggest one
approach that can be used to assess biodiversity in an
ecosystem context, assuming that this can thus inform
fisheries management. The steps are:
• Construct, using the Ecopath software, a food web model
of the ecosystem of interest, and including functional
groups representing all of the system in question;
• Identify/list the species included in each functional group;
• Incorporate the status (IUCN Red List, CITES, etc.) of
these species as constraint into policy explorations
conducted with Ecosim (e.g. via ‘Mandated Rebuilding’ or
Ecospace (e.g. via Marine Protected Areas);
• Formulate policies that account both for fisheries benefits
and for maintenance of biodiversity.
We have discussed previously how to
construct an Ecopath model, and need not
return to this here….
The next items is the area covered by the model.
Let’s assume it is a Large Marine Ecosystem
(LME)…
And let’s assume we select the Arabian Sea
(which is a bit large)…
First things first: we can link directly to
FishBase to list the fishes occurring there…
For many of these fishes, we will have access to
parameters relevant to model building, e.g. on
growth.
…and on diet composition, i.e., trophic levels
(as also needed for analyses of ‘fishing down.’
Indeed, these trophic level estimates allow us
to construct simple ‘pyramid’ models of
ecosystems.
Once the fishes are covered, we can move on
to other groups, e.g., the cephalopods (squids,
cuttlefishes, etc.).
We have added to CephBase a structure
enabling it to output LME and country lists…
…the trick being to interface maps of their
distribution with LME and EEZ maps.
Octopus globosus
Other groups will follow, notably macroalgae..
Though here, there is still a big job to do with
assignments to LME and EEZ.
This also applies to Reptiles (marine turtles,
sea snakes, etc.)…
This biodiversity is what support fisheries landings,
which must be re-expressed on a per- area basis…
…while temperature and other environmental
parameters also need to be considered…
Notably, Chlorophyll a…
and especially Primary Production.
Then we incorporate other things we know
about the system, e.g., from the NOAA website
on LME…
We intend to replicate the work presented here
at LME level at the finer level of countries
EEZ. This should allow for:
• A finer resolution, for both biodiversity
lists, and for Ecopath models, which will
lead to countries being better able to
document their marine biodiversity;
• A better understanding to be achieved
regarding the relationships between biomass
fluxes and the biodiversity they support.
There is obviously more to incorporating
biodiversity into fisheries management….
But what I have shown should keep up busy for
a while.
Thank you.