Need information on carrying capacity

[Hernandez Edwin]

Dear coral-listers:

I partially and respectfully disagree with Duncan
MacRae regarding his recommendation of not using diver
numbers as a management tool.  Under high densities,
diver numbers can have a negative effect on coral reef
benthic communities.

In Puerto Rico, there are still diving schools that
take out in some of their trips between 40 and 80
novice divers in a single boat trip. Similarly, we
have major hotels in PR that bring bunches of
unexperienced snorkellers to shallow reef areas that I
have personally seen stepping on living corals
everywhere.

Novice divers and snorkellers could be extremely
destructive in localized reef areas, mostly because
they are not familiar with the reefs (and they have
not been adequately educated during their trainng, if
any at all).  They can not adequately control yet
their buoyancy, most of them use diving gloves and
keep touching everything trying to avoid hitting the
bottom, etc. Also, most of the time, diving boats drop
anchor on the reef due to the lack of mooring buoys.
Thus, these combined effects have a high potential for
causing significant destruction.

Diver number could affect boat traffic, anchoring,
potential for fuel contamination, possible reef
trampling to access shore reefs, etc. And, in many
instances (e.g., Puerto Rico), this could translate
into severe indirect recreational spearfishing
effects. Yes, we do still have a LOT of spearfishing
diving trips everywhere!

Diver number HAS to be taken into consideration
because it is not the same having several trips with
few experienced and well-trained divers, than to have
a bunch of rookies around.

I think that to define management of diving activities
you have to consider:

1. Overall number of divers.
2. Number of diving trips.
3. Number of divers/trip.
4. Level of diver training.
5. Purpose of diving trip.
6. Ecological conditions of the diving place.
7. Education of reef etiquete and behavior (this
should be mandatory).
8. Shoreline entrances to the reef. My research
experience (Hernandez-Delgado et al., 2001;
Hernandez-Delgado et al., in preparation) has shown
that trampling to gain access to deeper reef areas can
be extremely destructive in localized areas. And, the
higher the number of people, the higher the damage.

Thus, diver number is a major part of the carrying
capacity formula that should not be left out.

Cheers,

Edwin

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