Expedition Initial Results
IMPACTS OF OVERFISHING:
When fishing occcurs on coral reefs, the first fish to be removed from
the system are the larger more desirable species like trevally (ulua).
Once the number of these fish decline, fishing pressure shifts to smaller,
less desireable fish. As time goes on, the resources, including coral,
decline. When these larger apex predator fish are removed, it has a profound
effect on the structure of the rest of the reef communities. By comparison,
as a result of intensive fishing pressure, coral reefs in the main Hawaiian
Islands are stressed and do not contain the full complement of species
and interrelationships that would prevail in the absence of humans. After
the large predators and desirable aquarium fish species are removed, the
only fish remaining are often less desirable, small-bodied species of
little economic or food value.
One of the few large bottom-dwelling predators found on
Hawaiian coral reefs is the Hawaiian Grouper or Hapu`u (Epinephelus quernus).
This species was frequently observed on Kure Atoll on the forereef and
was very curious towards divers and as a result is probably highly susceptible
to fishing pressure. Hapu`u are rare in diving depths in the MHI but were
observed quit commonly in as shallow as 30 feet on the forereef at Kure.
It was not observed at any other locations during our surveys other than
Midway. This species should be given high priority for protection owing
to its restricted range, curious nature, and status as an endemic species.
A number of species like the spectacled parrotfish or
uhu uliuli, Hawaiian hogfish or `a`awa, and Hawaiian bigeye or `aweoweo
are quite abundant and obtain a large size in the Northwestern Hawaiian
Islands compared to the MHI. These species are heavily exploited for subsistence
and recreational use in the main islands and their reduced number and
size is likely the result of overfishing. These species tend to be very
skittish in the presence of divers in the MHI but were easily approached
in the NWHI. Once again, this highlights the need for protection, as these
species are very vulnerable to exploitation.