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ECOSYSTEM
IMPACTS OF
FISHING
Sustainability factors
1) Fishery Management
2) Status of harvested fish populations
3) Ecosystem impacts of fishing
From “single-species” to
“ecosystem-based” management
Managing fisheries for sustainability
must address not only the conservation
of targeted species but also the
possible adverse impacts on associated
species and habitats that are part of
the ecosystem. The transition to the
ecosystem approach to management
in Hawaii began in 2005 for the
Fisheries Management Plan for pelagic
fish (WPRFMC 2005). When the transi-
tion is complete, ecosystem-based
fisheries management will likely include
actions that will consider the natural
variability of ocean ecosystems and
may include the use of physical or
biological indicators.
Impacts on Essential Fish Habitat
In contrast to the vital role played by
structural habitat like coral reef in
Hawaii’s inshore fisheries, the pelagic
habitat of the species caught in the
Hawaii longline fishery is the open-
ocean water column (NMFS 2001).
A great amount of information exists
on environmental fluctuations and
their effect on the productivity and
distribution of pelagic species. These
environmental influences are thought
to be the major factor affecting the
essential habitat for pelagic species.
In contrast, no data exist which indicate
that Hawaii’s pelagic fisheries have an
effect on the pelagic environment, or
the essential habitat for pelagic species,
that could be detected, being overshad-
owed by the oceanographic cycles that
dominate the pelagic ecosystem in the
Pacific Ocean (NMFS 2001).
Fishing vessels produce sewage,
garbage, oil and lost gear which may
have a negative effect on the marine
environment. The 2001 Environmental
Impact Statement of the Hawaii longline
fishery completed by NOAA concluded
that these types of fishery impacts are
likely to be small. The Hawaii longline
fishery follows the requirements of
the MARPOL Convention (International
Convention for the Prevention of
Pollution from Ships) enforced by the
U.S. Coast Guard. This prohibits the
at-sea disposal of plastics and limits
oil and other discharges. Loss of fishing
gear is minimal because it is standard
practice to use radio buoys to track the
position of longline gear. Consequently,
the direct effect on the pelagic habitat
is negligible.
The Hawaii longline fishery has bene-
ficial environmental impacts. While at
sea, Hawaii longline crews routinely
clean up after others by retrieving
derelict nets and other debris lost or
discarded by net fisheries and cargo
vessels for proper disposal on shore.
Fish bycatch
Fish bycatch is fishery waste.
Bycatch
can be defined as fish caught but
discarded at sea either dead or injured
with delayed mortality (Hall 1996).
Fish and other animals caught in fishing
gear, but released alive with a good
likelihood of survival are not bycatch
by this definition. The Hawaii longline
fishing industry and auction marketing
system have succeeded in emphasizing
high-quality high-value chilled fish,
maximizing the value and retention
of the fish species harvested. The
Hawaii market values most pelagic
fish species caught so that fish discards
are minimized and utilization of the
catch is maximized. It’s the responsible
thing to do.
In the Hawaii longline fishery, the highest
discards and releases are of sharks,
snake mackerels (gempylids), cutlass
fish (trichiurids), pelagic stingrays and
other fish species. In the Environmental
Impact Statement on the Hawaii Longline
Fishery, NOAA could not find data
which indicate that the fishery has a
discernable impact on the continued
existence of these species (NMFS
2001). These fish (other than mako
and thresher sharks) are generally
not considered edible or marketable.
Setting longline gear
Photo: NOAA Observer Program
S
ection
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