in 2004 as a conservation measure.
Practical and effective methods have
Sea turtle avoidance
measures implemented in the swordfish
fishery include the mandatory use of
large circle-shaped hooks instead of
“J”-shaped hooks and replacing squid
with mackerel-type bait (NMFS 2009).
Circle hooks are not as easily swallowed
by sea turtles. Mackerel-type bait is
easier than squid bait for turtles to
remove from hooks. By switching to
circle hooks and mackerel-type bait,
turtles are much less likely to ingest
the baited hooks and become hooked.
This simple and practical solution has
been a great success without reducing
the fish catch rate. The sea turtle
interaction rate has been reduced by
approximately 90% for loggerheads,
83% for leatherbacks, and 89% for
combined species (Gilman et al. 2007b).
The WCPFC is now considering the
Hawaii longline fishery as a model for
achievable reduction of longline fishing
impacts on sea turtles (Brouwer and
Protecting sea turtles requires inter-
national cooperation at sea and at the
Additional measures have been
implemented to protect sea turtles
after they are captured (NMFS 2009).
These include a requirement for annual
protected species training for vessel
operators and owners and for carrying
on board a prescribed set of tools
for safely handling, de-hooking and
releasing hooked and entangled turtles.
It is recognized that the decline in Pacific
sea turtles is also caused by land-based
activities in the vicinity of aggregations
of turtles at nesting beaches and fishery
impacts. To assist in turtle conservation,
the Hawaii longline fishery, its scientists
and managers have been involved
in international programs to help share
effective sea turtle bycatch reduction
methods with other fishing fleets and
to promote the protection of sea turtles
at nesting beaches.
Comparing sea turtle impacts associated
criteria for fishery impacts on sea
turtles are needed to determine the
environmental baggage associated
with seafood. Hawaii longliners set the
benchmark for low sea turtle Bycatch
to Fish Catch ratios (B/C) of all longline
fisheries compared that operate in
the Pacific (Bartram et al. 2009). The
B/C ratios of Hawaii longline fisheries
are based on the highest number of
observed longline sets and the highest
quality and quantity of data of any
longline fishery in the Pacific.
The Hawaii tuna longline fishery estab-
lished the low impact B/C benchmark
with a rate of 1 sea turtle interaction
per 190,000 kg of tuna caught. B/C
ratios give us an index for comparing
fisheries and their seafood products.
Hawaii’s tuna and swordfish both have
the lowest impact on sea turtles of any
of the other longline fisheries in the
Pacific supplying the same fish to the
market. The estimates of B/C ratios for
fleets outside of Hawaii are based on
very few observed longline sets. The
confidence in the B/C ratio estimates
will increase as the number of observed
sets increases in the future. Clearly,
Hawaii is the source of longline-caught
tuna and swordfish with the lowest
impact on sea turtles.
See Figure 7
Interactions with marine mammals in
the Hawaii longline fishery have been
documented but are infrequent events.
There are a few records of rare interac-
tions with 3 monk seals, 1 humpback
Photo: M. Johnson