Shark Predation on Hawaiian Monk Seals - Pacific Islands Fisheries ...

equested in the past is a reasonable and appropriate mitigation, and that all options up to and
including such an approach, (i.e., including nonlethal forms of shark deterrence) should be
explored thoroughly. To date, the Commission has not been asked to consider a large-scale
shark removal program, but I suspect it would be less inclined to support that approach given
its possible effect on an important reef predator and the atoll ecosystem. Recognizing that the
surgical removal of individual sharks has been frustrated by shark avoidance behavior, the
future success of any limited removal strategy may depend on our ability to obtain detailed
information on shark movement and behavior patterns that could indicate where and when
sharks patrolling atoll lagoons might be most vulnerable to being caught. Such information also
would be valuable for assessing the validity of the above-mentioned hypothesis and assuring
adverse ecosystem effects are avoided.
Workshop Discussion.--Mr. Laist reiterated that the hypothesis that a few individual sharks
are the source of predation is sensible and reasonable, and a limited removal (not a large-scale
removal) of sharks is agreeable. He emphasized that the solutions to this problem are dependent
on understanding the movement and behavior of each species (when and where predation is
occurring) and also information that a limited number of sharks are exercising this feeding
mode. He described two creative possibilities of behavioral modification: (1) to draw sharks
away from the pupping sites by using bait and (2) to use electronic instruments imbedded in
artificial shark decoys to shock seal pups as a way of teaching them to associate a negative
stimulus with a shark-shaped object. (These suggestions are examined in detail in the Section
III of this memorandum.)
HMSRT, abstract authored and presented by Bill Gilmartin
The HMSRT was informed of the increased rate of predation of Galapagos sharks on Hawaiian
monk seals at FFS at a mid-1990s HMSRT meeting. At that meeting and since that time, the
HMSRT has recommended that NMFS take immediate action to mitigate the shark threat to the
FFS population. A primary concern of the HMSRT has been that the behavior may spread
within the shark population and increase seal pup losses, hence the recommendation to resolve
the problem as soon as possible. With the initial reluctance of the Fish and Wildlife Service to
approve lethal takes of sharks without more information on the shark population, the HMSRT
also recommended that NMFS initiate the shark population and movement research necessary
to resolve these questions. While some limited actions (population research, lethal takes and
hazing) had been taken by NMFS, the problem continued unresolved into the mid-2000s, with
shark takes beginning to occur at other sites within the FFS Atoll. Immediate action on the
shark predation issue is required; shark predation is one of four key actions that are necessary
to turn around the species’ declining trajectory and foster recovery.
<strong>Shark</strong> Perspective
<strong>Shark</strong> ecologists addressed the following topics:
Global distribution, habitat use, and status of Galapagos sharks
Movement studies of Galapagos sharks in NWHI to date
Future research
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