The Fisheries & Environmental Sciences
Department conducts research on coastal marine resource issues.
Among other programs, we are currently conducting research
to determine the movement patterns and habitat use of Hawaiian
The Hawaiian bottom fish fishery is comprised of 12 species,
the most important of which are seven deep-water snappers in
the family Lutjanidae. In 1998, the Division of Aquatic Resources
in the State of Hawai‘i Department of Land and Natural
Resources (DLNR) developed a management plan that included the
creation of 19 restricted fishing areas (RFAs) where bottom fishing
is prohibited. The Kahoolawe Island Reserve (KIR) is another
area where bottom fishing is prohibited.
The objective of our research was to examine whether movement
of bottom fish occurred from the KIR to adjacent open fishing
areas. Live opakapaka (Pristipomoides filamentosus) were caught
and implanted with acoustic tags, and then released. We tracked
them over the course of two months with an array of passive acoustic
Five arrays were installed on the sea floor just outside the
western boundary of Kaho‘olawe at depths of 117-165 m.
Each consisted of a bottom weight, an offshore acoustic release,
a passive acoustic receiver, and a subsurface float and flag.
The receivers were deployed in June 2004.
The five receiver arrays were recovered August 26, 2004. Data
from each receiver were downloaded to a computer and data for
each acoustic tag were compiled into individual files and then
analyzed to generate estimates of hourly position.
Eighteen opakapaka were collected, implanted with acoustic tags,
and released. Of these, signals were recorded for 12 fish for
lengths of time from 0.1 to 1,485 hours. Signals were not recorded
for six of the fish released.
Results showed that opakapaka typically undertake diurnal movements
from the deeper area of the shelf during the day to the shallower
shelf slope at night. Patterns suggest that opakapaka are feeding
most actively at night.
There was also strong evidence of movement out of or into the
KIR from the adjacent open shelf. Most of the tagged fish showed
frequent movement in a generally east—west direction. This
movement often originated within the KIR, to the east of the
receiver array, took the fish across the area covered by the
receiver array, and showed evidence of residence to the west
of the array, well outside the KIR, for periods of hours to days
until the fish returned across the array area back into the KIR.