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Pelagic Fisheries Conservation Program (PFCP) |
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Mission:
The goal of PFCP is to
foster interdisciplinary research on pelagic fishes that will be used to
conserve biodiversity and maintain pelagic fish stocks in the Atlantic
and Pacific, with a special emphasis on fishes in the Gulf of Mexico.
Dr. Jay Rooker is the Director of PFCP and his team works with
scientists
from several institutions on a variety of research projects.
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Movement and stock structure of Atlantic blue marlin |
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Atlantic blue marlin support highly valuable
recreational and commercial fisheries through- out its range. Based upon
approximately 50 years of mark recapture data, Atlantic blue marlin
exhibit some of the longest movements ever recorded for oceanic fishes.
To better understand intra-population variability in movements, we have
been deploying pop-up archival tags on blue marlin in the Gulf of Mexico
(GoM) since 2003. Long deployments (up to 1 year) reveal diverse
movement patterns within the GoM. N to S seasonal changes in blue marlin
distribution occur and show strong correspondence with established
seasonal patterns of sea surface temperature and primary production.
During the summer spawning season, blue marlin often utilize outer shelf
and shelf edge waters in the northern GoM, and longer duration tracks
indicated overwintering habitats in the Bay of Campeche. Although some
egress occurs, our results indicate that a large fraction of the
Atlantic blue marlin have a more restricted geographic range of habitats
than previously recognized and that the GoM provides spatially dynamic
suitable habitat that is utilized year-round through seasonal
movements.
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Vertical and horizontal habitat use of
yellowfin tuna |
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The aim of this project is to quantify movement and habitat use of
yellowfin tuna in relation to large-scale oceanographic features in the
Gulf of Mexico (Gulf). We are using pop-up archival transmitting (PAT)
tag technology to provide detailed quantification of vertical and
horizontal habitat use of yellowfin tuna in the northern Gulf. Our goal
is to delineate essential habitat of yellowfin tuna and use these data
to improve current CPUE standardization procedures for evaluating stock
status. A total of 32 PAT tags were successfully deployed and horizontal
movements were within the same area that tagging activities occurred.
Average displacement distance (straight line distance from deployment to
pop-off) was 151 km (n=32 fish) over the entire study period. The
majority of time was spent at depths shallower than 80 m and at
temperatures usually within ~8 C of surface layer temperature.
Collaborators: John Hoolihan, Eric Prince, David Wells
Funding: NOAA Cooperative Fisheries Research Program
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Nursery origin of yellowfin and bigeye
tuna in the Hawaiian Islands
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Determining stock structure and
defining the degree of stock heterogeneity or mixing is critical to the
effective management of tropical tunas in the western and central
Pacific Ocean (WCPO). The aim of this project is to determine the stock
structure of bigeye and yellowfin tuna in WCPO using chemical tags in
otoliths that are linked to ambient physicochemical conditions and
dietary history. Work to date has shown the otolith chemistry of YOY
yellowfin tuna from different areas of the WPCO is distinct, and can be
used to determine an idividuals nursery origin. Mixed-stock analysis
suggests that a large fraction of the sub-adult yellowfin tuna collected
from the nearshore Hawaiian Islands originated from this same area,
highlighting the importance of local to the Hawaiian Island fishery for
yellowfin tuna.
Collaborators: David Itano,
David Wells
Funding: University of
Hawaii-Pelagic Fisheries Research Program
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Distribution and habitat associations of
billfish and swordfish larvae across mesoscale oceanographic features
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Our understanding of habitat use during the
critical early life period limited even though larval indices are
valuable for identifying spawning/nursery grounds and assessing
population trends. In addition, it is well recognized that larval
transport and/or survival varies as a function of time and location, and
therefore determining spatio-temporal patterns of habitat use during
early life as well as identifying the biological and physicochemical
attributes of presumed nurseries are needed to define essential habitats
of Atlantic billfish and swordfish populations. Since 2005, we have been
conducting ichthyoplankton surveys in surface waters of the northern Gulf
of Mexico (NGoM) to determine the relative value of this region as early
life habitat of billfishes (blue marlin, white marlin, and sailfish) and
swordfish. Work to date indicates that the distribution and abundance of
billfish and swordfish larvae varies spatially and temporally, and
several environmental variables (sea surface temperature, salinity, sea
surface height, distance to the Loop Current, current velocity, water
depth, and Sargassum biomass) are influential variables in generalized
additive models (GAMs) developed for each species. Mesoscale features in
the NGoM affected the distribution and abundance of billfish and
swordfish larvae, with densities typically higher in frontal zones or
areas proximal to the Loop Current. Habitat suitability of all four
species is strongly linked to physicochemical attributes of the water
masses they inhabit, and observed abundance and diversity are high in
slope waters with lower sea surface temperature and higher salinity. Our
results highlight the value of the NGoM as early life habitat of
billfishes and swordfish, and represent valuable baseline data for
evaluating anthropogenic effects (i.e., Deepwater Horizon oil spill) on
the Atlantic billfish and swordfish populations.
Collaborators: Scott Holt,
Joan Holt, John Graves
Funding: NOAA Fisheries
SEFSC, McDaniel Charitable Foundation
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Natal homing and trans-Atlantic mixing of
bluefin tuna
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Atlantic bluefin tuna populations are in steep
decline, and an improved understanding of connectivity between
individuals from eastern (Mediterranean Sea) and western (Gulf of Mexico)
spawning areas is needed to manage remaining fisheries. Chemical
signatures in the otoliths of yearlings from regional nurseries are
distinct and serve as natural tags for us to assess natal homing and
mixing. Recent results indicated that adult bluefin tuna show high rates
of natal homing to both eastern and western spawning areas.
Trans-Atlantic movement (east to west) is also significant and
size-dependent, with individuals of Mediterranean origin mixing with the
western population in the U.S. Atlantic. The largest (oldest) bluefin
tuna collected near the northern extent of their range in North American
waters appear to be almost exclusively of western origin, indicating that
this region represents critical habitat for the western population.
Collaborators: David Secor, John Neilson, Gregorio De Metrio,
Haritz Arrizabalaga
Funding: NOAA
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