Potential use of helminth parasites in stock identification of flying squid, Ommastrephes bartrami, in North Pacific waters

A survey of helminth parasites in 68 flying squid (Ommastrephes bartrami) from off the west coast of North America (between latitudes 41°03′ and 48°23′ N and longitudes 129°49′ and 133°08′ W) revealed the presence of numerous juvenile nematodes and cestodes. Larval Hysterothylacium sp. and metacestodes of Phyllobothrium sp. were common (prevalence: 100 and 94.1%, respectively; mean intensity: 54.6 ± 28.1 and 6.4 ± 4.5, respectively). In addition, nine flying squid had a total of 11 Anisakis simplex larvae, and one metacestode of Tentacularia sp. (probably T. coryphaenae) was found in the sample bag that held one flying squid. The only adult helminths recovered were seven specimens of Rhadinorhynchus sp. (Acanthocephala) from three squid. The parasite fauna of these squid was sufficiently different from that previously reported for O. bartrami from the northwestern Pacific Ocean to suggest that parasites may prove useful as a tool to determine if intermixing of squid stocks from their feeding grounds in the eastern and western North Pacific Ocean occurs on the spawning grounds.

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Horizontal distribution of Fukushima-derived radiocesium in zooplankton in the northwestern Pacific Ocean

Biogeosciences ◽

10.5194/bg-10-5729-2013 ◽

2013 ◽

Vol 10 (8) ◽

pp. 5729-5738 ◽

Cited By ~ 23

Author(s):

M. Kitamura ◽

Y. Kumamoto ◽

H. Kawakami ◽

E. C. Cruz ◽

K. Fujikura

Keyword(s):

Pacific Ocean ◽

High Activity ◽

North Pacific ◽

North Pacific Ocean ◽

Fission Products ◽

Tohoku Earthquake ◽

Horizontal Distribution ◽

Northwestern Pacific ◽

Mode Water ◽

Activity Concentrations

Abstract. The magnitude of the 9.0 Tohoku earthquake and the ensuing tsunami on 11 March 2011, inflicted heavy damage on the Fukushima Dai-ichi nuclear power plant (FNPP1). Fission products were emitted, falling over a broad range in the Northern Hemisphere, and water contaminated with radionuclides leaked into the ocean. In this study, we described the horizontal distribution of the Fukushima-derived radiocesium in zooplankton and in seawater in the western North Pacific Ocean (500–2100 km from the FNPP1) 10 months after the accident. 134Cs and 137Cs were detected in zooplankton and seawater from all the stations. Because of its short half-life, the 134Cs detected in our samples could only be derived from the FNPP1 accident. The highest 137Cs activity in zooplankton was the same order of magnitude as it was one month after the accident, and average activity was one or two orders of magnitude higher than 137Cs activities observed before the accident around Japan. Horizontally, the radiocesium activity concentrations in zooplankton were high at around 25° N while those in surface seawater were high at around the transition area between the Kuroshio and the Oyashio currents (36–40° N). We observed subsurface radiocesium maxima in density range of the North Pacific Subtropical Mode Water and the occurrence of many diel vertical migratory zooplankton. These suggested that the high activity concentrations in the subtropical zooplankton at around 25° N were connected to the subsurface radiocesium and active vertical migration of zooplankton. However, the high activity concentrations of radiocesium in subsurface seawater did not necessarily correlate with the higher radiocesium activity in zooplankton. Activity concentrations of radiocesium in zooplankton might be influenced not only by the environmental radiocesium activity concentrations but also by other factors, which are still unknown.

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Geostrophic Circulation in the Tropical North Pacific Ocean Based on Argo Profiles

Journal of Physical Oceanography ◽

10.1175/jpo-d-12-0230.1 ◽

2014 ◽

Vol 44 (2) ◽

pp. 558-575 ◽

Cited By ~ 25

Author(s):

Dongliang Yuan ◽

Zhichun Zhang ◽

Peter C. Chu ◽

William K. Dewar

Keyword(s):

Pacific Ocean ◽

North Pacific ◽

North Pacific Ocean ◽

World Ocean ◽

North Equatorial Current ◽

Northwestern Pacific ◽

Argo Data ◽

Vector Method ◽

Geostrophic Currents ◽

The North

Abstract Absolute geostrophic currents in the North Pacific Ocean are calculated from the newly gridded Argo profiling float data using the P-vector method for the period of 2004–11. The zonal geostrophic currents based on the Argo profile data are found to be stronger than those based on the traditional World Ocean Atlas 2009 (WOA09) data. A westward mean geostrophic flow underneath the North Equatorial Countercurrent is identified using the Argo data, which is evidenced by sporadic direct current measurements and geostrophic calculations in history. This current originates east of the date line and transports more than 4 × 106 m3 s−1 of water westward in the subsurface northwestern tropical Pacific Ocean. The authors name this current the North Equatorial Subsurface Current. The transport in the geostrophic currents is compared with the Sverdrup theory and found to differ significantly in several locations. Analyses have shown that errors of wind stress estimation cannot account for all of the differences. The largest differences are found in the area immediately north and south of the bifurcation latitude of the North Equatorial Current west of the date line and in the recirculation area of the Kuroshio and its extension, where nonlinear activities are vigorous. It is, therefore, suggested that the linear dynamics of the Sverdrup theory is deficient in explaining the geostrophic transport of the tropical northwestern Pacific Ocean.

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Genetic stock identification of overwintering chum salmon in the North Pacific Ocean

Environmental Biology of Fishes ◽

10.1007/s10641-011-9972-2 ◽

2011 ◽

Vol 94 (4) ◽

pp. 663-668 ◽

Cited By ~ 2

Author(s):

W. Tyler McCraney ◽

Edward V. Farley ◽

Christine M. Kondzela ◽

Svetlana V. Naydenko ◽

Alexander N. Starovoytov ◽

...

Keyword(s):

Pacific Ocean ◽

North Pacific ◽

Chum Salmon ◽

North Pacific Ocean ◽

Stock Identification ◽

Genetic Stock ◽

The North ◽

Genetic Stock Identification ◽

The North Pacific

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Stock identification of neon flying squid (Ommastrephes bartramii) in the North Pacific Ocean on the basis of beak and statolith morphology

Scientia Marina ◽

10.3989/scimar.03991.06a ◽

2014 ◽

Vol 78 (2) ◽

pp. 239-248 ◽

Cited By ~ 8

Author(s):

Xinjun Chen ◽

Zhou Fang ◽

Bilin Liu ◽

Jianghua Li ◽

Hang Su

Keyword(s):

Pacific Ocean ◽

North Pacific ◽

North Pacific Ocean ◽

Stock Identification ◽

Ommastrephes Bartramii ◽

The North ◽

Neon Flying Squid ◽

The North Pacific

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Horizontal distribution of Fukushima-derived radiocesium in zooplankton in the northwestern Pacific Ocean

Biogeosciences Discussions ◽

10.5194/bgd-10-6143-2013 ◽

2013 ◽

Vol 10 (4) ◽

pp. 6143-6170 ◽

Cited By ~ 1

Author(s):

M. Kitamura ◽

Y. Kumamoto ◽

H. Kawakami ◽

E. C. Cruz ◽

K. Fujikura

Keyword(s):

Pacific Ocean ◽

High Activity ◽

North Pacific ◽

North Pacific Ocean ◽

Fission Products ◽

Zooplankton Community ◽

Horizontal Distribution ◽

Northwestern Pacific ◽

Mode Water ◽

Activity Concentrations

Abstract. The magnitude of the 9.0 Tohoku earthquake and the ensuing tsunami on 11 March 2011, inflicted heavy damage on the Fukushima Dai-ichi nuclear power plant (FNPP1). Fission products were emitted, falling over a broad range in the northern hemisphere, and water contaminated with radionuclides leaked into the ocean. In this study, we described the horizontal distribution of the Fukushima-derived radiocesium in zooplankton and in seawater in the western North Pacific Ocean (500–2100 km from the FNPP1) 10 months after the accident. 134Cs and 137Cs were detected in zooplankton and seawater from all the stations. Because of its short half-lives, 134Cs detected in our samples could only be derived from the FNPP1 accident. The highest 137Cs activity in zooplankton was same order of magnitude as that one month after the accident, and average activity was one or two orders of magnitude higher than 137Cs activities observed before the accident around Japan. Horizontally, the radiocesium activity concentrations in zooplankton were high at around 25° N while those in surface seawater were high at around the transition area between the Kuroshio and the Oyashio Currents (36–40° N). We observed subsurface radiocesium maxima in density range of the North Pacific Subtropical Mode Water and occurrence of many diel vertical migratory zooplanktons. These suggested that the high activity concentrations in the subtropical zooplankton at around 25° N were connected to the subsurface radiocesium and active vertical migration of zooplankton. However, the high activity concentrations of radiocesium in subsurface seawater did not necessarily follow the higher radiocesium activity in zooplankton. Biological characteristics of zooplankton community possibly influenced how large was contamination of radiocesium in the community but it is still unknown what kind of biological factors were important.

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