Discrimination of Diaphus theta and Euphausia pacifica using underwater irradiance

2012 ◽  
Vol 131 (4) ◽  
pp. 3287-3287
Author(s):  
Matsuura Tomohiko ◽  
Sawada Kouichi ◽  
Uchikawa Kazuhisa
Keyword(s):  
Euphausia Pacifica ◽  
Underwater Irradiance ◽  
Diaphus Theta

Diet and sexual maturation of the neon flying squid Ommastrephes bartramii during autumn and spring in the Kuroshio–Oyashio transition region

2008 ◽  
Vol 88 (2) ◽  
pp. 381-389 ◽  
Author(s):  
Hikaru Watanabe ◽  
Tsunemi Kubodera ◽  
Taro Ichii ◽  
Mitsuo Sakai ◽  
Masatoshi Moku ◽  
...  
Keyword(s):  
Transition Region ◽  
Sexual Maturation ◽  
Prey Species ◽  
Feeding Strategy ◽  
Ommastrephes Bartramii ◽  
Neon Flying Squid ◽  
The Difference ◽  
Diaphus Theta ◽  
The Kuroshio ◽  
Prey Items

Diet and sexual maturation were examined in the winter–spring cohort of the neon flying squid, Ommastrephes bartramii, during its southward migration through the Kuroshio–Oyashio transition region of the western North Pacific. The main prey items are micronektonic animals and small pelagic fish, which were abundantly distributed throughout the study area. Among the prey species, O. bartramii was dependent on the Japanese anchovy Engraulis japonicus, which also migrate from the northern to southern transition region during the winter, and the micronektonic squid Watasenia scintillans throughout the study period. Other common prey items were Gonatopsis borealis, Diaphus theta, and Ceratoscopelus warmingii from October to November or December, and Tarletonbeania taylori after December. These dietary changes can be explained by the difference in the seasonal north–south migration patterns of the predator and prey species. Male sexual maturation progressed throughout the season, and most individuals were fully mature in January. In contrast, most of the females were immature throughout the study period. The feeding strategy of the squid in relation to their seasonal north to south migration and sexual maturation was discussed.

scholarly journals Acoustic biomass estimate of California headlightfish Diaphus theta, off eastern Hokkaido, Japan

2010 ◽  
Vol 76 (3) ◽  
pp. 362-369 ◽  
Author(s):  
HIROKI YASUMA ◽  
TATSUKI OHSHIMA ◽  
SATOSHI HONDA ◽  
KAZUSHI MIYASHITA ◽  
ICHIRO AOKI
Keyword(s):  
Biomass Estimate ◽  
Diaphus Theta

scholarly journals North Pacific krill Euphausia pacifica protein recovered by salt water treatment and its thermal gel-forming ability

2017 ◽  
Vol 83 (2) ◽  
pp. 207-214 ◽  
Author(s):  
KAYO AMANO ◽  
KIGEN TAKAHASHI ◽  
EMIKO OKAZAKI ◽  
KAZUFUMI OSAKO
Keyword(s):  
Water Treatment ◽  
North Pacific ◽  
Salt Water ◽  
Euphausia Pacifica ◽  
Gel Forming Ability

Calculating Irradiance Penetration into Water Bodies from the Measured Beam Attenuation Coefficient, II: Application of the Improved Model to Different Types of Lakes

2002 ◽  
Vol 33 (2-3) ◽  
pp. 227-240 ◽  
Author(s):  
Helgi Arst ◽  
Ants Erm ◽  
Anu Reinart ◽  
Liis Sipelgas ◽  
Antti Herlevi
Keyword(s):  
Attenuation Coefficient ◽  
Water Samples ◽  
Water Bodies ◽  
Diffuse Attenuation Coefficient ◽  
Beam Attenuation ◽  
Underwater Light Climate ◽  
Different Types ◽  
Underwater Irradiance ◽  
Beam Attenuation Coefficient

The method suggested earlier for estimating the spectra of diffuse attenuation coefficient of light in the water bodies relying on the beam attenuation coefficient measured from water samples, was improved and applied to different types of lakes. Measurement data obtained in 1994-95 and 1997-98 for 18 Estonian and Finnish lakes were used. The spectra of two characteristics were available for our investigations: 1) beam attenuation coefficient estimated from water samples in the laboratory with a spectrophotometer Hitachi U1000; 2) vertical irradiance (diffuse) attenuation coefficient measured in situ with an underwater spectroradiometer LI 1800UW. A total of 70 spectra were considered. Relying on these data the parameters of our earlier model were changed. The criterion of the efficiency of the new version of our model is the coincidence of the spectra of diffuse attenuation coefficient derived from Hitachi U1000 data (Kdc) with those obtained by underwater irradiance measurements (Kdm). Correlation analysis of the model's results gave the relationship Kdm=1.0023Kdc with correlation coefficient 0.961. The respective values of mean relative difference and standard deviation were 5.4% and 0.55 m−1. This method may be useful in conditions where in situ measuring of underwater irradiance spectra cannot be performed because of weather conditions. As the measurement of the underwater radiation field is often a complicated and expensive procedure, our numerical method may be useful for estimating the underwater light climate.

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