NIPPON SUISAN GAKKAISHI
Online ISSN : 1349-998X
Print ISSN : 0021-5392
ISSN-L : 0021-5392
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Volume 78, Issue 1
Displaying 1-50 of 56 articles from this issue
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Originals
  • Continuous monitoring of catch fluctuation of Japanese common squid Todarodes pacificus using load data of squid jigging machine
    TAKAFUMI SHIKATA, TOMOHIRO MIKI, GO TAKAYAMA, JUNICHI MOCHIHIRA, HIROS ...
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 1-7
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.1
    JOURNAL FREE ACCESS
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      In order to study the process from gathering to capture of Japanese common squid Todarodes pacificus under a jigging boat, it is necessary to monitor rapid changes of the catch of the squid during jigging operation. For this purpose, we developed a logging system to record the load of the automatic jigging machine and evaluated the usefulness of load data for estimating the number of squid caught per unit effort (CPUE). Thirty-four jigging operations were conducted by R/V Hakusan-maru (167 gross tons) in the Sea of Japan. The squid were caught by using 14 jigging machines and the load data of each machine were logged every second on a laptop computer. Number of squid caught was counted by hand or video images and CPUE was calculated. Average load during hauling of the jig line was closely correlated with the measured CPUE in consideration of body size, and an equation for estimating CPUE from load data was derived. The estimated CPUE were in good agreement with the measured CPUE over a wide time scale from one stroke of the jig line to the overall operation. These results indicate that the logging system is especially useful for high time-resolution monitoring of the catch.
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  • Estimation of population structure of herring caught around Funka Bay, Hokkaido based on tag recapture data
    HIROYUKI OKOUCHI, MASAHIRO NAKAGAWA
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 8-14
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.8
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      The population structure of Pacific herring Clupea pallasii caught in the coastal waters around Funka Bay, southern Hokkaido, was investigated by comparing recaptures of tagged juveniles and adults and catch in weight of herring around Funka Bay. Juvenile and adult herrings tagged and released in the coastal waters of northern Honshu were recaptured around Funka Bay during spring and autumn. Catches of herring around the bay were large during spring and autumn before 1991, but peaked in winter after 1999. Herring caught during spring and autumn around the bay seemed to be composed of feeding groups immigrating from northern Honshu. The increase in catches in winter after 1999 was supposed to have been caused by the increase of local population in the coastal waters around Funka Bay.
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  • Effects of spatio-temporal allocation of allowable catch on the population dynamics of the Pacific stock of chub mackerel
    CHIKAKO WATANABE, MAKI SUDA, TATSURO AKAMINE, ATSUSHI KAWABATA, HIROSH ...
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 15-26
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.15
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      We estimated the catch rates for each quarterly fishery season and fishery ground, and evaluated the impacts of fisheries on the population dynamics of the Pacific stock of chub mackerel Scomber japonicus during 1970-2006. The catch rates increased when the biomass declined during 1979-1980 and 1986-1990, and the selectivity of the immature fish stock increased. According to the biomass decline, The survival rate of each year-class steadily decreased during 1970-2006. We evaluated the effects of a moratorium at each fishing ground using a population dynamics model with multiple fishery seasons and grounds. The results showed that the moratorium at the area where immature fish were mainly distributed effectively conserved the spawning stock biomass. This result suggests that the management performance could be improved by considering the proper allocation of allowable biological catch (ABC) to each fishery season and ground.
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  • Mesh selectivity of Danish seine for Japanese sandfish Arctoscopus japonicus
    TOSHIAKI MIYAJIMA, NAOKI YAGISHITA, ATSUSHI YAMASAKI, TADASHI TOKAI
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 27-36
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.27
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      Mesh selectivity of Danish seine codend for Japanese sandfish Arctoscopus japonicus was determined to reduce bycatch of the small fish. Covered codend experiments using three different mesh openings of 35.6, 42.0, and 48.6 mm were conducted off Kyoto Prefecture from April to May in 2005. Two hauls were towed for each mesh opening. Logistic parameters were estimated by the SELECT method, considering sub-sampling. The Catch size dependent model of which logistic parameters were expressed as a function of codend catch, was chosen by AIC model selection, not only for the individual-haul selection curve, but also well for the master curve of size selectivity in terms of the ratio of fish length to mesh opening. From the master curve with the codend catch of 105 kg, body lengths of 50% retention were estimated to be 114, 138, and 163 mm for 35.6, 42.0, and 48.6 mm mesh openings, respectively. In Japanese sandfish caught by a commercial seiner with codend of 22 mm mesh opening in April 2005, enlargement in mesh opening to 38.8 and 42.0 mm could allow 72.0 and 91.0% of sand fish below 135 mm body length to escape out, while retaining 97.7 and 88.5% of larger commercial fish.
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  • Relationship between the shell height of the predatory moon snail Euspira fortunei and drilled hole diameter on the prey shell of Manila clam Ruditapes philippinarum
    TORU TANABE
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 37-42
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.37
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      In Miyagi Prefecture, the moon snail Euspira fortunei seems to have been brought from other prefectures or countries such as China or North Korea together with seeds of the clam Ruditapes philippinarum. This species is a predatory gastropod that drills holes in the shell of a prey and causes severe of damage for the fishery of R. philippinarum. The drilled holes produced by predatory gastropods are uniquely preserved on the prey shells and represent important evidence on the behavior of predators. In this study, the drilled-hole diameters were significantly correlated with predator size. The author collected drilled shells of dead R. philippinarum of Mangokuura and Torinoumi in Miyagi Prefecture, and calculated the E. fortunei shell height using the relationship between the drilled-hole diameter and shell height of E. fortunei. The prey sizes were correlated with calculated predator sizes in both areas, and the highest frequency of the predator-prey coefficient of shell length of prey (mm)/calculated shell height of predator (mm), was 0.7-0.8. These results indicate size-selective predation of E. fortunei.
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  • Estimating the feeding habits of largemouth bass and bluegill around Noda Lake, a satellite lake of Lake Biwa, based on stomach contents and fecal DNA
    SHOZO SUGIURA, TAKASHI TAGUCHI
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 43-53
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.43
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      Largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus are the dominant fish species in Lake Biwa, central Japan. Understanding their predatory and competing behaviors against native species is important to increase the effectiveness of stock enhancement with indigenous species and to restore diminished fisheries resources in Lake Biwa. We studied the feeding habits of largemouth bass and bluegill in one of the satellite lakes of Lake Biwa, Noda Lake, where there are large populations of these predatory species. Visual and microscopic examinations of stomach contents, quantitative PCR of fecal DNA, as well as sequencing of fecal DNA clone libraries collectively revealed that largemouth bass tended to prefer larger prey species, including ayu Plecoglossus altivelis, than smaller prey, such as crucian carp fry Carassius spp. (with the exception of the Gobiid fish Rhinogobius spp.). Bluegill showed algal-omnivorous feeding rather than piscivorous habits. Largemouth bass had a stronger feeding preference for Palaemon paucidens (including Macrobrachium spp.) over Atyiid shrimps, while bluegill showed the opposite preference. Feeding preference of largemouth bass for indigenous species could depend on the following factors: the kind and size of prey species, the degree of satiation of the predator fish, and the turbidity of the habitat.
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  • Testing of artificial reefs with substrates covered with chemical fiber fabric for the restoration of Gelidium beds on the shore of Miyakejima Island
    KENJI TAKIO, TAKUMI KIMOTO, TOMOHIRO TAKASE, HISAYUKI ARAKAWA
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 54-61
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.54
    JOURNAL FREE ACCESS
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      We designed artificial reefs installed with substrates (CCF bolts) covered with chemical fiber fabric for the restoration of Gelidium beds. We deployed experimental blocks onto the sea bottom at Ohashi on the eastern shore of Miyakejima Island where G. elegans beds had been devastated by the volcanic eruption. The Standing crop of G. elegans on the artificial reefs was significantly greater than that on the natural bedrocks, however, it was below the level measured before the volcanic eruption. On the other hand, G. elegans adhered quickly to the CFF bolts fixed on the artificial reefs, and the standing crop of G. elegans on the bolts was maintained at the level measured before the volcanic eruption after more than three years since the deployment.
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  • Genetic investigation of artificially raised red sea bream with abnormal vertebrae formation
    EITARO SAWAYAMA, MOTOHIRO TAKAGI
    Article type: Originals
    2012 Volume 78 Issue 1 Pages 62-68
    Published: 2012
    Released on J-STAGE: March 14, 2012
    DOIhttps://doi.org/10.2331/suisan.78.62
    JOURNAL FREE ACCESS
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      Artificially raised red sea breams with abnormal body shapes were morphologically characterized, and genetic investigations were conducted using microsatellite DNA markers. Normal and deformed individuals were collected at 68 days post-hatch. Deformed individuals were truncated because their dorsal regions were swelled and had scoliosis. A complex spinal column deformity consisting of a consecutive repetition of lordosis, kyphosis, and scoliosis from the head to the caudal fin was described by soft X-ray analysis. Four microsatellite markers, Pma-2*, -3*, -4*, and -5*, were used for parentage analysis, and two dams and sires generated significant numbers of deformed individuals. Genetic investigations were also conducted and genotype frequency revealed that 90% of deformed individuals had an allele-113 on Pma-4*, even though 60% of normal individuals also had the allele. Our results suggest that genetic factors may be one of the causes of the deformed individuals identified as juveniles of a hatchery population of red sea bream.
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Symposia
Quality improvement of fish and marine invertebrates by short-term rearing after catch
Forefront of studies on FUGU and technological development for TORAFUGU production
Mini-Symposium
Past and future of the East China Sea research—To enhance transboundary marine research network—
Damages to fisheries by the Great East Japan Earthquake and tsunami disasters
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Highlights in Fisheries Science Research
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