Why Do the Radionuclide Concentrations of Pacific Cod Depend on the Body Size?

Narimatsu, Yoji; Sohtome, Tadahiro; Yamada, Masatoshi; Shigenobu, Yuya; Kurita, Yutaka; Hattori, Tsutomu; Inagawa, Ryo

doi:10.1007/978-4-431-55537-7_10

Cited by 9 publications

(7 citation statements)

References 18 publications

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“…The existence of these two contamination histories was supported by simulation studies. These histories seem to be common to many other fish species (Tateda et al 2013;Wada et al 2013;Narimatsu et al 2014). …”

Section: Discussionmentioning

confidence: 79%

Radiocesium Contamination Histories of Japanese Flounder (Paralichthys olivaceus) After the 2011 Fukushima Nuclear Power Plant Accident

Kurita

Shigenobu

Sakuma

et al. 2015

Impacts of the Fukushima Nuclear Accident on Fish and Fishing Grounds

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Radiocesium (Cs) contamination histories of the Japanese flounder, Paralichthys olivaceus, after the 2011 Fukushima Nuclear Power Plant (FNPP) accident were examined by analysis of the spatiotemporal changes in observed Cs concentrations, by comparison of the dynamics of the Cs concentrations in several year-classes of fish, and by simulation studies. Two contamination histories were revealed: (1) severe contamination by water that was directly released from the FNPP with extremely high Cs concentrations for a few months after the accident, which had a highly variable spatial distribution; and (2) long-duration contamination at relatively low concentrations resulting from consumption of contaminated food. These two histories were supported by three observations. First, high Cs concentrations with high variability were observed in the first year after the accident. Second, the highest values of the minimum Cs concentrations were observed in the autumn of 2011. Third, Cs concentrations were lower with smaller variation for fish from the 2011 year-class and younger, which were not exposed to the highly contaminated directly released water, than for fish from the 2010 year-class and older. Simulation studies also indicated that the Cs concentrations in some individuals that were exposed to the directly released water might not be in an equilibrium state even at 3 years after the accident. On the basis of these contamination histories, it can be expected that the Cs concentrations in most Japanese flounder will continue to decrease.

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Section: Discussionmentioning

confidence: 79%

Radiocesium Contamination Histories of Japanese Flounder (Paralichthys olivaceus) After the 2011 Fukushima Nuclear Power Plant Accident

Kurita

Shigenobu

Sakuma

et al. 2015

Impacts of the Fukushima Nuclear Accident on Fish and Fishing Grounds

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“…Potential competitors for forage fishes, e.g., Pacific cod Gadus macrocephalus (Narimatsu et al ., ) increased. These changes should be caused by the change or variation of biotic and abiotic environments and a substantial decrease in fishing mortality because of the damage to fishery boats by the direct effects of the tsunami and temporal ban on fisheries owing to the radiocesium contamination (Kurita et al ., ; Narimatsu et al ., ). At present, we do not have any information on the increase in mortality of the population of Japanese flounder after migration from the nursery ground to recruitment, rather the abundance of adult fish increased (Kurita et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Impact of the great tsunami in 2011 on the quality of nursery grounds for juvenile Japanese flounder Paralichthys olivaceus in Sendai Bay, Japan

Kurita

Uehara

Okazaki

et al. 2017

Fisheries Oceanography

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The impact of the great tsunami, which was generated by the Great East Japan Earthquake on 11 March 2011, on the quality of a nursery ground for juvenile Japanese flounder Paralichthys olivaceus with a sandy bottom of <15 m in depth in Sendai Bay, Japan, was evaluated. Growth rates of juveniles, as an index of the quality of the nursery ground, were compared between before and after the tsunami. Recent growth rates (RGR; mm day−1) between 1 and 6 days before collection in 2011–2013, which were estimated from the width of otolith increments, ranged from 0.84 to 2.37 mm day−1 for juveniles of 24.8–146 mm in total length (TL). These figures are comparable to the maximum RGR for juvenile Japanese flounder in the literature. A linear model for RGR selected TL and bottom temperature but rejected biomass of the mysid Orientomysis mitsukurii, the main prey item, as explanatory variables, indicating that the growth rates of juveniles after the tsunami were not controlled by food density, i.e., optimal food condition occurred in the nursery. A linear model for observed growth rate (mm day−1), which was calculated from the temporal changes in the juvenile size frequency distribution, suggested the growth rate did not change between before and after the tsunami. Additional information on prey abundance and sediment size distribution also support this conclusion. Therefore, we conclude that the quality of the nursery ground for juvenile Japanese flounder in the study site has not been damaged by the great tsunami.

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“…1). The vertical distribution pattern of Pacific cod may differ seasonally and ontogenetically because of dependence on pelagic and/or benthic prey items changes with age and season (Narimatsu et al, 2015b). Taking into account seasonal and ontogenetic changes in vertical distribution in the water column, fishing efficiency of the gear was not considered in this analysis.…”

Section: Field Sampling and Data Analysesmentioning

confidence: 99%

“…Miyagi Prefecture is located south of Iwate Prefecture (Fig. 1), where fishermen continued to catch Pacific cod even post-2011 at almost same effort as pre-2011 (Narimatsu et al, 2015b). Additionally, restriction for catching of Pacific cod was completely canceled early in 2013 in Miyagi Prefecture.…”

Section: Effects Of the Incidentally Occurring Mpa On Pacific Cod Popmentioning

confidence: 99%

“…Pacific cod spawn from January to early March in the Tohoku area . Hatched cod begin to settle in the demersal area (40-120 m in depth) in June and migrate to the upper-continental slope (200-400 m) during the summer (Kitagawa et al, 2002;Narimatsu et al, 2015b). This population is commercially caught primarily by demersal trawl, and also by gill net, longlines, and set nets.…”

Section: Introductionmentioning

confidence: 99%

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Effects of a marine‐protected area occurred incidentally after the Great East Japan Earthquake on the Pacific cod (Gadus macrocephalus) population off northeastern Honshu, Japan

Narimatsu

Shibata

Hattori

et al. 2017

Fisheries Oceanography

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The population of Pacific cod inhabiting off northeastern Honshu Japan has remarkably increased in the 3 yr after the Great East Japan Earthquake in 2011. We examined the processes and factors leading to this increase based on the results of estimations of commercial catch and fishing activities, and trawl surveys. Pacific cod was highly exploited from 1 yr old before 2011. However, fishing pressure has markedly decreased after 2011 in the area around Fukushima waters. Fish abundance in 2013 and 2014 was estimated to be more than four‐fold of the maximum amount before 2011. The cohort structure of the population in 2013 and 2014 was primarily composed of 2–4‐yr‐old fish (2010–2011 yr classes) whereas the population in pre‐2011 was primarily of 1‐yr‐old fish. The 2010–2011 yr classes had almost the same population sizes until 1.3 yr old to the pre‐2009 yr classes, but became much higher more than 2.8 yr old. Pacific cod from 1.3 to 2.8 yr old were concentrated in the area off Fukushima Prefecture. These results suggest that Pacific cod increased post‐2011 not because of the occurrence of strong year classes followed by good recruitments but because of the lower mortality after recruitment owing to reduced fishing mortality. Waters off Fukushima, the primary nursery of Pacific cod, are effectively serving as a marine protected area after the tsunami events. A close coincidence between the nursery area of young fish and the protected area strongly altered the age composition of the population and enhanced fish abundance.

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Why Do the Radionuclide Concentrations of Pacific Cod Depend on the Body Size?

Cited by 9 publications

References 18 publications

Radiocesium Contamination Histories of Japanese Flounder (Paralichthys olivaceus) After the 2011 Fukushima Nuclear Power Plant Accident

Radiocesium Contamination Histories of Japanese Flounder (Paralichthys olivaceus) After the 2011 Fukushima Nuclear Power Plant Accident

Impact of the great tsunami in 2011 on the quality of nursery grounds for juvenile Japanese flounder Paralichthys olivaceus in Sendai Bay, Japan

Effects of a marine‐protected area occurred incidentally after the Great East Japan Earthquake on the Pacific cod (Gadus macrocephalus) population off northeastern Honshu, Japan

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