Fiscal Year
2014
Title
Environmental carrying capacity of cultured scallop in Ogatsu Bay
Project and Theme
Project 1. Study on ecological succession of fisheries ground
Representative Organization: Tohoku University
Theme4. Aquaculture environment in the coastal water of Miyagi Prefecture and innovation of aquaculture system| Representative person | Makoto Osada |
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| Organization | Tohoku University |
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| Department | Graduate School of Agricultural Science |
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Research InformationPeriod and Interval2015/01/01 - 2015/01/31
once a year
Research Area
Two stations in the Ogatsu Bay (St 1 & 2)
CategoryField survey
OverviewTotal amount of scallop production and the numbers of facility for scallop farming in Ogatsu Bay were obtained and used for calculation in order to compare with a pre-quake period. In addition, shell size and weight of several organs of the cultured scallops by ear hang method were measured and analyzed for their growth condition between two different depth conditions. The environmental capacity for scallop culture in Ogatsu Bay was evaluated by growth condition and food availability based on a primary production (i.e., monitoring of chlorophyll a concentration).
Overview of the Observation
Research Point Table
| Point | | Name | St 1 |
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| Coordinates | 38.487232,141.496177 |
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| Remarks | Survey area |
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| Name | St 2 |
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| Coordinates | 38.504135,141.510554 |
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| Remarks | Survey area |
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Research Point Map & Track Chart Map & Point List
Results and Future PlanIn the scallop culture at Ogatsu Bay in 2014, the number of facility for scallop farming recovered to about 66% and the annual production of the cultured scallop recovered to about 76% compared to the data in 2010 (before the earthquake disaster). To evaluate the productivity of scallop in Ogatsu Bay, the amount of production per rope where scallops were ear-hanged was calculated. The productivity in 2014 showed at 23.7 kg per rope even though the data in 2013 showed at 30.9 kg per rope. Total amount of chlorophyll a (above 20 m depth) throughout a year did not differ between 2014 and 2013 suggesting the same fluctuation level of the primary production as past. The poor growth (i.e., shell size, soft body weight) of scallop cultured in deeper layer previously found before the earthquake was observed at both stations in 2014 and the adductor muscle index (adductor muscle weight/whole soft body weight without gonad *100) showed at about 38 in both layers. These results suggest that a food availability for good growth of scallop is not sufficient for the scallops cultured in deeper layer in Ogatsu Bay in 2014. Thus, it might be a time that the producers need to re-consider the amount of production to be slightly reduced for sustaining good environmental capacity in Ogatsu Bay.
Investigation Item and Data Acquisition
| Investigation Item | Data Acquisition |
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| Comparison of shell growth | Shell size in each depth at two stations |
| Comparison of soft body growth | Soft body wight and indices of organs in each depth at two stations |
| Comparison for amount of production and number of farming facility | Total amount of production and number of farming facility for scallops in Ogatsu Bay |
| Monitoring of food availability | Concentration of chlorophyll a |
Reference
Person in charge of Investigation
| Representative person | Makoto Osada |
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| Organization | Tohoku University |
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| Department | Graduate School of Agricultural Science |
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| Fiscal Year | 2014 |
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| Organization | Tohoku University |
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| Category | Field survey |
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| Research Area | South Sanriku |
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| Discipline | Ocean physics -> Water temperature
Ocean environment -> Primary production
Ocean biology / Ocean ecology -> Physiology
Ocean biology / Ocean ecology -> Mollusks
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