Suspension feeding of the ark shell Scapharca subcrenata as a function of environmental and biological variables
In: Fisheries Science. Springer: Tokyo. ISSN 0919-9268; e-ISSN 1444-2906, meer
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| Trefwoord |
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| Author keywords |
ark shell;bivalves;clearance rates;Scapharca subcrenata |
| Abstract |
To assess the roles of the ark shell Scapharca subcrenata in material cycling in the northern part of Ariake Sound (Mae-no-umi), Japan, filtration of the ark shell fed on small diatoms was examined as a function of environmental and biological variables. The clearance rate (CR) specific to the soft-body dry weight (w) of the animals (shell length, 8–26 mm) followed a power function of w with an exponent of −0.35. Over the range of 10–20°C, CR increased 2.7 times, and filtration did not occur below a salinity of 14 practical salinity unit. Neither food concentration (10–40 µg/L of chlorophyll-a) nor weight-specific daily ration (0.5–6%/day in terms of ash-free dry weight) notably affected CR. Using this information on CR as well as data regarding abundance and size distribution, the population filtration rate was calculated to be 1.6 m3/m2 per day in the ark-shell culturing ground of Mae-no-umi (mean water depth, ∼3 m), corresponding to the potential to locally process a volume of water equivalent to the water column within 2 days. Because the culturing ground accounts for 12% of Mae-no-umi (mean water depth, ∼8 m), the ark shell seems to play an important role in its material cycling. |
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