Bivalve production and food chain efficiency in an experimental nursery system
Rodhouse, P.G.; Ottway, B.; Burnell, G.M. (1981). Bivalve production and food chain efficiency in an experimental nursery system. J. Mar. Biol. Ass. U.K. 61: 243-256
In: Journal of the Marine Biological Association of the United Kingdom. Cambridge University Press/Marine Biological Association of the United Kingdom: Cambridge. ISSN 0025-3154; e-ISSN 1469-7769, more
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| Keywords |
Aquaculture techniques
Cultures > Shellfish culture
Bivalvia [WoRMS]
Marine/Coastal |
| Authors | | Top |
- Rodhouse, P.G.
- Ottway, B.
- Burnell, G.M.
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| Abstract |
An experiment was performed to assess the productivity, food chain efficiency and nitrogen conversion efficiency of a semi-closed nursery system for bivalve spat held in upwelling columns. Algal blooms were encouraged by nutrient enrichment of onshore tanks and maintained for short periods under grazing pressure from bivalves. Blooms were dominated by diatoms, and standing stock in the tank used for feeding fell mostly in the range 300-1500 µg C/l (0.3-1.2 g C /m2 ). Net primary productivity estimated during one 11- and one 14-day period exceeded 1 g C/m2 /day at the height of bloom development when cell division rate was >1/day. Bivalve growth was limited by low summer water temperatures. Between April and Oct bivalve production was 19.1 g/m2 (total organic matter per unit tank area) and after mortality, yield was 16.3 g/m2 . Food chain efficiency (bivalve production: net primary productivity) during the experiment was 27% and ecological efficiency probably approached the same level. Conversion efficiency of inorganic nitrogen to bivalve protein nitrogen (soft tissue) was 19.1% and 16.9% was yielded after mortality. The system was less productive, on a unit area basis, than some natural populations of bivalves, but probably approached the maximum attainable in a semi-closed system relying on in situ primary productivity. |
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