Hydrodynamic Forcing of Long-Line Mussel Farms: Observations
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 133, Issue 3
Abstract
The first detailed observations of the motion and loading of a mussel (shellfish) aquaculture long-line are described in order to identify the dominant modes of flow-structure interaction and provide a baseline for prediction of future structures. A long-line is typically a long sequence of surface floats beneath which is looped rope bearing the mussel crop. Accelerometer and load cell data from sensors mounted on the structure along with remote radar data are examined in the context of wave and current measurements. The mussels comprise the largest mass and drag element of the structure, and the tidally affected pretensioning of the mooring lines dominates the background load. However, waves and currents increase the maximum load by potentially 100% over this value. The floats at each end of the long-line follow the wave orbital motion reasonably well, more so than the floats in the middle of the backbone. The mussel-laden loops of rope (droppers) clearly respond differently to the floats, implying flexibility in the vertical dimension. This suggests that flow around the droppers, which influences mussel feeding ability and hence production, is complex and highly three-dimensional.
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Acknowledgments
The writers would like to thank Ocean Marine Farms (Simon Acton-Adams) for allowing utilization of their structures. Richard Newton of the Canterbury Civil Engineering Department built the load cells; Gary Teear (OCEL Consultants) and John Fenwick and John McGregor (NIWA) facilitated the field sampling; and Bob Spigel (NIWA) and Roger Nokes and Mark Davidson (U. Canterbury) are thanked for their support of David Plew. Three reviewers provided useful comments on the work. Funding was provided by the New Zealand Foundation for Research Science and Technology NSOF/PGSF and the Royal Society ISAT Linkages Programme.
References
Ackerman, J. D., and Nishizaki, M. T. (2004). “The effect of velocity on the suspension feeding and growth of the marine mussels Mytilus trossulus and M. californianus: Implications for niche separation.” J. Mar. Syst., 49(1–4), 195–208.
Ahern, J. (2002). “Validation of wave measurement buoy.” Master’s thesis submitted in partial requirement for ocean engineering degree program, Univ. of New Hampshire, Durham, N.H.
DeCew, J., Fredriksson, D. W., Bougrov, L., Swift, M. R., Eroshkin, O., and Celikkol, B. (2005). “Numerical and physical modeling of a modified gravity type cage and mooring system.” IEEE J. Ocean. Eng., 30(1), 47–58.
Denny, M., and Roberson, L. (2002). “Blade motion and the nutrient flux to the kelp Eisenia arborea.” Biol. Bull., 203 (August), 1–3.
Elwany, M. H. S., O’Reilly, W. C., Guza, R. T., and Flick, R. E. (1995). “Effects of southern California kelp beds on waves.” J. Waterway, Port, Coastal, Ocean Eng., 121(2), 143–150.
Floyd, B. (2001). “Greenshell: New Zealand’s most successful seafood export?” Seafood New Zealand, 9(1), 41–42.
Fredriksson, D. W., Swift, M. R., Eroshkin, O., Tsukrov, I., Irish, J. D., and Celikkol, B. (2005). “Moored fish cage dynamics in waves and currents: Special issue on open ocean aquaculture engineering.” IEEE J. Ocean. Eng., 30(1), 28–36.
Grosenbaugh, M., et al. (2002). “Design and performance of a horizontal mooring for upper-ocean research.” J. Atmos. Ocean. Technol., 19(9), 1376–1389.
Heron, S. F., and Heron, M. L. (1998). “A comparison of algorithms for extracting significant wave height from HF radar ocean backscatter spectra.” J. Atmos. Ocean. Technol., 15(5), 1157–1163.
Jackson, G. A. (1997). “Currents in the high drag environment of a coastal kelp stand off California.” Cont. Shelf Res., 17(15), 1913–1928.
Johnston, D. M., Cole, J. W., and Houghton, B. F. (1997). “Physical volcanology of Miocene basaltic pyroclastic deposits at Pigeon Bay: Remains of flank scoria cones of Akaroa volcano, Banks Peninsula, New Zealand.” N.Z. J. Geol. Geophys., 40(1), 109–115.
Kaplan, D. M., Largier, J., and Botsford, L. W. (2005). “HF radar observations of surface current circulation off Bodega Bay (Northern California, USA).” J. Geophys. Res., 100, C10020.
Morison, J. R., O’Brien, M. P., Johnson, J. W., and Schaaf, S. A. (1950). “The forces exerted by surface waves on piles.” Trans. Am. Inst. Min., Metall. Pet. Eng., 189, 149–157.
Plew, D., Stevens, C. Spigel, R., and Hartstein, N. (2005). “Hydrodynamic implications of large offshore mussel farms.” IEEE J. Ocean. Eng., 30(1), 95–108.
Poulter, E. M., Smith, M. J., and McGregor, J. A. (1995). “S-band FMCW radar measurements of ocean surface dynamics.” J. Atmos. Ocean. Technol., 12(6), 1271–1286.
Raman-Nair, W., and Colbourne, B. (2003). “Dynamics of a mussel longline system.” Aquacultural Eng., 27(3), 191–212.
Seymour, R. J. (1996). “Discussion of ‘Effects of southern California kelp beds on waves’.” J. Waterway, Port, Coastal, Ocean Eng., 122(4), 207–208.
Seymour, R. J., and Hanes, D. M. (1979). “Performance analysis of tethered float breakwater.” J. Wtrwy., Port, Coast., and Oc. Div., 105(3), 265–280.
Stevens, C. L., Hurd, C. L., and Smith, M. J. (2004). “Interaction between fronds of the large intertidal seaweed Durvillaea antarctica.” J. Mar. Syst., 49(1–2), 145–157.
Stevens, C. L., Hurd, C. L., and Smith, M. J. (2001). “Water motion relative to subtidal kelp fronds.” Limnol. Oceanogr., 46(3), 668–678.
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Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 133 • Issue 3 • May 2007
Pages: 192 - 199
Copyright
© 2007 ASCE.
History
Received: Jul 18, 2005
Accepted: Apr 5, 2006
Published online: May 1, 2007
Published in print: May 2007
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