The effect of artificial vegetation density on growth and growth related parameters of Nile tilapia, Oreochromis niloticus (L.) fry

A growth response study was carried out to evaluate the influence of artificially submerged macrophytes on growth performance and supplemental feed utilization of Nile tilapia, Oreochromis niloticus (L.) fry under aquarium conditions. In glass aquarium (80 x 50 x 50 cm) filled with 140 litres of well-aerated tap water (25 to 28 °C), leafless stems of phragmites plant (0.7 m long and 0.5 cm diameter) were used at densities of 0, 25, 50, 75, 100 and 125 stems/m2. The final fish weight, weight gain and specific growth rate (SGR) decreased significantly with the increase in plant density (P<0.05). The lowest fish growth was obtained at densities over 75 stems/ m2. The higher feed intake was recorded at control, while the lowest one was obtained at densities of 75-125 stems/m2 (P<0.05). In contrast, feed conversion ratio (FCR) was only higher at the density of 125 stems/m2 (P<0.05). The protein efficiency ratio (PER), protein productive value (PPV) and protein growth rate (PGR) declined significantly at the density of 125 stems/m2 (P<0.05). Contents of moisture and crude protein in whole fish body increased slightly with the increase in plant density (P>0.05). The total lipid content was only decreased, while ash content increased significantly at plant density of 125 stems/m2. It could be recommended that submerged macrophytes, used as fish refuges from predators or for periphyton production, should be at low or moderate density, however, dense vegetation reduces significantly fish growth and feed utilization.

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Anderson, O. 1984. Optimal foraging by largemouth bass in structured environments. Ecology, 65: 851-861.

AOAC (Association of Official Analytical Chemists). 1990.Official Methods of Analysis. The 13th edition, Association of Official Analytical Chemists, Washington D.C., USA.

Barton, B.A., Schreck, C.B. and Barton, L.D. 1987. Effects of chronic cortisol administration and daily acute stress on growth, physiological conditions and stress responses '~m juvenile rainbow trout. Disease of Aquatic Organisms, 2: 171-185.

Beklioglu, M. and Moss, B. 1996. Existence of a macrophyte dominated clear water over a very wide range of nutrient concentrations in a small shallow lake. Hydrobiologia, 337: 93;106.

Brett, J. R. 1979. Environmental factors and growth. W. S. Hove, D. J. Randall and J. R. Brett (Eds.), Fish Physiology, Vol. VIII, Academic Press Inc., London: 599-675.

Cailteux, R.L., Porak, W.F. Crawford, S. and Connor, L. 1994. Food habits and growth of largemouth bass in vegetated vs. unvegetated lakes in central Florida. (Abstract). Lake and Reservoir Management, 9(2): 61.

Carpenter, S.R. and Lodge, D.M. 1986. Effects of submersed macrophytes on ecosystem processes. Aquatic Botany, 26: 341-370.

Cooks, W.L. and Streams, F.A. 1984. Fish predation on Notonecta (Hemipetra): relationship between prey risk and habitat utilization. Oecologia, 64: 177-183.

Crowder, L.B. and Cooper, W.E. 1982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology, 63: 1802-1813.

Dionne, M. and Folt, C.L. 1991. An experimental analysis of macrophyte growth forms as fish foraging habitats. Canadian Journal of Fisheries and Aquatic Sciences, 48: 123-131.

Dytham, C. 1999. Choosing and Using Statistics: A Biologist's Guide. Blackwell Science Ltd., London, UK, 147 pp.

Gregory, T.R. and Wood, CM. 1999. The effects of chronic plasma cortisol elevation on the feeding behaviour, growth, competitive ability, and swimming performance of juvenile rainbow trout. Physiological and Biochemical Zoology, 72: 286-295.

Jeppesen, E.M.; Lauridsen, T.L. Kairesalo, T. and Perrow, M.R. 1998. Impact of submerged macrophytes on fish-zooplankton interactions in lakes. In: E.M.

Jeppesen, M. S0ndergaard, M. S0ndergaard and K. Christoffersen (Eds.), The Structuring Role of Submerged Macrophytes on Lakes, Springer-Verlag, New York: 91-114.

Keshavanath, P., Gangadhar, B. Ramesh, T.J. van Dam, A.A. Beveridge, M.C.M. and Verdegem, M.C.J. 2004. Effects of bamboo substrate and supplemental feeding on growth and production of hybrid red tilapia fingerlings (Oreochromis mossambicus x Oreochromis niloticus). Aquaculture, 235 (1-4): 303 314.

Killigore, K.J., Morgan II, R.P. and Rybicki, N.B. 1989. Distribution and abundance of fishes associated with submersed aquatic plants in the Potomac River. North American Journal of Fisheries Mangement, 9: 101-111.

Lagler, K. F., Bardach, J.E., Miller, R.R. and MeyPassino, D.R. 1977. Ichthyology. The 2nd edition, John Wiley and Sons, New York.

Lyytikainen, T. and Ruohonen, K. 2001. The acute effect of cortisol implant on self-feeding activity of rainbow trout Oncorhynchus mykiss (Walbaum). Aquaculture Research, 32: 503-505.

Manatunge, J., Asaeda, T. and Priyadarshana, T. 2000. The influence of structural complexity on fish-zooplankton interactions: A study using artificial submerged macrophytes. Environmental Biology of Fishes, 58: 425-438.

Morgan, J.D. and Iwama, G.K. 1996. Cortisol-induced changes in oxygen consumption and ionic regulation in coastal cutthroat trout {Oncorhynchus clarki clarki) parr. Fish Physiology and Biochemistry, 15: 385-394.

Persson, L. 1993. Predator-mediated competition in prey refuges: the importance of habitat dependent prey resources. Oikos, 68: 12-22.

Randall, R.G., Minns, C.K. Cairns, V.W. and Moore, J.E. 1996. The relationships between an index of fish production and submerged macrophytes and other habitat features at three littoral areas in the Great Lakes. Canadian Journal of Aquatic Sciences, 53(Suppl.l): 35-44.

Roesch, R. 1992. Food intake and growth of larvae of Coregonus lavaretus. Effect of diet and light. Biology and Management of Coregonid Fishes, 39(3-4): 671-676.

Savino, J.F. and Stein, R.A. 1982. Predator-prey interaction between largemouth bass and bluegills as influenced by simulated, submerged vegetation. Transaction of the American Fisheries Society, 111: 255-266.

Schriver, P., B0gestrand, J., Jeppesen, E. and S0ndergaard, M. 1995. Impact of submerged macrophytes on fish-zooplankton-phytoplankton interactions: large scale enclosure experiments in a shallow eutrophic lake. Freshwater Biology, 33: 255-270.

Spitzer, P.M., Johanna, M. and Heck, Jr L.K. 2000. The effects of vegetation density on the relative growth rates of juvenile pinfish, Lagodon rhomboides (Linneaus), in big Lagoon, Florida. Journal of Experimental Marine Biology and Ecology, 244: 67-86.

Sveier, H., Raae, A.J. and Lied, E. 2000. Growth and protein turnover in Atlantic salmon (Salmo salar L.): the effect of dietary protein level and protein particle size. Aquaculture, 185: 101-120.

Wiley, M.J., Gorden, R.W., Waite S.W. and Powless, T. 1984. The relationship between aquatic macrophytes and sport fish production in Illinois ponds: a simple model. North American Journal of Fisheries Management, 4: 111-119.

Winfield, I. J. 1986. The influence of simulated aquatic macrophytes on the zooplankton consumption rate of juvenile roach, Rutilus rutilus, rudd, Scardinius erythrophthamus, and perch, Perca fluviatilis. Journal of Fish Biology, 29 (Supplement A): 37-48.