Ulva lactuca Biofilters for Marine Fishpond Effluents II. Growth Rate, Yield and C:N Ratio

A. Neori, I. Cohen, H. Gordin

Research output: Contribution to journalArticlepeer-review


The seaweed Ulva lactuca L. was cultured in effluents from intensive marine fishponds in Eilat, Israel. The specific growth rate and the yield of U. lactuca in nutrient-rich fishpond effluents were higher than in pulse-enriched fresh seawater. Both yield and specific growth rate of the seaweed showed positive hyperbolic correlations with N-flux which fitted the Michaelis-Menten kinetics. Maximal dry weight (DW) yield was 55 gm-2d-1and the maximal specific growth rate was 18% d-1. The C: N ratio in plant tissue showed a negative hyperbolic correlation with N-flux, dropping from over 15 to approximately 7 (w : w) when grown at low and high N-fluxes, respectively. As the stocking density increased up to 6 kg m-2 under N-sufficient conditions, both specific growth rate and yield decreased significantly, as did mostly also the C : N ratio. The data suggest the seaweed to be N-limited at low N-fluxes and light limited at high N fluxes, especially at high stocking densities. The high yields obtained show that fishpond effluents supply U. lactuca with all its required nutrients including inorganic carbon. For high yield and high nitrogen content, U. lactuca should be kept at densities of 1 —2 kg m-2 and at ammonia fluxes of about 0.5 moles m-2 d-1. Nitrogen content can be increased further, but at reduced yield, by increasing the stocking density to 4 or 6 kg m-2.

Original languageEnglish
Pages (from-to)483-490
Number of pages8
JournalBotanica Marina
Issue number6
StatePublished - 1991
Externally publishedYes

Bibliographical note

Funding Information:
We are grateful to H. Voet for help with statistical analyses and to S. Peled and the others at the NCM for their assistance. M. Friedlander and C. Dawes critically reviewed earlier versions of this manuscript. This research was supported by the Israeli Ministry for Energy and Infrastructure Mariculture Project, The Arava Research and Development Fund, BARD research grant No. 1-1634-89 and grant No. 3035189 from the Israeli Ministry for Science and Technology.

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Plant Science


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