title: GROWTH DYNAMICS OF ULVA ROTUNDATA (CHLOROPHYTA) IN A FISH FARM: IMPLICATIONS FOR BIOMITIGATION AT A LARGE SCALE(1).
abstract: Changes in biomass of several macroalgae [Ulva rotundata Bliding; Gracilariopsis longissima (S. G. Gmel.) Steentoft, L. M. Irvine et Farnham; Ulva intestinalis L.; and Cladophora sp.] and marine plants (Zostera noltii and Ruppia cirrhosa) growing naturally in earthen ponds of a fish farm (Acuinova, San Fernando, Southern Spain) were recorded during a year. The farm is mainly devoted to the culture of gilthered seabream (Sparus aurata). The most conspicuous algal species thriving in the ponds was U. rotundata, which reached densities up to 600 g dry mass · m(-2) and produced up to 20.45 g C · m(-2)  · d(-1) . Dissolved nutrients (phosphate and ammonium), tissue nutrient content, and growth rates of this species were estimated during 2001 and 2002. Evidence of natural biomitigation by U. rotundata when water circulates throughout the fish farm is presented. Due to the fish cultivation, both phosphate and ammonium increased as water circulated from the preculture ponds to the postculture ponds. As a consequence, U. rotundata tissue nitrogen (N) and phosphorus (P) increased from algae growing in preculture ponds to algae growing in the outflow channel, so that mean C:N:P ratio varied from 773:57:1 in preculture ponds to 567:64:1 in the outflow channel. Phosphorus limited growth of U. rotundata during the spring. As growth rates increased as a function of tissue P, data were fitted to the Droop equation. From this equation, the estimated maximal growth rate was 0.295 ± 0.041 d(-1) , the subsistence quota was 0.05 ± 0.01% P of dry mass, and the critical quota was 0.215% P of dry mass. The results suggest that management of the fish farm based on a large-scale integrated mariculture system of fish and macroalgae may increase the total ecological and economic benefits, both for the farm and for the environment.
authors.affiliation: Área de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain Marine Plant Ecology Research Group, CCMAR-Centro de Ciências do Mar, Universidade do Algarve, Gambelas, 8005-139 Faro, PortugalÁrea de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, SpainAcuinova SL, Apdo Correos 458, 11100 San Fernando, Cádiz, SpainÁrea de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Hernández
authors.affiliation: Área de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain Marine Plant Ecology Research Group, CCMAR-Centro de Ciências do Mar, Universidade do Algarve, Gambelas, 8005-139 Faro, PortugalÁrea de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, SpainAcuinova SL, Apdo Correos 458, 11100 San Fernando, Cádiz, SpainÁrea de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain.
authors.forename: Abraham
authors.initials: A
authors.lastname: Pérez-Pastor
authors.affiliation: Área de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain Marine Plant Ecology Research Group, CCMAR-Centro de Ciências do Mar, Universidade do Algarve, Gambelas, 8005-139 Faro, PortugalÁrea de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, SpainAcuinova SL, Apdo Correos 458, 11100 San Fernando, Cádiz, SpainÁrea de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Mateo
authors.affiliation: Área de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain Marine Plant Ecology Research Group, CCMAR-Centro de Ciências do Mar, Universidade do Algarve, Gambelas, 8005-139 Faro, PortugalÁrea de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, SpainAcuinova SL, Apdo Correos 458, 11100 San Fernando, Cádiz, SpainÁrea de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain.
authors.forename: Cesar
authors.initials: C
authors.lastname: Megina
authors.affiliation: Área de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain Marine Plant Ecology Research Group, CCMAR-Centro de Ciências do Mar, Universidade do Algarve, Gambelas, 8005-139 Faro, PortugalÁrea de Ecología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, SpainAcuinova SL, Apdo Correos 458, 11100 San Fernando, Cádiz, SpainÁrea de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz. 11510 Puerto Real, Cádiz, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Vergara
keywords: integrated mariculture; land-based aquaculture; macroalgae; nitrogen; phosphorus; subsistence quota