Employment of Halophylous Compost in Coastal Aquaculture and Its Relation to Water Quality

Detritus and nutrients derived from compost (NH₄⁺, PO₄³⁻, COD) were obtained experimentally after a 90 day decomposition pretreatment of coastal halophytes (Sesuvium sp. Cressa sp. Suaeda sp. and Salicornia sp.). The detritus obtained was added as fertilizer to 15 cages placed in Caimanero Lagoon, for 35 days. During the first 10 days in situ orthophosphates were recorded at levels of 7.3 to 2.0 µg-at l⁻¹, and ammonium varied from 7.3 to 4.9 µg-at l⁻¹, values that are considered adequate for primary producers and the quality of the water. The availability of nutrients showed that the use of this compost, added to the shrimp culture cages with a surface area of 4 m² and a height of 1.2 m, at a rate of one kilogram of halophytes per 200 liters of water, did not modify the content of nutrients in the water inside and outside of the cages. The halophylous detritus (quantified by BOD and COD, representative of the easily available organic carbon load), went through three phases: first, abatement phase during in the first four days; second, up to 10 days, and third, up to 35 days.