Culture of Chondracanthus teedei and Gracilariopsis longissima in a traditional salina from southern Spain

Abstract

The cutivation of two red macroalgal species, Chondracanthus teedei (Martens ex Roth) and Gracilariopsis longissima (S.G. Gmelin) Steentoft M, L.M. Irvine & W.F. Farnham, was assessed in a traditional salina, a system of earthen ponds used for marine salt extraction taking advantages of solar evaporation and tidal cycle. Vegetative thalli of both species were cultivated in rafts holding polypropylene ropes, from January to June 2015, when lock-gates were opened during the period of no salt production. The effects of three factors in the net growth rate were analysed: seedling density, water motion and seasonality. Water motion and seasonality showed a significant effect in the growth of both species. Seedling density only showed a significant effect in the growth of Gp. longissima, being the growth rates improved at high seedling densities. Values of tissue N were generally lower than critical quotas, suggesting that maximum growth was limited by the concentrations of dissolved nutrients. In addition, the high salinity and temperatures in late spring seemed to condition the values of net growth rate. The study suggested that macroalgal cultivation of these two valuable species could be a promising complementary activity in the integrated management of the salina during winter and early spring, when salinity is lower than 40 PSU, if nutrients in the water are increased with the semi-intensive fish cultivation and the hydrodynamic conditions along the rafts are enhanced. Response to Reviewers:Comments for the Author:Reviewer #1: Authors have improved the manuscript accordingly but I still have some comments before the manuscript can be recommended for acceptance.

Culture of Gracilaria gracilis and Chondracanthus teedei from Vegetative Fragments in the Field and Carpospores in Laboratory

“…This salina is currently used for salt exploitation and extensive fish farming (e.g., seabream and European eel). The channel system included an open lock-gate to regulate the water level and to enable the free exchange of water between ponds, which allowed high hydrodynamics in the tidal channel [29]. The bottom of the culture site is rocky in nature.…”

“…The bottom of the culture site is rocky in nature. The mean environmental variables of the site ranged between 14.2 and 24.6 • C (water temperature) and 37.5 and 44‰ (salinity) [29,42]. The tidal range was approximately 1 m [42].…”

“…For this reason, it is necessary to seek out the periods when the populations are fertile in the natural environment [64]. At the collection sites, a particular occurrence is that the biomass decreases from early summer to late autumn (June-December) and increases in early winter until late spring (December-June) [29]. Our observations are consistent with the studies carried out in the Bay of Cadiz, with the collection periods favourable for spore growth in the laboratory being late March for Gracilaria gracilis and May for Chondracanthus teedei, just when the biomass in the field is increasing.…”

“…It is only in the last 15 years that initiatives have been developed to promote macroalgae cultivation in the region [28]. There are studies based on rope cultures and the effect of environmental variables that show that it is possible to cultivate red seaweeds in the Bay [29][30][31]. However, there is a great lack of knowledge about reproduction through spores or sporocultures, and therefore we studied the spore germination process produced by Gracilaria gracilis and Chondracanthus teedei under particular environmental conditions of temperature, salinity, irradiance and light:dark cycle in addition to several culture medium: Provasoli enriched seawater medium (ES medium), Miquel A + B, and f/2.…”

Chondracanthus teedei var. lusitanicus: The Nutraceutical Potential of an Unexploited Marine Resource

“…One of the lesser known seaweeds, Chondracanthus teedei , has already proved to be a viable food source, and a well-adapted species that can be produced through aquaculture [ 20 , 21 ], showing that may be grown with consistency in terms of nutrients, assuring as a safe food product and, decreasing the risk of dangerous compounds ingestion [ 1 , 2 ].…”