Invasive potential of Kappaphycus alvarezii off the south coast of Rio de Janeiro state, Brazil: a contribution to environmentally secure cultivation in the tropics

Abstract

The carragenophyte Kappaphycus alvarezii has been introduced into tropical regions, including Brazil, for aquaculture purposes. Our study estimated the biomass loss of farmed cuttings, the establishment of cuttings outside the rafts, the occurrence of spores, and evaluated the invasive potential of K. alvarezii at three sites in Rio de Janeiro state. Temperature, salinity, water transparency, wind velocity and direction (hydrodynamic indicator) and solar radiation (irradiance availability indicator) varied spatially. We found no spores in cultivated cuttings and no verified spore recruitment on artificial substrata. Biomass loss of cuttings varied temporally; however, it was restricted to the cultivation management area of one site and was low compared to native algal biomass. The establishment of cuttings was apparently limited by herbivory at Ilha Grande Bay and controlled by water transparency, hydrodynamics and temperature at Sepetiba Bay. The invasive potential of K. alvarezii was considered remote. However, the use of environmental protocols for cultivation activities is necessary to prevent environmental impacts, mainly in tropical regions.

Molecular identification of the exotic lineage of <i>Kappaphycus alvarezii</i> (Rhodophyta, Solieriaceae) cultivated in the tropical region of Brazil

“…Previous studies demonstrated that K. alvarezii has remote invasion potential in southern and southeastern Brazil (Paula et al 1999, Bulboa & Paula 2005, Bulboa et al 2008, Castelar et al 2009, Hayashi et al 2011. Reproductive structures in cultivated K. alvarezii are rare (Doty 1985, Areces 1995, Castelar et al 2009Hayashi et al 2011), and even the spores produced in the laboratory are not all viable (Bulboa et al 2008).…”

“…All programs involved in the evaluation of the economic feasibility and the environmental risks of introducing K. alvarezii for the mariculture were authorized by the Governmental Agency Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (IBAMA) (Paula et al 1999). Experimental studies have focused on the introduction of the species and the resulting environmental risks in southeast and south Brazil (Paula et al 1999, Bulboa & Paula 2005, Bulboa et al 2008, Castelar et al 2009, Góes & Reis 2011, 2012, Hayashi et al 2011. Thus, following 18 years of research, the results showed favorable characteristics for commercial cultivation such as productivity and remote potential invasion (Paula et al 1999, Bulboa & Paula 2005, Bulboa et al 2008, Hayashi et al 2007a, b, 2010, Castelar et al 2009, Góes & Reis 2011, 2012.…”

“…Based on these results, the cultivation of K. alvarezii in limited area of southeast Brazil was authorized by IBAMA through the Normative Instruction 185/2008. Currently, commercial scale production of K. alvarezii occurs only along the coast of Rio de Janeiro, a subtropical region of Brazil (Castelar et al 2009, Góes & Reis 2011, 2012.…”

Cultivation of the red algae Kappaphycus alvarezii in Brazil and its pharmacological potential

“…Lamouroux had been depleted and the country was dependent on imported raw materials. Commercial farming began in 1998 at Ilha Grande Bay and in 2003 at Sepetiba Bay, both located on the south coast of Rio de Janeiro State (Castelar et al, 2009). Subsidized the Brazilian Government, in vitro and in situ experiments were performed to understand the invasive potential of Article K. alvarezii introduced into Brazilian waters and to define the commercial areas as an aid to promoting a responsible introduction.…”

“…Attempts should also be made to improve cultivation technologies for native algae, stimulating their aquaculture, especially in sites where exotic algae can be invasive, such as in the northeastern region of Brazil where there are 3,000 km of reefs in one of the priority areas for worldwide conservation (Castelar et al, 2009). Promising surveys are being carried out with algal species that are cultivated in other countries and, in Brazil, on a small scale, such as Gracilaria spp.…”