The gracilarioids in South Africa: long-term monitoring of a declining resource

Rothman, Mark D.; Anderson, R. J.; Boothroyd, C. J. T.; Kemp, F. A.; Bolton, John J.

doi:10.1007/s10811-008-9364-y

Cited by 11 publications

(5 citation statements)

References 25 publications

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“…longissima (Steentoft et al, 1995). These species have been used equally as a source of agar in South Africa (Wakibia et al, 2001;Rothman et al, 2009), and probably in India and China, where the synonym G. verrucosa is still used (Huo et al, 2011;Padhi et al, 2011). The species have also been proposed as a potential source of bioetanol and other compounds of interest for pharmaceutical and biotechnological applications (Stabili et al, 2012;Shukla et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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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.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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“…Recently, other uses have been suggested, such as abalone feed (Rothman et al 2009). As a consequence of its economic importance, the genus has been the subject of many studies worldwide (Oliveira and Plastino 1994).…”

Section: Introductionmentioning

confidence: 99%

Color inheritance and pigment characterization of red (wild-type), greenish-brown, and green strains of Gracilaria birdiae (Gracilariales, Rhodophyta)

Costa

Plastino

2011

J Appl Phycol

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Species of Gracilaria are some of the most useful algae in the world for the production of agar. As a consequence of its economic importance, the genus has been the subject of many studies worldwide. Color variants of Gracilaria birdiae have been found in the natural population on the Brazilian coast, and they have also been isolated from plants cultivated in laboratory. These findings raised new questions regarding intraspecific variation and the prospects of cultivating such variants for their agar production. Therefore, this work aimed to determine the mode of color inheritance for two G. birdiae strains: a greenish-brown strain (gb) found in a natural population and a green strain (gr) which had arisen as a spontaneous mutation in a red plant cultured in the laboratory. The pigment contents of these strains, as well as the red wildtype (rd), were also characterized. Crosses between female and male plants of the same color (rd, gr, or gb) and between different colors were performed. Crosses between plants of the same color showed tetrasporophytic and gametophytic descendents of the parental color. Recessive nuclear inheritance was found in the greenish-brown strain, and cytoplasmic maternal inheritance was found in the green strain; both had lower phycoerythrin and higher concentrations of allophycocyanin and phycocyanin than the wild-type. Chlorophyll a contents were similar among all strains. Taken together, our results contribute to knowledge about the variability of this important red algae. In addition, since greenish-brown and green strains showed stability of color, both could be selected and tested in experimental sea cultivation to evaluate if mutants have advantageous performance when compared with red strain.

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“…is annually cleared from a single beach in west Cork and disposed of (Tabassum et al, 2017;Wan et al, 2017), while in Namibia 15 000 wt of Gracilaria were regularly washed ashore at Lüderitz (Critchley et al, 1993); South Africa has built its seaweed industry on the beach collection of both Gracilaria and kelps (Amosu et al, 2013). Beach wash-ups of Gracilaria in southern Africa, as a whole, have declined considerably and the industry was significantly reduced as of 2017 (Rothman et al, 2009;H. Rotmann, personal communication).…”

Section: Wild Harvest Of Seaweedsmentioning

confidence: 99%

Sustainable harvesting of wild seaweed resources

Monagail

Cornish²,

Morrison

et al. 2017

European Journal of Phycology

170

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Macroalgae have played an important role in coastal communities for centuries. In the past, they have been harvested and gathered from shorelines around the world for traditional uses such as food, animal feed and a crude fertilizer (marine manure). Today, seaweeds are used in a multitude of applications with expanding global industries based on hydrocolloids, cosmetics and food supplements, and also as a potential biofuel source. However, of the approximately 10 000 algal species reported to exist, only a small number are commercially utilized. While representing only a small fraction of total global seaweed production, harvesting and gathering 'wild' seaweeds has had, and continues to have, an integral role in many coastal societies, often being intrinsically linked to the cultural identity of those coastal communities. Today, 32 countries actively harvest seaweeds from wild stocks, with over 800 000 t harvested annually from natural beds. It is vitally important that seaweeds are utilized sustainably and that natural resources are effectively managed by coastal communities with vested interests around the world. As the popularity of seaweeds increases and the use of less traditional species with novel applications comes to the fore, it is critically important to make certain that the sustainability of the resource is ensured given the increased pressures of harvesting. Issues exist regarding ownership of the resource and its over-exploitation, and the implementation of environmentally damaging harvesting techniques must be avoided. Resource scientists, managers, conservationists, governments, and other stakeholders need to be proactive in the sustainable management of these vulnerable, yet valuable, resources.

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The gracilarioids in South Africa: long-term monitoring of a declining resource

Cited by 11 publications

References 25 publications

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

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

Color inheritance and pigment characterization of red (wild-type), greenish-brown, and green strains of Gracilaria birdiae (Gracilariales, Rhodophyta)

Sustainable harvesting of wild seaweed resources

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