Improved Palmaria palmata hatchery methods for tetraspore release, even settlement and high seedling survival using strong water agitation and macerated propagules

New hatchery methods for efficient spore use and seedling production of Palmaria palmata (dulse)

“…Twenty-seven days after the initiation of Day 6-9 seeding period, some of the propagules on the bottom were dislodged ( Fig. 4B), suspended in 400 mL enriched (10% F/2) seawater and macerated to break propagule Schmedes et al (2019). The propagules were photographed before and after the maceration treatment ( fig.…”

“…Taking into account these results and observations, it is clear that there is a bottleneck in spore use efficiency within P. palmata hatcheries. This particular matter was addressed in a recent study suggesting a GMA-seeding method (Germination, Maceration, and Agitation method) as an alternative seeding method for P. palmata (Schmedes et al 2019). This study found that germinated propagules (i.e.…”

“…P. palmata can be cultivated in tanks using vegetative growth (Morgan and Simpson 1981;Pang and Lüning 2004;Matos et al 2006;Corey et al 2014), but the prospects of cultivating the species from tetraspores has lately received increasing attention in Europe (Edwards and Dring 2011;Werner and Dring 2011;Sanderson et al 2012). However, despite studies founding the essential understanding of the life cycle (van der Meer and Chen 1979;van der Meer and Todd 1980) and cultivating P. palmata from spores (Browne 2001;Sanderson 2006;Werner and Dring 2011;Grandorf Bak 2019;Schmedes et al 2019), the methodology for large-scale hatchery production in Europe is still in its infancy.…”

“…However, the extensive use of this seeding method is still unknown. Besides the use of this seeding strategy, the use of male gametes of P. palmata to fertilize female gametophytes has been suggested as a potential hatchery step to optimize the hatchery production (Mine and Tatewaki 1994;Le Gall et al 2004;Schmedes et al 2019). When using sori for spore-seeding, a mixture of male and female spores develop after attachment, however, only the males will develop into a harvestable thallus unless a fertilization step, enabling zygote formation in the female gametophyte, is included.…”

“…Because of the continued challenges in producing P. palmata sporophytes and gametophytes, this present study investigated hatchery methods and strategies based on Schmedes et al (2019) to further improve the utilization of spores for cultivation of P. palmata on substrates. Five strategies to improve the hatchery protocol were tested: 1) A vertical seeding tank in flow-through condition agitated with air bubbles to promote dispersal of spores.…”