Natural biocontrol of a Porphyra sp. pest on farmed Gracilaria chilensis by a pythiosis outbreak

Gracilaria chilensis (a.k.a. pelillo) is the most produced seaweed in Chile and Latin America, yet its cultivation has historically faced lots of pest-associated constrains that threat its profitability and sustainability. Pests show temporal cycles of recruitment, growth and death/senescence, variation normally linked with sharp changes in environmental factors occurring in estuarine areas whereby Gracilaria is cultivated. Here we report the appearance of a bladed Bangiales species epiphytic on long-line farmed Gracilaria and identified as Porphyra. This species recruits to cover up to 50–72