First record of potential epiphyte grazing species in commercial seaweeds (Kappaphycus spp.), Philippines

Abstract

Commercial seaweeds (Kappaphycus spp.) being widely cultivated at sea face inevitable challenges such as ice-ice disease and epiphyte infestations. Hence, this research provided the first record of potential epiphyte grazing species associated with cultivated seaweeds. A total of 26 seaweed farms were surveyed for 7 months, from April to October 2022, to record the occurrence and abundance of blenny fish. Results from the visual census survey showed a total of 984 sightings of blenny fish (Petroscirtes spp.). The highest occurrence of blennies was recorded in planted seaweeds (81.4%), followed by ropes (12.3%) and floats/buoys (6.3%). Blennies are found to spend the majority of their time resting, swimming, and grazing on the algal epiphytes that are attached to seaweeds. These tiny fish, which are associated with cultivated seaweeds but are overlooked in seaweed farms, are critically important and can contribute little pressure to controlling epiphytes.