Effect of low salinity on survival and ingested food of the common octopus, Octopus vulgaris Cuvier, 1797

Abstract

ABSTRACTThis study analyzes the effect of low salinity on survival and daily food ingestion of octopus subjected to three different water salinities (20, 25, and 30 psu) for 3 days. During the 3-day experiment, octopuses at 20 psu immediately stopped eating, and all died during the first day; at 25 and 30 psu, the octopuses gradually reduced their feed intake and stopped eating after 2 days, but all survived, and when normal salinity conditions were reestablished (34–35 psu), they ingested 30–40 (~27.5% of the initial food intake) and 70–90 g of food/day (~63% of the initial food intake) respectively over the 5-day recovery period. Water salinity of 30 psu could be considered as the recommended lower limit below which actions, such as transferring the commercial floating cages to another location or submerging them, should be taken in order to prevent the negative effects of low salinities on farmed octopuses.