 This means that they adapt to match the osmotic pressure of their environment, and because there is no osmotic gradient, there is no net movement of water from the organism to the seawater, or from the seawater into the organism.Octopuses have an average minimum salinity requirement of 27g/l, and that any disturbance introducing significant amounts of fresh water into their environment can prove fatal.In terms of ions, however, a discrepancy does seem to occur between ionic concentrations found in the seawater and those found within cephalopods.