Both Bestiary 4 and the d20pfsrd say the following about the Seaweed Siren's Water Dependency:
d20pfsrd wrote:
Water Dependency (Ex) A seaweed siren can survive out of the water for 1 hour per point of Constitution (typically 22 rounds). Beyond this limit, a seaweed siren begins to suffocate.
The appendix helpfully disagrees with both:
bestiary 4 wrote:
Water Dependency (Ex) A creature with this special ability can survive out of water for 1 minute per point of Constitution. Beyond this limit, this creature runs the risk of suffocation, as if it were drowning.
but of course that's likely meant as a default: the karkenoid and oceanid (also in Bestiary 4) explicitly list water dependency as 1 hour per point of constitution, while the lorelei says nothing (thus presumably is the default 1 minute per point). Other monsters in other bestiaries have their own rules (1 minute per CON, 1 hour per CON, or a flat 2 hours).
Obviously I can choose any of the three, but I'm curious what the consensus is as to which was meant. I am guessing they meant 1 hour per point of con, since the creature can talk and converse (which it probably does to most victims outside the water) so hours make more sense...
