Weresharks cannot breathe water.

[The Sideromancer]

A lycanthrope (or entothrope) are type Humanoid (shapechanger). This is unmodified by what the base animal/vermin is. Because several creatures have the ability to breathe water through the (aquatic) subtype, lycan/entothropes of those creatures cannot breathe water even in animal/vermin form (unless either part grants the amphibious SQ).

Since we probably won't get an errata on this with PF1 support being discontinued and all, what is the best way to resolve this?

1. Amphibious SQ is granted when mixing air- and water-breathers (allowing access in all forms)
2. Amphibious is granted to they hybrid while the other two use their base method of breathing
3. Hybrid defaults to the humanoid's method of breathing while the other two forms use their base.
4. Hybrid defaults to the animal/vermin's method of breathing while the other two use their base.
5. Aquatic subtype is retained, forcing all forms to breathe water
6. status quo, forcing all forms to breathe air.

[roguerouge]

It polymorphs into a shark when it needs to breath water.

[avr]

If a polymorph spell grants a swim or burrow speed then the polymorphed creature can breathe when using them. I think this is the point RR is making, and it seems very reasonable to apply it to shapeshifting monsters.

[The Sideromancer]

Ah, it's buried in Change Shape.

[Cavall]

I don't think buried is the word. It's in the place it needs to be when discussing what happens when you change shape.

[The Sideromancer]

It's not in either of the two published statblocks (since the bestaries always use humanoid and hybrid forms), nor is it in the two sections where one standardly looks for breathing (type and SQ). It may not be buried deep, but you do have to move something above it out of the way.