Thanks to everyone for your feedback!
@machinic Hah, we have similar names! I custom programmed my own flocking but it's probably pretty similar to boids. Each critter tries to move towards the closest other critter but also towards the mouse pointer. Also there's a very primitive scatter that happens when you click the screen. The radius of it increases when you have more critters.
@tete Wow, I wasn't sure if it was possible to get over 30. 31 is impressive!
@someone It's possible to avoid the whale consistently up to around 21 but you have to move orthogonal to it at just the right time. The scatter helps and it scatters more the larger your flock is. If it's large enough, you can scatter right before the whale arrives and then regroup behind it. But it's pretty tricky to get that timing right.