If its grey with no spots its a School Shark (Tope).
If its brown with lots of spots, no spike and a pad instead of teeth its a Rig (Lemon, Smoothhound)
If it has a few spots and spikes with teeth its a dogfish.
Whitebait Season starts 1 September 2026 and ends 30 October (inclusive). Chatham Islands: 1 December to the last day of February (inclusive)