The future of whitebait populations in the Hawke's Bay lies in the hands of local whitebaiters, says the Department of Conservation (DOC).
The 2016 season begins this Monday.
DOC compliance officer Rod Hansen said whitebait season dates and fishing hours were set to give whitebait the opportunity to return to their spawning grounds.
Mr Hansen said when people did not follow those regulations, it harmed whitebait populations to a point where they might not recover.
"Unfortunately four of the five species are categorised as either threatened or at risk due to declining numbers and habitat. Fishers are encouraged to only take what they need and to think about the sustainability of the fishery for future generations.
"It's good to see more conservation measures such as planting and fencing off spawning grounds and adult habitat. We urge people to contact their local DOC or Regional Council office if they see overhanging culverts or other barriers that stop whitebait migrating."
DOC administers regulations that cover fishing methods, location, legal fishing times and net size. Illegal whitebaiting carries a maximum fine of $5000 and whitebaiting equipment can be seized.
Whitebaiting is permitted between 5am and 8pm or between 6am and 9pm when daylight saving starts on 28 September.