The Seafood Industry Council says the entire fishing industry has a responsibility to take more care with its methods.
The Ministry of Agriculture and Forestry is appealing for information from the public after two Hector's dolphins were found washed up on a North Canterbury beach in an illegal set net earlier this week.
Set nets are banned under the Fisheries Act along the entire east coast of the South Island to protect the endangered dolphins.
MAF is investigating, but says evidence points towards the net being for recreational use rather than a commercial net. It wants to hear about anyone using set nets around the Waimakariri River mouth.
Seafood Industry Council chief executive Peter Bodeker says recreational fishermen must also be held to account.
"There's been a significant set net ban ... from Banks Peninsula right up to Kaikoura which has impacted on the commercial fishing activity.
"We accepted that, because it was to protect these dolphins and other marine mammals, and now we see a situation where it looks as though it was a recreational net that's caused the death of two of these animals.
Mr Bodeker says the council supports MAF's investigation.