The Inland Fisheries Service said the charges against Barry John McDermott related to 7.86 kilograms of whitebait fisheries officers seized from a home in Devonport in November 2019 while executing a search warrant.

He appeared in the Devonport Magistrates Court on May 14 and was convicted, fined $1344 and ordered to pay $85.86 in court costs.

Inland Fisheries said illegal fishing was an ongoing problem for the whitebait fishery.

"Every year, IFS officers actively target poachers to ensure the long-term viability of the recreational whitebait fishery," it said.

"We strongly urge anyone that suspects illegal activity at our inland waters to report it to us (on 0438338530 or 1300463474 or at infish@ifs.tas.gov.au).

According to the IFS 2019-20 annual report:

That was in a year when angler activity dropped significantly between March and early June due to coronavirus restrictions.

"As a result, angler checks and offences detected were reduced from previous years," Inland Fisheries said.

There were 2417 angling licences and 157 whitebait licences inspected during the year.

Meanwhile, the IFS was pleased by results from its most recent monitoring of native fish - spotted galaxias, Shannon paragalaxias and Great Lake paragalaxias - in Penstock Lagoon and Shannon Lagoon.

"This year we caught a very large number of both the spotted galaxias and, more pleasingly, the threatened Shannon paragalaxias," it said.

"This is the highest numbers of this species that have been found ... for many years.

"The third species, the Great Lake paragalaxias, which is much harder to find and occurs only in low numbers in these lagoons, was found within both lagoons.

"This is a great outcome and indicates the overall health of these waters is good."