"Israeli naval vessels besieged a fishing boat off the coast of the southern Gaza Strip's city of Rafah, hitting it with machinegun fire before detaining the three fishermen who were on board," union head Nizar Ayyash told The Anadolu Agency on Wednesday.
The Israeli army has not issued an official comment on the three fishermen's detention or stated its reasons for holding them.
In early December, the Israeli navy detained 12 Palestinian fishermen off the Gaza coast after besieging their boats, according to union officials.
The Israeli navy routinely shoots at Palestinian fishing boats on the pretext that they have gone beyond the allowed fishing area, Ayyash said, noting that Israeli attacks usually target the livelihoods of Palestinian fishermen.
In late August, Israel allowed Palestinian fishermen to ply their trade up to six nautical miles off the Gaza coast, as opposed to three miles previously.
A cease-fire reached between Israel and Palestinian factions on August 26 ended 51 days of relentless Israeli attacks on the Gaza Strip, in which over 2,160 Palestinians were killed.
According to Ayyash, some 50,000 Gazans earn their living from fishing. He estimated their combined losses during Israel's recent war on the enclave at more than $6 million.
Ever since Palestinian faction Hamas won 2006 legislative polls, Israel has imposed a tight land and sea blockade on the Gaza Strip.