The Saury Seasonal Mini Event is expected planned to be begin on October 9th, 2015. During the duration of the mini event, you will be able to collect Suary which you'll be able to collect from the regular maps. For information on the update please read the October 9th 2015 update
How to Obtain
During the event, Saury can be obtained, substituting the normal ship drop. They will drop more commonly in comparison of the Hishimochi, but will require you to have an appropriate equipment set up to collect the Saury.
On top of that, most fish will only be
Fishing Zones in the following maps
Saury will drop in various fishing zone locations, some will drop within fishing zones of EO of the Naval Base Waters and the Northern Waters which will grant a high chance of gaining saury while other locations outside of EO will grant a chance to gain Saury when the new BGM cues.
1-1
1-5
Exchange
Saury Quests
Isokaze Drop Locations
Along with the update, Isokaze will become available as a normal drop in the following locations: