Here's a reply I got straight from the head DEC office in Albany:
Dejon,
According to New York State Freshwater Fishing Regulations "A person may not fish for a species (not even catch and release) during the closed season for that species on a given water." This regulation can be found on page 17 of the current Regulations Guide. Therefore, you would not be able to fish for trout on the East Branch of the Delaware (from Pepacton Reservoir highwater mark upstream) outside of April 1 - September 30. For the special regulation concerning the Pepacton Dam downstream to Shinhopple Bridge where "angling is prohibited from Oct. 16-March 21 to protect spawning trout," this is for ALL angling. You cannot fish in that section for any species during that time. Angling is still permitted from the Pepacton Reservoir highwater mark upstream outside of April 1-September 30, just NOT for trout. You can fish for any species, but you cannot target trout.
If you're interested in fishing for trout in the area, you can try the following waters:
E. Br. Delaware- Shinhopple Bridge downstream to the mouth at Hancock CATCH AND RELEASE ONLY Oct. 16- Nov. 30
There is also a CATCH AND RELEASE ONLY year-round season for the Beaver Kill 1) from Sullivan Co. line (below Roscoe) downstream 2.5 miles to the old railroad trestle and 2) from one mile upstream to 1.6 miles downstream of iron bridge at Horton.
As a side note, please keep in mind, an open season for trout is not considered a "harvest" season. It's simply an open season, where fish may or may not be harvested.