I was part of a five-person party who fished the Beach River system on Montague Island in Prince William Sound during the last week in Aug. starting Aug. 20th, 2008. In summary this system showed some potential as a silver salmon fishery, but it did not end up being the coho homerun that some books have touted it to be. I personally caught 15 silvers and about 10 bright chums in 7 days of fishing. I also lost about 10 or so silvers/chum during this time. However, I fished long and hard so these catch rates were not particularly impressive.
Nearly all of the silvers caught by our group we taken from within ½ mile of the high tide mark, and because only a modest number of fresh silvers came into this river each day, those silvers holding in the lower reaches of this system tended to become "jaded" after a few days of having every fly in the book thrown at them. Although it is difficult to say for sure, the river was shallow and usually clear and we estimated about 10-20 new silvers entered the river each day. These fresh fish were either caught, hooked and lost, or put down by repeated attempts to catch them. It did seem as if more fresh silvers were showing towards the end of our week there, but there was no breakout day when a big pulse of new fish moved into the system. However, the fish we caught were often quite large (i.e. up to 15 lbs) and usually male, which may have indicated the run was just starting to heat up. So maybe if we had visited this system two weeks latter we would have caught quite a few more silvers.
On the other hand, there were clear indications this river system might blow out easily with even moderate rains for this region. In most of the lower ≈ 4 miles of this river the channel was down-cut by 20 ft. The channel was also quite wide (i.e. about ½ mile) for the flows we observed while there. There were also large peat deposits in the river channel, which indicated recent erosion. On the days when it rained 1-2 inches, the turbidity in the river increased rapidly. So arriving several weeks latter could have meant there might have been far more silvers in the system, but it could also have meant the river might have been too high and turbid to fish effectively. During the week we were there, the river was easily wadeable in most places, but it is easy to imagine this would not be the case if the river received much more than 2-3 inches of rain in a day. If this system came up more than 1 ft, it would restrict access to some of the holes the silvers were holding in. Overall, this river looked a lot like the lower reaches of the Mad River in Arcata California.
During the time we were there, the river 1-4 miles upstream of the mouth had outstanding fishing for dolly varden in the 16-20 inch range. Most likely looking holding water contained a dolly or two, but some pools had large aggregations and it was possible to catch 10-30 fish before putting the school down. These fish were fat and quite sporty. However, if the flows came up by a foot, these upper pools would be hard to reach and probably too turbid to fish. Besides dollies and silvers, we caught a smattering of bright chum, and quite a few pinks many of which were also quite bright. We saw a handful of sockeye that were beginning to show color. Overall, this river did not seem like it would hold up to heavy fishing pressure. Fortunately, it appears to get very little pressure. Nobody had been to the cabin in at least 6 months.
The river itself was quite scenic especially a few miles up from the mouth. The uplands immediately adjacent to the channel was also quite pretty (when not clear-cut). The channel was highly braided in the upper reaches and contained lots of large woody debris and large-sized peat deposits, but was generally very wide and flat and easily traversed. We had a spirited discussion within our group about whether the channel down-cutting was most related to the clear cuts that we quite evident in the watershed or due to tectonic uplift that occurred in this area during the 1964 earthquake. This region of Montague Island has been estimated to have uplifted by 30 ft during that event. Because of this down-cutting, the lower river was moderately high gradient by Alaska silver salmon river standards, but compared small coastal rivers in the PNW it was fairly typical.
Access to this river and cabin is greatly complicated by the fact that bush planes have to land on the beach during particularly low tides. This means periods of a week or so regularly occur when it is difficult to get on or off the island. This has a major impact on trip planning logistics. We purposely planned our trip so that we had several shots into Montague at the beginning and a series of favorable tides at the end. Because this was the most favorable tidal window, we also took this trip a week earlier than we would have preferred. There was a private landing strip near the cabin, but our bush pilots told us it was currently overgrown and unusable.
The cabin itself was well built, sufficiently spacious for a party of five, and in good condition. The wood stove worked great. We did not use the oil stove, but it appeared to be in good condition. The cabin was a ½ mile hike to the river, which could be reached via the beach or a trail through thick woods. When we arrived, the cabin was very littered with old food, equipment, dirty clothes, abandoned sleeping bags, etc. The immediate area around the cabin was totally overgrown with salmonberry bushes. The outhouse was in a bad state and was in imminent risk of overflowing with deposits of a "sedimentary nature". We hypothesized the smell from the current and former outhouses was an effective bear repellent.
Numerous reports in the cabin logbook indicated the clear cuts around the cabin were excellent places to hunt deer in Nov. and Dec. These reports were consistent with a success rate of one deer person per day. Apparently, bears availed themselves of many of these deer. Due to the tidal issues mentioned above, it is not clear how the deer hunters managed to get on and off the island in late fall. Some parties mentioned been stranded at the cabin for up to 8 days. We saw lots of bear-sign and a few of the real deal. Five or so seals patrolled the river mouth daily. We tried digging for razor clams at low tide with no success. One member of our group found 2 glass fishing floats, everybody else looked and struck-out.