The source of the Glaslyn is Llyn Glaslyn, which lies directly under the western slopes of Snowdon. It then flows through Llyn Llydaw down the Gwynant Valley to one of the most beautiful lakes in Wales, Llyn Gwynant.
From there it passes through Llyn Dinas, Beddgelert and Aberglaslyn Pass before reaching the sea at Porthmadog. The river has suffered in the past from acid rain and forestation, but there has been a vast improvement in the last few years in the water quality.
This has resulted in increased fry and smolt activity, which bodes well for the future. The Glaslyn is a short river being some 14 miles long and the Glaslyn Angling Association holds the rights for most of both banks from Porthmadog to Beddgelert. The association holds rights for Dinas Lake and Llyn Gwynant but boat fishing is restricted to local members.
The river is regulated by a system of tidal gates at Porthmadog. These close approximately 2 hours before high water and open approximately 3 hours after high water. These times depend on the river levels and the size of the tides. River flow is affected as far up the river as Llyn y Bont. This section of the river fishes best when the gates are open.
There is rich feeding in the lower section, both for sea trout and mullet, brown trout are also found here. They have a deep yellow colour and are sometimes called yellowbellies. Mullet are present in their hundreds and provide excellent fishing.
There are no obstacles to the fish travelling as far as Nant Dwr Oer even on low water. This is the main night fishing area.
In 2015 there were 27 salmon caught and 623 sea trout of which 22 salmon and 500 sea trout were returned.
In 2014 there were 24 salmon caught and 562 sea trout of which 16 salmon and 454 sea trout were returned.
The river has been in continuous flood throughout most of the winter but fortunately there has now been a respite from the rain and river levels are getting closer to normal. The Glaslyn is known for its early runs of sea trout and spring salmon. In 2014 a total of 40 sea trout were caught in March and 132 in April. Opening day is the 20th of March for fly and spinner with bait angling commencing on the 15th of April. Anglers will have the opportunity, weather permitting, to catch early running sea trout on the lower reaches near the Cob and the railway bridge before the clocks are turned to summer time!
Please be aware that there may be numerous kelts still in the river and if any are caught they must be carefully returned unharmed.
If you are hardy enough to brave the weather I'm sure I will see you on the river on opening day.
Early reports confirm that at least 25 sea trout have been caught this opening month with a fine three and a half pound bar of silver falling to a spinner. April is usually a productive month with good runs of early sea trout. Day time fly fishing can be very productive when the flood gates are open in Porthmadog providing a good flow to work the fly.