The River Tamar rises near the north coast, and for most of its course forms the boundary between Devon and Cornwall. It is always a lowland stream flowing through farmland and this fact is reflected in the size of its Trout which have a larger average size than those in the acid moorland streams. Around Launceston, the Tamar is joined by six tributaries - Ottery, Kensey, Carey, Wolf, Thrushel and Lyd - which offer good Trout fishing, as does the Inny which enters a few miles downstream. There is a good run of Salmon and Sea Trout, the latter being particularly numerous on the Lyd. There are also Grayling in places.