1861 c. 109 §4 Whether known by the names..salmon..grilse, botcher, blue cock, blue pole.
1880–4 F. Day II. 87 The ‘blue poll’ and ‘blue cock’ of the Fowey in Cornwall,..are sold in Billingsgate as ‘Cornish salmon’.
1885 J. P. Traherne in H. C. Pennell et al. (Badminton Libr. of Sports & Pastimes) I. 185 (note) Up near Builth in December, beautiful fish called Blue Cocks appear.