254 SALMONID^ OF BRITAIN". 



HYBRIDS. 



A brief account of hybridism among fishes, more especially as observed in tbe 

 salmon family, has been already given (pp. 46-50 ante), and it has been shown 

 that the existence of hybrids in this country has been recorded for at least the 

 last two centuries. But, nevertheless, various authors now and again, even at the 

 present day, have ignored the labours of their predecessors, and while admitting 

 the existence of these salmonoid hybrids, have boldly asserted that they were their 

 first undoubted discoverers ! Another class has maintained that hybrids are 

 unable to breed (see p. 49), for how else could the commingling of genera and 

 species be obviated ? Again we have an intermediate class, who, admitting the 

 existence and fertility of hybrid races, hold to the opinion that we have yet 

 to learn through how many generations such fertility can extend ; and what will 

 be the effect of interci'ossing these hybrids among themselves, or re-crossing them 

 Avith one of the original parents or any pure breed ? 



To partially solve some, at least, of these interesting questions, Sir James 

 Maitland, F.z.s., at Howietoun, has devoted a very great amount of trouble, and 

 gone to great expense during the last eight years or more, and when carrying out 

 his experiments has given mo the opportunity of being present while the ci'osses 

 were being made, jDormitted me unlimited access to his hatching-houses and fish- 

 ponds, and has supplied me with specimens whenever I have required them. 

 Consequently, unless otherwise expressed, all the following experiments were 

 made at the private fish farm at Howietoun by the owner himself. 



Of course, on obtaining a fish from a stream of certain appearance, it may 

 convey to a competent naturalist the belief that it is undoubtedly a hybrid, but 

 we require conclusive evidence first that such can occur between two distinct 

 species, and secondly proof as to what will be the appearance of these hybrids. 

 Here fish culture gives us undeniable evidence that hybrids can occur, that they 

 are not necessarily sterile, and also what their appearance may be. From these 

 we may decidedly recognize some forms by their colours, as those between trout 

 and American char, one of which I received in 1882 from Sir Pryse Pryse, of 

 Goggerdan, in North Cardiganshire ; whilst we have instances recorded of these 

 two species of fish having been observed forming redds together in this country* 

 when iu a wild condition, and several anglers have informed me that they inter- 

 breed in the Wandle as well as in Cardiganshire and elsewhere. 



If hybrid salmonidce are to be worth cultivating, the first question which arises 

 must be which is the finest breed to employ, and whether the size of the parent 

 has any peculiar modifying influence on that of the offspring ? In the British 

 Museum collection are very fine examples, some termed " Bull-trout," others, 

 " male salmon." I have never observed in rivers yellow bands on the cheeks of 

 any except pure salmon, but they are distinctly visible upon a 43 lb. fish labelled 

 "Bull trout of the Tweed " (Giinther, Brit. Mits. Catal. vi, pp. 25-28), while this 

 specimen has thirteen scales passing downwards and forwards from the adipose 

 dorsal fin to the lateral-line, and only forty-three cascal appendages. In this case 

 the question arises whether it might not probably be a hybrid, and in another fish 



* During Christmas week, 1885, Mr. Thomas Ford observed in a stream at Caistor, in very- 

 shallow and perfectly clear water, a female brook trout which had made a large hole, and a male 

 fontinalis. There were half-a-dozen more common trout in the pool, but the fontinalis drove 

 them all away, although they were the larger fish. "When shooting its eggs the body of the 

 trout was subject to a tremulous motion, whilst its back fin was occasionally out of the water. At 

 times the fontinalis remained almost immovable just above the trout, but now and then it would 

 go completely over and under the female fish. It was quite evident that the female trout 

 preferred the company of the fontinalis to that of its own species. This is the second time that 

 I have observed the crossing of the species in a state of nature." He watched it a quarter of an 

 hour (Field, Jan. 9th, 1886). 



