70 Tzvciity-src'ciith Annual Meeting 



Prof. Birge : Mr. Clark is anxious to hear the paper by 

 Prof. Bumpus, and if there is no objection I will read it first. 



Consent was given. 



Prof. Birge then read a paper prepared by Dr. H. C. Bumpus, 

 entitled "The Identification of Adult Fish that have been Arti- 

 ficially Hatched," which follows. 



THE IDENTIFICATION OF ADULT FISH THAT HAVE BEEN 

 ARTIFICIALLY HATCHED. 



Although the planting of artificially hatched fish in the in- 

 land waters may, and often does, yield inimediate and undoubted 

 increase, the results of fish culture along the coast are often 

 much less definite, and conclusions are too often based upon the 

 mere opinions of observant, but unscientific, fishermen. The 

 recent excessive abundance of cod along the shores of New 

 England, is probably the result of the extensive operations at 

 the Woods Hole Hatchery. The facts that these fish were small 

 when they first appeared, that they have since increased in size, 

 that thev have occurred in localities where cod had never before 

 been caught, and that they are reported to be of a different 

 color from the native variety, are interesting, although to the 

 skeptical they are not absolutely convincing. There is need of 

 some scheme whereby the adults of fish hatched artificially may 

 be distinguished from those native to the locality. 



To mark the fry is, of course, out of the question ; but is 

 it not possible that the fry mark themselves, i. e., is there not a 

 slight difiference between the fish of the same species, but of 

 different, even though contiguous, localities? And if there is a 

 slight difference, does it not present itself in a measurable man- 

 ner? We all know that the bony rays, which support the dorsal 

 fins, are subject to variation, both in respect to their length and 

 their number. In fishes which have a large nrmiber of fin-rays, 

 the variation is often considerably greater than those possessed 

 of only a few. This variation is above or below a certain aver- 

 age or mean number, and the amplitude of variation (that is, the 

 amount of normal increase or decrease in the number) is definite 

 for any given locality. During the latter part of March of the 

 present year several hundred flatfish were examined at the sta- 

 tion at Woods Hole with the purpose of determining the amount 

 of variation in animals collected at different localities. The dia- 

 gram marked "Woods Hole" is intended to illustrate the varia- 

 tion in the number of dorsal fin-rays presented by one hundred 



