104 REroKT OF COMMISSIONER OF FISH AND FISHERIES. 



attended their tnmsfer to water of ordinary temperature. In faet, 

 tliry were kept for twenty-four liours in a temperature as low as ;J2^F. 

 wit liout injury. The expediency of resorting to thismethod is, however, 

 (HU'stionablr, on account of tlui extra trouble and expense of manipu- 

 lation where the work is carried on upon a large scale. Experience 

 has taught that in nearly all fish-cultural operations it is best to con 

 ilnct them under natuial conditions as far as jtossible. 



The observations nuule by Br. C. F. Hodge, during the summer of 

 1889, respecting tjie feeding of young h)bsters in confinement, while 

 not successful from a practical standpoint, furnished some interesting 

 facts regarding the larval habits of this si)ecies. The stomachs of speci- 

 mens, about one month old, taken at the surface in Woods lloll har- 

 bor, contained fragments of copepods ami of the larval stages of crabs, 

 showing, so far as these examinations go, that their normal food at this 

 age consists of active crustacean forms having the same pelagic habits 

 as themselves. In the aquaria they were supplied with all sorts of 

 food, botli animal and vegetable, wliich it was conjectured might be 

 suited to their tastes and needs, including surface towiugs brought in 

 from the harbor. They did not appear to touch anything of a vegeta- 

 ble nature or any preparations made from flour. They will eat almost 

 any character of animal food if suitably prepared, but while some kinds 

 seem to be beneficial to them, others are more or less harmful, the 

 yolks of hard-boiled eggs and freshly coagulated milk belonging to the 

 former category. When well supplied Avith nutriment they rapidly 

 gorge themselves, and it was found necessary to take much pains in 

 dividing the solid particles, which should be neither too fine nor too 

 coarse, to insure their ])r<)per feeding and prevent their becoming en- 

 tangled in the loose tissues. In none of the trials, however, did more 

 than a small percentage of the larvte survive for any considerable 

 h'ugth of time. Tliey appeared to rest nuiinly upon the bottom of the 

 aquarium at night, but rose toward the surface whenever a light was 

 brought near them. In the daytime, also, they feed chiefly on the bottom, 

 and are apt to spend much of their time there even when not so occupied. 



Dr. Hodge is inclined to believe that the dilliculties in the way of 

 raising ycmng lobsters in the aquaria do not arise entirely from their 

 r<'eding habits, but are due in ])art to otlu^r causes, not at present un- 

 derstood. He experimented upon the eliects of light, of temperature, 

 of the conditions of the water, etc., but without producing any modih- 

 cations in his results. Larvae confined in floating cars off the wharf, 

 moreover, fared no better than those kept in the labiuatory. It has 

 been suggested tliat a )iiLimte, protozoan, which constantly swarmed 

 about tlie living young, and completely infested their dead bodies, may 

 to some extent have been instrumental in their destructhm, a nnitter 

 that could rea<lily be determined by a sterilization of the Avater, but it 

 is improbable that such a widespread mortality could result from such 

 a cause. 



