228 BULLETIN OF THE BUREAU OF FISHERIES. 
THE METHOD. 
ESSENTIAL FEATURES AND POSSIBLE VARIATIONS. 
A method by which lobsters can be reared through the larval stage in such 
proportions and numbers and at such a cost that it may be called a “‘ practical” 
method has been gradually evolved at the floating laboratory of the Rhode 
Island Commission of Inland Fisheries at Wickford, R. I. (fig. 1, pl. vm). Essen- 
tially, the method consists of confining the larval lobsters in cars, either of porous 
material or provided with screen ‘‘ windows,” set into the ocean itself, and of 
maintaining within the cars, by mechanical means, a continuous gentle current 
of water having a rotary and upward trend. In details the method allows of 
wide variation. Good results have been obtained in small cars made out of 
water pails; in cars approximately 1 foot, 3 feet, 6 feet, and ro feet in horizontal 
diameter and 1, 3, or 4 feet deep; and in either square or circular cars of cotton 
or linen scrim, of bobbinet, of canvas, or of wood. Any constant motive power 
can be used, according to the exigencies of particular cases—steam, hot-air, or 
gasoline engines; spring, weight, or water motors; or the water can be stirred 
by hand, with much labor but good results, as in our early experience. Various 
forms of power transmission may also, of course, be utilized; belt and rope 
drives over pulleys and sheaves, and steel shafting with mitered gears, worms, 
etc., have all been successfully utilized. 
” 
HOW THE METHOD MEETS THE DIFFICULTIES. 
The way in which this very simple method overcomes the many difficulties 
of confining larval lobsters may be described in general terms as follows: In the 
first place the rearing cars are placed directly in the sea, and thereby all the 
disturbing factors so difficult to control in case of aquarium water which has 
been pumped and forced through closed pipes, stored in tanks, aerated by air 
pumps, etc., are at once avoided, and at the same time the various known and 
the subtle unknown requisites of healthy sea water are assured. The continu- 
ous upward spiral current of the contained water is the panacea of numerous 
troubles. By the upward trend of the current the larve are kept always afloat, 
which is their normal condition and the only one to which they are by structure 
and habit adapted. The strength of the current easily overpowers their own 
weak efforts at swimming, sweeps them round and round, and effectually 
prevents their congregating in common response to the stimuli of light. 
When the fry are prevented from getting to the bottom and from congre- 
gating anywhere, several difficulties vanish. The effects of cannibalism, which 
constitute perhaps the most serious difficulty of all, are thereby greatly alle- 
viated, for the fry are to a comparatively great extent prevented from reach- 
ing one another, and of course the disastrous effects of their becoming stranded 
on the sides or lying entangled and fouled at the bottom are also obviated. 
