Oct. 4, 1883] 



NA TURE 



543 



are entirely satisfactory, but two of them are used with 

 moderate results. The first is a rectangular wooden box 

 with a wire-cloth bottom, and lateral openings even with 

 the water-line covered with the same material. Around 

 the outside of the box, just below the openings, is a strip 

 of wood four inches wide which rests upon the surface of 

 the water and serves as a float to keep it in position. 

 This float forms an inclined plane leading to the lateral 

 openings, and the waves striking against it run up the 

 slight incline passing through the wire covering into the 

 interior of the box, thus giving a constant circulation 

 from above, the surplus water passing out through the 

 bottom. The other form consists of an ordinary hatching 

 trough divided into compartments by means of transverse 

 partitions. The trough is placed at a slight incline, and 

 the water passes from one compartment to another 

 through a shallow tin spout placed in a notch at the top 

 centre of the partition. In these compartments are smaller 

 wooden boxes with wire-cloth bottoms. These are so 

 placed in the compartments that their forward ends shall 

 rest under the spouts that conduct the waste water from 

 the compartment above, the free ends being thrown slightly 

 upward by their own buoyancy. With a box thus placed 

 in a compartment filled with water, the stream that is 

 kept constantly running falls into its deepest part, creating 

 a circular current, the waste water passing out through the 

 bottom and up around the sides on its way to the next 

 compartment, the wire-cloth preventing the escape of 

 the eggs. 



Much of the apparatus for adhesive eggs, like those of 

 the herring {Clupeu harengus), is very primitive, consist- 

 ing simply of boxes lined with pine and spruce boughs 

 or twigs, in which the parent fish are kept during the 

 spawning period, the eggs adhering to the pine boughs. 

 In some, the pine boughs are fastened to movable frames 

 to admit of their transportation to other waters, but in 

 most they are stationary, the fry being intended for the 

 waters in which they are hatched. A decided improve- 

 ment on the abov-e are the more modern forms intended 

 for artificially impregnated eggs. Unquestionably the 

 best apparatus exhibited is a wooden trough with plates 

 of glass placed at right angles to its length, invented by 

 Frank N. Clark, of Northville, Michigan. The eggs arc- 

 taken and impregnated upon these glass plates, and at 

 once spread evenly over the surface by means of a 

 feather. They soon adhere to the plates, which are 

 then placed in grooves which have been cut into the side 

 of the trough, three-fourths of an inch from each other. 

 The grooves are so cut that every alternate glass shall 

 rest on the bottom of the trough, with the others half an 

 inch above, so that the water shall pass over the top of 

 the first, beneath the lower ed^e of the second, over the 

 third, &c, on its way through the trough, thus supplying 

 a constant current to the eggs. Other apparatus made ot 

 muslin is exhibited, but this, for several reasons, chief 

 among which is the tendency of the cloth to retain any 

 sedimentary matter that may be in the water, is less 

 effective. 



Formerly the material of which hatching apparatus was 

 composed was a matter of much importance to the rish- 

 culturist ; but the introduction of asphalt varnish has 

 rendered the choice of materials a secondary considera- 

 tion : the fish-culturist has now to consider the adapta- 

 bility and cost of materials only, for almost any substance, 

 whether metal or wood, if properly coated with asphalt, 

 can be successfully employed. 



Illustrations of recent methods of securing and re- 

 taining the adult fish until the eggs have been secured, 

 are exhibited. At one of the hatching stations in Canada 

 the fish taken along the shores are transported to saltwater 

 ponds, where they are kept until the eggs and milt have 

 fully developed. A decided advantage is claimed in salt over 

 fresh water, as in it there is a much smaller percentage of 

 loss among the fish, the presence of fungus {Saprolegnia 



fsrax), that dreaded foe of all fish-cultural operations, 

 being entirely unknown. In the McCloud River, C .li- 

 fornia, a dam is placed across the stream directly opj>o site 

 the hatchery, and the fish, finding further progress impos- 

 sible, drop back into the deeper portions of the channel, 

 a few rods below, where they can be easily caught by the 

 aid of a haul-seine. In Grand Lake Stream, Maine, nets 

 are stretched across the mouth of the river to direct the 

 fish into basins of netting, where they are retained till the 

 spawning season arrives. 



In localities where the supply of eggs is obtained from 

 the ripe fish taken in the nets of the fishermen, the United 

 States Fish Commission some time since introduced 

 steam launches for visiting the fishing grounds and distri- 

 buting the spawn-takers among the more important fishing 

 stations, and again bringing them with their take of eggs 

 to the hatchery. This plan worked well, and enabled the 

 Commission to obtain a much larger number of eggs than 

 formerly, with little or no increase in expense. In 1882 

 the plan of stationing professional spawn-takers at the 

 larger fishing shores, to remain during the height of the 

 spawning season, was adopted. These are expected to 

 examine every fish landed, and to secure all ripe 1 

 which, after impregnation, are placed upon wire trays 

 covered with damp cloths, and set in a cool place to await 

 the arrival of the steam launch, which usually makes daily 

 trips to collect the eggs and carry them to the hatchery. 

 In the absence of the launch the eggs are often shipped 

 by the ordinary river steamers. 



The improvements in hatching apparatus, with a view 

 to economy of space were important steps in the pro- 

 gress of fish culture, as the introduction of new forms 

 greatly increased the capacity of the hatcheries in which 

 such apparatus was employed. But even with these im- 

 provements fish-culturists have often found it difficult to 

 handle as many eggs as they desired, owing to the limited 

 duration of the spawning period. Their hatcheries were 

 crowded for a short time, and the simultaneous hatching 

 of the eggs required a large force of messengers to dis- 

 tribute the fry. As the spawning season had usually 

 passed by the time the first fish were hatched, no more 

 eggs could be secured, and the hatchery had to be 

 closed till the following year. This difficulty is now prac- 

 tically overcome in several ways. It is found by Sir James 

 Maitland that the spawning season for fish kept in arti- 

 ficial ponds is considerably affected by food. An abun- 

 dance of hearty food at the time when the ovaries are 

 beginning to enlarge hastens their development, while a 

 scanty supply of coarse food considerably retards their 

 growth. By judicious feeding one can arrange to have 

 the fish of different ponds spawn at different da! 

 that two crops instead of one can be produced at his 

 hatchery. Refrigerators are now successfully employed 

 in cases of wild fish, when the spawning time cannot be 

 controlled by food. The surplus eggs, after the hatchery 

 has been filled, are placed on cloth trays and corded up 

 in the refrigerator until such time as there is room for 

 them in the hatchery. They should be examined at in- 

 tervals, and if in poor condition should be washed in ice 

 water and again returned to the trays. Trout ova three, 

 five, and seven months old respectively were exhibited in 

 the German department, the eggs being apparently in 

 excellent condition. The use of refrigerators, however, 

 is at present limited to winter-spawning fishes. With 

 summer-spaw ners it has thus far resulted disastrously. 



Those interested in the acclimatisation of fishes have 

 much to stimulate and encourage them. From all quar- 

 ters come encouraging reports of the successful introduc- 

 tion of fishes into new waters. The shad of the Atlantic 

 coast of America (Alosa sapidissima) is now taken in 

 such quantities in the rivers of California as to claim a 

 place among the food fishes' of the Pacific. The Califor- 

 nia trout (Salmo iruieus) is now grown in the waters of 

 Australia, Japan, and Germany : with the fish-culturists 



