144 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



is greatly reduced by local conditions. Even when other conditions 

 are satisfactory, if neither high nor low water occurs about sunset but 

 few ripe fish are caught. The large seines land toward the last of the 

 ebb tide, and gill net fishermen can do nothing except on the change of 

 the tide — on slack water. The fish spawn at a certain time of day, 

 and when taken at other hours are not in spawning condition. Thun- 

 derstorms sometimes occur for days in succession about sunset, the 

 very hour when most disastrous. 



A scarcity of male fish toward the end of the season often cuts short 

 operations when eggs are plentiful. Unsuccessful attempts have 

 been made to capture the males at such times by using gill nets with 

 meshes smaller than those in the nets of market fishermen. Attempts 

 have been made to pen the adults, but without success, as the fish 

 become diseased and their eggs spoil within them. In gill nets the 

 adult is entangled in the mesh and can not escape by struggling, and 

 it therefore remains comparatively quiet. 



The quality of shad eggs is generally impaired where the fish are 

 held for an hour or more in trap nets or seines. The eggs from fish 

 taken in large seines are usually of bad quality, but those from short 

 seines, which are landed quickly after the fish have been surrounded, 

 are usually good; and those from trap nets, in which the fish have been 

 held for some hours, are valueless. Eggs are rarely susceptible to fer- 

 tilization longer than 20 minutes after the fish are taken from the water, 

 though there are exceptions to this rule. On May 23, 1895, Potomac 

 shad were stripped which had been out of the water about 1^ hours; 

 they were kept separate, and at the end of 48 hours produced 100,000 

 eggs, which yielded 98,000 fry. 



The shad dies very quickly after capture and is immediately respon- 

 sive to electrical storms, the catch of seines and nets of all kinds falling 

 off promptly when a thunderstorm develops. Even in seines already 

 laid out in the water, with lead line on the bottom, there is an appre- 

 ciable decrease in such event. On the Delaware Eiver, May 29, 1887, 

 nearly 50 per cent of the shad eggs on board the steamer Fish Hawli 

 perished during an electrical storm which continued from 6 p. m. to 

 midnight. There were 4,481,000 eggs with embryos well formed, and 

 without perceptible change in water temperature 1,918,000 were killed, 

 many turning white by 8 p. m. 



Heavy freshets cause an abrupt suspension of fishing, but the effect 

 of a single freshet is usually temporary. The shad which have gone 

 above are backed down before the muddy water, but reappear upon its 

 outward i)assage. An occurrence of this kind will effect a great 

 increase in egg receipts if the water temperature before muddy water 

 comes is suitable. The shad that were scattered above being thrown 

 back in a body, reascend in a body. 



A season of clear water is undesirable both for fishermen and hatching 

 work, as the fish see the nets and avoid them, gill nets being put out 

 only on the night tide and half the fishing being thus lost. The water 



