EFFECTS OF DYNAMITE EXPLOSIONS ON FISH LIFE 



29 



SESSIONAL. PAPER No. 22a 



To test the accuracy of this story, six lobsters were obtained from a local fisherman. 

 They were secured on the plea that the biologists required them for scientific purposes. 

 The open season was over, and many of the lobster pots were lying high and dry along 

 the shores, but on sailing out to the sand bar, or to Bass rock, it was easy to see that 

 some of the fishermen were using lobster traps for ' scientific ' purposes as well as our- 

 selves. 



The first experiment consisted in putting off a blast of 3 largxi sticks of dynamite 

 at a distance of 80 feet from a trap containing 2 lobsters, and at a distance of 40 feet 

 from a small lobster that was tethered by a piece of twine. The explosion produced 

 no effect whatever upon any of the lobsters. 



In the second experiment 2 large sticks of dynamite were exploded at a distance 

 of 20 feet from the small lobster. The animal was uninjured so far as we could see. 



The third experiment consisted in setting off two sticks of dynamite within 10 

 feet of a medium sized lobster. No result. 



Finally, 3 sticks were exploded 15 feet away from a trap which contained 5 lob- 

 yters. These animals had all been used in the previous experiments. The explosion 

 overturned the trap, nearly overturned one of the piles on which the wharf was built, 

 but it seemed to have no effect upon the lobsters. 



We concluded, therefore, that the 500 lobsters of the sailor's yarn had died — not 

 from the effects of a dynamite explosion, but from suffocation. They had been con- 

 fined in too small a pound for too great a time, and the explosion was co-incident with 

 the fisherman's discovery of their dying condition. 



Further experiments are necessary to determine the effects upon lobsters at con- 

 siderable depths, ours being at 12 to 15 feet. 



ON THE OTTAWA RIVER. 



Experiments on the Ottawa river were conducted at only one point, viz., about 

 half a mile below L'Orignal village wharf. Twenty years ago, this point was con- 

 sidered a fine spot for pickerel, but to our amazement we obtained nothing but bull- 

 heads and suckers. The villagers and inhabitants generally claimed that the govern- 

 ment dam at Carillon prevented the fish from coming up the river as they used to do, 

 and that the better kinds of fish w^ere decreasing in number. 



EFFECTS ON MINUTE LIFE. 



After several explosions in fresh water and one or two at sea, a small tow-net was 

 drawn over the site of the explosions and the material collected was examined under 

 the microscope the next day. Many living organisms such as copepods, phyllopods, 

 &c., were found, and also dead ones, but it was impossible to determine whether the 

 latter were dead when caught, or had died during the night. 



Are fish eggs and larvae killed by dynamite explosions ? Because, if they are, this 

 is one of the strongest objections that can be urged against the practice. Here again 

 surface netting failed to show that the percentage of dead eggs or larvae was increased 

 to any appreciable extent. As is well known pelagic ova and fry both live near the 

 surface of the sea, and it is difiicult to understand how these, or any other tiny organ- 

 isms could be killed by dynamite explosions any more than by the waves of a big 

 storm. Of course, eggs which are laid on the bottom would certainly be destroyed, 

 if they were near the site of any explosion, but further investigation is necessary on 

 these points. 



EFFECTS ON THE NERVOUS SYSTEM.. 



The brains of a dozen fish, half of them killed by dynamite, and half caught by 

 hook and line, were preserved and subsequently examined under the microscope, Leitz 



