SODIUM CYANIDE AS A FISH POISON 



INTRODUCTION 



Within the past 20 years the use of fish 

 poisons has gradually become accepted as an 

 important tool in freshwater fishery manage- 

 ment. However, no entirely satisfactory 

 poison is in use today. There is definite need 

 for a fish poison that will facilitate the remov- 

 al and permit the revival of affected fishes. 

 Of the fish poisons presently in use, rotenone 

 is the only one that enjoys widespread accept- 

 ance and popularity. Rotenone does not allow 

 the revival of affected fishes but does possess 

 the desirable properties of being highly toxic 

 to fishes and dissipating within a reasonable 

 length of time. The purpose of this study was 

 to evaluate the use of sodium cyanide as a fish 

 poison, using as criteria all three of the above 

 properties . 



Considerable literature exists dealing 

 with the toxicity of cyanides to fishes (Burdick 

 and Lipschuetz, 1948; Doudoroff, 1956; Down- 

 ing, 1954; Ellis, 1937; Lipschuetz and Cooper, 

 1955; Renn, 1955). In general, these works 

 view cyanides in relation to industrial pollution. 

 No reference was found to sodium cyanide or 

 other cyanide compounds for use in fishery 

 management. 



MATERIALS AND METHODS FOR 

 LABORATORY EXPERIMENTS 



Three series of laboratory experiments 

 were designed to determine toxicity, duration 

 of toxicity, and whether affected fishes could 

 revive. The information obtained from these 

 experiments was utilized later in field investiga- 

 tions . 



Six species of fishes were used in the lab- 

 oratory experiments: longnose gar (Lepisosteus 

 osseus ), goldfish (Carassius auratus), carp 

 (Cyprin us, carpio), yellow bullhead (Ictalurus 

 natalis), largemouth bass (Micropterus salmoides ), 

 and green sunfish (Lepomis cyanellus). The 

 fishes were collected from various ponds near 

 Carbondale, Illinois. They were kept in the 

 laboratory in large galvanized holding tanks 



supplied with Carbondale municipal water . The 

 water in the tanks was aerated with compressed 

 air. Periodically, part of the water was drained 

 and fresh water allowed to drip into the tanks . 

 The tanks were located in a partially shaded 

 and well ventilated glass room where the tem- 

 perature closely followed that of the outdoors. 

 Green sunfish, yellow bullhead, carp, and gold- 

 fish were fed canned horsemeat. The bass and 

 longnose gar were fed small minnows. All the 

 fishes seemed to be in good health during the 

 course of the experiments. Before being sub- 

 mitted to any of the tests the fishes were kept 

 in the holding tanks from 10 to 30 days. Food 

 was withheld for at least 2 days preceding the 

 tests. Total lengths of the fishes were recorded 

 to the nearest inch. Ranges in length were as 

 follows: longnose gar, 11 to 13 inches; goldfish, 

 2 to 4 inches; carp, 8 to 12; yellow bullhead, 

 4 to 6; largemouth bass, 7 to 12; and green sun- 

 fish, 2 to 4. 



The water used as a diluent -- the water 

 to which the poison was added to form the test 

 solution --in all of the experiments was taken 

 from the same holding tanks that were used to 

 keep the experimental fishes. At the beginning 

 of each experiment determinations were made 

 of the pH and temperature of the diluent. Gen- 

 erally, subsequent determinations were not made. 

 The pH values were determined colorimetrically. 

 The original conditions of the diluent were mod- 

 ified for 4 toxicity experiments. Acetic acid 

 was used to lower pH values to 5.5 in two of 

 them . In the other two, temperatures were 

 lowered to 54° F . by the addition of ice. 



Two sizes of glass aquariums were used. 

 In tests made in the large aquariums 100 liters 

 of the test solution was used. Two different 

 volumes of solution were used in the smaller 

 aquariums, 25 liters and 50 liters. Fifty liters 

 of solution was used in 80 percent of the experi- 

 ments conducted. 



The sodium cyanide used in all experi- 

 ments was in the original form, a small pellet 

 weighing approximately one ounce, sold under 

 the trade name, Cyanegg. Cyanegg contains a 



