554 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



of sand grains. We have not observed the male 

 in the process of nest-building. 



As stated in the literature the male, having 

 constructed the nest, induces one or more females 

 to enter it and lay eggs which he immediately 

 fertilizes. He then maintains a guard over the 

 eggs and newly hatched young, and perhaps pro- 

 vides aeration by his swimming or fanning move- 

 ments. 



In Karluk Lake many stickleback eggs have 

 been found more or less scattered through aquatic 

 vegetation. Possibly these eggs were deposited 

 free, without construction of nests. 



At Bare Lake, in 1955, C. W. Huver stripped 

 eggs from female sticklebacks, fertilized them 

 with macerated testes from mature males, and 

 succeeded in hatching them in a bowl floated in 

 a tub. At a water temperature varying from 

 9° to 16° C, the eggs were eyed in 9 days and 

 started hatching at 14 days. 



The embryological development of the three- 

 spine stickleback has been studied by Vrat (1949), 

 who published a series of drawings of various 

 stages. The development follows a pattern typi- 

 cal in teleost fishes. 



Physiology and Behavior 



The literature, at least in North America, con- 

 tains little information regarding physiological 

 responses, tolerances, and adaptations of the 

 three-spine stickleback. It is believed to be a 

 hardy fish in many respects. For instance, it 

 is known to survive over winter in shallow lakes 

 in northern temperate and subarctic zones, where 

 the chemical conditions become severe. Dissolved 

 oxygen sinks to a trace, and dissolved carbon 

 dioxide and other gases build up considerable 

 tensions. The mechanism for survival is not 

 known ; presumably it combines a greatly re- 

 duced metabolic rate with the ability to extract 

 oxygen at low pressure. 



The threespine stickleback has been used, par- 

 ticularly in Europe, as an aquarium fish. Pos- 

 sibly it would be a satisfactory subject for tank 

 and jar experiments on physiological responses 

 and adaptations. However, Cope et al. (1949) 

 state that "Sticklebacks could not stand holding 

 in the live jars, and mortalities were high at 

 24 hours." These authors used Gasterosteus acu- 

 leatus for some experiments in tolerance to cer- 



tain insecticides. They found the stickleback to 

 be more tolerant to emulsions of DDT, benzene 

 hexachloride, chlorinated camphene, and chlordan 

 than were salmonid fishes (the criterion of toler- 

 ance being the amount of agitation after 15-min- 

 ute test periods). However, in certain tests with 

 acetone solutions of pyrethins they noted that 

 the sticklebacks "were rendered helpless within 

 the time of treatment, while only a few salmonids 

 were so affected." They suggest that selective 

 poisoning might possibly be used in control of 

 sticklebacks. Jones (1935, 1938, 1939, 1947) has 

 made extensive use of Ga-ste?'ostevs aculeatus as 

 a test fish, particularly in determining the tox- 

 icity of various metals to fish. 



The sticklebacks in Karluk and Bare Lakes 

 apparently suffer a heavy mortality after spawn- 

 ing. The physiology of this post-spawning mor- 

 tality is not known. Feeding apparently con- 

 tinues until the time of spawning but perhaps 

 ceases with spawning. The dead, spawned-out 

 fish picked up along shores are extremely ema- 

 ciated. 



Except for spawned-out fish, nutrition is satis- 

 factory. All individuals are in reasonably plump 

 condition throughout the summer. Nothing is 

 known concerning diseases in the Karluk and 

 Bare Lake sticklebacks. 



These fish harbor various parasites. One of 

 these is the ligualid cestode, Schistocephalus, the 

 plerocercoids of which lie in the abdominal cav- 

 ity of the fish. Crustacea are the host of the 

 initial larval stage, and fish-eating birds, such as 

 mergansers, of the adult tapeworm. At least 

 20 percent of the adult sticklebacks are infested. 

 These cestode larvae reach 20 mm. or more in 

 length, and one larva can fill all the available 

 space in the fish and cause a visible distension 

 of the abdomen. A few of the infested fish have 

 from 2 to 8 of the worms each. 



Morton (1942) states that the stickleback in 

 Karluk Lake carries in its intestines the larva 

 of a proteocephalid cestode, presumably Proteo- 

 cephahis arcticus Cooper. The adult worm is 

 found in the intestine of the lake charr, SaVoelinus 

 alpimts, which feeds on the stickleback. 



Also reported by Morton, a larval cestode of 

 the Dyphyllobothriid type, provisionally called 

 Dibothrhim fasteni, is found in the stickleback 

 as well as in the lake charr and in young red 



