the fishing operation. The outermost light is 

 turned on for a time until a substantial number 

 of fish are attracted. This light is then extin- 

 guished, and another somewhat closer to the fish- 

 ing operation is illuminated. Each light in the 

 series is lighted and extinguished in sequence, 

 attracting in turn the fish gathered about the pre- 

 ceding one. 



Besides the properties of the lig'ht itself, cei-tain 

 factors of the environment govern the effectiveness 

 of the light, especially in relation to the time of 

 day or time of year it is used. Kawamoto (1959) 

 showed that in some species of fish the light-seek- 

 ing tendency was stronger in the daytime than at 

 night. Tamura ( 1959) , discussing this phenomenon 

 and certain physiological changes in the eye of the 

 fish when adapted from light to darkness, sug- 

 gested "this may be one of the fundamental reasons 

 why fishing with the use of light is usually more 

 effective before than aft-er midnight." The results 

 of my own experiments with herring show a 

 greater attraction to light of light-adapted fish, 

 especially the initial attraction. All of these ob- 

 servations suggest that fishing with a lig'ht would 

 be most effective shortly after dusk. 



I can find no reference to the effect of tempera- 

 ture on the response of herring to light except as 

 it relates to their passage through the thermocline; 

 there are records, however, indicating that temper- 

 ature does affect the response to light of other spe- 

 cies of fish. Andrews (1946) showed that the posi- 

 tive phototaxis of suckers {Catastorrvus) was 

 weakened at high temi>erature ; Grubisic (1962) 

 stated that the attraction of sardines {Sardina 

 pilchardvs) to light was weaker in the sununer- 

 time than at other seasons and that this weakness 

 was "more e\adent when the summers are more 

 than normally hot." 



Because the attraction of herring to light seems 

 also to be weakened at high temperature, success 

 in fishing for them with artificial lights might well 

 depend in part on the season of the year and the 

 temperature characteristics of particular localities. 

 Moreover, temperature seems not only to affect di- 

 rectly the attraction to light, but also to modify 

 the effects of light position and previous adapta- 

 tion to light or darkness. 



My purpose in the experiments involving tem- 

 perature was limited to finding out whether tem- 

 perature had any effect at all. Obviously, it did, but 



the critical values of both experimental and adap- 

 tation temperatures need yet to be defined. It is 

 possible that the temperatm'e preferendum de- 

 scribed elsewhere (Stickney, in press) represents 

 the critical point above which tlie light i-esponse 

 weakens. 



The use of lights in the herring fishery of the 

 Canadian and United States Atlantic Coast has 

 been in disfavor for some time and is even illegal 

 in many places. Even wliere it is still legal, it is a 

 method of little importance probably because fish- 

 ermen believe that lights frighten the herring away 

 (Scattergood and Tiblxi, 1959). Fishing at night 

 is earned on with as little light showing as pos- 

 sible. Because above-water lights, excessively 

 bright lights, and lights suddenly flashed on or 

 moved about do apparently frighten herring, the 

 caution used in showing lights is probably justi- 

 fied. On the other hand, practical experience and 

 biological evidence indicate that lights properly 

 used under some circumstances can attract herring 

 effectively. It would seem that artificial lights used 

 in accordance with what is known about herring 

 behavior would provide an extremely useful 

 method for controlling the lierring schools so that 

 they would be in locations most conducive to set- 

 ting purse seines or stop seines around them. 



LITERATURE CITED 



Andrews, C. W. 



1946, Effect of heat on the light behaviour of fish. 

 Proc. Trans. Roy. Soc. Can., Ser. 3, 40 : 27-31. 

 Blaxteb, J. H. S. 



1964. Spectral sensitivity of the herring, Clupea 

 harengus L. J. ESp. Biol. 41 : 155-162. 

 Blaster, J. H. S., and F. G. T. Holliday. 



1963. The behaviour and physiology of herring and 

 other clupeids. In F. S. Russell (editor). Advances 

 in marine biology, vol. 1, pp. 261-393. Academic 

 Press, London and New York. 

 Blaster, J. H. S., and B. B. Parrish. 



19.58. The effect of artificial lights on fish and ma- 

 rine organisms at sea. Mar. Res. Scot. 2 : 1-25. 

 CoLTON, John B., Robert R. Mabak, Samuel R. Nickeb- 

 soN, and Ruth R. Stoddard. 



1968. Physical, chemical, and biological obser^'ations 

 on the Continental Shelf, Nova Scotia to Long Is- 

 land, 1964-66. U.S. Fish Wildl. Serv., Data Rep. 

 23, V + 190 pp. on 3 microfiches. 

 Draoesund, Olav. 



1958. Reactions of fish to artificial light, with special 

 reference to large herring and spring herring in 

 Norway. J. Cons. 23 : 213-227. 



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