FISHES OF THE GULF OF MAINE 



89 



traveling as a rule in schools of hundreds or thou- 

 sands; single fish are seldom seen, or even small 

 companies of a few dozen. As a rule all the indi- 

 vidual members of a school are about the same 

 size, whether large or small. It is not known how 

 long any given school may preserve its identity as 

 such. Fridriksson and Aasen, 21 it is true, found 

 that herring tagged and released together might be 

 recaptured from widely separated localities, sug- 

 gesting that schools are more or less temporary 

 formations. But this may not apply to schools 

 that have assembled under natural conditions. 



When a school is at the surface, as often hap- 

 pens on a calm day, its presence is betrayed by a 

 fine rippling of the water, but we have never seen 

 herring "finning" or lifting their noses above the 

 surface as menhaden often do (p. 114). They 

 come to the surface most often by night, when 

 their presence is betrayed by their luminous trails, 

 if the water is "firing," as we have often seen. A 

 school is likely to be more or less stationary when 

 feeding, its members swimming slowly to and fro 

 and drifting as a whole with the current. 22 But 

 at other times schools are seen traveling with in- 

 dividual fish swimming side by side, rank below 

 rank, as far down in the water as the eye can see 

 from a boat, all heading in one direction appar- 

 ently with some purposeful intent. We have 

 often watched schools of "sardine" size streaming 

 close past a certain rocky headland in the southern 

 side of Massachusetts Bay, seemingly in unending 

 procession . 



As Dr. Huntsman points out, "There is no in- 

 dication that herring swim against the current 

 unless the water is somewhat turbulent." 23 If 

 they do so under such conditions, it depends on 

 the relationship between their rate of swimming 

 and the strength of the current whether they ac- 

 tually make headway against it or lose ground, 

 tail first. 



We might also add that schools of herring, like 

 schools of menhaden, are not so easily frightened 

 by the approach of a boat, as mackerel often are, 

 and striped bass. Herring do not jump unless 

 frightened. But the smaller sizes are often seen 

 jumping when pursued from below by larger pred- 



" Eept., Norwegian Fisb. Mar. Invest. Skriftcr, vol. 9, No. 11, Rept. 1, 

 1950, p. 22. 



"Huntsman (James Johnstone Memorial Vol., 1934, p. 83) gives an in- 

 teresting account of the movements of herring schools in Passamaquoddy 

 Bay. 



» James Johnstone Memorial Vol., 1934, p. 84. 



210941—53 7 



atory fishes, such as silver hake or striped bass, 

 a common spectacle. Fridriksson and Aasen 

 found that herring, held in live-nets, swam con- 

 stantly at a rate of about 0.2 to 0.25 sea miles per 

 hour (6-8 meters per minute) when not disturbed. 

 And it is certain that they are capable of long 

 journeys, for a number of herring tagged on the 

 northeast coast of Iceland have been recaught in 

 southern Norway, and some vice-versa. 24 



The activity of the herring is controlled in great 

 part by the temperature of the water. In Pas- 

 samaquoddy Bay, for example, they are "ob- 

 served to move very sluggishly when the water is 

 coldest in February and March," 25 and probably 

 this applies all around the periphery of our Gulf, 

 for the upper 20 fathoms ordinarily cools to about 

 33 to 36° F. during those months, with the sur- 

 face often chilling to the freezing point of salt 

 water in bays and harbors. The herring become 

 active again when the water has warmed to about 

 40 to 43°. 



Food.— The herring is a plankton feeder. When 

 first hatched, and before the disappearance of the 

 yolk sac, the larvae (European) feed on larval 

 snails and crustaceans, on diatoms, and on 

 peridinians, but they soon begin taking copepods, 

 and depend exclusively on these for a time after 

 they get to be 12 mm. long, especially on the 

 little Pseudocalanus elongatus.^ As they grow 

 older they feed more and more on the larger 

 copepods and amphipods, pelagic shrimps, and 

 decapod crustacean larvae. Examination of 1,500 

 stomachs 27 showed that adult herring near East- 

 port were living solely on copepods and on pelagic 

 euphausiid shrimps (.\ftganyctiphanes norwegica), 

 fish less than 4 inches long depending on the former 

 alone, while the larger herring were eating both. 



When feeding on euphausiids, we have often seen 

 them pursuing the individual shrimps, which 

 frequently leap clear of the water in their efforts 

 to escape. Even in winter, when shrimp are 

 rarely seen at the surface, Moore found them an 

 important article in the diet of the Eastport 

 herring. And it is likely that the local appear- 



» Fridriksson and Aasen, Rept. Norwegian Fish. Mar. Invest., Skrifter, 

 vol. 9, No. 11, Rept. 1, 1950, pp. 26-27. 



" Huntsman. James Johnstone Memorial vol., 1934, p. 83. 



» The diet of herring, young and old, in the English Channel and in the 

 North Sea has been described by Lebour in a series of papers (see especially 

 Jour. Mar. Biol. Assoc. United Kingdom, vol. 12, 1921, pp. 458-467), by Hardy 

 (British Fisheries Invest., Ser. 3. vol. 7, No. 3, 1924), and by Jesperson (Medd. 

 Komm. Havund. Ser. Plankton, vol. 2, No. 2, 1928, Copenhagen). 



» Moore, Rept. U. S. Comm. Fish. (1896), 1898, p. 402. 



