712 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



greatly with the work of the fishermen, and often good cod-fishing was 

 spoiled by their sudden appearance. At the present time halibut oc- 

 cur in much smaller numbers on these grounds, and no such difficulty 

 is noticeable. Indeed, it is found that cod occur in greater or less num- 

 bers with the halibut on the outer banks, where they seem to live peace- 

 ably together ; and we are led to believe that it was the abundance of 

 the halibut in former times, when they literally covered the ground, 

 rather than any hostilities l)eween the species, that drove the cod from 

 the banks. 



Just how the large cod is affected by the presence of the pollock 

 (PoUacliws carhonarhis) we are unable to say, but the young living near 

 the shore finds in them its most deadly enemy. Young pollock are ex- 

 ceedingly abundant all along the shore during a greater part of the 

 year, often moving in large schools as well as singly, and frequently 

 many barrels are taken in a single day in each of the many traps along 

 the coast. They are especially abundant in the waters off Cape Ann, 

 and being exceedingly voracious, attack and devour almost any small 

 fish that comes in theii- way. TTe have often watched their movements 

 in the clear water of Gloucesrer Harbor, and noted the sudden dispers- 

 ion of a school of several hundred young cod of six months' growth 

 at the approach of a single pollock seven or eight inches in length. 



These little fish show great fear of them, and usually remain near the 

 long kelps and sea-weeds that are growing on the piling of the wharves, 

 and at once dart in among these for protection at the first approach of 

 the pollock, reappearing very cautiously only after the lapse of several 

 minutes. At times a poUock succeeds in approaching unnoticed, when 

 it suddenly darts into the midst of the school and seizes one of the lit- 

 tle fish as its prey. Even when of equal size the cod exhibit the same 

 fear, and on putting several of each about ten inches in length into a 

 large tank of water, the cod sought refuge beneath some strips of board 

 that were stretched across one corner, while the pollock swam about 

 freely in the water. On being driven from their hiding place they soon 

 returned, and it was not until the poUock were taken out that they 

 would freely venture from their hiding place. 



5.— REPRODUCTION. 



Evidence is not wanting to show that cod spawn every year, and that 

 they deposit the entire number of eggs in the ovaries each season. We 

 have examined hundreds of specimens and have failed to find a single 

 instance where the condition of the ovaries did not clearly indicate, to 

 our minds at least, that such was the case. During the first of the sea- 

 son no mature fish were found in which eggs were not present, though 

 they often varied greatly in development from very small to nearly ripe. 

 Again, later in the season, no spent fish were seen with any eggs remain- 

 ing in the ovaries ; and no fish were found during the spawning period 

 in which the condition of the ovaries did not indicate that the eggs were 



