yvr KEPOKT OF THE COMMISSION KR OF FISHERIES 



<»ieatest of all our fislierj'^ resources, it has been exploited since the 

 time of the first settlements in New England, when it proved to 

 be an important factor in the success of the newly established colo- 

 nies. In spite of an extensive fishery, which has been maintained 

 for many years, this resource has shown no definite signs of de- 

 pletion, but the intensity of the fishing is being constantly increased 

 by the addition of fleets from the European side of the Atlantic. 

 At the present time the banks are being fished by ships from the 

 United States, Canada, Newfoundland, Spain, Portugal, France, 

 and probably other nations. Adequate statistics of the total catch 

 are not available, since we have no data for several of the countries 

 engaged. 



The results of this increase in the intensit}^ of fishing can not be 

 foretold, but the importance of the industry to the American ])eople 

 iiiid the desirability of maintaining the resource unimpaired are 

 such that an investigation of the biology of the cod, pollock, and 

 haddock has been undertaken with the idea of determining the 

 factors responsible for any fluctuations in abundance which may be- 

 come api)arent. It is important for an understanding of the general 

 principles of fishery conservation to know how such a great fishery 

 can withstand intensive exploitation over a long period of time 

 without depletion. Such knowledge should throw much light on 

 the problem of maintaining other fisheries which do show signs of 

 depletion due to overfishing, and the data Avould be invaluable if 

 the bank fisheries themselves should become reduced. 



The program includes extensive tagging experiments for the pur- 

 j>ose of discovering the extent and nature of the migrations of the 

 adult fish. Over 10,000 fish, principally cod, Avere tagged during 

 the season of 1924. and nearly 5,000 during the first part of the sea- 

 son of 1925. Approximately 800 tags have been recovered since the 

 beginning of the operations in 1923, and many important data have 

 been secured on the migrations and rate of growth. Evidence of a 

 winter migration southward along the coast, which was given by 

 trigging done during 1923, was confirmed in 1924, and additional 

 data were secured which make it appear certain that there is very 

 little interchange between the populations of the various banks. In 

 connection with the tagging opei-ations. scales have been secured 

 from nearly every fish tagged and from several hundred others. 

 These are being studied to determine age, rate of growth, and any 

 peculiarities that may be found between the fish on the various 

 i)anks. 



An investigation of the early history of the cod, designed to 

 supplement and complete the studies of the adults, has been under- 

 Vk'ay during the past year. The vvork was done in Massachusetts 

 and Ipswich Bays and along the coast of Maine. The main problem 

 involves a study of the spawning of the cod, the conditions existing 

 (hiring the period of incubation of the eggs, the early larval history, 

 food habits of the larvae and young fish, their enemies, and the 

 gradual changes in the feeding habits and migrations during the 

 first year. It has been found that after completing their larval de- 

 velopment the young cod and pollock seek shallow water and in 

 April and May are to be taken along the shores. As the temperature 

 rises in June they leave the shallow water and seek deeper areas. 

 Just where thev go at this time has not vet been discovered. 



