XX EEPORT TO THE SECRETARY OF COMMERCE 



the commercial fishernieii of Canada, all of whom exploit the pike 

 perches as sports fishes in the United States waters and as a commer- 

 cial fisher}' in the Missisqiioi Bay region of Quebec. The chief 

 features of the biology of these species will be determined in order to 

 judge the interdependence of the waters on both sides of the inter- 

 national boundary in the hope of reaching an amicable settlement of 

 this old controversy. 



SHELLFISH INVESTIGATIONS 



Oysters. — Oyster investigations during the past year consisted in 

 the experimental study of oyster culture in New England, Georgia, 

 Texas, and Washington, in a study of the physiology of adult and 

 larval oysters, in a study of the effect of pulp-mill waste on oysters 

 of the Puget Sound, and in an investigation of the biology of the 

 natural enemies of the oyster such as the oyster drill and starfish. 

 Several years' investigations of the oj^ster fishery resulted in a number 

 of publications recently issued. Much interest has been aroused in 

 the oyster industry by the development of a new and more efficient 

 type of oyster spat collector, consisting of a cement-coated paper 

 crate resembling egg crate partitions, with the result that this method 

 of increasing seed oyster production is being generally adopted by 

 the industrJ^ 



Studies of oyster culture in lower Puget Sound, begun last year, 

 indicated that the beds in Oakland Bay were being destroyed. A 

 hydrobiological and a physiological investigation was undertaken to 

 determine the cause of this failure. Laboratory tests showed that 

 waste sulphite liquor from a pulp mill in the vicinity would kill 

 oysters or interfere with their feeding activities. On the basis of 

 calculations of the amount of liquor dumped into the bay during the 

 past two years and from tidal studies it is estimated that the bay 

 contained sulphite liquor in sufficient concentration to produce such 

 toxic effects. A preliminary report was prepared in which it was 

 recommended that sulphite liquor be excluded from waters in which 

 oysters are produced. 



Studies on the control of starfish pests on the oyster beds of Long 

 Island Sound give promise of developing an efficient treatment for 

 killing the starfish soon after the spawning of these animals in the 

 spring by means of copper sulphate. Because of the practical 

 importance of this work the investigation will be continued. 



Fresh-water mussels. — Investigations of improved methods of mussel 

 culture were continued during the early part of the fiscal year. A 

 thoroughly successful laboratory method for artificial propagation of 

 the valuable fresh-water mussels has been hindered in large-scale pro- 

 duction by the extensive pollution of the upper Mississippi River 

 system. An extensive survey of the waters of Arkansas, Louisiana, 

 Texas, and northern Mexico, as well as tnbutaries of the Mississippi 

 farther north, was undertaken to discover areas suitable for the 

 extension of mussel culture, and a systematic effort was made in the 

 spring of 1930 to secure a breeding stock free from the effects of 

 pollution and suitable for obtaining spawn for incubation. 



The scientific staff engaged on these problems has been reorganized, 

 field headquarters have been established at the University of Missouri, 

 Columbia, Mo., and experiments have been undertaken to test the 

 suitability for artificial culture of mussels from widely spread localities. 



