1120 '^■- S- BUREAU OF FISHERIES " 



outlined for it in last veai's annual report. It was then stated that 

 particular attention would be <iiven to developin<i; individual mussel 

 cul'ture units to handle a j^reater number of «ilochidia at a time. 

 The capacity of these units has been tripletl in the course of the 

 last six months, so that each unit will now handle one and one-half 

 million at a time. Several such units have been operated to capacity, 

 several times producing some five or six million j'Ouno- mussels in 

 the course of the summer and fall. These were held sufficiently loni:^ 

 to determine that they were normal and healthy. Then at interval's 

 portions of them were analyzed to determine proportions of essential 

 chemicals at the various periods. 



The young mussels actually produced in the feAv mussel culture 

 units used were sufficiently great in number to warrant the assump- 

 tion that the large-scale production of mussels is established as 

 economically feasible. Two million of the young mussel's produced 

 at Fairport were removed to the University of Missouri by car, 

 where they arrived in perfect condition. This made certain that 

 young mussels may be transported safely to streams for planting. 



Further experiments at the university regarding this last prob- 

 lem have shown that transportation may be made with maximum 

 success during the first three days after completion of metamorphosis 

 from the glochidial stage, or after a period of three week^- from 

 this date. 



Mussel sw^ieys. — During the summer of 1929 considerable atten- 

 tion was given to the problem of determining chemical requirements 

 of waters suitable for the planting of mussels. A trip was made by 

 Doctor Ellis and Mr, Chamberlain to mussel waiters of Arkansas, 

 Louisiana, Texas, and Mexico where many waters w^ere examined 

 ranging from some very decidedly alkaline to others distinctly acid. 

 Notes were also made of the mussel fauna, if an3% present in each. 

 At the same time the mussel resources of the Rio Grande Valley, on 

 both sides of the international boundary, were given a hurried 

 surve}'. 



Texas has not had a reputation in the past as a mussel-producing 

 State, but as a result of the increased cost of commercial mussel 

 shells during the past few years, it has proved economic to ship shells 

 to the pearl button manufacturing centers in the Middle West and 

 in the East. As a result the nnissel resources of Florida and of 

 Texas, but particularly of the latter, have been given increased atten- 

 tion during the past two years. The hundreds of miles of irrigation 

 canals built in the citrus section of the lower Kio (Jrande Valley were 

 found to contain an extensive supply of mussels of commercial value. 

 In addition several rivers in Texas have produced many carloads of 

 shells during the past year. 



Depletion. — The evidence of further mussel depletion in most of 

 the heavily worked mussel waters of the country during the past 

 year has been striking. A survey during the past summer of the 

 formerly productive Lake Pepin, between Minnesota and Wisconsin, 

 has shown a pronounced decline in mussel population. 



The same depletion has been evident in many mussel waters with 

 the result that the price of raw material has most seriously mounted. 

 How far the newly developed mussel territory in Texas and Florida 

 will meet the deficiency is noi 3'et known. Some effort to meet the 



