48 REPORT OF THE COMMISSIONER OF FISHERIES. 
subjects under consideration at Fairport during the yeat. One of the 
investigations pursued at this laboratory was of particular interest 
in establishing the fact that mussels may absorb nutritive sub- 
stances in solution in the water not only through the alimentary tract 
but directly through the surface cells. Other studies in progress 
relate to the propagation of species of mussels not yet susceptible to 
practical cultural methods, the relations of fishes and mussels in 
nature, the possibilities of rearing mussels without parasitism, the 
food of mussels, the copepod parasites of fishes, and the constitution 
of the blood of fishes. 
The equipment of the station in ponds and other facilities for the 
efficient prosecution of its work has been materially increased during 
the year. A bulletin descriptive of the equipment and functions 
of the Fairport station has just been published. 
MISCELLANEOUS INVESTIGATIONS. 
The Bureau has taken advantage of an opportunity to utilize the 
services of a specialist traveling abroad to secure information regard- 
ing recent significant developments in foreign pearl fisheries and 
expects to have a report available within the next year. 
he imperative necessity for seeking new sources of potash for use 
in agricultural and commercial enterprises has led to the sudden 
development of an industry of kelp harvesting, especially in the 
region of San Diego, Cal. Simultaneously there arose questions as to 
the possible effect of the cutting of kelp upon the fisheries. Just 
before the close of the fiscal year it had been arranged to begin a 
study of the kelp fields and the method of harvesting with the view of 
securing definite information as to the relations of fish and shellfish 
to the kelp groves as they might be affected by the operations of 
harvesting. 
For two or three years the Bureau has been searching for suitable 
supplies of hydroids, or the ‘‘sea moss” of commerce, which had 
previously been imported from Europe in considerable quantities. 
The dyed product is used for decorative and millinery purposes, and 
the importations for the only year for which statistics are available 
(1909) amounted to more than 300,000 pounds, valued at $47,558. 
In connection with the survey of the Chesapeake Bay, considerable 
quantities were located at depths of 18 to 30 fathoms, and experiments 
were made to devise efficient methods of collecting. An experienced 
manufacturer accompanied the investigator on one of the cruises and 
pronounced the material of excellent quality. Further observations 
must be made to determine the seasons when the moss may be found 
in greatest abundance and highest quality. 
ne of the most serious handicaps upon the halibut fishery of the 
northwest coast is the occurrence of “mushy” halibut, which is 
especially characteristic of certain grounds and which begins to be 
noted in early summer, increasing in prevalence until the unmarketable 
fish form so large a proportion of the catch as to compel the abandon- 
ment of the fishery or iis removal to other and less accessible grounds 
for the remainder of the season. Through the study of material 
supplied to a specialist in the employ of the Bureau, it has been 
ascertained that the “mushy” condition is caused by a minute 
protozoan ‘parasite which multiplies abundantly and brings about 
