BIOLOGY AND NATURAL HISTORY 243 



By December the general movement of loose Gracilaria has ceased. It has 

 washed ashore, drifted out to sea, or come to rest in certain shallow, pro- 

 tected areas where it will remain throughout the winter. When the water 

 temperature falls below i8° C, growth ceases and there is a slow decay of 

 plants with fragmentation at decayed spots, and a general settling down of 

 the entire mass. Part of this material survives the winter and grows the 

 following spring. 



CONSERVATION 



The life history of sterile, unattached Gracilaria confervoides indicates 

 that those areas where the plant survives the winter should be protected 

 from collecting after growth has ceased in the fall, as this constitutes the 

 only known "seed material" for the following year's crop. A good tentative 

 rule is to cease collecting after January i. Extensive collection of winter 

 dormant Gracilaria by the Van Sant Company during January, February, 

 and March, 1945, may have been partly responsible for the reduced abun- 

 dance of the following fall, along with low salinities. Since most of the 

 Gracilaria that is present in the fall ultimately washes ashore if not collected, 

 it is doubtful whether commercial collecting in the fall reduces the next 

 year's crop. 



With Gracilaria foliijera and Hypnea musciformis conservation is a 

 different problem. The abundance of the crop of any given year depends 

 upon a favorable combination of environmental factors, but even with ideal 

 conditions, the number of plants is limited by surface for attachment (shells 

 and stones) for which they must compete with non-economic species. It is 

 doubtful whether any degree of commercial collecting would reduce the 

 spores shed to a point where the environment would not be "seeded" with 

 more spores than it could support. By the time the abundance of these species 

 makes collecting profitable, spores have been shed by countless millions. 



POSSIBILITIES OF CULTIVATION 



Cultivation of seaweeds involving the planting of "seed" material and 

 later harvesting a crop has not yet been accomplished. With Gracilaria con- 

 fervoides, the reason that the species does not grow in abundance in certain 

 areas that appear to be suitable habitats may be determined and, if tide 

 currents do not interfere, it might prove profitable to distribute chopped-up 

 pieces of plants in June or July. If the absence of the species is due only to 

 absence of "seed" material, the Gracilaria distributed should increase 100- 

 fold within a month or two if conditions are favorable. With G. folliifera 

 and Hypnea, cultivation efforts are most likely to be successful if shells or 

 stones are distributed over an area when spores are being produced by 



