12 N. J. Agricultural Experiment Stations, Circular 139 



gouldi, a close relative of Bankia fimbriata, according to Sigerfoos 

 (7) becomes full grown in about a year in California waters, at which 

 time it may attain a length of 2 feet. 



The exact date when the larvae of Teredo became attached to the 

 platform is unknown, but as it must have occurred soon after July 3, 

 it is probable that the growth of the pileworms to sexual maturity, 

 with incidentally the complete destruction of the platform, must have 

 occurred in about 5 weeks. 



One reason for the very heavy infection of the platform by borers 

 was the unusually high density of the water. From the reports of 

 the United States Weather Bureau for New Jersey we find that the year 

 1921 was one of the five driest on record. The rainfall for the state as a 

 whole was 8.08 inches below the normal, and for the seacoast area, 

 10.6 inches below the normal. During these 22 days in July when 

 the platform was in Barnegat Bay, the water at the bottom near the 

 platform ranged in salinity from 10,125 to 10,170, with an average of 

 10,145 (fresh or distilled water being 10,000), This is from 40 to 

 60 parts per 10,000 higher than would be found here in normal years. 

 The average temperature of the water at the bottom during this 

 period was 78° F., with a maximum of 80° and a minimum of 76°. 

 During the period the platform was in the creek, the maximum dens- 

 ity observed was 10,125, and the minimum 10,090. The maximum 

 temperature during the same period was 87°, and the minimum 70°. 



A remarkable feature of the higher salinity of last year, and one 

 which should receive full recognition by engineers, is that during the 

 summer water of relatively high salinity crept upstream along the 

 bottom far above its normal limits. For example, on July 8 water 

 samples taken in Toms River, just below the last boathouse in the 

 town of Toms River, showed a salinity of 10,040 at the surface, while 

 at the bottom, 6 feet, it was 10,095. The bottom sample contained 

 numerous clam and oyster larvae which had worked at least 3 miles 

 up the river from the nearest beds. The larvae of Teredo were not 

 found at this time, but the salinity of the water was such that had 

 they settled on the piling of the water front of the town of Toms 

 River, they would have been able to develop into mature pileworms. 



A Situation Dangerous to Oyster Shippers and Wharf Owners 



Little fear is felt ordinarily of the attacks of marine borers in the 

 bottoms of vessels which return every few days or oftener to a harbor 

 in fresh water. The native shipworms, Bankia fimbriata, probably do 

 not live in waters the density of which falls much below 1010 for 

 any long periods. 4 



In contrast to this, however, according to the experience in San 



_ 4 A platform similar to the one sunk jn Barnegat Bay was put out in the 

 tidal creek some 50 feet below the laboratory houseboat on May 23. When 

 examined on August 15 it was found to be slightly infected with Bankia fim- 

 briata. The salinity of the water during this entire period, deduced from 

 records which were taken twice daily, varied from 1006 to 1012, averaging 

 about 1010. ' ■ 



