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BIOLOGICAL SECTION 



By Charles A. Kofoid and Robkrt C. Miller 

 with the collaboration of 

 Edgar L. Lazier, Walter H. Dore, 

 Harold E. Blum, and 

 Edgar Van Slyke 



CHAPTER XII 



BIOLOGICAL ASPECTS OF THE MARINE BORER PROBLEM 



The problem of the control of marine wood boring animals is as old as the history 

 of the navigation of the sea. No doubt the first adventurers who undertook the hazards 

 of maritime travel by means of rafts or crude boats inauspiciously learned a lesson 

 in the natural history of these organisms. Certainly they were unpleasantly familiar 

 to the Greeks and Romans, as is indicated by unmistakable references to them in 

 the works of Theophrastus, Cicero, Ovid and Pliny. A lost work of Clitarchus is 

 said to deal with an expedition sent out in the time of Alexander the Great to seek 

 for a teredo-resistant wood. 



In man's conquest of the forces of nature, the most powerful enemies with which 

 he has to cope are those which of themselves appear mean and insignificant. The 

 physical obstacles which loomed large in the early history of marine transportation 

 — the dangers of storm and shipwreck, delays due to adverse winds and currents, 

 and the hazards of navigating uncharted seas — have been more and more nearly 

 eliminated. The biological problems involved, however, have not been so successfully 

 coped with. The barnacles and other marine animals which attach themselves in 

 countless millions to the bottoms of ships are quite as much a nuisance now as in 

 days gone by. The shipworm continues to take its toll of wharf piling and wooden 

 boats and barges, even as when Theophrastus (371-286 B. C.) pessimistically ob- 

 served: "On the land worms destroy the wood, in the sea it is the teredo." 



With the rapid increase of shipping in the past two hundred years, the marine 

 borer problem has become more and more a matter of cosmopolitan concern. There 

 are few seaports in the world that are not infested with one or more species of borer, 

 and the facility with which these organisms adapt themselves to new conditions of 

 life has brought about their successful, if unintended, transportation from place 

 to place in connection with shipping, so that in some harbors the damage wrought 

 by indigenous species has been multiplied many times by the importation of more 

 malignant exotic forms. A striking illustration of this is the tremendous damage 

 occasioned by Teredo navalis in San Erancisco Bay within a few years after its intro- 

 duction to this locality, damage far in excess of that produced by the native wood- 

 boring moUusk, Bankia setacea, which has been known here since the earliest history 

 of the port. 



The history of the ravages of marine borers, throughout the world, so far as 

 records are available, has been one of more or less periodically recurring devastations, 

 separated by intervals, often lengthy, of comparative freedom from attack. It is 

 now evident that this apparent cyclical recurrence of heavy borer attack is dependent 

 on combinations of conditions particularly favorable to the growth and multiplication 



