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THE QUESTION REGARDING THE OCCURRENCE OF TEREDO NAVALIS 

 IN SAN FRANCISCO BAY 



Some question has arisen as to whether or not the species of Teredo responsible 

 for the recent damage in the upper portions of San Francisco Bay is actually identical 

 with the Teredo vavalis of European waters. This matter is of itself of little import, 

 and would not merit extensive discussion except for the fact that certain rather weighty 

 practical considerations are involved. If the species of Teredo with which we are 

 working be not the Teredo navalis of Europe, then our problem in San Francisco Bay 

 is more or less detached, and of only passing interest elsewhere. If, however, the 

 organism which has appeared in recent years in San Francisco Bay is indeed the well 

 known pest of the Old World, a number of important considerations are immediately 

 evident. 



The first of these considerations is that Teredo navalis is an organism of potentially 

 cosmopolitan distribution, at least within the confines of the temperate zones. It is 

 capable of being carried from place to place in the path of commerce, of establishing 

 itself in new localities, and repeating its history of depredations in regions where it 

 has been previously unknown. 



A second and equally important consideration is that, if the organism with 

 which we are dealing be the true Teredo navalis, our findings in connection with it will 

 be applicable elsewhere, wherever this species is now distributed or may in future 

 appear. Hence, on the intrinsically unimportant problem of the identity of this 

 organism hinges the question as to whether the present investigation is of merely 

 local, or of cosmopolitan, interest. 



The organism found by Barrows (1917) in the Mare Island dykes in 1914 and 

 subsequently, was identified by Bartsch as Teredo diegensis. It was later identified 

 by Kofoid (1921) as Teredo navalis. Bartsch (1922) thereupon rescinded his original 

 identification, and stated that the organism in question was Teredo townsendi (a 

 synonym of Teredo diegensis; see p. 198). This, however, is undoubtedly erroneous, as 

 Teredo diegensis ( = lownsendi) occurs at only one locality in San Francisco Bay — 

 South San Francisco — and there is no evidence of its ever having penetrated into 

 San Pablo Bay. 



Bartsch (1921) had in the meantime described certain specimens from San Pablo 

 Bay as a new species, Teredo beaclii. It was reaftirmed by Kofoid and Miller (1922) 

 that the organism occurring in San Pablo Bay was identical with the well known 

 Teredo navalis of European waters, and it was shown by Miller (1922 and 1923) that 

 the characters by which T. beaclii was presumed to be differentiated from T. navalis 

 were matters of individual or environmental variation, and not of specific rank. 



The authors are convinced that the organism in question is true Teredo navalis 

 on the ground of its close resemblance to that species as occurring in European waters, 

 and from the following additional considerations: 



The hardy nature of the organism and its ability to survive for long periods 

 under adverse conditions indicate that it may readily be carried from place to place 

 in connection with shipping, and succeed in establishing itself in new localities. Our 

 experiments have shown that it will live indefinitely in salinities of from 5 parts per 1000 

 to 60 parts per 1000 (nearly twice that of normal sea water), and that it will survive 

 for long periods of time in an almost complete absence of oxygen. In short, it has 

 withstood in the laboratory conditions of stress to whicli it would rarely or never be 

 exposed in nature. The evolution of the organism has been in a direction to enable it 

 to take advantage of submerged timber wherever found. It has become adjusted to 

 this one major factor rather than to salinity, temperature, depth, or similar factors 



