PREFACE ix 



SESSIONAL PAPER No. 38a 



gasolene launch. After being boiled, the meat is removed from the shells and many 

 pearls and slugs are found, some of value. The increasing violence of floods, in the 

 rivers studied, must have been injurious to mussel beds, and the regulation of the flow 

 of water is essential. Vegetable detritus on river beds, and small diatoms, etc., appear 

 to form the food of these mussels, and favourable conditions for such food should be 

 maintained. 



The prohibitive steps suggested include annual close times, size limit, restriction 

 of methods, closed reserves, and a license system, as well as the adoption extensively 

 of mussiel culture. No less important are the stocking of waters by transferring mus- 

 sels, and the rearing of the best species by mussel inoculation, etc. 



IV. THE SHIP-WORM (TEREDO) ON THE ATLANTIC COAST OF 

 CANADA— (Dr. E. M. Kindle). 



The destructive character of the ship-worm (Teredo) has long been known; but 

 its rapidity in boring timbers is not so well known, and the author instances a beech 

 log, at the west side of the entrance of CharlottetoAvn harbour. Prince Edward Island, 

 thoroughly honeycomed recently during the short period of eleven months. A half- 

 tone illustration shows this log, and demonstrates how much more rapidly Teredo 

 works than the boring shrimp (Limnoria) which destroys soft timber at the rate of 

 half inch per year. Timlber cut from February to ]\Iay best resists Teredo's attacks, 

 and in the cold winter season* it is inactive. The tunnels bored, lime-lined, do not 

 intersect, and it is rare for Teredo to pass from one timber to another. At the water- 

 line and in the false keel of vessels are the main places of attack. Teredo spawns from 

 April to August in Iceland, but in Canada it is probably about July. Mud seems to 

 deter the boring operations; but, where the bottom is sandy, injury is more prevalent. 

 Thorough application of creosote (14 to 16 pounds impregnation to the cubic foot) is 

 effective; but at Christiania, piles were attacked when 10 pounds to the square foot 

 were applied. The ship-worm survives for 10 days, but not beyond two weeks when 

 removed from the water and kept in a cool place. Freezing (temperature 6°C.) does 

 not kill them; but they die in two hours in fresh water. A large ship- worm reaches 

 a length of about a foot (30 cm). The prevailing European species {T. norvegica) 

 ranges from the Mediterranean to southwest Norway, but within Arctic limits. Prof. 

 G. O. Sars records it only in piles in west Finmark. Teredo navalis the species, in 

 Canada, shows discontinuous distribution on the Atlantic shores of North America 

 (see Dr. Kindle's sketch map). Rare or absent in the Bay of Fundy, and scarce north- 

 east of Halifax, it occurs abundantly all round Cape Breton and the southern shore of 

 the gulf of St. Lawrence, including the shores of Prince Edward Island. According 

 to Dr. Murphy it is especially destructive about Sydney harbour. 



The presence or absence of the shii>worm may be due to temperature, salinity, and 

 amount of fresh water, and probably turbidity or silt in the water. It is often asso- 

 ciated with the boring shrimp in its range, and may overlap, but one becomes less 

 plentiful, it may be said, as we advance into the territory of the other. A number of 

 molluscs associated with Teredo in their distribution occur in warm areas, and show 

 similar isolation and discontinuity. Off southeast Nova Scotia the 20-fathom line 

 approaches within half a mile of the coast, and everywhere a narrow zone of shoal 

 water inside the lOO-fathom line renders it colder than the Northumberland straits, 

 where 20 to 10 fathoms or less prevails over a large extent. A zone of shallow water, 

 if close to and unprotected from deep water, is as effective a faunal barrier as a land 



