The beastie shown above has been known as a “teredo,” sometimes with an additional descriptor — “worm” — tacked on at the end. They aren’t worms, although they do bear a striking resemblance; they are mollusks. Technically, they are called Teredo Navalis or, more colloquially, “shipworms”.
Teredos live in and on wood. They were once ravenous for underwater wood stock in the Vancouver area, not only for wooden-bottomed ships, but also for the wooden piles that supported rail trestles and other bridges in the city that crossed relatively high-saline and temperate water.
Teredos in False Creek!
The brief article reproduced below was my first exposure to teredos and the “fearful havoc” they can wreak.
CLOSE CAMBIE STREET BRIDGE
Draw Span Pier Will be Rebuilt — Teredos Work Havoc on Piles — Draw Cants and Bridge Tenders Cannot Close It Properly — Contract let for $3500.
Cambie street bridge will be closed probably next Wednesday for a period of three weeks until much needed repairs are made to the pier which supports the draw. For some time it has been noticed that the south side of the draw span canted a little and made it difficult to close the bridge. A diver was employed to go down and examine the piles and found that the teredo worm was working fearful havoc and they would require to be renewed at once. The board of works met last night and awarded the contract to Armstrong and Morrison for $3500 and work will start as soon as they can get their material.
— Vancouver Daily World. April 24, 1909.
How do the teredos accomplish their nasty work? For a short video that demonstrates their work more effectively than I can explain it, see here. Essentially, these creatures get their nourishment from wood. They tunnel into timber, and leave in their wake calcium casings in the wood. A piece of wood that has been thoroughly consumed by teredos will be honeycombed with tunnels, rendering it of much reduced integrity. In short, after teredos have finished off a piece of wood, it is of little value or use; it will crumble away in your hands.
It is widely believed in the scientific community that teredos are not native to the Pacific coast; they are believed to have been native to Atlantic/European oceanic waters. But the question as to where the teredos originated has become academic as, due to their ship-munching ways, teredos became, effectively, a worldwide export. Well, not exactly worldwide, but they were found to be up to their wood-munching habits most places where where there was saltwater of high enough salinity (in the 5-45 parts per thousand range) and the water was relatively temperate (in the range of 1-30 degrees celsius).¹
There is evidence from early Vancouver years that teredos were busy whittling away at underwater wood along Vancouver’s coast at least at the following locations:
- First CPR Wharf: The wharf was built ca1886. In ca1889, according to Arthur J. Ford, a Vancouver pioneer who, in conversation with Vancouver’s first archivist, J. S. Matthews in 1946, said: “This is a section cut from the piles of the first Canadian Pacific Railway wharf at the foot of Granville Street. It was being taken out to be replaced and I was standing nearby and asked them to cut these pieces off for me as I wanted to keep it as a curiosity. I don’t know the precise year, but I should think it would be about 1889. That would mean that the piles were in [Burrard] inlet for about three years.” The ‘section’ to which Mr Ford referred was a “small section of wood, about eight inches square, full of toredo [teredo] worm bore holes.²
- At Site of Future Lion’s Gate Bridge (where the wreck of the Beaver was for several years beneath Prospect Point): Mr. W. L. Gove reported the following to Matthews in a letter dated March 27, 1950: “My recollection of “Beaver” was when the tide was low, I would climb on to the paddlewheel frame-work and onto the boiler, then search in the sand and under any small rocks for copper rivets, copper nails and some sheet copper. Then, on extreme low tides it was possible to get pieces of beams and parts of the keel with rivets or long bolts in such pieces. At that time there was no top works of the cabin left. It had been removed to make canes as curios for tourists. If the hull was taken away, whoever took it forgot to take the keel because I pulled up a piece four feet long, eight inches by eight inches. This piece was, as all other wood, below water, perforated by toredos [teredos] and that was about 1913.³
- Royal Vancouver Yacht Club: This location (in Coal Harbour) was reported in 1920 to have need of replacement piles due to teredo activity.∞
- Cambie (Connaught) Bridge: See article from 1909 shown above. This is evidence that teredos were active at least as far east as Cambie Bridge in that period.
Surrey and New Westminster, which were reputed to have fresh water, were apparently free from the ravages of teredos.
Until c1910, the only solution to the ravaging ways of teredos was to replace teredo-tunnelled wood with virgin timber. Around 1910, however, a commercial band-wagon of sorts was started of products that claimed to “teredo-proof” wood. In other words, these companies offered a preemptive solution to the teredo problem.
One firm that advertised extensively in Vancouver was the Gold Teredo-Proof Pile Co. Products like that of Edward Gold consisted of a secret paint formulation that, when applied to the surface of wood, allegedly would be a ‘turn-off’ to teredos and they would leave the wood alone. There was another firm with a paint product about which similar claims were made: B&A Anti-Teredo Manufacturing, later called Pipers, Ltd. (after President C.T.W. Piper).
It isn’t clear to me how successful the application of these paints were in discouraging the munching habits of teredos.
Teredos in Vancouver Today?
Today, teredos aren’t believed to be as much of a threat to bridge foundations and boats because the materials composing bridges less often consist much of lumber products (more often of much less teredo-tasty concrete) and the ships that still have wooden hulls do not sail mainly in temperate, higher-saline waters (where teredos are more likely to thrive), but in more freshwater lakes and streams.
However, I’ve been in contact with a friend who is a member of the Vancouver Wooden Boat Society to ask him if he is aware of an increase in teredo activity in the Vancouver harbour. He inquired of some of the older members and reported back that teredos have’t been a big problem here; however as the water temperature creeps upward, it is becoming gradually worse.
Look out, Vancouver… the Teredos (May) Strike Back!
¹This Smithsonian Marine Station site shows these salt and water temperature tolerances measured for toredos in various locations around the world.
²J. S. Matthews, Early Vancouver, Volume 7, p. 132.
³Matthews, Volume 7, pp. 50-51.
∞Vancouver Daily World 6 February 1920, p.14.