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Volume 22
Number 2
Fall 2004
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[Thumbnail photo]. The Atlantic periwinkle, <i>Littorina saxatilis,</i> arrived in San Francisco Bay with shipments of Maine baitworms.<br>
CREDIT: ANDREW N. COHEN Invasions in the sea

By Andrew N. Cohen
Published: 4 Sep 2015 (online)  •  14 Sep 2015 (in print)
  Worm attack
Marine invaders
On the move
Marine invasions and the National Park System
Managing invasions
The big picture
Literature cited
About the author
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Worm attack

Needing a base on the Pacific Coast in 1852, the U.S. Navy went searching for a site that was “safe from attack by wind, wave, enemy, and marine worms” (Lott 1954). The attack worm that worried the Navy was the native Pacific shipworm, Bankia setacea. Shipworms bore tunnels in wood, severely damaging wooden pilings and ship hulls.

The Navy built its base in the northern part of San Francisco Bay, where the water is too fresh for the Pacific shipworm. No enemies attacked until an Atlantic shipworm, Teredo navalis, which tolerates fresher water than its Pacific cousin, arrived in the bay. The Atlantic shipworm multiplied rapidly and proceeded in 1919 to bore its way through the available habitat, dropping wharves, piers, ferry slips, and other maritime facilities into the water at an average rate of one major structure every two weeks for a period of two years (fig. 1). In current dollars, the worm caused between $2 billion and $20 billion in damage.

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This page updated:  29 October 2006

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From the Guest Editor(s)
Information Crossfile
Book Reviews
Short Features
Meetings of Interest
Masthead Information
The challenge of effectively addressing the threat of invasive species to the National Park System
A retrospective on NPS invasive species policy and management
Assessing the invasive species issue
The role of fire and fire management in the invasion of nonnative plants in California
  Invasions in the sea
Under water and out of sight: Invasive fishes in the United States
Ecological effects of animal introductions at Channel Islands National Park
Hemlock woolly adelgid and the disintegration of eastern hemlock ecosystems
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