Ascidians at the Pacific and Atlantic entrances to the Panama Canal

Mary Carman,Rosana Rocha,James Roper,Stephan Bullard,Mimi Carman,Gretchen Lambert,Elisabete Vail,Anne Goodwin,Jennifer Dijkstra

doi:10.3391/ai.2011.6.4.02

Abstract

The Panama Canal region is susceptible to non-native species introductions due to the heavy international shipping traffic through the area. Ascidian introductions are occurring worldwide but little is known about introductions at the Panama Canal. Surveys were conducted in 2002, 2008, and 2009 within the Pacific and Atlantic entrances to the canal. We found a high diversity of ascidians on both sides of the canal, dominated by non-native species; six species occurred at both Pacific and Atlantic Panama sites. This is the first report of Polyandrocarpa anguinea and P. sagamiensis in Atlantic Panama waters and Ascidia incrassata, Ascidia sydneiensis, Botrylloides nigrum, Botryllus planus, Didemnum perlucidum, Diplosoma listerianum, Microcosmus exasperatus, Polyandrocarpa zorritensis, Polyclinum constellatum, Symplegma brakenhielmi, Symplegma rubra, and Trididemnum orbiculatum in Pacific Panama waters. The canal may serve as a major invasion corridor for ascidians and should be monitored over time.

Highlights

The narrow isthmus of Central America separates the Pacific and Atlantic Oceans and the Panama Canal has provided intra-oceanic passage for commercial and recreational ships for almost a century
We found ascidians attached to bricks, rocks, corals, bivalves, barnacles, mangrove roots, docks, pilings, mooring lines, and a shipwreck in subtidal shallow waters
At the Pacific entrance to the Panama Canal we found 20 taxa: 17 identified species (3 native, 7 introduced, 7 cryptogenic species), a presumed new species (Ascidia sp.), and two taxa identified only to genus (Botrylloides sp. and Didemnum sp.)

Summary

Introduction

The narrow isthmus of Central America separates the Pacific and Atlantic Oceans and the Panama Canal has provided intra-oceanic passage for commercial and recreational ships for almost a century. Due to the heavy international shipping traffic through the area, the Panama Canal region is susceptible to non-native species introductions. Cohen (2006) documented the presence of non-native invertebrates at the Panama Canal, including the ascidians Botryllus schlosseri (Pallas, 1766) on the Pacific side of the canal and Botrylloides perspicuum Herdman, 1886, Cnemidocarpa irene (Hartmeyer, 1906), Diplosoma virens (Hartmeyer, 1909), and Polyandrocarpa zorritensis (Van Name, 1931) on the Atlantic side of the canal. Transport of exotic species around the world is increasing due to increased activities associated with international trade and movement of people (Cohen 1999), and an increased volume of shipping traffic is concentrated at canal zones (Cohen 2006). The Caribbean coast has more stable oceanographic conditions, small tidal range (

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E Pacific