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VOL. 76 (2), 189-208, 2010 THE IGNORED STOWAWAYS: WORLDWIDE...

antifouling. Un análisis de fluctuación ha demostrado que la adap-
tación genética debida a raras mutaciones espóntaneas, que ocurren
anteriormente a la exposición al TBT, es el mecanismo que le per-
mite a las microalgas adaptarse a la pintura antifouling y su poste-
rior dispersión en el biofouling. Hay alrededor de tres mutantes re-
sistentes al TBT por cada 10–4 células sensibles en la población. Esto
asegura la rápida colonización de la obra viva de los barcos para
viajar largas distancias.

Palabras clave: Adaptación; Biofouling; HABs; Algas tóxicas;
Especies introducidas; TBT.

1. INTRODUCTION

Numerous introduced species (also called exotic, non-indigenous,
or alien species) proliferates worldwide outside its native distributio-
nal range usually as a consequence of human activities. Invasion by
introduced species can change the functions of ecosystems causing
unpredictable emergent novelties, environmental damage and loss in
biodiversity (1). Economic cost assigned to introduced species in USA
was estimated in $138 billion (2).

Marine ecosystems are specially affected by introduced species (3).
As an example, the introduced algae Caulerpa taxifolia represents a
major risk for sublittoral Mediterranean ecosystems (4, 5). Invasion
of toxin producing phytoplankton is particularly worrisome because
of their potentially devastating impacts on aquaculture, fishery and
public health (6-8). Ballast water has been considered the major vector
by which (mainly phytoplankton) have invaded ecosystems worldwide
where they did not previously occur (9-14). Consequently, biocide
treatments and other management strategies are carried out in ballast
water to minimize introduction of alien species (15, 16).

The hypothesis of ballast water as mechanisms of dispersion of
marine organisms is attractive. However, few ships (mainly tankers
and containers) used ballast water (17). Most ships (including
recreational yachts) do not use ballast water. In contrast, any boat
or ship afloat has an underwater body that can be rapidly colonized
by thousands of marine species of algae, crustacean and mollusc
attaching themselves to the hull forming a dense biofouling.

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