Friday 21 December 2012

An invasive Serpulid Worm in the La Encrucijada Biosphere Reserve, Mexico.

The Serpulid Worm Ficopomatus uschakovi was first described from Sri Lanka in 1960. Like all Serpulid Worms is an encrusting, sessile Polychaete that secretes a tube of calcite (calcium carbonate) in which it dwells. Unlike most other Serpulids Ficopomatus uschakovi inhabits brackish waters in estuaries and lagoons rather than fully saline waters. It can form large, reef-like masses and rapidly dominates ecosystems where it is present, outcompeting other invertebrates such as Barnacles, Oysters and Mussels.

In the 1970s the species was found to be living along the West Coast of Africa, where colonies were reported to have first appeared in the 1950s. Since this time the species has been found in the Philippines, Indonesia, Australia, Brazil and Venezuela. Because of its ability to modify ecosystems it is considered to be an invasive pest, associated with contamination by introduced with Shrimp farms; many invasive marine organisms are associated with ballast water and hull fouling of shipping, but since Ficopomatus uschakovi is not thought able to colonize fully marine waters this seems improbable for this species.

In a paper published in the journal ZooKeys on 5 November 2012, Rolando Bastida-Zavala and Socorro García-Madrigal of the Laboratorio de Sistemática de Invertebrados Marinos at the Universidad del Mar describe the discovery of colonies of Ficopomatus uschakovi in coastal lagoons in  La Encrucijada Biosphere Reserve in Chiapas State, on the south coast of Mexico.

Ficopomatus uschakovi from La Encrucijada Biosphere Reserve. (A) tubes
on mangrove roots. (B) Tubes on the shell of the gastropod Thaisella kiosquiformis. (C) Mangroves in the collecting site. (D) Tubes forming small aggregations. (E) Large, single tube. (F) Complete specimen in dorsal view. (G) Complete specimen with mass of sperm attached to the abdomen. (H) Operculum in dorsal view. (I) Operculum in aboral view. Bastida-Zavala & García-Madrigal (2012).

There are no Shrimp farms in La Encrucijada Biosphere Reserve, and the nearest port is at Puerto Chiapas, 70 km to the south. It is therefore unclear how the Worms reached the lagoons, suggesting that they have a means of dispersal that scientists are unaware of. At the moment the infestation appears limited in scope, with no reef-like structures observed. How the Worms will affect the reserve in the future remains unclear; Bastida-Zavala and García-Madrigal recommend that the situation should be monitored carefully.

(A) World-wide distribution of Ficopomatus uschakovi; circles represent previously described colonies, the triangle the new colonies described in this study. (B) Study area and the localities where specimens of Ficopomatus uschakovi were recollected. 1: Zacapulco; 2: Barra San Juan; 3: Las Garzas boat pier. Bastida-Zavala & García-Madrigal (2012).

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