World Congress of Malacology Antwerp ... - Unitas Malacologica

Genetic diversity of an exploited population of banded Murex, Hexaplex (Trunculariopsis)
trunculus: Implications for stock enhancement and conservation
González-Tizón, Ana 1 ; Fernández-Moreno, Mercedes 1 ; Vasconcelos, Paulo 2 ;
Gaspar, Miguel B 2 ; Moreno-Escalante, Óscar 3 ; Martínez-Lage, Andrés 1
1. Departamento de Biología Celular y Molecular, Universidade da Coruña, A Zapateira s/n, E-15071
La Coruña, España,
Email: andres@udc.es; hakuna@udc.es
2. Instituto Nacional de Investigação Agrária e das Pescas (INIAP/IPIMAR), Centro Regional de
Investigação Pesqueira do Sul (CRIPSul), Avenida 5 de Outubro s/n, P-8700-305 Olhão, Portugal,
Email: pvasconcelos@cripsul.ipimar.pt; mbgaspar@cripsul.ipimar.pt
3. IFAPA - Centro Agua del Pino, Ctra Cartaya - Punta Umbría s/n, Apdo 104, E-21071 Huelva,
España,
Email: oscar.moreno@juntadeandalucia.es
The banded murex, Hexaplex (Trunculariopsis) trunculus, is distributed throughout the
Mediterranean Sea, whereas in the Atlantic Ocean occurs from the Portuguese coast southward to
Morocco and to Madeira and Canary Archipelagos. In Portugal, T. trunculus is subjected to an
artisanal fishery in the Ria Formosa lagoon (southern Portugal), traditionally undertaken by hand
harvesting during low tide and with an illegal fishing gear locally known as “wallet-line”.
Additionally, the agglomerations of females during collective spawning are subjected to hand
harvesting during low tide and scuba divers operating illegally inside the lagoon have also been
collecting substantial quantities of this species.
Probably due to over-fishing, detrimental collecting practices and disregard to the minimum landing
size, the abundance of T. trunculus in the Ria Formosa decreased noticeably over the last years,
possibly indicating over-exploitation. Altogether, the growing demand for gastropods in the seafood
market, the reduced catches and high commercial value of the banded murex, have raised
expectations about the potential of T. trunculus for molluscan aquaculture, both for commercial
production and for stock enhancement in the Ria Formosa.
Analyses of genetic diversity are required to establish adequate and successful stock enhancement
programmes. In this context, molecular analyses of nuclear (5S rRNA) and mitochondrial (12S
rRNA, 16S rRNA and Citochrome Oxidase subunit I) genes were performed to investigate the
genetic diversity of T. trunculus from the Ria Formosa and compare it with two adjacent populations
of this species (Ria de Alvôr - southern Portugal and Río Piedras - southern Spain), which could
eventually constitute source-populations for stock enhancement in the Ria Formosa. A low genetic
variability was detected among populations, with a higher similarity between Portuguese populations
comparatively to the Spanish population. These slight inter-population differences allow for the
potential use of any of these source-populations for stock enhancement initiatives.
Evolution of the molluscan assemblage on a seagrass meadow (Zostera marina) affected by
trawling activity
González, Alexandre R.; Maestre, Manuel J.; Ruiz, Aurora; Gordillo, Ismael; Sánchez, Emilio;
García-Gómez, José C.
Laboratorio de Biología Marina, Facultad de Biología, Departamento de Fisiología y Zoología,
Universidad de Sevilla, Avda. Reina Mercedes 6, 41012, Sevilla, Spain,
Email: bioroi@gmail.com
A study to identificate the composition of the molluscan assemblages associated to a Zostera marina
meadow in the coastal waters of Malaga (South Spain) was started in the summer of 2004. In 2005
the meadow was severely affected by illegal trawling activities, losing most of the vegetable cover.
The degradation process continued in 2006 with no signs of recovery.
The annual sampling was carried out in summer and was located on each of the 4 cardinal meadow
edges (North, South, East, West). The taxonomic identification was carried out to the species level.
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