Poaching accounts for the loss of up to 60% red coral biomass in the Medes Islands Marine Reserve, according to an article published in the journal Conservation Biology, signed by the first author Cristina Linares, a biologist from the University of Barcelona's Department of Ecology. The article reports the first study of poaching and its effects in the marine reserve and raises the alarm about the impact of recreational diving on the coral population of the Medes Islands.
The article is also signed by the experts Bernat Hereu and Mikel Zabala (Department of Ecology, UB), Joaquim Garrabou (Institute of Marine Sciences, CSIC), David Díaz (Spanish Institute of Oceanography), Christian Marschal (Center of Oceanology of Marseille) and Enric Sala (Centre for Advanced Studies of Blanes, CSIC).
The "reserve" effect in the Medes area has improved the conservation of many marine species in their natural habitats. In the case of red coral (Corallium rubrum), an endemic Mediterranean species that is harvested both legally and illegally along the Catalan coastline, the study finds that poaching is the principal threat to colonies of this prized marine invertebrate.
Poaching, the greatest threat
In ancient times, Greeks and Romans valued red coral for its use in jewellery, a commercial exploitation that survives to this day. As Cristina Linares explains, "Coral is a very fragile and vulnerable organism, with an extremely slow growth rate of 0.3-0.5 mm of basal diameter per year. In the western Mediterranean Basin, with the exception of some French marine reserves, most red coral colonies are in a very similar situation, exhibiting very small stems."
During the study, carried out over the period from 1992 to 2005, the experts monitored the basal diameter and density of Corallium populations inside out outside the Medes Islands Marine Reserve, comparing their results with the data for marine protected areas in France (Banyus, Carry-le-Rouet and Scandola), where fishing and diving are not permitted. The results show that the red coral colonies in the Medes area are smaller than expected and below the levels observed in protected areas in France, which are free of fishing and diving activity. The study also found that the species is more abundant in the Medes Island Marine Reserve than in outlying areas.
"The impact of poaching causes irretrievable losses in populations of Corallium rubrum," says Cristina Linares, "which is why new guidelines on protection from fishing and diving should be considered to preserve the populations." The expert Bernat Hereu, co-author of the study, adds that "On the Catalan coast, coral is found at lesser depths than in other areas of the Mediterranean. This is financially beneficial to the tourist sector but also means that poachers can reach colonies with little difficulty."
Replanting coral on the sea bed
In addition to their applied research, aimed at supporting the development of new management and conservation tools, the experts also work with the Montgrí, Medes Islands and Baix Ter natural parks to reverse the effects of poaching on Corallium colonies. This initiative, contributed to by the researcher Joaquim Garrabou from the Institute of Marine Sciences (ICM-CSIC), will lead to new legal protocols for confiscating coral from poachers and replanting it on the sea floor.
"This is a stop-gap measure," notes Cristina Linares, "that will never be a definitive solution to the coral problem. It is a way of recovering part of the coral that is still alive, replanting it on the rocky substrate and creating a natural community that is integrated into the marine ecosystem." Reintegrating colonies retrieved from poachers is a delicate operation, the success of which depends on many factors. To gauge its progress, we will need to constantly monitor the replanted colonies too see whether they have established themselves as viable populations.
Red coral: protection through legislation
Many of the large coral colonies found along the Catalan coast have disappeared as the result of human activities. The genus Corallium, which is protected by the Barcelona Agreement, has not yet been included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Applying the results of this research and increasing efforts in the area of management and conservation will be the main challenges in maintaining the beauty of Catalonia's coastal coral populations. This is the view of the UB experts involved in the study, members of the former Marine Zoobenthos Ecology Group and current MedRecover research group, which studies the direct and potential combined effects of global change on the conservation of marine biodiversity.
It is over thirty years since the UB began to conduct research in the Medes Islands, one of the most ecologically valuable marine reserves in the Mediterranean. The earliest descriptive studies of marine communities, begun in 1973, led to the publication of the book Els sistemes naturals de les illes Medes (1983), by the UB professor of ecology Joandomènec Ros and the CSIC experts Ignasi Olivella and Josep M. Gili, which became a key reference work in future initiatives for the protection of natural spaces.
- Linares, Cristina; Garrabou, Joaquim; Hereu, Bernat; Díaz, David; Marschal, Christian; Sala, Enric; Zabala, Mikel. Assessing the Effectiveness of Marine Reserves on Unsustainably Harvested Long-Lived Sessile Invertebrates. Conservation Biology, 18 NOV 2011 DOI: 10.1111/j.1523-1739.2011.01795
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