Under an agreement between VIMAR and the Parc Natural del Montgrí, les Illes Medes i el Baix Ter, since 2012 we have been conducting a regular monthly sampling of opisthobranch molluscs within the Natural Park, performing scuba diving at different points of the Medes Islands, and at selected points along the Costa del Montgrí.
Until 2009, a total of 46 opisthobranch mollusc species were cited in Medes Islands, according to the literature (Altimira, 1981) and (Ros, 1984) and BIOCAT database (Ballesteros, 2007).
Later, the Grup de Recerca d’Opistobranquis de Catalunya initiated a series of point samplings, developed between 2010 and 2011, that resulted in the extension of the islands opisthobranchs catalog in 30 new species. These data, however, not yet have been published in scientific circles.
During 2012, VIMAR continued this task, with the result of 5 new species that have never been cited before in the Medes Islands. Thus the catalog of opisthobranch molluscs registered in the Medes Islands was expanded up to 81 species, meaning that, despite the Medes Islands are a very limited area, it is of the richest biodiversity places of the entire Catalan coastline.
The 2013 opisthobranch monitoring results in the Parc Natural del Montgrí, les Illes Medes i el Baix Ter were presented on August 7, 2014 by Dr. Manuel Ballesteros of the University of Barcelona, scientific advisor of the VIMAR group. Among other interesting facts, he described 5 new opisthobranchs species that have not been cited before in the Natural Park but could be certified by our samplers.
A monitoring dive at Ferranelles (Medes Islands), December 2013
The 2014 monitoring campaign rendered 957 specimens of 45 different species, 5 species never seen before at the Medes Archipielago because of their small size (about 5 mm) and their camouflaging abilities with their environment.
In 2015 VIMAR extended the monitoring range from the Medes Islands to the nearby Montgrí coast and the Natural Park western influence area , because the low knowledge of opisthobranch populations (and their habitats) in that zone. The monitoring campaign rendered 683 specimens of 56 species, of which 2 species had never been reported before in the Natural Park.
With these results the opisthobranch catalog of the Parc Natural del Montgrí, les Illes Medes i el Baix Ter rises up to 96 different species reported.
Since 2016 we collaborate with Sepia Project, which was born with the aim of improving the cephalopods’ breeding and repopulating the Emporda (Girona, Spain) shores.
Cuttlefish used to lay their eggs on tree branches carried by the rivers or on fishermen pound nets. Today, neither the rivers bring enough water with dragged branches nor the fishermen use pound nets, instead they use nets for their captures every day, often with sepia spawns embedded in the net. Even returned to the sea in good faith, those eggs eventually become fish food.
Due to the large decline in cuttlefish fisheries, fishermen no longer can live on them, and this has economic, social and environmental consequences. Precisely as an answer to these problems the Sepia Project was born.
Thanks to a scientific study conducted by the Montgrí, Medes Islands and Baix Ter Natural Park in collaboration with the Fishermen’s Association of L’Estartit, it has been concluded that the mastic tree (Pistacia lentiscus) branches are preferred by these cephalopods to tie their eggs on, and therefore they designed a system to sink a 1,000 meters line with mastic branches tied where these cephalopods can lay their spawn.
Initiative results periodical check
VIMAR collaborates in fortnightly dives monitoring, bringing our wide experience with underwater fauna and helping on the photographic documentation of the evolution of the project.
The promoters of this pioneer project, and an European reference in its area, are the fisheries technician Isaac Moya and the biologist Boris Weitzmann, along with the Fishermen’s Association of L’Escala, with the support of L’Escala City Council, Hostal Empúries, Orca Diving, L’Escala Nautic Club, Quercus Sapiens, Rycsa, Tònic and the Spanish Marine Science Institute (CSIC).