Recovery of Endangered Mollusc Patella Ferruginea Population by Artificial Inert Mobile Substrates in Mediterranean Sea

PROJECT DESCRIPTION

BACKGROUND

The problem of preserving the ferruginous limpet (Patella ferruginea) manifested during the last decades of the twentieth century. This species is endemic to the western Mediterranean Sea and, for the abundance of shells on archaeological sites, it is known that during the Neolithic it was distributed virtually throughout the coastline. But their range has been undergoing a gradual and marked reduction, increased over the nineteenth and twentieth centuries, and particularly in the second half of the last century.

 

The population on the Spanish coast of the Iberian Peninsula reduced to its southernmost part, formed by small groups of individuals which, given their number and size, may not constitute core players. The species still retains some stocks in very specific enclaves of the coast of Corsica and Sardinia and small islands nearby. There are also small populations in Tunisia and other small islands near the Strait of Sicily. However, the only current populations with a high contingent of specimens are all located in the North African coast, noting especially four locations: Chafarinas Islands, Melilla, and Ceuta (all Spanish) and Habibas Islands (Algeria).

 

For these reasons, in line with the objectives of the Strategy for the Conservation of ferruginea limpet (Patella ferruginea) in Spain (MIMAM, 2008), the diversification of the geographical distribution of P. ferruginea, through empowerment and the establishment of viable reproductive specimens in a higher number of locations, is one of the key factors that could decrease the true risks of extinction of the species in a short or medium term.

OBJECTIVES

The main objective of the project was to design, test and implement new techniques and methods for the management of Patella ferruginea specimens based on the knowledge of its biology and ecology and on previous scientific experience, which could contribute significantly to the recovery of the species by repopulation or their introduction into new areas, in line with the National Strategy Conservation for the species.

 

Specific objectives were the following:

1. To move, with the highest success rate, 500 specimens of this limpet species from a donor area with large population to a receiving area with population in regression.
2. Use artificial inert mobile substrates (AIMS) to collect naturally fixed larvae of P. ferruginea in which the specimens will form the home scar, so that the specimens could be moved without separate from the substrate.
3. Obtain the most suitable design for AIMS to be used as a more effective measure for the translocation of specimens.
4. Develop protocols for the management of the species and its habitat and disseminate to the authorities responsible for their management and the scientific community.
5. Develop a demonstrative integrated management scheme for the species Patella ferruginea, in which public authorities, research groups and private companies are involved, foreseeing the future inclusion of additional stakeholders such as fishermen's associations, environmental organizations, diving groups, etc.
6. Promote a change of attitude in the population and get the social support and participation needed to reduce main threat for the species through the design and implementation of dissemination and environmental education and training activities.

RESULTS

First of all, it is important to point out that both the methodology developed within LIFE REMoPaF and all lessons learnt about the translocation of ribbed Mediterranean limpet (Patella ferruginea) by using Artificial Inert Mobile Substrates (AIMS), seem to constitute an outstanding demonstration of an integrated management scheme for this species.

 

The project has contributed to developing an innovative production system of AIMS, which were used to translocate endangered limpets from Melilla Port to Algeciras Bay. Thus, following the analysis of seven different versions and combining different technologies and characteristics (3D and conventional construction techniques), the beneficiaries designed and installed the most viable version of the so-called AIMS v6, by means of 3D technology to construct the mould, which obtained the appropriate roughness and resistance to reproduce the surface of the Patella ferruginea natural habitat. Finally, 650 AIMS were installed.

 

Regarding the translocation campaigns, the beneficiaries carried out three campaigns throughout the project period, in which 125 AIMS were transported from Melilla Port to La Línea Port (Algeciras Bay, Cádiz), with a result of 188 individuals translocated of the endangered limpet Patella ferruginea. However, the ceiling of 500 individuals was not reached because the distribution rate of the species in the Donor Area (Melilla Port) was 6 times lower than foreseen at the project objectives' design. Nevertheless, the objective to translocate a viable population to Algeciras Bay can be considered as reasonably implemented.

 

Overall, the project was completed satisfactorily, and all conservation, monitoring and dissemination actions were implemented in compliance with the proposal and respecting, for most of the actions, the set schedule. Moreover, even though the dissemination tasks were implemented successfully, the website had to be updated just before the project's end.

 

Scientific article published in Frontiers in Marine Science: Joining technology and biology to solve conservation problems through translocation in the endangered limpet Patella ferruginea. The article summarises the research and the main scientific and technical evidence on the effectiveness of the relocation methodology designed in the LIFE REMoPaF project.

 

Finally, regarding the project management, it is important to highlight the technical change to the third phase translocation, in order to "make a significant contribution to adjusting the methodology for developing a demonstration integrated management scheme for the species". Thus, the translocation methodology that is in place is one of the main objectives of the project, which was satisfactorily achieved, and throughout the project implementation, technical and financial management were also carried out without relevant problems. Therefore, the project has shown interesting lessons learnt regarding the translocation methodology of mollusks like Patella ferruginea. Therefore, after achieving a good survival rate (in fact, beneficiaries have successfully translocated 188 individuals within this LIFE project period and the survival rate reached 67% at the end of the project), the translocation by means of AIMS can be found as a solution for this endangered species, or at least a step forward in the species conservation.

 

The recent publication of the new conservation strategy for this species, approved by the Environment Conference (led by the Ministry of Ecological Transition) in October 2023, mentions the project and its mains results, giving it at example of a possible line of future research.