Final Report Summary - CORGARD (Mediterranean red coral management and conservation)
Final publishable summary report
1. Executive summary
Octocorals are keystone species in the Mediterranean coralligenous assemblage since they provide three-dimensional complexity, increasing habitat biodiversity (Gili and Coma 1998; Ballesteros 2006). Several of the most common Mediterranean octocoral species have been affected by mass mortality (Cerrano et al. 2000; Garrabou et al. 2001, Bramanti et al. 2005; Cupido et al. 2009), putatively caused by global climate change. Recovery from disturbance can take decades, due to low population resilience and slow recolonisation (Linares et al. 2005; Santangelo et al. 2007), thus, in some cases, active restoration could be desirable.
Restoration techniques such as transplantation of coral fragments, branches and whole colonies have been pioneered since the 70s through pilot studies, but, until recently, this management option has not been widely applied (Edwards et al. 1998; Lindahl 1998). Although recent technical progresses in colony transplantation resulted in an increase of population recovery, theoretical concepts have not yet matured to a well-established discipline (Rinkevich 2005). Transplantation techniques imply manipulation of colonies that could result in high mortality of the transplants (Yap et al. 1992; Edwards et al. 1998; Fujiwara and Omori 2004). Therefore alternative techniques based on transferring colonized settlement plates into damaged habitat may give better results than transplanting adult colonies (Weinberg 1979; Oren and Benayahu 1997; Bramanti et al. 2007).
Red Coral (Corallium rubrum, L. 1758) is a precious octocoral, endemic to the Mediterranean Sea . The high economic value of the axial calcium carbonate skeleton of this species, carved into pieces of art by a specialized jewellery industry, led to a harvesting pressure that reduced the commercial stocks (Santangelo et al. 2004; Tsounis et al. 2007, 2010). Therefore it is meaningful to develop restoration strategies, keeping in mind that: (a) it is desirable to actively improve the natural recovery of communities (Edwards et al. 1998); (b) despite the increasing stress on Mediterranean coral populations, there has been relatively little efforts in developing active restoration tools (Linares et al. 2008a); (c) there are few studies on restoration techniques on Mediterranean octocorals in comparison to tropical corals (Oren and Benayahu 1997; Bramanti et al. 2005; Guest et al. 2009); (d) natural calcareous substrates (marble tiles) were discovered to be highly suitable for the settlement of coralligenous epibenthic invertebrates, such as Corallium rubrum (Bramanti et al. 2007).
The project CORGARD was designed to make advances in the conservation or the red coral (Corallium rubrum) by means of coral gardening techniques. The international community needs to develop one hand tools for the management of this precious species, and on the other hand tool for the restoration of depleted banks. Coral gardening techniques have been developed for tropical corals but until recently they remained poorly used for the high economic costs. In the Mediterranean sea coral gardening technique have never been applied. Moreover C.rubrum is one of the most precious marine species and the recovery of depleted banks could be economically feasible. In the framework of this project a study on the economic value of C.rubrum alternative to the value of raw material for jewellery have been performed. Techniques of transplanting and gardening have been developed also if the slow growth rates of the species and the fact that it reproduce only once e year made the results difficult to have at the short time scale of the project. Monitoring and data acquisition are still going on. The CORGAD project cooperated with the BENTOLARV project (P.I. Dr. Sergio Rossi) in order to study the biochemical balance of C. rubrum colonies from different sites. The cooperation with the FP7 project MedSeA (Coordinator Dr. Patrizia Ziveri) opened the possibility for an exciting new field of investigation related to the effects of Ocean Acidification. Results have been presented at the International Symposium on Ocean Acidification in Monterey (USA) and a paper in under revision.
Porposed objective and achievement:
The project was organized in different objective. Apart of the initial objective, in the course of the project new question arised and other species were involved. Particularly the project gave the possibility to a wider research line focussed on other Mediterranean benthic suspension feeders. The techniques proposed and developed in the framework of the project (initially targeted to Corallium rubrum) have been applied also to Paramuricea clavata, Eunicella singularis, Eudendrium racemosum, and to Cold Water Coral (CWC) communities.
1) Settlement of red coral larvae on semi-artificial substrate
A system for the settlement of red coral colonies base don the galvanic electro deposition of CaCO3 was developed in the course of the project. I the specific larval settlement was studied on three different CaCO3 substrata, lithogenic (marble), electro-accreted calcium carbonate in the presence and in the absence of cathodic polarisation. The last two substrata consisted of stainless steel plates galvanically coupled with Zn anodes (Fig.1). The electrochemical characterization of the settlement device was studied in order to investigate correlations between cathodic parameters (polarisation potential, current density, calcareous deposit composition) and larval settlement. The results obtained in the natural habitat (at 35 m depth) showed that settlement was five times lower on the electroaccreted aragonite in the presence of low cathodic current densities compared to both marble tiles and electro-accreted aragonite in the absence of polarisation. These last two substrata showed similar settlement values. The implications of these findings on restoration strategies for C. rubrum are discussed.
Results were published in peer-reviewed papers.
2) Gardening of newly settled colonies
Larvae settled on marble tiles and galvanic electro accreted iron tiles were transferred in aquarium tanks in the facilities of the ICM of Barcelona (Fig. 2). Competitors were removed in order to raise the survival probabilities of the newly settled colonies. Settled tiles were maintained 1 year in the aquarium facilities.
Survival rates resulted significantly higher than in the natural environment. Plates were re-transplanted in the natural environment after 1 year of permanence in the aquarium tanks. Survival rates will be followed during the next years
3) Direct Transplantation of adult colonies
Adult colonies were collected in the field, reared in aquarium facilities for one year in order to have larval release. Unfortunately it was not possible to obtain the release of larvae in aquarium tanks. Nevertheless colonies were transplanted in natural environment in a place were the local population was depleted by illegal harvesting. Transplanted colonies were monitored and are still under monitoring in order to determine survival rate and recruitment.
The experiment was extended to another important species of the coralligenous: Paramuricea clavata. Differently by the red coral, it was possible to obtain larvae from Paramuricea colonies transplanted in the aquaria (Fig. 3). Results were part of a Master thesis and a manuscript is under preparation.
4) Transplantation of colony fragments (“coral nubbins”)
Coral fragments have been obtained by wild colonies and by colonies sequestrated by authorities from a illegat fisherman. Survival of the fragments was high and revealed to be a possibility for the utilization of tips of harvested coral. Tips of the colonies does not have any economical value and a method to transplant the tip of legally harvested colonies could help the sustainability of the harvesting. Due to the slow growth of the colonies the method is still under development. Mortality, colony growth and number of polyps are monitored.
5) Effects of population structure on transplanted corals
In order to develop and study the best transplantation pattern and method, three groups of juvenile colonies were transplanted in the Cap de Creus Marine Park (NE Spain), The first group of transplants were patterned with high colony abundance, as observed in young populations, and the second with low abundance, as observed in older, deep water populations. Mortality and colony growth are still under monitoring.
9) Socioeconomic analysis
A socio economic study is going on in cooperation with the FP7 project MedSeA. Estimates of the cost of population damage and restoration allows the production of a decision flowchart that enables ecosystem managers to evaluate various options. Moreover the economical value of living colonies will be confronted with the value of colonies as raw material for jewellery. Moreover a citizen science approach was adopted in order to have data on the perceived value of red coral as living resource. The sustainable value of living colonies linked to associated biodiversity could strengthen management and conservation actions. Results will be published in peer-reviewed papers.
10) Population dynamics of other suspension feeders
The study of the dynamics of red coral performed in the project gave the opportunity to make comparisons with other cnidarian. In particular a comparative study of the dynamics of long lived species and fast growing species have been performed and published in peer reviewed journal.
11) Other benthic suspension feeders
As a part of the project I was interested in the comparative study of other benthic suspension feeder in order to explore the possibility of the application of the techniques developed in the course of the project to other systems. The investigation resuted in 2 published papers on Eunicella sp and on cold water corals with Dr. A.Gori and the preparation of other manuscript that are now submitted.
12) Ocean Acidification
The techniques developed in the course of the project and the facilities used for the implementation of the project (Fig. 4) opened the opportunity to investigate on the effects of Ocean Acidificatio on the targeted species. Joining the FP7 MedSeA project I performed a long term study on the effects of Ocean Acidification on Corallim rubrum. Results have been presented in the course of the International Symposium on Ocean Acidificatio in Monterey (USA) and the manuscript is at the moment under revision in Global Change Biology
1. Executive summary
Octocorals are keystone species in the Mediterranean coralligenous assemblage since they provide three-dimensional complexity, increasing habitat biodiversity (Gili and Coma 1998; Ballesteros 2006). Several of the most common Mediterranean octocoral species have been affected by mass mortality (Cerrano et al. 2000; Garrabou et al. 2001, Bramanti et al. 2005; Cupido et al. 2009), putatively caused by global climate change. Recovery from disturbance can take decades, due to low population resilience and slow recolonisation (Linares et al. 2005; Santangelo et al. 2007), thus, in some cases, active restoration could be desirable.
Restoration techniques such as transplantation of coral fragments, branches and whole colonies have been pioneered since the 70s through pilot studies, but, until recently, this management option has not been widely applied (Edwards et al. 1998; Lindahl 1998). Although recent technical progresses in colony transplantation resulted in an increase of population recovery, theoretical concepts have not yet matured to a well-established discipline (Rinkevich 2005). Transplantation techniques imply manipulation of colonies that could result in high mortality of the transplants (Yap et al. 1992; Edwards et al. 1998; Fujiwara and Omori 2004). Therefore alternative techniques based on transferring colonized settlement plates into damaged habitat may give better results than transplanting adult colonies (Weinberg 1979; Oren and Benayahu 1997; Bramanti et al. 2007).
Red Coral (Corallium rubrum, L. 1758) is a precious octocoral, endemic to the Mediterranean Sea . The high economic value of the axial calcium carbonate skeleton of this species, carved into pieces of art by a specialized jewellery industry, led to a harvesting pressure that reduced the commercial stocks (Santangelo et al. 2004; Tsounis et al. 2007, 2010). Therefore it is meaningful to develop restoration strategies, keeping in mind that: (a) it is desirable to actively improve the natural recovery of communities (Edwards et al. 1998); (b) despite the increasing stress on Mediterranean coral populations, there has been relatively little efforts in developing active restoration tools (Linares et al. 2008a); (c) there are few studies on restoration techniques on Mediterranean octocorals in comparison to tropical corals (Oren and Benayahu 1997; Bramanti et al. 2005; Guest et al. 2009); (d) natural calcareous substrates (marble tiles) were discovered to be highly suitable for the settlement of coralligenous epibenthic invertebrates, such as Corallium rubrum (Bramanti et al. 2007).
The project CORGARD was designed to make advances in the conservation or the red coral (Corallium rubrum) by means of coral gardening techniques. The international community needs to develop one hand tools for the management of this precious species, and on the other hand tool for the restoration of depleted banks. Coral gardening techniques have been developed for tropical corals but until recently they remained poorly used for the high economic costs. In the Mediterranean sea coral gardening technique have never been applied. Moreover C.rubrum is one of the most precious marine species and the recovery of depleted banks could be economically feasible. In the framework of this project a study on the economic value of C.rubrum alternative to the value of raw material for jewellery have been performed. Techniques of transplanting and gardening have been developed also if the slow growth rates of the species and the fact that it reproduce only once e year made the results difficult to have at the short time scale of the project. Monitoring and data acquisition are still going on. The CORGAD project cooperated with the BENTOLARV project (P.I. Dr. Sergio Rossi) in order to study the biochemical balance of C. rubrum colonies from different sites. The cooperation with the FP7 project MedSeA (Coordinator Dr. Patrizia Ziveri) opened the possibility for an exciting new field of investigation related to the effects of Ocean Acidification. Results have been presented at the International Symposium on Ocean Acidification in Monterey (USA) and a paper in under revision.
Porposed objective and achievement:
The project was organized in different objective. Apart of the initial objective, in the course of the project new question arised and other species were involved. Particularly the project gave the possibility to a wider research line focussed on other Mediterranean benthic suspension feeders. The techniques proposed and developed in the framework of the project (initially targeted to Corallium rubrum) have been applied also to Paramuricea clavata, Eunicella singularis, Eudendrium racemosum, and to Cold Water Coral (CWC) communities.
1) Settlement of red coral larvae on semi-artificial substrate
A system for the settlement of red coral colonies base don the galvanic electro deposition of CaCO3 was developed in the course of the project. I the specific larval settlement was studied on three different CaCO3 substrata, lithogenic (marble), electro-accreted calcium carbonate in the presence and in the absence of cathodic polarisation. The last two substrata consisted of stainless steel plates galvanically coupled with Zn anodes (Fig.1). The electrochemical characterization of the settlement device was studied in order to investigate correlations between cathodic parameters (polarisation potential, current density, calcareous deposit composition) and larval settlement. The results obtained in the natural habitat (at 35 m depth) showed that settlement was five times lower on the electroaccreted aragonite in the presence of low cathodic current densities compared to both marble tiles and electro-accreted aragonite in the absence of polarisation. These last two substrata showed similar settlement values. The implications of these findings on restoration strategies for C. rubrum are discussed.
Results were published in peer-reviewed papers.
2) Gardening of newly settled colonies
Larvae settled on marble tiles and galvanic electro accreted iron tiles were transferred in aquarium tanks in the facilities of the ICM of Barcelona (Fig. 2). Competitors were removed in order to raise the survival probabilities of the newly settled colonies. Settled tiles were maintained 1 year in the aquarium facilities.
Survival rates resulted significantly higher than in the natural environment. Plates were re-transplanted in the natural environment after 1 year of permanence in the aquarium tanks. Survival rates will be followed during the next years
3) Direct Transplantation of adult colonies
Adult colonies were collected in the field, reared in aquarium facilities for one year in order to have larval release. Unfortunately it was not possible to obtain the release of larvae in aquarium tanks. Nevertheless colonies were transplanted in natural environment in a place were the local population was depleted by illegal harvesting. Transplanted colonies were monitored and are still under monitoring in order to determine survival rate and recruitment.
The experiment was extended to another important species of the coralligenous: Paramuricea clavata. Differently by the red coral, it was possible to obtain larvae from Paramuricea colonies transplanted in the aquaria (Fig. 3). Results were part of a Master thesis and a manuscript is under preparation.
4) Transplantation of colony fragments (“coral nubbins”)
Coral fragments have been obtained by wild colonies and by colonies sequestrated by authorities from a illegat fisherman. Survival of the fragments was high and revealed to be a possibility for the utilization of tips of harvested coral. Tips of the colonies does not have any economical value and a method to transplant the tip of legally harvested colonies could help the sustainability of the harvesting. Due to the slow growth of the colonies the method is still under development. Mortality, colony growth and number of polyps are monitored.
5) Effects of population structure on transplanted corals
In order to develop and study the best transplantation pattern and method, three groups of juvenile colonies were transplanted in the Cap de Creus Marine Park (NE Spain), The first group of transplants were patterned with high colony abundance, as observed in young populations, and the second with low abundance, as observed in older, deep water populations. Mortality and colony growth are still under monitoring.
9) Socioeconomic analysis
A socio economic study is going on in cooperation with the FP7 project MedSeA. Estimates of the cost of population damage and restoration allows the production of a decision flowchart that enables ecosystem managers to evaluate various options. Moreover the economical value of living colonies will be confronted with the value of colonies as raw material for jewellery. Moreover a citizen science approach was adopted in order to have data on the perceived value of red coral as living resource. The sustainable value of living colonies linked to associated biodiversity could strengthen management and conservation actions. Results will be published in peer-reviewed papers.
10) Population dynamics of other suspension feeders
The study of the dynamics of red coral performed in the project gave the opportunity to make comparisons with other cnidarian. In particular a comparative study of the dynamics of long lived species and fast growing species have been performed and published in peer reviewed journal.
11) Other benthic suspension feeders
As a part of the project I was interested in the comparative study of other benthic suspension feeder in order to explore the possibility of the application of the techniques developed in the course of the project to other systems. The investigation resuted in 2 published papers on Eunicella sp and on cold water corals with Dr. A.Gori and the preparation of other manuscript that are now submitted.
12) Ocean Acidification
The techniques developed in the course of the project and the facilities used for the implementation of the project (Fig. 4) opened the opportunity to investigate on the effects of Ocean Acidificatio on the targeted species. Joining the FP7 MedSeA project I performed a long term study on the effects of Ocean Acidification on Corallim rubrum. Results have been presented in the course of the International Symposium on Ocean Acidificatio in Monterey (USA) and the manuscript is at the moment under revision in Global Change Biology