Cold-water corals research in the lab and in the field: (1) growth rates of four CWC species maintained in aquaria, (2) new research areas: the Galicia Bank and the Avilés canyon (Atlantic and Cantabrian Sea), a scientific and methodological approach

Growth rates of 4 Cold-water Coral (CWC) species (Madrepora occulata, Lophe/ia pertusa, Desmophyllum cristagalli and Dendrophyllia cornigera) from the Mediterranean Sea have been measured under the same and controlled laboratory conditions over a nine months period. Results showed that M. occulata grew faster than the other three species, which presented similar growth rates. These results are discussed and also compared with the growth of tropical coral species maintained in aquaria, but in different light and temperature conditions, which corresponded to the usual culture conditions of these corals. It appeared that the zooxanthellate tropical coral Galaxea fascicularis exhibited similar growth rates than the CWC M. oculata. Further we present new research areas on the Atlantic and Cantabrian continental margin, the Galicia Bank and the Aviles canyon, which are part of the zones studied in the Spanish LIFE project INDEMARES, as well as possible targets as Marine Protected Areas (MPAs) for the NATURA 2000 network. Both areas are studied considering an ecosystem approach, aboarding an integrated study of the physical scenario (hydrography, geomorphology), all ecosystem compartments (fish, endo-, epi-, and suprabenthic and benthopelagic fauna) and the trophic relationships between them. All this information, together with the study of the impact of the fisheries working in the areas, will be integrated in a trophodynamic mass-balance model and will be used to identify vulnerable ecosystems (VE) (as the CWC habitats are) and essential fish habitats (EFH). This methodological approach offers a holistic view of these deep-sea ecosystems and can be used to design more effective and successful management strategies for MPA

The Exploitation and Conservation of Precious Corals

51 pages, 5 figures, 2 tablesPrecious corals have been commercially exploited for many centuries all over the world. Their skeletons have been used as amulets or jewellery since antiquity and are one of the most valuable living marine resources. Precious coral fisheries are generally characterized by the ‘boomand- bust’ principle, quickly depleting a discovered stock and then moving on to the next one. Most known stocks are overexploited today, and populations are in decline. The unsustainable nature of most fisheries is clearly revealed by analyzing all available data. Precious corals belong to the functional group of deep corals and are important structure-forming organisms, so called ecosystem engineers, that provide shelter for other organisms, increasing biodiversity. Yet, their management is usually focused on single species rather than a holistic habitat management approach. This review compares the biology of precious corals as well as the historical ecology and the socioeconomy of their fisheries to improve precious coral management and conservation. The analysis demonstrates that a paradigm shift is necessary in precious coral exploitation, not only to conserve habitats of high biodiversity but also to achieve sustainable fisheries and stabilize a specialized jewellery industryPeer Reviewe

Patterns of variation in recruitment and post-recruitment processes of the Mediterranean precious gorgonian coral Corallium rubrum

7 pages, 6 figures, 3 tablesThis research seeks to quantify recruitment, early survival and early colony growth in different populations of the precious Mediterranean red coral. Although basic to our understanding of red coral ecology and population dynamics, these early life-history descriptors are still poorly understood. To fill this lack of knowledge, marble settlement tiles were placed at 35 ± 1 m depth within 3 populations of Corallium rubrum dwelling in the coralligenous habitat of different geographic areas of the north-western Mediterranean: Calafuria and Elba Island (Italy), and Medes Islands MPA (Spain), following a multifactorial ANOVA model and sampled photographically for four years (2003–2006). Overall, 517 red coral recruits settled on the tiles during the experiment, 189 of which (126 at Calafuria and 63 at Elba) were still surviving, in 2007, when the tiles were removed. The recruitment density at Medes was only one tenth of that at Calafuria and Elba (0.56 ± 0.21 vs. 6.06 ± 1.75 and 4.66 ± 1.01 recruits dm− 2, mean ± SE). No colony survived after four years at Medes, where the lowest recruitment rate was also found. As the age of each new settled colony was known, it was possible to measure the early growth rates of individual colonies. The growth rates thus obtained were two to three times higher than that measured in older colonies and differed significantly between the geographic areas (the growth of colony basal diameter was 0.68 ± 0.02 and 0.59 ± 0.19 mm/year at Calafuria and Elba), while no significant difference was found between the actual colony growth and that previously measured in the former area. A test for secondary substrate selectivity, carried out in one area, showed that red coral preferentially settles on tubes of Serpulida than on other encrusting organisms. However, since recruitment density at Medes was lower despite the four-fold higher cover of Serpulida found there, other factors, intrinsic to the populations, such as different size–age structures or densities, leading to different larval output, may likely have determined red coral recruitment rates in the studied areasThis research was supported by the common Italy–Spain exchange project: Proyecto Cooperación Csic/Cnr 2004t0040 and Azioni Integrate Italia-Spagna 2008. GS was funded by the PRIN 2007 project 200777BWEP: Mathematical population theory. LB was funded by Marie Curie IEF (CORGARD, Project No. 221072) and SR was funded by Ramón y Cajal contract (RYC-2007-01327). We thank Fischer Italy for economical support and A. Cafazzo for his revision of the English textPeer reviewe

Determination of Corallium rubrum population age structure

International Workshop on Red Coral Science, Management, and Trade: Lessons form the Mediterranean, 23-26 September 2009, Naples, Italy.-- 4 pages, 2 figuresManagement approaches based on a detailed knowledge of specific population demographic features are fundamental to ensure long-term exploitation sustainability (Knittweis et al. 2009). Demography focuses on the specific dynamics of each population, allowing to project population structure over time. This approach allows setting out local conservation strategies for wildlife and for exploited species structured into discrete local populations, such as the Mediterranean red coral (Abbiati et al. 1993). Regarding corals, long-term studies are scarce due to their slow growth and longevity (Connell 1997; Garrabou and Harmelin 2002). Because of its high economic value, the precious Mediterranean red coral Corallium rubrum (Cnidaria, Octocorallia, Gorgonacea) has been harvested for more than 2000 years and its shallow-water populations (living between 20 and 70 m depth), indicate a regression and even a partial economic extinction (Tsounis et al. 2007). Demographic studies based on sound age structure and growth rate assessment in different populations are nevertheless scarce (Santangelo et al. 2009). In this study we compared the age structure and the basal growth rate of two shallow Corallium rubrum populations dwelling in two marine protected areasThis study was funded by the Common research project between the University of Pisa, Department of Biology (Italy) and CSIC-ICM (Spain): “Population dynamic of Corallium rubrum.”Peer Reviewe

Applying cathodically polarised substrata to the restoration of a high value coral

12 pages, 7 figures, 1 tableLarval settlement of the high value red coral, Corallium rubrum, was studied on three different CaCO3 substrata, viz. 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. 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 electro-accreted aragonite in the presence of low cathodic current densities (i ≤ 1 μA cm−2) 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 discussedL.B. was funded by Marie Curie IEF (CORGARD, project No. 221072) and S.R. by a Ramon y Cajal contract. Part of the project was funded by the Italy–Spain exchange program UNIPI-CSIC and PRIN 2007. Thanks to Fischer Italia and SSI Italia for support and to BDK for the UBS 40 SCR unit used for the underwater samplingPeer reviewe

Experimental comparison of skeletal growth rates in the cold-water coral Madrepora oculata Linnaeus, 1758 and three tropical scleractinian corals

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Prey-capture rates in four Mediterranean cold water corals

Little is known about the basic biology of deep-water coral species. In this study, we experimentally assessed the rates of ingestion of Artemia salina adults and nauplii by the 4 Mediterranean cold water coral species Dendrophyllia cornigera, Desmophyllum cristagalli, Madrepora oculata, and Lophelia pertusa. All species ingested A. salina in adult and nauplii forms. L. pertusa showed the highest grazing rate for both prey types, whereas M. oculata showed the lowest capture rates among the 4 species, and was practically unable to ingest adult prey. Capture rates of the 4 coral species ranged between 5 and 8 adult A. salina, and 50 and 280 nauplii polyp–1 h–1. Surprisingly, both capture rates and carbon uptake (adult Artemia ingestion: 994 to 3542 µg C polyp–1 h–1; nauplii ingestion: 78.1 to 462 µg C polyp–1 h–1) were within the range of values found in some tropical corals (which often ingest 0.004 to 3600 prey items polyp–1 h–1). The results show that the capture rates and energy input of the studied cold water coral species appear to be on a level that is comparable to that of other corals, even tropical zooxanthellate speciesPublicado

Long-term growth rates of four Mediterranean cold-water coral species maintained in aquaria

Growth rates of the cold-water corals (CWC) Madrepora oculata, Lophelia pertusa, Desmophyllum dianthus and Dendrophyllia cornigera were measured over 8 mo under controlled conditions (12°C in the dark, fed 5 times a week) by means of the buoyant weight technique. Additionally, linear growth rates were measured in M. oculata and L. pertusa for 2 and 1 yr, respectively. The weight measurements revealed growth rates, expressed as percent growth per day (mean ± SD), of 0.11 ± 0.04 for M. oculata, 0.02 ± 0.01 for L. pertusa, 0.06 ± 0.03 for D. dianthus and 0.04 ± 0.02 % d–1 for D. cornigera. Growth in M. oculata was significantly higher (p < 0.0001) than in the other 3 CWC species. For M. oculata and L. pertusa, also linear growth was recorded. These values (mean ± SD) were 0.014 ± 0.007 and 0.024 ± 0.018 mm d–1 for M. oculata and L. pertusa, respectively. This is the first study that compares the growth rates of 4 different CWC species under the same experimental conditions of water flow, temperature, salinity and food supply. These corals have different growth rates, both in terms of total weight increase and linear increase, and these growth rates can be related to interspecific physiological differences. Data on growth rates are essential to understand the population dynamics of CWC as well as the recovery capacity of these communities after disturbancePublicado

Survey of deep-dwelling red coral (Corallium rubrum) populations at Cap de Creus (NW Mediterranean)

13 pages, 6 figures, 2 tablesThe distribution and population structure of the eurybathic gorgonian Corallium rubrum were studied off Cap de Creus (Costa Brava, Northwestern Mediterranean Sea). Red coral is endemic to the Mediterranean Sea and the adjacent NE Atlantic coast, where it has been over exploited for centuries. This study presents, the first quantitative data on the spatial distribution and structure of a population extending between 50 (common SCUBA limits) and 230 m depth, and compared it with shallow populations previously studied in the same area. Different remotely operated vehicles (ROV) and two methodological approaches were employed during four cruises between 2002 and 2006: 1-Extensive surveys: sea to coast transects in which red coral density and patch frequency were recorded; 2-Intensive surveys, in which parameters describing colony morphology were recorded. Most of the hard substrate between 50 and 85 m depth was inhabited by red coral colonies, showing a patch frequency of 8.3 ± 7.9 SD patches per 100 m-transect (total transect area: 34 m2), and within-patch colony densities of 16–376 colonies m−2 (mean of 43 ± 53 colonies m−2). Below 120 m depth red coral was less abundant, and rather than forming dense patches as in shallow water, isolated colonies were more common. The population structure differed between sites that are easily accessible to red coral fishermen, and remote ones (both at similar depth, 60–80 m), as colonies in easily accessible locations were smaller in height and diameter, and showed a less developed branching pattern. At shallower locations (10–50 m depth) the population structure was significantly different from those at deeper locations, due to the heavy harvesting pressure they are exposed to in the shallows. Twenty-five to forty-six percentage of the deeper colonies were taller than 6 cm, while only 7–16% of the shallow water colonies exceeded 6 cm colony height. Forty-six to seventy-nine percentage of the colonies in deeper waters were large enough to be legally harvested, while only 9–20% of the shallow water colonies met the 7 mm legal basal diameter to be collected. The branching pattern was also better developed in deeper colonies, as up to 16% of the colonies showed fourth order branches, compared to less than 1% of the shallow water colonies (of which 96% consisted of only one single branch). The results thus confirm that C. rubrum populations above 50 m depth are exposed to a higher harvesting intensity than deeper populations in the same areaThis study was funded by European funds to the Department of Fisheries and Agriculture of the Government of Catalonia in Spain, PCC:30103, European Project Hermes (Contract number GOCE-CT-2005-511234-I) and the MEC project Deep-Coral CTM2005-07756-C02-01/MARPeer reviewe