A review of selected indicators of particle, nutrient and metal inputs in coral reef lagoon systems

This review presents environmental and biological indicators of the impact of three major categories of inputs in coral reef lagoons i.e. particles, nutrients and metals. Information was synthesized to extract well established indicators together with some interesting new concepts currently under development, and to provide the reader with an assessment of their respective advantages and drawbacks. The paper has been organized according to the capacity of three categories of indicators to respond either in a specific or a non specific way to a given source of input. The first section focuses on abiotic indicators which main interest is to respond instantaneously and in a truly specific way to a given source of input. The second and third sections present informations on bioindicators either at the sub-individual level or at the individual to community level, indicator specificity generally decreasing as a direct function of biological or ecological complexity. This review showed that even though significant work has already been done on coral reef ecosystems, much more scientific studies are still needed to answer the growing local demands for simple and truly validated tools to be used in environmental surveys. It is further stressed that, due to the biological and environmental diversity of coral reef lagoons, a preliminary step of on-site validation must be considered as an absolute prerequisite when indicators are planned to be used in the frame of a local environmental monitoring programme

Introductions biologiques et parasitisme en milieu récifal (risques et conséquences. L'introduction d'espèces dans l'archipel Hawaiien)

L introduction d espèces en milieu marin est un problème environnemental et économique majeur dont la fréquence ne cesse d augmenter. Néanmoins, les risques parasitaires liés à ces déplacements sont encore très souvent négligés et l évolution des communautés parasitaires reste généralement peu connue. Le travail réalisé au cours de cette thèse s inscrit dans le contexte particulier de l évolution des communautés parasitaires chez les poissons marins, introduits en milieu naturel. Le déplacement volontaire de poissons dans l archipel Hawaiien depuis la Polynésie, à la fin des années 1950, est un modèle original offrant une opportunité sans précédent pour comprendre les conséquences épidémiologiques, écologiques, moléculaires et morphologiques de l introduction d espèces parasites au sein d un nouvel écosystème, en milieu corallien.PARIS-BIUSJ-Sci.Terre recherche (751052114) / SudocBANYULS/MER-Observ.Océanol. (660162201) / SudocSudocFranceF

Behavioural aspects of parasitism

The behavioural aspects discussed in this Chapter are not unique to marine parasites. Parasites do change the behaviour of their hosts in all environments, and cleaning symbiosis is widespread on land and in fresh water. The ability of some parasites to drastically change a host's behaviour, often leading to behaviour patterns favouring the parasite and ensuring its transmission to other hosts, has been known for some time. It is a fascinating area of research that deserves much greater attention in future work. As pointed out by the authors of this section, numerous examples of host manipulation by parasites remain to be discovered, but the examples already known show that manipulation has the potential to interfere with ecological and evolutionary processes. Research in this area may resolve important issues relating to ecosystem functioning and biodiversity

Parasite communities in eels of the Island of Reunion (Indian Ocean) : a lesson in parasite introduction

Eel populations from the small rivers on the Island of Reunion (French Overseas Department in the Indian Ocean) were investigated with respect to the occurrence and abundance of helminths during the autumn of 2005. The native species Anguilla marmorata (n = 80), Anguilla bicolor (n = 23), and Anguilla mossambica (n = 15) were studied. Six species of helminths were identified, four of them having a definitely nonnative status. Furthermore, unidentified intra-intestinal juvenile cestodes and extra-intestinal encapsulated anisakid nematode larvae were present in a few eels. We found that the invasive swim bladder nematode Anguillicoloides (Anguillicola) crassus had been introduced into the island. Six specimens were collected, four from A. marmorata, one from A. bicolor and one from A. mossambica. The maximum intensity of infection was two worms. The other helminths also showed a low abundance. These species were the monogenean gill worms Pseudodactylogyrus anguillae and Pseudodactylogyrus bini and the intestinal parasites Bothriocephalus claviceps (Cestodes), Paraquimperia africana (Nematodes), and the acanthocephalan Acanthocephalus reunionensis Warner, Sasal, and Taraschewski, 2007. The latter species, found as intra-intestinal immatures, is thought to utilize amphibians as required hosts; its status, introduced or native, could not be determined. P. africana was described from A. mossambica in South Africa and has not been recorded outside Africa. The other species are known from populations of European and American eels. However, A. crassus and the two Pseudodactylogyrus species originate from East Asia, where they are indigenous parasites of Anguilla japonica. Both an assignment test based on seven specific microsatellite loci and subsequent sequencing of mitochondrial haplotypes of a partial fragment of cytochrome c oxidase 1 strongly suggest that the A. crassus may originated around the Baltic Sea. According to the results presented here, populations of the indigenous eel species from Reunion can be considered to harbor extremely isolationist alien parasite communities. Our findings support the hypothesis that during the present time of global biological change, invasion by a nonnative species into a target island is more likely to reflect the political affiliation of the colonized environment and the pathways of trade and tourism than geographic proximity between donor and recipient areas or other natural circumstances.publishe

Use of Medicinal Plants in Aquaculture

Plants have been reported to produce various effects such as antistress, growth promotion, appetite stimulation, immunostimulation, aphrodisiac and to have antipathogen properties in fish and shrimp aquaculture due to their varied active principles such as alkaloids, terpenoids, tannins, saponins and flavonoids. To date, most scientific studies on the use of medicinal plants in aquaculture have focused on identification of biological activity rather than natural product determination. The plant species that have displayed the highest potential for use in aquaculture are garlic (Allium sativum), pomegranate (Punica granatum), bermuda grass (Cynodon dactylon), Indian ginseng (Whitania somnifera) and ginger (Zingiber officinale). Algae are considered to be a rich source of original bioactive molecules which display multiple bioactivities. In aquaculture, several recent studies have showed the potential of algae for the treatment of pathogens or to improve fish fitness

Anguilla sp. Diseases Diagnoses and Treatments: the Ideal Methods at the Cross Roads of Conservation and Aquaculture Purposes

International audienceAnguilla anguilla, A. japonica and A. rostrata are the most fished and consumed eel species. However, these species are Critically Endangered, Endangered and Endangered respectively. A combination of factors is thought to be responsible for their decline including fisheries, climate change, habitat destruction, barriers to migration, pollution and pathogens. Among them, viruses, bacteria and parasites are causing weakening of wild eels and serious economic losses for fishermen and eel farmers. Early detection of pathogens is essential to provide appropriate responses both for conservation reasons and to limit economic losses. Classic diagnosis approaches are time consuming and invasive and usual treatments e.g. antipathogenic substances are becoming obsolete because of pathogen resistance and environmental impact problems. The need for early and noninvasive diagnostic methods as well as effective and environmentally friendly treatments has increased. Vaccine development and diet supplementation have known a growing interest since their use could allow prevention of diseases. In this review, we summarize the main pathogens-viruses, bacteria and parasites-of the three northern temperate eel species, the methods used to detect these pathogens, and the different treatments used. We discussed and highlighted the need for non-invasive, rapid and efficient detection methods, as well as effective and environmentally friendly treatments for both conservation and aquaculture purposes

Shark Provisioning Influences the Gut Microbiota of the Black-Tip Reef Shark in French Polynesia

International audienceThere is an increasing interest in touristic observations of top predators in the wild. Sharks are probably the most sought-after animal in marine ecosystems by divers. Regulations have been put in place, and even if they are more or less respected, providing food is still used in some places in order to attract wild animals. Because of the difficulty in sampling shark guts, few studies have analyzed the microbiota of sharks, and none have evaluated the effect of feeding on this microbiota. In this work, we compare microbiota assemblages of black-tip sharks between sites with and without regular feeding. Our results revealed a significant feeding effect on both alpha and beta diversities of microbiota. Notably, the alpha diversity of fed sharks was lower than unfed sharks. We hypothesize that this result is related to a lower diversity of food intake by sharks in places where feeding is regularly provided. More studies need to be conducted in order to estimate the impact of feeding on shark physiology

Biological and Ecological Roles of External Fish Mucus: A Review

International audienceFish mucus layers are the main surface of exchange between fish and the environment, and they possess important biological and ecological functions. Fish mucus research is increasing rapidly, along with the development of high-throughput techniques, which allow the simultaneous study of numerous genes and molecules, enabling a deeper understanding of the fish mucus composition and its functions. Fish mucus plays a major role against fish infections, and research has mostly focused on the study of fish mucus bioactive molecules (e.g., antimicrobial peptides and immune-related molecules) and associated microbiota due to their potential in aquaculture and human medicine. However, external fish mucus surfaces also play important roles in social relationships between conspecifics (fish shoaling, spawning synchronisation, suitable habitat finding, or alarm signals) and in interspecific interactions such as prey-predator relationships, parasite-host interactions, and symbiosis. This article reviews the biological and ecological roles of external (gills and skin) fish mucus, discussing its importance in fish protection against pathogens and in intra and interspecific interactions. We also discuss the advances that "omics" sciences are bringing into the fish mucus research and their importance in studying the fish mucus composition and functions

First checklist triggering the inventory of marine fish ectoparasites in the Syrian coast (Eastern Mediterranean)

The checklist of the ectoparasites of Syrian marine fish is provided. This fauna comprises (28) species, representing (20) genera, (15) families, (9) orders and (8) classes. The checklist  is arranged alphabetically; with additional details for each species include the hosts, infected  site, prevalence and intensity, and references or the source of these data. Considering these  very limited data, we discussed the results found and highlighted the importance to conduct  more parasitological studies in the region

Characterisation of the gill mucosal bacterial communities of four butterflyfish species: a reservoir of bacterial diversity in coral reef ecosystems

International audienceWhile recent studies have suggested that fish mucus microbiota play an important role in homeostasis and prevention of infections, very few studies have investigated the bacterial communities of gill mucus. We characterised the gill mucus bacterial communities of four butterflyfish species and although the bacterial diversity of gill mucus varied significantly between species, Shannon diversities were high (H = 3.7–5.7) in all species. Microbiota composition differed between butterflyfishes, with Chaetodon lunulatus and C. ornatissimus having the most similar bacterial communities, which differed significantly from C. vagabundus and C. reticulatus. The core bacterial community of all species consisted of mainly Proteobacteria followed by Actinobacteria and Firmicutes. Chaetodonlunulatus and C. ornatissimus bacterial communities were mostly dominated by Gammaproteobacteria with Vibrio as the most abundant genus. Chaetodonvagabundus and C. reticulatus presented similar abundances of Gammaproteobacteria and Alphaproteobacteria, which were well represented by Acinetobacter and Paracoccus, respectively. In conclusion, our results indicate that different fish species present specific bacterial assemblages. Finally, as mucus layers are nutrient hotspots for heterotrophic bacteria living in oligotrophic environments, such as coral reef waters, the high bacterial diversity found in butterflyfish gill mucus might indicate external fish mucus surfaces act as a reservoir of coral reef bacterial diversity