Human impacts on the endangered fan mussel,Pinna nobilis     

Fikret ndes  Michel J. Kaiser  Harun Gülüsoy 《水产资源保护:海洋与淡水生态系统》2020,30(1):31-41

1. Pinna nobilis is a sensitive and vulnerable species and is hence considered a good indicator of anthropogenic pressures on marine ecosystems.
2. This study provides novel data on the density and distribution of endangered P. nobilis on the Turkish coasts. Threats to the status of P. nobilis, including by‐catch and illegal collection, were assessed, as was the general awareness of people about the endangered status of fan mussels.
3. The data sources consisted of direct observations from diving surveys and the local ecological knowledge (LEK) of fishers and scuba‐divers.
4. Results demonstrated that the density of P. nobilis significantly changed with environmental parameters, such as depth, and among different sampling areas. The number of damaged individuals was lowest in the areas that were distant from human influences such as ports and tourist beaches. The density estimations of P. nobilis across a wide geographic area around the Turkish coasts revealed that the density of fan mussels was highest around western coasts in comparison with southern coasts.
5. Fishers and divers indicated that the population of this species has decreased during the last decade. The main causes of this decline were suggested to be the impacts of fishing gear, poaching, pollution, and boat anchoring. The highest volume of by‐catch was estimated to be taken by trawls. In general, the knowledge and local awareness of the conservation importance and status of fan mussels was poor.
6. The study has identified those areas where fan mussels occur at a high density, and hence may indicate areas for possible conservation protection status. Second, areas exposed to the illegal harvesting of fan mussels were highlighted. Societal concern would benefit from educational activities to raise awareness of the ecological importance and conservation needs for fan mussels in Turkey.

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Marine protected areas: the importance of being earnest     

Michel J. Kaiser 《水产资源保护:海洋与淡水生态系统》2004,14(6):635-638

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Experiences de conditionnement d'alevins de bar (Pisces,Dicentrarchus labrax) a differents aliments composes     

Maria Helena Barahona-Fernandes  Michel Girin  Robert Metailler 《Aquaculture (Amsterdam, Netherlands)》1977,10(1):53-63

Two series of experiments were performed on pellet adaptation, each with five batches of 100 sea bass larvae, reared until the age of 50 days at 18°C and fed with living food. Each experiment was followed for 25 days. Three different pellet formulas, with different amounts of Artemia powder incorporated, were compared with a diet of living prey only. The incorporation of 10% of Artemia powder to the pellets appeared to give better results. However, much clearer results were obtained with the different types of pellet composition, being mainly shown in terms of final survival rates. In spite of the stress due to the change of feeding habits, there is evidence that the same growth and survival can be achieved either on living food or on pellets.  相似文献   

Molecular evolution of neurohypophysial hormones in relation to osmoregulation: the two fish options     

R. Acher  J. Chauvet  M.T. Chauvet  G. Michel  Y. Rouillé 《Fish physiology and biochemistry》1997,17(1-6):325-332

In vertebrates, water and osmolyte homeostasis is controlled by at least three hormonal systems: the hypothalamo-neurohypophysial system, the renin-angiotensin-aldosterone system and the atrial natriuretic factor system. The first system implies neuroendocrine reflexes involving an afferent neural limb from osmo- and baroreceptors to hypothalamus and an efferent endocrine limb from secretory neurons to target cell receptors and transduction to intracellular effectors, namely water and sodium channels. Evolution can affect any level of this molecular cascade. Whereas virtually all vertebrate species have two neurohypophysial hormones, an oxytocin-like and a vasopressin-like peptides, the most primitive vertebrates, Cyclostomata (lampreys and hagfishes) possess a single peptide, vasotocin, so that an early gene duplication occurred before the emergence of fishes, about 400 million years ago. The remarkable evolutionary stability of neurohypophysial hormones in bony vertebrates allows us to trace two main lineages: isotocin-mesotocin-oxytocin and vasotocin-vasopressin. In contrast, in cartilaginous fishes, the oxytocin-like peptides display a great evolutionary diversity: we have identified glumitocin in rays, aspargtocin and valitocin in the spiny dogfish, asvatocin and phasvatocin in the spotted dogfish, and oxytocin in the chimaera. Whereas bony vertebrates regulate their blood osmotic pressure (about 250–450 mOsm kg^-1 H₂O) essentially through salts, cartilaginous fishes use urea as the main osmolyte for adjusting their osmotic pressure above the external medium (about 1050 mOsm kg^-1 H₂O for marine fishes). The hypothesis is made that the stability of neurohypophysial hormones in bony vertebrates is due to their implication in ion-based osmoregulation (selective evolution), whereas in Chondrichthyes the occurrence of urea-based osmoregulation has relieved the hormones from this function and therefore made them free to vary (neutral evolution).  相似文献   

Effects of silage preservation on astaxanthin forms and fatty acid profiles of processed shrimp (Pandalus borealis) waste     

Alain Guillou  Michel Khalil  Lucien Adambounou 《Aquaculture (Amsterdam, Netherlands)》1995,130(4):351-360

Acid silage of shellfish processing waste has been reported to be a good and economical technique to protect these biomasses from bacterial decomposition. Shrimp (Pandalus borealis) by-products contain some value-added nutrients for the aquaculture industry such as carotenoid pigments (mainly astaxanthin) and n − 3 polyunsaturated fatty acids. The aim of this work was to determine the effect of ensiling shrimp waste during a long period of time (more than 3 months) on some unstable components such as the astaxanthin forms (free, mono- and diesterified) and polyunsaturated fatty acids. Comparisons of astaxanthin forms and the fatty acid profiles were performed on defrosted shrimp waste and on a 14-week-old shrimp waste silage. No significant difference (P ≥ 0.05) in the total lipids extracted from the two forms of shrimp waste was observed. Nevertheless, a small quantity of the red pigment, presumably an astaxanthin portion, was observed to stay firmly bound to the shrimp carapace after the solvent extraction in shrimp waste compared to the full recovery obtained in ensiled shrimp waste. This may explain the significantly (P < 0.05) higher concentration of total astaxanthin (4.57 vs 3.99 mg/g) found in the crude oil extracted from shrimp waste silage. Higher percentages (P < 0.01) of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were found in esterified astaxanthin from shrimp waste silage (43.9% and 45.5%) in comparison with their shrimp waste (24.7% and 20.3%) counterparts. This suggests that EPA and DHA are the principal fatty acids esterified with the portion of astaxanthin linked to chitin in the shrimp carapace. The utilization of shrimp waste silage as a pigmenting component of salmonid feeds is also discussed.  相似文献   

Effect of substrate provision on performance and behaviour of laying hens in the pecking and scratching area of furnished cages     

A. Huneau-Salaün  M. Guinebretière  V. Michel 《British poultry science》2014,55(4):409-418

1. An experiment was set up to study the effects of substrate provision on performance and behaviour in the pecking and scratching area (PSA) of non-beak-trimmed hens housed in large furnished cages (60 hens/cage).

2. Three layer hybrids (two brown and one white, ISA-Hendrix Genetics, France) and two substrate conditions (with or without wheat bran automatically distributed on the PSA) were compared in a 3 × 2 experimental design with 12 cages per treatment.

3. Substrate distribution improved laying rate with no impact on the frequency of dirty or cracked eggs.

4. Substrate distribution improved the viability and body integrity of hens, which were not beak-trimmed.

5. Distribution of substrate tended to increase the number of hens in the PSA and enhanced their pecking and scratching behaviours but had a negative impact on the number of dust bath bouts per cage and encouraged dust bathing on the wire floor close to the feeder.

6. The white hens laid more eggs in the nest than the brown birds and used the PSA more for pecking, scratching and dust bathing at the end of the day than the brown hens, underlining the necessity to adapt cage furnishing and rearing management to specific behaviours of each layer genotype.  相似文献   

Human leptospirosis: An emerging risk in Europe?     

Julien Dupouey  Benoît Faucher  Sophie Edouard  Hervé Richet  Angeli Kodjo  Michel Drancourt  Bernard Davoust 《Comparative immunology, microbiology and infectious diseases》2014

Leptospirosis has been reemerging in both developed and developing countries including Europe, where, this phenomenon has notably been associated with urban transmission. However, the comprehensive data that are needed to fully understand the ongoing epidemiological trends are lacking. In this article, we report surveillance data from throughout Europe, especially in France, to have an overview of this neglected disease in temperate countries. Our results underline the important role of wild rodents as reservoir of leptospirosis, and highlight the potential danger of a reemergence of this under-reported infectious disease in European cities, associated with the important expansion of the rat population in urban areas.  相似文献   

Immunogenicity and efficacy of fowlpox-vectored and inactivated avian influenza vaccines alone or in a prime-boost schedule in chickens with maternal antibodies     

Alexandra Richard-Mazet  Sylvain Goutebroze  Fran?ois-Xavier Le Gros  David E Swayne  Michel Bublot 《Veterinary research》2014,45(1)

Inactivated and fowlpox virus (FP)-vectored vaccines have been used to control H5 avian influenza (AI) in poultry. In H5 AI endemic countries, breeder flocks are vaccinated and therefore, maternally-derived antibodies (MDA) are transferred to their progeny. Results of three immunogenicity and one efficacy studies performed in birds with or without MDA indicated that the immunogenicity of an inactivated vaccine based on a H5N9 AI isolate (inH5N9) was severely impaired in chicks hatched from inH5N9-vaccinated breeders. This MDA interference was lower when breeders received only one administration of the same vaccine and could be overcome by priming the chicks at day-of-age with a live recombinant FP-vectored vaccine with H5 avian influenza gene insert (FP-AI). The interference of anti-FP MDA was of lower intensity than the interference of anti-AI MDA. The highest interference observed on the prime-boost immunogenicity was in chicks hatched from breeders vaccinated with the same prime-boost scheme. The level of protection against an antigenic variant H5N1 highly pathogenic AI isolate from Indonesia against which the FP-AI or inH5N9 alone was poorly protective could be circumvented by the prime-boost regimen in birds with either FP or AI MDA. Thus, the immunogenicity of vaccines in young chicks with MDA depends on the vaccination scheme and the type of vaccine used in their parent flocks. The heterologous prime-boost in birds with MDA may at least partially overcome MDA interference on inactivated vaccine.  相似文献   

The effects of environmental change on the spatial and environmental determinants of community-level traits   总被引：1，自引：0，他引：1  

Matt J. Michel  Jason H. Knouft 《Landscape Ecology》2014,29(3):467-477

An advantage of trait-based approaches to ecology is the ability to predict the response of a species assemblage to environmental change through trait–environment relationships. Because species assemblages are also known to be affected by spatial processes, variation in community-level traits may be similarly affected by spatial structure. Furthermore, the importance of spatial structure may vary with changes to the environment. Using a dataset describing a local stream fish assemblage and environmental variables, we examine the relative contribution of environmental and spatial factors in explaining variation in community-level traits across seasons. We also test for any spatial structuring of community-level traits. For most traits, seasonal environmental change did not seem to alter the relative importance of environmental factors. Traits that did not vary consistently with environmental variables across seasons exhibited significant spatial structure. Overall, relationships between traits and environmental variables seemed to operate on a continuum with ‘environmental traits’ (those that were strongly correlated with environmental variables in response to environmental change) at one end to ‘spatial traits’ (those that did not correlate with environments, but exhibited spatial structure) at the other. We suggest that the distinction between these types of traits is important, as different modeling approaches would be appropriate in using community-level traits to predict the response of species assemblages to environmental change.  相似文献   

Allometric models for aboveground biomass in dry savanna trees of the Sudan and Sudan–Guinean ecosystems of Southern Senegal     

Cheikh Mbow  Michel M. Verstraete  Bienvenu Sambou  Amadou Tahirou Diaw  Henry Neufeldt 《Journal of Forest Research》2014,19(3):340-347

This paper presents new allometric models for woody savanna of the dry Sudanian zone of the southern part of Senegal and contributes to the needs for accurate and precise carbon estimates through improved statistical models and methods. The results are based on statistical relationships between the total dry biomass and either tree diameter at breast height (DBH) or tree height for a set of 101 individuals of different sizes from 13 dominant species in 6 protected forests. The statistical regression (cubic order 3) generated for DBH (5–41.5 cm) and tree height (2.5–15.6 m) showed significant R ² of 0.934 and 0.813, respectively. Using the same database, species-based models for the most represented genera (Acacia sp., Combretum sp. and Terminalia sp.) show more precision than the generic model. The model residual standard error and relative errors showed a good fit between observed and predicted data. Species-based models showed smaller errors compare to generic models outputs.  相似文献