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Louvain-la-Neuve, Belgium

Mauffret A.,Procter and Gamble | Mauffret A.,Institute Ciencias Marinas Of Andalucia | Gillan D.C.,Laboratoire Of Biologie Marine | Eriksson K.M.,Gothenburg University | And 3 more authors.
Ecotoxicology and Environmental Safety

Marine biofilms were established on glass beads with or without deliberate pre-exposure to LAS (20μg/L) in Spain (Cadiz) and Sweden (Kristineberg). The ability of each community to mineralize LAS (100μg/L) was then assessed in biometers at four experimental temperatures (between 6 and 21°C). Genetic diversity and biomass of the biofilms were assessed by genetic fingerprinting (DGGE) and direct bacterial counts. With biofilms from Sweden, where LAS was not detected in seawater (n=3), deliberate pre-exposure to LAS resulted in lower genetic diversity and higher mineralization rate constant; however, with biofilms from Spain, where 6.4±3.9μgLAS/L (n=3) was measured during the colonization, pre-exposure did not affect the bacterial community. Bacterial acclimation therefore appeared to have been induced at environmental concentrations <6μgLAS/L. Environmental pre-exposure was not a pre-requisite for featuring the full consortia of LAS degraders in the biometers. The mineralization rate was described using an Arrhenius equation at experimental temperatures within the typical annual range; however, they departed from this model below this range. © 2011 Elsevier Inc. Source

Ndiaye A.,Montpellier University | Sanchez W.,INERIS | Durand J.-D.,Montpellier University | Budzinski H.,University of Bordeaux 1 | And 4 more authors.
Environmental Science and Pollution Research

The study highlights the potential of the black-chinned tilapia to be used as a sentinel to assess environmental contaminants based on the use of a set of biomarkers. The usefulness of fish species as sentinels for assessing aquatic environment contamination was tested using a set of biomarkers in Senegalese environments characterized by multi-pollution sources. The black-chinned tilapia (Sarotherodon melanotheron) was selected as a sentinel because of its abundance, wide distribution in all coastal aquatic ecosystems and physiological properties. The potential influence of confounding factors such as salinity on biomarker in the tilapia has been examined. Individuals were sampled during two seasons (dry and wet) in eight sites characterized by various degrees of anthropogenic contamination and different salinities (from 0 to 102 psu). Biomarkers-including growth rate (GR), condition factor (CF), biotransformation enzymes such as 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST), lipid peroxidation (TBARS) and acetylcholinesterase (AChE)-were measured. Chemical contaminant [polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs)] levels showed different sources of contamination with relatively high concentrations of PAHs in the Hann Bay and Foundiougne locations. The most sensitive biomarker present in different sites according to the principal component analysis is EROD. Few variations of the AChE activity and TBARS levels were found. No clear relationship was found between biomarker responses and salinity, but GR and CF were lower in hypersaline conditions. Tilapia is responsive to environmental contaminants such as PAHs, OCPs and PCBs. The S. melanotheron multiparametric approach showed a better discrimination of sites. © 2012 Springer-Verlag. Source

Bouveroux Th.,Laboratoire Of Biologie Marine | Mallefet J.,Laboratoire Of Biologie Marine
Journal of the Marine Biological Association of the United Kingdom

Social organization is an important attribute of the animal society. We describe the social structure of a bottlenose dolphins population living in Panama City, a seaside resort located on the north-west coast of Florida. Study was conducted with 46 individuals. Dolphins are associated on average half weight index of 0.11. Preferred long-term associations are observed. The proportion of the non-zero association indices suggests that some dolphins seem to avoid others. Associations between and within sex-classes were investigated using only dolphins of known sex and observed at least 4 times. Highly significant differences are found in associations between and within sex-classes (Mantel test, t = 3.7987; P = 1); indeed, male associations are stronger than between inter-sexual associations or between females only. Sociogram of males reveals a complex network with strong associations between pairs or trios that reach up to 0.97, whereas female associations are lower than males. The cluster analysis shows no clear division in the social organization of bottlenose dolphins in Panama City, except for dyads, triads and their multiple networks. The population structure seems to be temporally stable over the study and constant companionships are observed in the dolphin population in Panama City. © Marine Biological Association of the United Kingdom, 2009. Source

Ba A.,Cheikh Anta Diop University | Diouf K.,Laboratoire Of Biologie Marine | Guilhaumon F.,Montpellier University | Panfili J.,Montpellier University
Journal of Fish Biology

Age and growth of Rhizoprionodon acutus were estimated from vertebrae age bands. From December 2009 to November 2010, 423 R. acutus between 37 and 112 cm total length (LT) were sampled along the Senegalese coast. Marginal increment ratio was used to check annual band deposition. Three growth models were adjusted to the length at age and compared using Akaike's information criterion. The Gompertz growth model with estimated size at birth appeared to be the best and resulted in growth parameters of L∞ = 139·55 (LT) and K = 0·17 year-1 for females and L∞ = 126·52 (LT) and K = 0·18 year-1 for males. The largest female and male examined were 8 and 9 years old, but the majority was between 1 and 3 years old. Ages at maturity estimated were 5·8 and 4·8 years for females and males, respectively. These results suggest that R. acutus is a slow-growing species, which render the species particularly vulnerable to heavy fishery exploitation. The growth parameters estimated in this study are crucial for stock assessments and for demographic analyses to evaluate the sustainability of commercial harvests. © 2015 The Fisheries Society of the British Isles. Source

Ba B.A.,Cheikh Anta Diop University | Diop M.S.,Commission Sous Regionale des Peches en Afrique de lOuest CSRP | Diatta Y.,Laboratoire Of Biologie Marine | Justine D.,Commission Sous Regionale des Peches en Afrique de lOuest CSRP | Ba C.T.,Cheikh Anta Diop University
Journal of Applied Ichthyology

Summary: The diet of the milk shark, Rhizoprionodon acutus, from the Senegalese coast (12°30′N-14°45′N) was investigated in 3600 specimens with total lengths ranging from 44 to 113 cm for females and from 45 to 110 cm for males. Conducted from May 2010 to April 2011, the study revealed that of the 3600 stomachs examined, 577 contained food (16.03%). Cumulative prey diversity curves reached a stable level at 175 stomachs and thus the sample size was large enough to describe the overall milk shark diet. Relevant differences in the diet were found between sexes, maturity stages, sampling seasons and locations. The milk shark diet was composed of teleosts, crustaceans, mollucs, nematodes, annelids, and unidentified invertebrates. R. acutus seemed to have a preference for teleosts (98.75% in terms of IRI). The trophic level of milk shark calculated in this study was 4.2. © 2013 Blackwell Verlag GmbH. Source

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