Reproductive Cycle and Plasma Levels of Sex Steroids in Female Eurasian Perch Perca Fluviatilis

From April 1995 to April 1996, the annual reproductive cycle of the Eurasian perch Perca fluviatilis was studied at the Fishfarming Lindre Center (Moselle, France). At monthly intervals (at intervals of 10 days during the periovulatory period), 5 females were caught and dissected. From sampled organs, the gonado-, hepato- and viscerosomatic indexes (GSI, HSI, VSI) were calculated, oocyte diameters (OD) and the plasma levels of testosterone (T), 17P-estradiol (E2), 17,20P-dihydroxy-4-pregnen-3-one (17,2Op-P) and protein-phosphorus (PPP) were measured. After the sexual resting period observed from May to August (GSI \u3c 1 %, OD \u3c 200 urn, VSI = 4-6 %), oogenesis began in September when the water temperature decreased from 26.4 to 14.1 “C. The GSI increased progressively until mid March (15 %), then rapidly until spawning (25 %, OD = 850 urn) which occurred in April (14- 15 “C). The plasma levels of T, E,, 17,2Op-P and PPP were low during the sexual resting period. E, and PPP levels increased significantly at the onset of the oogenesis in September, then the E, level raised abruptly in November (3-4 ng mL-‘). In December, the T level increased rapidly to 15-20 ng . mL-’ The testosterone, E, and PPP levels remained very high until spawning, indicating the existence of active vitellogenesis. The highest HSI (2.1-2.2 %) recorded in winter confirmed this. During the periovulatory period, a peak of E, (4 ng . mL-‘) appeared, whereas T level diminished. In this study, 17,2Op-P levels remained low (0.2-0.6 ng mL-‘) and relatively constant. No 17,2Op-P peak was observed during the periovulatory period. Sampling at 10 day intervals was probably inadequate to specify the hormonal variations related to the final oocyte maturation and the ovulation. 0 Ifremer-Elsevier, Paris

Reproductive Cycle and Plasma Sex Steroid Profiles in Male Eurasian Perch Perca Fluviatilis

From April 1995 to April 1996, the annual reproductive cycle of male Eurasian perch Perca fluviatilis was studied at the Lindre Center (Moselle, France). At monthly intervals, five males (mean body weight of 133 ± 43 g and total length of 175 ± 9 mm) were caught. From sampled organs, the gonadosomatic (GSI), hepatosomatic (HSI) and viscerosomatic indexes (VSI) were calculated and plasma testosterone (T) and 11-ketotestosterone (11KT) levels were measured. After the spawning period in mid-April, GSI and HSI dropped and VSI increased to 3.8 ± 0.1 %. In September, GSI reached its maximum (8.5 ± 1.8 %). At this time, spermatocytes, spermatids and spermatozoa were abundant, whereas in June only spermatogonia were observed. During winter, GSI was stable at approximately 5 %, HSI reached its maximum (1.9 ± 0.3 %) and VSI was low (2.6 ± 0.2 %). From April to November 1995, plasma T and 11KT concentrations were low (\u3c 0.5 ng·mL–1). Plasma T levels increased significantly in December and reached peak levels (12.3 ± 2.1 ng·mL–1) in January, then decreased in February and increased again until spawning in April (6.8 ± 2.1 ng·mL–1). This second elevation could be related to the beginning of a new spermatogenic cycle. Plasma levels of 11KT increased significantly from October to February 1996 (4.9 ± 1.1 ng·mL–1). From February to the spawning period (April 1996), plasma 11KT decreased significantly, but values were significantly higher than those measured in fall. Males were spermiating from January to spawning in April. © 2000 Ifremer/Cnrs/Inra/Ird/Cemagref/Éditions scientifiques et médicales Elsevier SA

The Acclimation of European Sea Bass (Dicentrarchus labrax) to Temperature: Behavioural and Neurochemical Responses

Studies on fish behavioural and neurophysiological responses to water temperature change may contribute to an improved understanding of the ecological consequences of global warming. We investigated behavioural and neurochemical responses to water temperature in European sea bass (Dicentrarchus labrax) acclimated to three temperatures (18, 22 and 28°C). After 21 d of acclimation, three groups of 25 fish each were exposed to four behavioural challenges (foraging, olfactory, aversive and mirror tests). The expression of choline acetyltransferase (ChAT) was then analysed by Western blotting in CNS homogenates (from a subset of the same fish) as a marker for cholinergic system activity. In both foraging and olfactory tests, fish acclimated to 28°C exhibited significantly higher arousal responses than fish acclimated to lower temperatures. All specimens showed fright behaviour in the aversive test, but the latency of the escape response was significantly less in the fish at 28°C. Finally, the highest mirror responsiveness was exhibited by the fish acclimated to 22°C. As in the case of cholinergic neurotransmission, significantly higher ChAT levels were detected in the telencephalon, diencephalon, cerebellum and spinal cord of fish acclimated to 22 or 28°C in comparison with those maintained at 18°C. Lower ChAT levels were detected in the mesencephalon (optic tectum) at 22 and 28°C than at 18°C. These data indicate that neuronal functions are affected by water temperature. Increases or decreases in ChAT expression can be related to the functional modulation of brain and spinal cord centres involved in behavioural responses to temperature change. Overall, the results of this study suggest that the environmental temperature level influences behaviour and CNS neurochemistry in the European sea bass.Studies on fish behavioural and neurophysiological responses to water temperature change may contribute to an improved understanding of the ecological consequences of global warming. We investigated behavioural and neurochemical responses to water temperature in European sea bass (Dicentrarchus labrax) acclimated to three temperatures (18, 22 and 28 degrees C). After 21d of acclimation, three groups of 25 fish each were exposed to four behavioural challenges (foraging, olfactory, aversive and mirror tests). The expression of choline acetyltransferase (ChAT) was then analysed by Western blotting in CNS homogenates (from a subset of the same fish) as a marker for cholinergic system activity. In both foraging and olfactory tests, fish acclimated to 28 degrees C exhibited significantly higher arousal responses than fish acclimated to lower temperatures. All specimens showed fright behaviour in the aversive test, but the latency of the escape response was significantly less in the fish at 28 degrees C. Finally, the highest mirror responsiveness was exhibited by the fish acclimated to 22 degrees C. As in the case of cholinergic neurotransmission, significantly higher ChAT levels were detected in the telencephalon, diencephalon, cerebellum and spinal cord of fish acclimated to 22 or 28 degrees C in comparison with those maintained at 18 degrees C. Lower ChAT levels were detected in the mesencephalon (optic tectum) at 22 and 28 degrees C than at 18 degrees C. These data indicate that neuronal functions are affected by water temperature. Increases or decreases in ChAT expression can be related to the functional modulation of brain and spinal cord centres involved in behavioural responses to temperature change. Overall, the results of this study suggest that the environmental temperature level influences behaviour and CNS neurochemistry in the European sea bass

Étude de la collection de vestiges fauniques du site préhistorique du Cuzoul de Gramat (46).

Study of the faunal remains found during the recent excavations of the Mesolithic site of Cuzoul de Gramat. This site was excavated by R. Lacam between 1923 and 1954. These excavations have participated to elaborate, in the 30s, the first models of chrono-cultural structuring of the Mesolithic time in France. New excavations began in 2005 under the direction of N. Valdeyron, professor at the University Toulouse II Jean Jaurès. Marine Gardeur, a doctoral student in archaeozoology, is studying at the TRACES UMR 5608 laboratory, the bone remains of animals hunted and consumed on the site.Étude des restes de faune retrouvés lors des fouilles récentes du site mésolithique du Cuzoul de Gramat. Ce site à été fouillé anciennement par R. Lacam entre 1923 et 1954. Ces fouilles ont participé a élaborer, dans les années 30, les premiers modèles de structuration chrono-culturelle du Mésolithique en France. De nouvelles fouilles ont démarré en 2005 sous la direction de N. Valdeyron, professeur à l'université Toulouse II Jean Jaurès. Marine Gardeur, doctorante en archéozoologie, étudie, dans les locaux du laboratoire TRACES UMR 5608, les vestiges osseux d'animaux chassés et consommés sur le site

Tri et remontage de la faune mise au jour sur le site préhistorique du Cuzoul de Gramat (46)

Study of the faunal remains found during the recent excavations of the Mesolithic site of Cuzoul de Gramat. This site was excavated by R. Lacam between 1923 and 1954. These excavations have participated to elaborate, in the 30s, the first models of chrono-cultural structuring of the Mesolithic time in France. New excavations began in 2005 under the direction of N. Valdeyron, professor at the University Toulouse II Jean Jaurès. Marine Gardeur, a doctoral student in archaeozoology, is studying the bone remains of animals hunted and consumed on the site. At the TRACES UMR 5608 laboratory, she is sorting and reassembling the bones, an operation that allows us to ascertain, or not, the stratigraphic integrity of the remains.Étude des restes de faune retrouvés lors des fouilles récentes du site mésolithique du Cuzoul de Gramat. Ce site à été fouillé anciennement par R. Lacam entre 1923 et 1954. Ces fouilles ont participé a élaborer, dans les années 30, les premiers modèles de structuration chrono-culturelle du Mésolithique en France. De nouvelles fouilles ont démarré en 2005 sous la direction de N. Valdeyron, professeur à l'université Toulouse II Jean Jaurès. Marine Gardeur, doctorante en archéozoologie, étudie les vestiges osseux d'animaux chassés et consommés sur le site. Elle réalise, dans les locaux du laboratoire TRACES UMR 5608, le tri et le remontage des ossements, opération qui permet de s’assurer, ou non, de l'intégrité stratigraphique des vestiges

Deux vertèbres de chevreuil retrouvées sur le site préhistorique du Cuzoul de Gramat (46)

Study of the faunal remains found during the recent excavations of the Mesolithic site of Cuzoul de Gramat. This site was excavated by R. Lacam between 1923 and 1954. These excavations have participated to elaborate, in the 30s, the first models of chrono-cultural structuring of the Mesolithic time in France. New excavations began in 2005 under the direction of N. Valdeyron, professor at the University Toulouse II Jean Jaurès. Marine Gardeur, a doctoral student in archaeozoology, is studying the bone remains of animals hunted and consumed on the site. At the TRACES UMR 5608 laboratory, she shows the articulation between two roe deer vertebrae.Étude des restes de faune retrouvés lors des fouilles récentes du site mésolithique du Cuzoul de Gramat. Ce site à été fouillé anciennement par R. Lacam entre 1923 et 1954. Ces fouilles ont participé à élaborer, dans les années 30, les premiers modèles de structuration chrono-culturelle du Mésolithique en France. De nouvelles fouilles ont démarré en 2005 sous la direction de N. Valdeyron, professeur à l'université Toulouse II Jean Jaurès. Marine Gardeur, doctorante en archéozoologie, étudie les vestiges osseux d'animaux chassés et consommés sur le site. Elle montre, dans les locaux du laboratoire TRACES UMR 5608, l'articulation entre deux vertèbres de chevreuil