Sources of variation in growth of the European eel (Anguilla anguilla) estimated from otoliths

Back-calculation usually requires measurements of growth marks revealed on otoliths by specific preparations. The standardization of the grinding (or sectioning) plane is necessary, but difficult. In order to show the importance of the grinding plane, tetracycling labelling of eel otoliths (#Anguilla anguilla L.$) has been used. This marking has a calcio-traumatic effect on otoliths, which can be revealed with staining techniques. Unless the grinding plane is incorrect, the tetracycline labelling and the staining of the ground surface are then superposed. (Résumé d'auteur

Long-term monitoring on the occurrence of a myxosporean parasite <i>Kudoa camarguensis</i> (Myxosporean) on the common goby (Teleostei, Pisces) <i>Pomatoschistus microps</i>

The evolution of a host-parasite system composed of Pomatoschistus microps-Kudoa camarguensis was investigated in the Vaccares lagoon (Rhone river Delta, France) from 1993 to 1997. During this long-term monitoring, centennial flooding of the Rhone river occurred, leading to an inrush of about 110 million m3 of freshwater in the Vaccares lagoon. The salinity drastically dropped from 14 to 5 g l-1 in 1 Wk. We observed that the annual prevalence and abundance of the myxosporean parasite decreased from 12.18 in 1993 to 3.7% in 1997 and from 1.10 in 1993 to 0.27 in 1997, respectively. Here, we discuss the possible reasons for the rapid decline of this host-parasite system following the flood

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.Animal science

(Téléostéen, Cyprinidae) espèce invasive, nouvel agent du maintien et de la dissémination de l'anguillicolose en France ?

Pseudorasbora parva (Téléostéen, Cyprinidae) est une espèce invasive d'origine est-asiatique. Présente dans le sud-est de l'Europe, elle est signalée en France depuis 1983 et dans le delta du Rhône, en Camargue, depuis 1993 où elle forme d'importantes populations. L'étude parasitologique d'un échantillon de 203 individus, a montré que 35 % étaient porteurs de larves L3 du nématode Anguillicola crassus

Pseudorasbora parva (Téléostéen, Cyprinidae) espèce invasive, nouvel agent du maintien et de la dissémination de l'anguillicolose en France ?

Pseudorasbora parva (Téléostéen, Cyprinidae) est une espèce invasive d'origine est-asiatique. Présente dans le sud-est de l'Europe, elle est signalée en France depuis 1983 et dans le delta du Rhône, en Camargue, depuis 1993 où elle forme d'importantes populations. L'étude parasitologique d'un échantillon de 203 individus, a montré que 35 % étaient porteurs de larves L3 du nématode Anguillicola crassus

Sources of variation in growth of the European eel (Anguilla anguilla) estimated from otoliths

Back-calculation usually requires measurements of growth marks revealed on otoliths by specific preparations. The standardization of the grinding (or sectioning) plane is necessary, but difficult. In order to show the importance of the grinding plane, tetracycling labelling of eel otoliths (#Anguilla anguilla L.$) has been used. This marking has a calcio-traumatic effect on otoliths, which can be revealed with staining techniques. Unless the grinding plane is incorrect, the tetracycline labelling and the staining of the ground surface are then superposed. (Résumé d'auteur