Short Note on the Effects of Cadmium on the Gill of the Glass Eel (Anguilla anguilla)

Freshwater-adapted glass eels have been exposed to cadmium (5 mg/l) for 3 days and then transferred in clean water for 28 days. Perturbations occurred very early (after 2 hrs only of exposure to cadmium) and concerned mainly the respiratory epithelium: the epithelial cells were very swollen and they showed an important dilation of the endoplasmic reticulum and nuclear membrane. After the decontamination period, signs of recovery appear. Perturbations of osmo-regulatory and respiratory processes are suggested.     

Gestion des barrages estuariens et migration d'anguilles. Estuary Dams Management and Eel Migration

Estuary dams often constitute the first obstacles of the colonization of rivers by eels. To reduce their impact, this study shows results of a special management of sluices and gates based on the glass eel migratory behaviour.     

Environmental factors affecting migration of the European eel in the Rivers Severn and Avon, England

Studies were conducted during 1991–1993 on environmental factors affecting the upstream migration of eels in the Rivers Severn and Avon, England. Migrants (> 156 000 pigmented elvers and > 189 000 juveniles) were trapped as they attempted to ascend weir or sluice barriers. Multiple regression models were developed to compare catches per trap per night (C) with data for various key environmental parameters at seven sites, from the tidal limit to a maximum of 42.5 km upstream. The key stimulus for migration of both elvers and juveniles at the tidal limit was water temperature, with some weaker monthly influences related to seasonal temperature increases. Smaller annual influences probably related to earlier glass eel recruitment into the lower estuary. A weak early tidal effect was demonstrated only once, in 1993 in the Severn. Temperature also exerted significant effects on C of juvenile eels at the tidal limit and in the non-tidal rivers, although effects weakened with distance upstream. Year, month, river flows and whether traps were mounted on weirs or sluices made only small contributions at a few sites. Distance between traps also contributed to combined data for upper Severn sites. The threshold temperature in all cases was 14–16°C, with low to zero catches below 10–11°C, catch maxima being achieved above 18–20°C. The implications of strong temperature-dependence of migration in relation to stock recruitment and management are discussed. Special reference is made to recent decreases in recruitment of eels to Europe and N. America and possible long-term effects of global warming.     

Cloning and Sequencing of Cytochrome P450 1A Complementary DNA in Eel (Anguilla japonica)

Cytochrome P450 1A (CYP1A) complementary DNA was isolated from eel (Anguilla japonica) liver treated with 3-methylcholanthrene. The cDNA contained a 5′ untranslated region of 163 bp, an open reading flame of 1560 bp coding for 519 amino acids and a stop codon, and a 3′ untranslated region of 1730 bp. The predicted molecular weight was approximately 58.4 kDa. The deduced amino acid sequence exhibited identities with reported CYP1A sequences of 80% for rainbow trout, 79% for scup, 76% for plaice and butterfly fish, and 74% for toadfish. When compared with mammalian CYP proteins, the eel CYP1A was more similar to CYP1A1 (54%–56%) than to CYP1A2 (49%–52%). Northern and Southern blot analyses showed two distinct bands, suggesting the existence of another 3-methylcholanthrene-inducible CYP1A gene in eel. Received December 19, 1998; accepted February 18, 1999     

A Quick Method for Species Identification of Japanese Eel (<Emphasis Type="Italic">Anguilla japonica</Emphasis>) Using Real-Time PCR: An Onboard Application for Use During Sampling Surveys

To compensate for the limited number of morphological characteristics of fish eggs and larvae, we established a convenient and robust method of species identification for eggs of the Japanese eel (Anguilla japonica) using a real-time polymerase chain reaction (PCR) that can be performed onboard research ships at sea. A total of about 1.2 kbp of the mitochondrial 16S ribosomal RNA gene sequences from all species of Anguilla and 3 other anguilliform species were compared to design specific primer pairs and a probe for A. japonica. This real-time PCR amplification was conducted for a total of 44 specimens including A. japonica, A. marmorata, A. bicolor pacifica, and 6 other anguilliform species. Immediate PCR amplification was only observed in A. japonica. We then tested this method under onboard conditions and obtained the same result as had been produced in the laboratory. These results suggest that real-time PCR can be a powerful tool for detecting Japanese eel eggs and newly hatched larvae immediately after onboard sampling during research cruises and will allow targeted sampling efforts to occur rapidly in response to any positive onboard identification of the eggs and larvae of this species.     

Cloning, Sequencing, and Phylogenetic Analysis of Complementary DNA of Novel Cytochrome P-450 CYP1A in Japanese Eel (Anguilla japonica)

Complementary DNA of cytochrome P-450 CYP1A, in addition to CYP1A1, has been isolated from Japanese eel (Anguilla japonica) liver treated with 3-methylcholanthrene. The cDNA contained a 5′ untranslated region of 66 bp, an open reading frame of 1554 bp coding for 517 amino acids and a stop codon, and a 3′ untranslated region of 1166 bp. The predicted molecular weight of the Japanese eel CYP1A was approximately 58.5 kDa. The nucleotide sequence exhibited identities with the reported CYP1A1 sequences of 77% for Japanese eel, 75% for rainbow trout, 72% for scup, plaice, and butterfly fish, and 71% for toadfish. The deduced amino acid sequence exhibited identities with the reported CYP1A1 sequences of 78% for Japanese eel, 77% for rainbow trout, 75% for scup, 74% for toadfish, 73% for plaice, and 72% for butterfly fish. The novel eel CYP1A obtained had less similarity to the other teleost CYP1A1 proteins (72%–78%) than that of the eel CYP1A1 (74%–80%). When compared with mammalian CYP proteins, the novel eel CYP1A was more similar to the CYP1A1 proteins (54%–56%) than to the CYP1A2 proteins (50%–53%). The phylogenetic tree of the teleost CYP1A genes constructed using the maximum likelihood method suggested that the novel eel CYP1A is ubiquitous among the Anguilliformes. Received August 25, 2000; accepted November 30, 2000     

Étude des principaux facteurs influençant l‘émission d'attractifs sexuels synthétiques à partir de diffuseurs en caoutchouc et en plastique

Deux types de diffuseurs en caoutchouc (Michelin) et en plastique polystratifié (Hercon^®) sont testés en laboratoire pour étudier quelques aspects des phénomènes de diffusion. Trois composantes phéromonales, le Z9-12: Ac, le 12: Ac et le Z9-14: Ac imprégnées dans ces différents supports servent à détermineer le rôle joué par la longueur de la chaîne de la molécule et la présence de doubles liaisons sur la vitesse de diffusion. L'influence de la température, de la vitesse du vent et de l'humidité est déterminée en cellules climatisées.Parmi les facteurs relatifs à la structure chimique, l'influence de la longueur de la chaîne est prédominante par rapport à la présence d'une double liaison. Parmi les facteurs climatiques, le vent agit plus que la température sur la diffusion, alors que l'humidité paraît secondaire.     

Annual variability in upstream migration of glass eels in a southern USA coastal watershed

We investigated the environmental factors that affected temporal variability of eel recruitment and upstream migration in a freshwater coastal river along the southeastern US. Glass eels Anguilla rostrata were collected through ichthyoplankton sampling in the lower Roanoke River, North Carolina. Monthly samples were taken from fixed stations from May 2001 through June 2003. There was no evidence of consistent seasonal migration patterns for glass eels in Roanoke River. From May through December in 2001, glass eels were captured only during August. In 2002, glass eels arrived in February and remained in ichthyoplankton samples through October, with the exception of samples from September. Peak catch occurred in March at 4.02 ± 1.2 and declined through June to 0.18 ± 0.07 (#/1,000 m³). By August, the mean density increased to 0.96 ± 0.82 and to 3.59 ± 2.77 by October. In 2003 from January through June, glass eels were captured only during February and March. Glass eels were routinely collected when river discharge rates were <150 m³ s⁻¹. River discharge rates >650 m⁻³ s⁻¹ resulted in no glass eels in our samples. Upstream migration during 2002 was not correlated with water temperature or related to lunar phase. Glass eel freshwater upstream migration was initiated when water temperatures exceeded a threshold range of 10°C to 15°C; however, glass eels continued to migrate when water temperatures approached 30°C. The overall negative effect of river discharge suggests that changes in the water release schedules of upstream hydroelectric facilities during glass eel migration could strongly influence their recruitment success.     

Les structures d’occupation gravettiennes en Europe centrale : le cas de Grub/Kranawetberg,Autriche

Grub/Kranawetberg, a multilayered Gravettian site in Lower Austria, is one of many Gravettian open-air sites of Central Europe. These sites are well-known since a long time for their settlement structures, but also rich lithic inventories as well as organic tools, personal adornments, and art objects (e.g., Pavlov, Dolní Vestonice). While old excavation and recording techniques do not allow a detailed intrasite spatial analysis of these sites, the ongoing fieldwork at Grub/Kranawetberg provides us with abundant and detailed information about spatial organization of a Gravettian open-air site in Central Europe. The site is excavated since 1993 and yielded four archaeological horizons with abundant finds (including numerous personal adornments) and some evident structures. The main focus of this paper is on the GIS-based methodology of intrasite spatial analysis, especially emphasizing the possibilities of recognizing formation processes, size-sorting and locating a possible dwelling. Application of various methods, among them piece-plotting, mapping of find quantities, application of kernel density estimates and ring and sector analysis, in the 1995 and 1996 excavation area showed latent structures which are interpreted as evidence for a dwelling in this area of the site. In the last part of the paper the evidence of Grub/Kranawetberg is discussed and compared with other European Gravettian sites.     

Les Oppeliidae (Ammonitina) de l'horizon à Collotiformis (Callovien supérieur, zone à Athleta) de la région dijonnaise (Côte-d'Or, France)

In the Dijon area, the top of the Athleta zone contains rich ammonite fauna dominated quantitatively by two families: Perisphinctidae and Oppeliidae. The Oppeliidae are diversified and make up a numerically larger proportion of the ammonite fauna than in the underlying strata (up to 57 %). The exceptional state of preservation of the ammonites has permitted a precise study to be made of ontogenesis and intraspecific variability. Four sub-families are found (Oppeliinae, Hecticoceratinae, Distichoceratinae and Taramelliceratinae), within which sexual dimorphs have been recognised. One small form, characterized by lappets and a body chamber with ellipticoidal-trending coiling, is interpreted as the microconch dimorph of the Paralcidia genus which was unknown until now. One specimen of Creniceras, the oldest collected in Côte-d'Or, can be interpreted as the microconch dimorph of Taramelliceras.

Résumé

Dans la région dijonnaise, le sommet de la zone à Athleta renferme une riche faune ammonitique, quantitativement dominée par deux familles : Perisphinctidae et Oppeliidae. Par rapport aux niveaux sous-jacents, la famille des Oppeliidae est diversifiée et représente une part numériquement plus importante de la faune ammonitique (jusqu'à 57 %). L'excellente conservation des ammonites a autorisé une étude précise de l'ontogenèse et de la variabilité intraspécifique au sein de la famille. Quatre sous-familles sont représentées (Oppeliinae, Hecticoceratinae, Distichoceratinae et Taramelliceratinae), au sein desquelles les dimorphes sexuels ont été reconnus. Une petite forme, caractérisée par des apophyses jugales et une chambre d'habitation à enroulement à tendance ellipticoïde, est interprétée comme le dimorphe microconque, inconnu jusqu'à présent, du genre Paralcidia. Un spécimen de Creniceras, le plus ancien récolté en Côte-d'Or, pourrait correspondre au dimorphe microconque des Taramelliceras.     

Monthly changes in the swim bladder morphology of the female Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> in the coastal waters of Mikawa Bay,Japan

In the coastal area of Mikawa Bay, central Japan, specimens of the female Japanese eel Anguilla japonica could be divided into two groups according to the degree of swim bladder development. In one case, they were undeveloped, and in the other, they were highly developed with large rete mirabile, thick submucosa, and a well-developed gas gland. The morphology of the swim bladder in the latter group was comparable with that in the artificially fully maturated eel. The specimens with an undeveloped swim bladder were caught during all months, although their number was small. The specimens with a highly developed swim bladder were most abundant in November and December. During these months, catch of the specimens also increased sharply, by more than 10 fold compared to that in other months. These observations indicate that most of the eel appearing in coastal Mikawa Bay from October to January have a highly developed swim bladder adapted for a deep-sea environment. It was also conjectured that these specimens most likely migrated from rivers feeding into Mikawa Bay, toward spawning grounds in the open sea, and that this occurred after development of their swim bladders was completed. Actually, the specimens caught in the upstream of the Toyo River feeding into Mikawa Bay from late August to early October already had highly developed swim bladders.     

Toxicité du cuivre vis à vis de Microcystis aeruginosa Kütz. et d'Aphanizomenon flos-aquae Ralfs

We studied the toxicity of copper on Microcystis aeruginosa and Aphanizomenon flos-aquae. The toxicity phenomena can be described by the survival dose relationship which allows us to define the three parameters: threshold concentration (Cs), sensitivity (k) and a NL. 50%. The latter corresponds to the copper concentration which reduces the number of cells at the end of the exponential phase by 50%. A. flos-aquae is very clearly less tolerant than M. aeruginosa to copper. Viable cell counts based on electron transport activity showed that M. aeruginosa cultures can detoxify copper.     

Nouveaux restes postcrâniens d'hominoidea du miocène inférieur de napak, ouganda hommage à w. w. bishop

During reorganisation of the palaeontology collections at the Department of Antiquities and Museums, Kampala by the Uganda Palaeontology Expedition, several primate postcranial remains from Napak, an Early Miocene site, were found. Several large limb bones are attributed to Proconsul major, already known, already known from the locality on the basis of dental and gnathic remains, but hitherto poorly known postcranially. One specimen belongs to a smaller species of hominoid not represented at Napak by teeth and jaws. Both hominoids show quadrupedal and climbing adaptations, but they differ from each other. Thus Proconsul major praticed ‘power’ climbing whereas the smaller hominoid would have been more ‘agile’. In both cases, the hominoids moved frequently between the trees and the ground, and both were well adapted to their palaeoenvironment, which was dry forest. A further important result of this study is that the postcranial remains of r indicat indicate that it was heavier than had previously been envisaged on the basis of its dental remains. It would have weighed about the same as female gorillas, between 75 and 90 kg. The small species weighed about 20 kg.

Resumé

Lors d'un réaménagement des anciennes collections paléontologiques de l'Uganda Museum, des restes postcrâniens de primate provenant du site Miocène inférieur de Napak ont été retrouvés. Certaines pièces de grandes dimensions sont attribuées à Proconsul major, déjà signalé sur le site à partir de restes dentaires et gnathiques, mais dont l'anatomie postcrânienne était mal connue. D'autres spécimens sont rapportés à un Hominoidea de plus petite taille et non représenté par des dents ou des mâchoires. Les deux hominoïdes montrent des caractéristiques de quadrupèdes pratiquant le grimper mais de façons différentes. Alors que r pratique un gr pratique un grimper puissant, l'Hominoidea de petite taille pratique un grimper plus agile. Quoi qu'il en soit, ces deux espèces se déplaçaient souvent et activement au sol et dans les arbres. Ils vivaient dans une forêt sèche. Cette étude confirme que r, Hominoidea de, Hominoidea de grande taille, avait une masse corporelle plus importante que celle envisagée auparavant à partir des mesures dentaires. Il devait avoir une masse équivalente à celle d'un gorille femelle et peser entre 75 et 90 kg. L'espèce plus petite, quant à elle, aurait pesé 20 à 25 kg environ.