Introduced and allopatric populations of brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss were sampled in Slovenia for stable isotope analysis to assess dietary niche shifts through ontogeny and estimate the propensity for cannibalism. Both S. trutta and O. mykiss are cannibals, with higher average relative contribution of conspecific assimilated energy for S. trutta (27·9%) compared with O. mykiss (7·7%). The sm...

The effect of extreme floods on the genetic composition of marble trout Salmo marmoratus living in Lipovscek, a tributary of the Soca River in Slovenia, which has been affected by multiple destructive flood events for centuries was investigated. By monitoring genetic variability during the period 2004–2011, apparent signatures of genetic erosion including a decline in observed and expected heterozygosities and allelic richness...

A simple approach is proposed to fit a body growth model for the European eel Anguilla anguilla to data‐poor case studies. The model is a modified von Bertalanffy curve allowing for delayed sex determination and sexual dimorphism. The proposed procedure provides preliminary estimates of model parameters on the basis of average age and body length of silver eels.

An eco‐genetic model tuned on a population of marble trout Salmo marmoratus subject to periodic flood events was used to explore how the evolution of growth rates interacting with density‐dependent processes can modify size at age and population structure and in turn influence the resilience of populations. Fish with greater growth potential were assumed to have higher mortality rates. The results of simulations were compared...

Total length ( L T ) (range 24–1000 mm; mean ± s.e . = 170·21 ± 0·36 mm) and mass ( W ) (range 0·10–9590 g; mean ± s.e . = 76·03 ± 0·87 g) of 36 460 specimens of marble trout Salmo marmoratus were used to compute a standard mass ( W s ) equation for this species by means of the empirical percentile (EmP) method. The EmP W s equation calculated was: log 10 W s = −5·208 + 3·202 log 10 L T − 0·046 (log 10 L T ) 2 ( L T range 90–5...

This study compares two alternative indices for quantifying the gross pathology of the swimbladder of eels, Anguilla anguilla (L.), infected with the nematode Anguillicoloides crassus . Two observers recorded twice the scores obtained by the two indices on the same set of 71 wild caught eels (from elver to silver eels, French Mediterranean lagoons). The Length Ratio Index (LRI), performed better than the Swimbladder Degenerati...

The fine scale morphological and genetic dynamics of successive waves of Anguilla anguilla glass eel recruitment was studied over a 2 year period at a southern European Mediterranean location (Camargue, France) with continuous recruitment. Using morphometric [total length ( L T ), mass ( M ), condition ( K ) and pigmentation stage] as well as genetic (allozyme) markers, the aim was to test for the existence of temporally separ...

Maturation rates in three European eel Anguilla anguilla populations increased from September to October and were slightly lower in fresh water than in brackish waters. Average and variance of total length at maturation were larger in females than males.

Body growth parameters, age and total length at sex differentiation were compared in three European eel Anguilla anguilla populations from Mediterranean sites with different salinity. Whilst body growth was faster in brackish than in freshwater environments, the present analysis shows that body size at sex differentiation might be a physiological invariant.

Age and total length ( L T ) data from a 11 year monitoring of the Anguilla anguilla eel population of the Camargue lagoons (Rhône delta, southern France) were collected for glass, yellow and silver eels. Three distinct models were calibrated to describe the growth process of undifferentiated eels, females and males, respectively. Uncertainty of parameter estimates was evaluated by bootstrapping. Females were characterized by...

Variations in the liver and spleen masses of the eel Anguilla anguilla were analysed in relation to the parasite load of Anguillicola crassus at autopsy (current infection by swimbladder lumen worms) and in relation to the severity of damage observed in the swimbladder (a way of assessing the intensity of past infections). None of these measures of parasite pressure were shown to account for variation in the relative liver mas...

Populations of the marble trout ( Salmo marmoratus ) have declined critically due to introgression by brown trout ( Salmo trutta ) strains. In order to define strategies for long‐term conservation, we examined the genetic structure of the 8 known pure populations using 15 microsatellite loci. The analyses reveal extraordinarily strong genetic differentiation among populations separated by

Among individuals of female three‐spined sticklebacks Gasterosteus aculeatus from a population in the Camargue, southern France, studied in 12 successive years, adult L T ranged from 31–64 mm, clutch size ranged from 33–660 eggs, and mean egg diameter per clutch ranged from 1.15–1.67 mm. Because the population was strictly annual, inter‐annual variation corresponded to variation among generations having experienced different e...

The spawning period of the common goby Pomatoschistus microps from 1993 to 1997 in the Vaccarès lagoon did not vary, except in 1997 when it was longer due to the reproduction of the young‐of‐the‐year. Egg size and number, and reproductive allocation varied greatly with one year to another. Female common gobies increased both their fecundity per spawning act and their egg size from 1993 to 1995. The annual variation in the repr...

There were significant correlations between colour pattern, LDH ‐5*, genotype and certain meristic characters in 59 hybrid trout Salmo , sp. from the Volarja stream, Soca River basin, Slovenia. It is concluded that panmixia between native Salmo marmoratus , and introduced S. trutta , of Atlantic, Danubian and Mediterranean origin had not been reached in this zone, despite the long period of introgression. The result is in agre...

Life history traits and migratory status of the Sand goby Pomatoschistus minutus were investigated in a brackish lagoon of the Rhône river Delta (Mediterranean Sea, south of France).