Unsupervised estimation of the age at sea departure of Atlantic salmon using magnesium, manganese, and zinc otolith chemistry.

Investigating the age at sea departure of returning Atlantic salmon is critical to better understand the role of emigration timing in survival. Among the methods available, the use of otolith chemistry can be challenging in anadromous fish, as the elements frequently used (i.e.

Effect of metabolic rate on time-lag changes in otolith microchemistry: an experimental approach using Salmo trutta.

Ecologists have long been interested in relevant techniques to track the field movement patterns of fish. The elemental composition of otoliths represents a permanent record of the growing habitats experienced by a fish throughout its lifetime and is increasingly used in the literature. The lack of a predictive and mechanistic understanding of the individual kinematics underlying ion incorporation/depletion limits our fine-scale temporal interpretation of the chemical signal recorded in the otolith.

The biology and feeding ecology of Arctic charr in the Kerguelen Islands.

Subsequent to their introduction in the 1950s, Arctic charr Salvelinus alpinus have been able to establish a self-sustaining population that has adapted to the unique conditions of the sub-Antarctic Kerguelen Islands. Here, 48 individuals (198-415 mm) were caught with gillnets and their basic biology and feeding ecology were examined using stable isotope analysis. The Lac des Fougères population split use of littoral and pelagic resources evenly, although larger fish relied more heavily on littoral production and appear to follow the size-dependent life history habitat template seen in many Scandinavian lakes where smaller sized individuals occupy the pelagic zone and larger individuals dominate the littoral habitat.

Functional effect of vaterite - the presence of an alternative crystalline structure in otoliths alters escape kinematics of the brown trout.

The fast-start escape response is the main locomotor behaviour observed in fish to evade predatory attacks and thereby increase their probability of survival. Thus far, this high-speed sensory motor control has been extensively studied in relation to extrinsic factors. In contrast, there has been surprisingly little consideration of intrinsic individual factors that can mediate sensorial perception, such as inter-individual variability in mechanosensory systems.

Sexually dimorphic gene expressions in eels: useful markers for early sex assessment in a conservation context.

Environmental sex determination (ESD) has been detected in a range of vertebrate reptile and fish species. Eels are characterized by an ESD that occurs relatively late, since sex cannot be histologically determined before individuals reach 28 cm. Because several eel species are at risk of extinction, assessing sex at the earliest stage is a crucial management issue.

Invasion dynamics of a fish-free landscape by brown trout (Salmo trutta).

Metapopulation dynamics over the course of an invasion are usually difficult to grasp because they require large and reliable data collection, often unavailable. The invasion of the fish-free freshwater ecosystems of the remote sub-Antarctic Kerguelen Islands following man-made introductions of brown trout (Salmo trutta) in the 1950's is an exception to this rule. Benefiting from a full long term environmental research monitoring of the invasion, we built a Bayesian dynamic metapopulation model to analyze the invasion dynamics of 85 river systems over 51 years.

An invasive fish and the time-lagged spread of its parasite across the Hawaiian archipelago.

Efforts to limit the impact of invasive species are frustrated by the cryptogenic status of a large proportion of those species. Half a century ago, the state of Hawai'i introduced the Bluestripe Snapper, Lutjanus kasmira, to O'ahu for fisheries enhancement. Today, this species shares an intestinal nematode parasite, Spirocamallanus istiblenni, with native Hawaiian fishes, raising the possibility that the introduced fish carried a parasite that has since spread to naïve local hosts.

The use of geometric morphometrics in understanding shape variability of sclerotized haptoral structures of monogeneans (Platyhelminthes) with insights into biogeographic variability.

The sclerotized attachment organ of monogeneans has been widely used to address fundamental questions in ecology and evolution. However, traditional morphometric techniques appear to be partially inadequate and non-optimal. Traditional linear measurements mainly provide information on the size of sclerites but provide very little information, if any, on their shape.

Multiscale determinants of parasite abundance: a quantitative hierarchical approach for coral reef fishes.

During recent decades, there have been numerous attempts to identify the key determinants of parasite communities and several influential variables have been clarified at either infra-, component or compound community scales. However, in view of the possible complexity of interactions among determinants, the commonly-used exploratory and statistical modelling techniques have often failed to find meaningful ecological patterns from such data. Moreover, quantitative assessments of factors structuring species richness, abundance, community structure and species associations in parasite communities remain elusive.

Multiple parasite introduction and host management plan: case study of lutjanid fish in the Hawaiian Archipelago.

The bluestriped snapper Lutjanus kasmira and the blacktail snapper L. fulvus were deliberately introduced in the Hawaiian Archipelago from French Polynesia in the late 1950s to enhance local fisheries. These species rapidly spread all over the Windward Islands, became extremely abundant and, therefore, caused controversial environmental concerns.

Monogeneans of the grouper Epinephelus tauvina (Perciformes, Serranidae) off Moorea, French Polynesia, with a description of Pseudorhabdosynochus pai n. sp. (Monogenea: Diplectanidae).

Specimens of the greasy grouper Epinephelus tauvina (Forsskål), caught off Moorea, French Polynesia, harboured four species of gill monogeneans. The diplectanid Pseudorhabdosynochus pai n. sp.

Host introduction and parasites: a case study on the parasite community of the peacock grouper Cephalopholis argus (Serranidae) in the Hawaiian Islands.

The peacock grouper (Cephalopholis argus) was intentionally introduced to the Hawaiian coastal waters 50 years ago to enhance the local fisheries. Following introduction, this species spread rapidly and became extremely abundant. A comparison of the metazoan parasite community of C.