%0 Journal Article %J Journal of Applied Ecology %D 2016 %T Trans-Amazonian natal homing in giant catfish %A Fabrice Duponchelle %A Marc Pouilly %A Pecheyran, Christophe %A Hauser, Marilia %A Renno, Jean-Francois %A Panfili, Jacques %A Darnaude, Audrey M. %A García-Vasquez, Aurea %A Carvajal-Vallejos, Fernando %A Carmen García-Dávila %A Doria, Carolina %A Bérail, Sylvain %A Donard, Ariane %A Sondag, Francis %A Santos, Roberto V. %A Jesus Nuñez-Rodriguez %A Point, David %A Labonne, Maylis %A Baras, Etienne %K 87Sr/86Sr ratios %K Amazon %K anthropogenic activities %K Brachyplatystoma spp %K freshwater fish %K giant catfish %K hydroelectric dams %K Migration %K otoliths %X

1.Knowledge of fish migration is a prerequisite to sustainable fisheries management and preservation, especially in large international river basins. In particular, understanding whether a migratory lifestyle is compulsory or facultative, and whether adults home to their natal geographic area is paramount to fully appraise disruptions of longitudinal connectivity resulting from damming.2.In the Amazon, the large migratory catfishes of the Brachyplatystoma genus are apex predators of considerable interest for fisheries. They are believed to use the entire length of the basin to perform their life cycle, with hypothesized homing behaviours. Here we tested these hypotheses, using the emblematic B. rousseauxii as a model species.3.We sampled adults close to major breeding areas in the Amazon basin (upper Madeira and upper Amazonas) and assessed their lifetime movements by measuring variations in 87Sr/86Sr along transverse sections of their otoliths (ear stones) using laser ablation multicollector mass spectrometry (LA-MC-ICPMS).4.We demonstrate that larvae migrate downstream from the Andean piedmont to the lower Amazon, where they grow over a protracted period before migrating upstream as adults. Contrary to prevailing inferences, not all fish spend their nursery stages in the Amazon estuary. By contrast, the passage in the lower or central Amazon seems an obligate part of the life cycle. We further evidence that most adults home to their natal geographic area within the Madeira sub-basin. Such long-distance natal homing is exceptional in purely freshwater fishes.5.Synthesis and applications. By using otolith microchemistry, we were able to demonstrate a seemingly compulsory basin-wide migratory life cycle of large Amazonian catfishes. This makes them the organisms performing the longest migrations (>8000 km) in fresh waters. This exceptional life history is already jeopardized by two dams recently built in the Madeira River, which block a major migration route and access to a substantial part of their spawning grounds. Major impacts can be anticipated from the current and forthcoming hydroelectric development in the Amazon basin, not only on the populations and fisheries of this apex predator, but also on Amazonian food webs through trophic cascades.This article is protected by copyright. All rights reserved.

%B Journal of Applied Ecology %V 53 %P 1511-1520 %G eng %U http://dx.doi.org/10.1111/1365-2664.12665 %R 10.1111/1365-2664.12665 %0 Journal Article %J Journal of Applied Ichthyology %D 2015 %T Description of the skeletal anatomy of reared juveniles of Pseudoplatystoma punctifer (Castelnau, 1855) with notes on skeletal anomalies %A Estivals, G %A Carmen García-Dávila %A Darias, Maria %X

This study aimed at describing the normal bony skeleton of Pseudoplatystoma punctifer juveniles to use as a reference when assessing the adequacy of nutritional and environmental conditions in experimental rearing during the early developmental stages and to provide a baseline for characterizing skeletal anomalies that might appear in rearing trials with this species. Fertilized eggs and newly hatched P. punctifer larvae were incubated at 27.8 ± 0.4°C in two 60-L tanks (50-L water volume) connected to a clear water recirculating system. At 3 days post fertilization – dpf (2 days post hatching – dph) larvae were reared in three 40-L tanks (30-L water volume; initial n = 2700 larvae per tank; 28.3 ± 0.4°C, pH 6.9 ± 0.2, dissolved oxygen 8.2 ± 0.5 mg L−1, N–NO2 0.04 ± 0.02 mg L−1, N–NH4 0.14 ± 0.05 mg L−1; 0L:24D photoperiod) and fed as follows: non-enriched Artemia spp. nauplii from 4 to 21 dpf (3–20 dph) and a commercial compound diet from 18 dpf onwards. Pseudoplatystoma punctifer juveniles (23.2 ± 5.5 mm standard length, SL, n = 58) were stained with alizarin red and their skeletal structures analysed and identified under stereoscope. Pseudoplatystoma punctifer presents an osseous skeleton typical of catfishes, consisting of a broad and depressed skull containing small eyes, 43–44 vertebrae (44 being the most frequent), a caudal fin complex composed of one epural, five hypurals, one parhypural and two hypurapophyses, dorsal and pectoral fins with spines and anal and adipose fins. The observed occurrence of several skeletal anomalies indicates that the rearing conditions might have been suboptimal.

%B Journal of Applied Ichthyology %V 31 %P 88–97 %G eng %U http://dx.doi.org/10.1111/jai.12983 %R 10.1111/jai.12983