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Duponchelle F.,Montpellier University | Duponchelle F.,University of Lima | Ruiz Arce A.,Institute Investigacion Of La Amazonia Peruana Iiap | Waty A.,Montpellier University | And 13 more authors.
Aquatic Living Resources | Year: 2012

In Amazonian fisheries, the silver arowana, Osteoglossum bicirrhosum (Cuvier 1829) is heavily exploited for human consumption as an adult, and for the aquarium trade as a small juvenile (yolk sac juvenile mainly). The periodicity of annuli formation on otoliths and growth variability of the silver arowana were studied in different river river-basins of the Peruvian Amazon between 2006 and 2009. Transverse stained sections of 606 individual otoliths were analysed from four different river-basins, the Amazonas, Ucayali, Napo and Putumayo, of which 554 could be interpreted. These belonged to 274 females ranging from 15 to 91 cm (standard length) and 280 males ranging from 30 to 91 cm. In addition, yolk sac juveniles of known age were collected to improve growth modelling. Monthly proportions of stained otolith edges validated the formation of a single annulus per year in two different river-basins with lagged hydrological cycles: the Amazonas-Ucayali and the Putumayo. Stained growth mark counts resulted in a longevity estimate of at least 16 years for the silver arowana in the Peruvian Amazon. This fish grew quickly during the first two years, and asymptotic growth was reached after four to five years, except in the Putumayo where it was reached slightly earlier. Results showed no significant growth dimorphism between sexes within basins, but indicated significant growth differences among river basins. Silver arowanas measured, on average, between 38 and 40 cm at the end of their first year. Length-at-age differences among river basins increased with age to reach over 14 cm (and >3 kg) after 7 years between the faster and slower growing populations (Amazonas and Putumayo, respectively). The growth differences observed emphasize the need for further investigation on the population structure of this species as, although these differences might merely be phenotypic responses to contrasted environmental conditions, they could alternatively reflect the existence of several populations with distinct genetic and life history characteristics. The consequences of such differences would be very important for the management and conservation of this fragile and extensively exploited species. © EDP Sciences, IFREMER, IRD 2012.

Zebiri I.,CNRS Institute of Molecular Chemistry - Reims | Haddad M.,IRD Montpellier | Duca L.,University of Reims Champagne Ardenne | Harakat D.,CNRS Institute of Molecular Chemistry - Reims | And 7 more authors.
Phytochemistry | Year: 2016

Twelve oleanane saponins, zebiriosides A-L, were isolated from the roots of Dendrobangia boliviana Rusby, together with two known saponins, talunùmoside I and 3-O-β-d-glucuronopyranosyl serjanic acid. These saponins are glycosides of serjanic or phytolaccinic acid. Their structures were established on two basis: first, their spectral data, mainly HR-TOFESIMS, 1D-NMR (1H, 13C, DEPT) and 2D-NMR (1H 1H COSY, TOCSY, HSQC, HMBC, and ROESY), and second by comparison with literature data. These compounds were evaluated for their cytotoxic, antileishmanial and hemolytic activities. No antileishmanial or hemolytic activities were revealed, however zebirioside C and zebirioside I showed cytotoxicity against fibroblasts with IC50 of 6.4 and 5.6 μM, respectively. © 2016 Elsevier Ltd.

PubMed | Institute Investigacion Of La Amazonia Peruana Iiap
Type: Journal Article | Journal: Journal of fish biology | Year: 2010

The main life-history traits of the dorado Brachyplatystoma rousseauxii, a large Amazonian catfish undertaking the largest migration known for a freshwater fish species (from the nursery area in the estuary of the Amazon to the breeding zones in the head waters of the western Amazon basin close to the Andes), were determined from a 5 year sampling of >15,000 specimens in the Peruvian Amazon. The breeding season occurred during the falling and low-water periods, which is hypothesized to be an adaptation to maximize the chances of young stages to reach the estuary. The size at first sexual maturity was slightly larger for females than males, c. 91 and 83 cm standard length (L(S)), respectively. Both males and females reproduce for the first time at >3 years old. The fecundity per spawning event ranged from 481,734 to 1,045,284 oocytes for females weighing 25 and 34 kg, respectively. Seasonal variations of body condition were similar among sexes, but differed between immature specimens that had a higher condition during the low-water period and lower condition during rising waters, and mature individuals that showed the opposite pattern. The growth characteristics were estimated by L(S) frequency analysis. For females, the best fitting models gave a mean birth date in August, during the height of the breeding cycle, with the following von Bertalanffy growth function parameters: L(Sinfinity) = 153.3, K = 0.29 and t(0) =- 0.37 years. For males, the best fitting model gave a mean birth date in July, also during the height of the breeding period, with L(Sinfinity) = 142, K = 0.30 and t(0) =- 0.36 years. At a given age, females were systematically larger than males and the size difference increased with age. The largest females sampled (148 cm L(S)) was 11 years old and the largest male (134 cm L(S)) was 9 years old. The mortality estimates were higher for males total (Z) = 1.34, natural (M) = 0.52 and fishing (F) = 0.82 than for females (Z = 0.98, M = 0.50, F = 0.48). The life-history patterns of B. rousseauxii are discussed in light of the available knowledge about this species and the understanding of its complex life cycle.

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