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Management Decisions Support System for Rhodeus Amarus (Bloch, 1782) Species Populations in Oltul Mijlociu – Cibin – Hârtibaciu Natura 2000 Site (Romania)

100%

Bănăduc D. , Cismaș I.-C. , Trichkova T. , Curtean–Bănăduc A.

Management of Sustainable Development

2014

tom 6

nr 2

35-47

The main threats to the Rhodeus amarus (Bloch, 1782) populations in the Natura 2000 site Oltul Mijlociu - Cibin - Hârtibaciu are the hydro technical modifications of the riverbeds, chemical pollution and poachery. ADONIS:CE is used in general for modeling business processes, but here was used in ecology/biology domain. The authors obtained a Rhodeus amarus model which included all the habitat species requirements, the indicators that provide favourable conservation status and the existing threats and pressures. The maintaining of the minor riverbed morphodynamics is very important - the meanders presence is very important for the local molluscs which are living in the inner U shape parts of the river. The places, where the sediments (sand, mud) are relatively stable, provide suitable habitats for molluscs important for the breeding of Rhodeus amarus. The maintaining of the actual regimes of liquid flows and oxygenation, and the avoidance of increasing of the sediments deposition rate in the water are necessary also for those molluscs species presence conservation. The extraction of sediments in these rivers should be made in correspondence with their natural rate of refilling and at sites at a distance of minimum five kilometres from each other.

Life history pattern of the Bitterling Rhodeus amarus (Bloch, 1782) in Siahroud River (southern Caspian Sea- Iran)

72%

Patimar R. , Seifi T. , Farahi A. , Ezzati M.

International Journal of Ecohydrology and Hydrobiology

2010

tom 10

nr 1

A total of 272 specimens of R. amarus caught in Siahroud River at the southern Caspian Sea from March 2006 to February 2007 were examined for life history attributes. Length-at-age was different between sexes. The von Bertalnffy growth function fit to backcalculated size at age data were: Lt= 94.16 [1-e-0.31(t+0.321)] and Lt=92.33[1-e-0.32(t+0.488)] for males and females respectively. WLR was estimated as W=0.0074TL3.4546 for males and W=0.0133TL3.0550 for females, positive allometric for both sexes. There was no significant difference from parity in the overall sex ratio. The reproductive season is extended from March to June, with a culmination point in April. Two kinds of eggs were found; small eggs measuring between 0.42 and 0.91mm with a mean value of 0.57±0.08, and large yolk-filled eggs ranged from 0.88 to 2.20mm with a mean value of 1.49±0.24 (S.D.). The average absolute and relative fecundities were 329.74 eggs and 187.40 eggs g-1 respectively. Variability of life history patterns of the fish in the basin could be interpreted as species response to basin condition.