Effects of flow regulation in the life-cycles of a mediterranean cyprinid species, the Iberian chub (Squalius carolitertii Doadrio, 1987)

Streamflow is considered a driver of inter and intra���specific life���history differences among freshwater fish. Therefore, dams and related flow regulation, can have deleterious impacts on their life���cycles. The main objective of this study is to assess the effects of flow regulation on the growth and reproduction of a non���migratory fish species. During one year, samples were collected from two populations of Iberian chub, inhabiting rivers with non���regulated and regulated flow regimes. Flow regulation for water derivation promoted changes in chub���s condition, duration of gonad maturation and spawning, fecundity and oocyte size. However, this non���migratory species was less responsive to streamflow regulation than a migratory species analysed. Findings from this study are important to understand changes imposed by regulated rivers on fish and can be used as guidelines for flow requirements implementations; RESUMO: O caudal �� um dos fatores respons��veis pelo funcionamento dos ciclos de vida das esp��cies pisc��colas dulciaqu��colas. As barragens, e a regulariza����o de caudal associada, podem ter impactes nos ciclos de vida destas esp��cies. O objetivo deste estudo prende���se com a avalia����o dos efeitos da regulariza����o de caudal no crescimento e reprodu����o de uma esp��cie pisc��cola n��o���migradora. A an��lise de amostras recolhidas em popula����es de escalo do Norte provenientes de dois rios de caudal regularizado e n��o regularizado, identificaram impactes significativos a n��vel da condi����o corporal, da matura����o das g��nadas e desova, da fecundidade e da dimens��o dos o��citos. Esta esp��cie n��o���migradora parece ser menos responsiva �� artificializa����o do caudal que uma esp��cie migradora previamente analisada. Estes resultados permitem compreender as altera����es impostas pela regulariza����o do caudal e podem ser usados em programas de reabilita����o fluvial.