29 research outputs found
Reproduction of the surubim catfish (Pisces, Pimelodidae) in the São Francisco River, Pirapora Region, Minas Gerais, Brazil Reprodução do surubim (Pisces, Pimelodidae) do Rio São Francisco, Região de Pirapora, Minas Gerais
The reproductive biology of the surubim, P. coruscans of the São Francisco River, in the Pirapora region was studied from December/98 to November/99. Reproduction occurred between October and January with high frequency of fishes in the advanced ripening/mature and spawned/spent stages along with higher values of the gonadosomatic index. Macroscopic and microscopic analyses indicated that P. coruscans presents total spawning. The reproductive period coincided with highest rainfall and water turbidity values in the region. The smallest male captured had a total length of 63.3cm and the smallest female 92.0cm in total length. The largest male in the maturation stage was recorded to be 97.0cm and the largest female 144.1cm in total length. Surubim were more frequently captured than females, at a proportion of approximately one female to three males. The gonadosomatic, hepatosomatic, stomach repletion, and coelomic fat indexes, as well as the condition factor were related to stages of the reproductive cycle.<br>Estudou-se a biologia reprodutiva do surubim Pseudoplatystoma coruscans do Rio São Francisco, na região de Pirapora, Minas Gerais no período de dezembro/98 a novembro/99. A reprodução ocorreu entre outubro e janeiro, com alta freqüência de peixes em maturação avançada/maduros e desovados/espermiados, e os maiores valores do índice gonadossomático nesse período. Análises macro e microscópicas indicaram que P. coruscans apresenta desova total. A época reprodutiva coincidiu com maior turbidez da água e maior incidência de chuva na região. O menor e maior macho capturado em maturação apresentou 63,3cm e 97,0cm e a menor e maior fêmea neste estádio 92,0cm e 144,1cm de comprimento total, respectivamente. Registraram três machos para cada fêmea e somente as fêmeas apresentaram comprimento acima de 100cm. Os índices biológicos gonadossomático, hepatossomático, repleção estomacal, gordura celômica e fator de condição foram relacionados aos estádios do ciclo reprodutivo
Recommended from our members
In Situ Geochronology for the Next Decade: Mission Designs for the Moon, Mars, and Vesta
Geochronology is an indispensable tool for reconstructing the geologic history of planets, essential to understanding the formation and evolution of our solar system. Bombardment chronology bounds models of solar system dynamics, as well as the timing of volatile, organic, and siderophile element delivery. Absolute ages of magmatic products provide constraints on the dynamics of magma oceans and crustal formation, as well as the longevity and evolution of interior heat engines and distinct mantle/crustal source regions. Absolute dating also relates habitability markers to the timescale of evolution of life on Earth. However, the number of terrains important to date on worlds of the inner solar system far exceeds our ability to conduct sample return from all of them. In preparation for the upcoming Decadal Survey, our team formulated a set of medium-class (New Frontiers) mission concepts to three different locations (the Moon, Mars, and Vesta) where sites that record solar system bombardment, magmatism, and habitability are uniquely preserved and accessible. We developed a notional payload to directly date planetary surfaces, consisting of two instruments capable of measuring radiometric ages, an imaging spectrometer, optical cameras to provide site geologic context and sample characterization, a traceelement analyzer to augment sample contextualization, and a sample acquisition and handling system. Landers carrying this payload to the Moon, Mars, and Vesta would likely fit into the New Frontiers cost cap in our study (∼$1B). A mission of this type would provide crucial constraints on planetary history while also enabling a broad suite of complementary investigations 2021. The Author(s). Published by the American Astronomical Society. © 2021. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]