Influence of seasonal, diel, lunar, and other environmental factors on upstream fish passage in the Igarapava Fish Ladder, Brazil

Abstract

Upstream fish passage was evaluated during 12 months in the vertical-slot Igarapava Fish Ladder constructed around Igarapava Dam, in the heavily dammed Grande River, Southeast Brazil. A video monitoring system was used to observe 61,621 fish that passed the ladder, of which 93.5% were identified to 15 taxa. Among the migratory species, the most abundant were Pimelodus maculatus (33.6% of all fish), Leporinus octofasciatus (31.4%), Leporinus friderici (4.5%), and Prochilodus lineatus (3.1%). Seven taxa were classified as nonmigratory, and of these taxa, the small Bryconamericus stramineus was the most abundant (12.7%) of all fishes. Passage of the 'nonmigratory' taxa upstream in the ladder shows they are migratory in this system and have a strong behavioural drive to move to upstream habitat. Passage of most taxa had a strong seasonal pattern. While some species passed primarily during the day, others showed a distinct nocturnal pattern. Lunar phase and water temperature also strongly affected passage of some taxa. Rainfall and dam discharge had a small or null influence on most taxa; perhaps due to the fairly small catchment area of the reservoir and the highly regulated discharge at Igarapava Dam.

Daily movement behavior of two Neotropical armored catfish species (Ancistrusaff. cirrhosusValenciennes, 1836 andHypostomus ancistroidesIhering, 1911) at a road-stream crossing culvert

“…The gravitational pull of the moon causes tides, which have profound effects on community structure (Kruse, Taylor, Muhando, & Reuter, ; Zimecki, ). However, in streams, the moon's gravitational effect on water is insignificant, and fish movements are related to the luminosity of the different moon phases: diurnal species are active during the full moon, whereas many nocturnal species are active during new and quarter‐moon phases (Bizzotto et al., ). The low melatonin levels of nocturnal fish inhibit their activity during nights with a full moon (Oliveira, Duncan, Pousão‐Ferreira, Mañanós, & Sánches‐Vázquez, ; Takemura et al., ; Zimecki, ); therefore, the high activity levels of A .…”

All that goes up must come down? Absence of downstream passage through a fish ladder in a large Amazonian river

“…Sampling in the ladder occurred bimonthly during daylight hours, from November 2007 to October 2008. Previous studies have reported higher fish abundance in ladders during daytime (Fernandez et al, 2007;Bizzoto et al, 2009), even though Siluriformes species are more active at night. Bimonthly captures were combined within months and expressed as fish/m 2 .…”

Environmental and lunar cues are predictive of the timing of river entry and spawning‐site arrival in lake sturgeon Acipenser fulvescens

“…Initiation of spawning migrations into streams and the timing of reproduction in fishes represent important behavioural decisions that are elicited by external cues such as seasonal photoperiod (Quinn & Adams, 1996; Bizzotto et al , 2009) and other environmental variables (Kamler, 2002). There is strong selection for adults to reproduce at times and in locations that are conducive to offspring survival.…”