Relationships between hydrology, spatial heterogeneity, and fish recruitment dynamics in a temperate floodplain river

Abstract

Fish populations in the Brazos River, Texas, were surveyed monthly for 2 years to determine the relative influence of hydrology and habitat characteristics on the recruitment dynamics of seven species representing three divergent life history strategies. Surveys were conducted in two oxbow lakes with different flood recurrence intervals and the main river channel. The first year was relatively dry with few oxbow-river connections, whereas year 2 was relatively wet and connections between the main channel and floodplain habitats were common. Oxbow lakes supported greater juvenile abundances of most species relative to the main channel and were particularly important for nest building species with parental care. The river channel supported small species with extended reproductive periods and large, long-lived species that are able to store reproductive potential during sub-optimal periods. Hydrologic isolation was associated with greater rotifer densities in oxbows, and species with the greatest fecundity produced strong year classes during this period. Hydrologic connectivity did not increase juvenile production for most species, suggesting that recruitment dynamics in the Brazos River are similar to predictions of the low flow recruitment hypothesis (LFR). These results suggest that both hydrology and habitat heterogeneity interact with fish life history strategy to determine optimal conditions for recruitment and all three factors must be considered in restoration strategies for floodplain rivers.

Seasonal changes in the gonadossomatic index, allometric condition factor and sex ratio of an auchenipterid catfish from eastern Amazonia

“…The reproductive period was identified with greater intensity during the flood period, in which the flooded forest forms a rich environment for fish (Goulding, 1980), suggesting the flood pulse as the primary environmental factor influencing fish recruitment (Zeug & Winemiller, 2008). In auchenipterids, Trachycorystes galeatus (=Trachelyopterus galeatus) presented the same pattern of asynchrony between males and females (Silva & Viana, 2003).…”

The effect of water level on lateral movements of fish between river and off-channel habitats and implications for management

“…new fishways, re-introduction of large woody debris; Nicol et al 2004;Barrett and Mallen-Cooper 2006). Off-channel habitats are, however, also important for fish populations because of the increased habitat diversity offered by floodplains, with heightened survival, feeding and reproduction opportunities (Junk et al 1989;Zeug and Winemiller 2008). Improving lateral connectivity is also important for fish populations as floodplains provide feeding and nursery zones (Copp 1997;Castello 2008), and fish community structure, functioning and subsequent fishery production can relate to river-floodplain connectivity (Junk et al 1989).…”

Influence of the flood pulse on the reproduction of Tocantinsia piresi (Miranda Ribeiro) and Auchenipterus nuchalis (Spix & Agassiz) (Auchenipteridae) of the middle Xingu River, Brazil

“…The role of the flood pulse in fish reproduction has been discussed by a number of authors (Zeug and Winemiller, 2008;Bailly et al, 2008;Prudente et al, 2015).…”

“…The variation in the hydrological cycle also plays a significant role in the maturation of the gonads, spawning season, and the larval development of fish species (Goulding, 1980;Ruffino and Isaac, 1995;Zeug and Winemiller, 2008;Queiroz et al, 2010;Freitas et al, 2011;Maciel et al, 2011;Prudente et al, 2015). Spawning during the filling and flood season may contribute to reproductive success in many fish species (Godinho et al, 2010), due in particular to the increased availability of habitats that favour the survival of larvae and fry (Agostinho et al, 2004).…”