Riverine spawning, long distance larval drift, and floodplain recruitment of a pelagophilic fish: A case study of golden perch (Macquaria ambigua) in the arid Darling River, Australia

Abstract

1. Pelagic spawning riverine fish (pelagophils) spawn in free-flowing river habitats with downstream drift of eggs and larvae but the spatial scale is often unknown, and this constitutes a major ecological knowledge gap.

No quarter: Lack of refuge during flow intermittency results in catastrophic mortality of an imperiled minnow

“…In a comparison between regulated and unregulated headwater streams in Australia, fish were extirpated in regulated streams with barriers and were unable to recolonise them during release of environmental flows, while fishes in unregulated streams persisted through prolonged drought (Chester et al., 2014). Without longitudinal connectivity, species with long‐distance dispersals may not be able to persist in upstream reaches (Kerezsy, Balcombe, Tischler, & Arthington, 2013; Stuart & Sharpe, 2020). Effective fish passage, even in the presence of environmental flows, is critical for recovery of RGS minnow and other similar species (Carson, Osborne, & Turner, 2020; Perkin et al., 2015).…”

A compendium of ecological knowledge for restoration of freshwater fishes in Australia

“…Case study 4: recruitment variability Recruitment rates of golden perch are highly variable spatially and temporally. Recruitment in the less unregulated productive rivers and floodplain lakes of the NMDB appears more frequent than in many rivers of the highly regulated SMDB (Sharpe 2011;Zampatti et al 2019;Stuart and Sharpe 2020). In addition, within both regions, the natal origin of recruits in given localities may be temporally variable.…”

“…In addition, within both regions, the natal origin of recruits in given localities may be temporally variable. Individuals spawned in certain rivers can substantially augment populations in other rivers, and the contribution of different recruitment sources varies as a function of hydrology, nursery habitats and connectivity (Zampatti et al 2018;Stuart and Sharpe 2020). For golden perch populations, this knowledge reinforces the need for management over broad spatial scales and consideration of inter-regional movements.…”

“…8c). The flowrelated ecology and population dynamics of golden perch operate over greater spatial scales than previously thought (Zampatti et al 2018(Zampatti et al , 2019Stuart and Sharpe 2020), and understanding these dynamics, including the variety of movement types exhibited by different life stages, is essential to improving fish passage science (White et al 2011;O'Connor et al 2015), managing river connectivity issues and maintaining population structure for this wide-ranging species (Silva et al 2018). This knowledge is increasingly important as water management planning progresses from site to connected catchment, and to basin scales (Stewardson and Guarino 2018).…”

“…However, recruitment is noticeably higher when associated with overbank flows (Mallen-Cooper and Stuart 2003;Ye et al 2008;Ebner et al 2009b;Sternberg et al 2012;Cockayne et al 2013 (FRGP); Zampatti and Leigh 2013a, 2013b; King et al 2016) Larval survival depends on high densities of appropriately sized zooplankton at first feeding (Rowland et al 1983;Arumugam and Geddes 1987), and spawning may not necessarily translate to recruitment if this is not available (Roberts et al 2008; Significant increases in juvenile abundance occur in the lower Murray River in years during overbank flooding compared with lowflow years (Zampatti and Leigh 2013b). However, some of this change in abundance appears to have resulted from spawning and recruitment in the Darling River, with 1þ fish moving downstream and then into the Murray River (Sharpe 2011; Zampatti and Leigh 2013b; Zampatti et al 2015; Stuart and Sharpe 2020) Inundated floodplain lakes can provide juvenile nursery habitats, which may increase survival and therefore recruitment to main channel populations after reconnection (Sharpe 2011) The collection of YOY on the floodplain in the NMDB suggests this provides rearing habitats (Rolls and Wilson 2010) Nursery habitats such as Menindee Lakes in the NMDB and large, 'slow travel' flows that promote high productivity have been suggested to enhance recruitment rates (Stuart and Sharpe 2020). The level of natural recruitment upstream of Torrumbarry Weir in the Murray and lower Goulburn rivers is thought to be low, with little evidence of localised recruitment (records of late-stage larvae, 0þ and 1þ fish are rare; King et al , 2009aKoster et al 2009).…”