Growth, survival, and starvation resistance of Colorado squawfish larvae

Abstract

SynopsisGrowth and survival of Colorado squawfish, Ptychocheilus lucius, larvae under fluctuating 18, 22, and 26° C (5 0 C diel fluctuations) and constant 18, 22, 26° C, and 30° C temperature conditions and ration size corresponding to 12 .5, 28, 64,142, 320 brine shrimp nauplii fish -'day-'was determined from laboratory experiments . Growth was optimal at 31° C and high at temperatures of 26° C to 30° C, at the highest food abundance . Lowest growth was under lowest food rations and highest temperatures . Growth of Colorado squawfish larvae declined substantially at temperatures < 22° C. Neither growth nor survival was significantly different between fluctuating or constant regimes . Survival of Colorado squawfish larvae was highest (95%) at 26 .2° C and 235 nauplii fish -' day-' and high at temperatures of 20 to 30° C with food abundance > 180 nauplii fish -' day-' . Survival was lowest when food abundance was low and temperature was high . Highest mortality occurred more than 20 days after experiments began and mortalities occurred sooner in higher than lower temperatures . Colorado squawfish larvae denied food for 5, 10, or 15 d after first feeding could have begun (6 d), had survival greater than 87 % which was equivalent to continuously fed controls . Survival of fish denied food for 17 .5 d after feeding could have begun declined from 84% before feeding to 57% after feeding . Point of no return was estimated between 17 .5 and 20 d . Colorado squawfish have relatively high starvation resistance. Low, stable flows that simulate natural hydrographs may enhance growth, survival, and recruitment of early life stages of Colorado squawfish by increasing water temperature and food abundance in regulated rivers of the Colorado River basin .

First Reproduction by Stocked Bonytail in the Upper Colorado River Basin

“…Growth of otolith-aged specimens was rapid (0.63 and 0.52 mm/d, respectively, assuming 5.5 mm TL at hatching; Snyder et al 2016) but similar to growth rates reported for the early life stages of other native Green River cypriniform fishes in warm, food-rich environments (Bestgen 1996(Bestgen , 2008Bestgen et al 2006). Based on spacing of otolith increments, growth was faster during approximately the first 30 d of life than later, perhaps indicating reductions in food supply or increased stress beginning in late July or early August.…”

Daily Increment Validation and Effects of Streamflow Variability and Water Temperature on Growth of Age‐0 Flathead Chub

“…Growth patterns of Flathead Chub in Fountain Creek differed within seasons, where early collected fish grew more than 20% faster than later collected fish in both 2012 and 2013. Higher water temperatures are often positively correlated with growth of larval fish up to a thermal optimum (Kucharczyk et al 1997;Green and Fisher 2004;Bestgen 1996Bestgen , 2008, which may explain growth differences between early and later collected age-0 Flathead Chub. Thermal (2012,2013), including number (n), mean and range of total length (TL), mean and range of growth rates (GR), and otolithbased age estimates (d) of age-0 Flathead Chub from Fountain Creek, Colorado.…”

“…Some of the fastest growing individuals in both early and later seining collections were hatched during periods following 2012 flow spikes that receded rapidly ( Figure 5). Peak flows may have increased growth opportunities through creation of new habitat or increased prey availability as a result of introduction of floodplain nutrients or food items (Junk et al 1989;Bestgen 1996Bestgen , 2008Hoagstrom and Turner 2015). Within-season differences in growth rates among larval cohorts have been reported for a variety of species (Crecco and Savoy 1985;Rice et al 1987;Bestgen et al 2006), including Flathead Chub, where individuals with an early hatch date grew faster than fish hatched later in the year (Durham and Wilde 2005).…”

Importance of parental effects on larval survival in Sardina pilchardus

“…Although a great amount of work exists on egg biochemical composition, most studies focus on variability in biochemical composition of developing fish eggs and larvae (Rønnestad et al 1992, Finn et al 1995, 1996, Rainuzzo et al 1997) and how biochemical composition of the egg affects vertical distribution of eggs in the water column (Craik & Harvey 1987, Nissling & Vallin 1996, Thorsen et al 1996, Guisande et al 1998.…”

“…Starvation is suggested to be one of the major causes of mortality during the period when larvae change from endogenous to exogenous feeding (Canino et al 1991, Bailey et al 1995 and has been proposed as a primary agent of mortality in all early larvae (Bisbal & Bengtson 1995, Clemmensen et al 1997, Jonas & Wahl 1998. However, the significance of starvation in larval mortality can be variable depending on the species and location studied (Theilacker 1986, Bestgen 1996, Theilacker et al 1996, Rooker et al 1997, Chícharo 1998.…”