Dispersal of Larval Fishes in a Regulated River Tributary

Abstract

We investigated longitudinal distributions, nearshore movements, and drift of larval native fishes (humpback chub Gila cypha, speckled dace Rhinichthys osculus, bluehead sucker Catostomus discobolus, and flannelmouth sucker Catostomus latipinnis) in the Little Colorado River, a tributary to the regulated Colorado River in Grand Canyon, Arizona, to determine spawning sites, larval dispersal patterns, and amount of drift into the mainstem Colorado River. Larval distributions and drift indicated native fishes spawned throughout the terminal 14.2 km of the Little Colorado River. In addition, distribution, drift, and trap data suggest an active component to dispersal for all four native species. Drift of larval native fish was greater near shore than midchannel, and except for speckled dace larvae, which were prone to drift at night, larval native fish did not exhibit diel periodicity in drift. During a 46-d period in 1993, we estimated that over 370,000 native fish larvae drifted out of the Little Colorado River into the Colorado River. Regulated discharge from Glen Canyon Dam has all but eliminated spring-summer ponding of tributary mouths that occurred when ascending flows in the Colorado River coincided with descending and base flows in tributaries; thus, drifting larvae are allowed to pass directly into the Colorado River. Survival of larvae now transported into the Colorado River is probably poor because of perennially cold water temperatures and instability of nearshore habitats.

Analysis of fish eggs and larvae flowing into the Three Gorges Reservoir on the Yangtze River, China

“…We did not attempt to compensate for potential diel fluctuations in egg and larva abundance. This method has also been used in many other studies [8,[20][21][22].…”

Patterns and processes in the drift of early developmental stages of fish in rivers: a review

“…The peak in spawning-and hence drift activity is presumably adaptive and initiated by environmental cues that promise favourable conditions for the progeny (Somarakis et al 2000). The most important factors, in this respect, are water temperature (Carter et al 1986;Johnston 1997;D'Amours et al 2001;Reichard et al 2002b;Hay et al 2008) and discharge (Johnston et al 1995;Robinson et al 1998;Araujo-Lima and Oliveira 1998;Auer and Baker 2002). Either because fish do not spawn or produce viable eggs and larvae (i.e.…”

“…de Graaf et al 1999;Copp et al 2002;Araujo-Lima and Oliveira 1998). But what catalyses fish larvae to drift in the first place, how far they drift, how they navigate to settlement sites, how they detect these sites, how they exit the current, how they avoid predation and other hazards en route, and how significant this dispersal is to population dynamics, are largely unknown (but see Johnston 1997;Robinson et al 1998;Schludermann et al 2012). …”

Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River

“…No eff ort was made to compensate for potential diel fl uctuations in egg and larval abundance. This method has been used in many other studies (Yi et al, 1988;Robinson et al, 1998;Copp et al, 2005;Martin and Paller, 2008;Jiang et al, 2010;Mu et al, 2014). The total numbers of eggs and larvae were calculated according to the following formulae (see also Mu et al, 2014),…”