Use of Remote‐Site Incubators to Produce Arctic Grayling Fry of Wild Parentage

Abstract

Remote‐site incubators (RSIs) adjacent to five streams were evaluated as part of a program to reestablish spawning stocks of Arctic grayling Thymallus arcticus in Upper Red Rock Lake in southwest Montana. From 2000 to 2002, wild adult Arctic grayling were caught from the only study stream that currently supports natural spawning. Adults were artificially spawned, and the fertilized eggs were immediately placed into 12 RSIs in 2000, 8 in 2001, and 10 in 2002. Apart from daily removal of dead eggs and dead fry, no prophylaxis was administered. Median numbers of accumulated degree‐days (and calendar days) to first observation of eye‐up, hatch, and swim‐up were 106.1 (10.5), 139.2 (14.0), and 169.2 (17.5), respectively. Mean (±95% confidence interval) percent emergence was greater in 2000 (73.4 ± 15.1%) than in 2001 and 2002 (pooled mean, 26.5 ± 11.9%). Mean percent emergence at a warm (∼13°C) site (East Elk Springs Creek; 69.8 ± 22.0%) was higher than the pooled mean for the other four sites (35.3 ± 15.0%). In 2002, Arctic grayling were observed spawning in the main‐stem Elk Springs Creek downstream from two RSI sites on tributaries; the species was last reported in this creek in the late 1960s. We believe that the fish observed spawning in 2002 emerged from the RSIs during 2000. Remote‐site incubators are useful, cost‐effective tools that could help reestablish Arctic grayling spawning stocks.

Juvenile Movement among Different Populations of Cutthroat Trout Introduced as Embryos to Vacant Habitat

“…The RSIs are designed to consistently supply embryos with freshwater, while avoiding sedimentation problems associated with buried incubators, and have been used previously to successfully introduce other species of salmonid embryos (e.g., Donaghy and Verspoor 2000;Kaeding and Boltz 2004;Al-Chokhachy et al 2009). Hatched fry absorbed the yolk sac while in the RSI.…”

Evaluating the Reintroduction Potential of Lahontan Cutthroat Trout in Fallen Leaf Lake, California

“…For Fallen Leaf Lake, these alternative reintroduction strategies may include (1) using hydroacoustic surveys to locate areas of high habitat complexity, (2) using the survey information to target multiple stocking sites, and (3) stocking during periods of thermal stratification, thus minimizing predator encounter rates (Beauchamp et al 1999). Next, the use of remote-site incubators (RSIs) should be evaluated as a cost-effective means for reintroductions (e.g., Kaeding and Boltz 2004). There should be an explicit evaluation of the effectiveness of RSIs by quantifying young-of-year survival from Glen Alpine Creek to the lake.…”

A review of factors influencing artificial salmonid incubation success and a spate river‐specific incubator design

“…Over the past 50 years, incubators have become increasingly used in conservation programmes to improve salmonid ova survival and redistribute or re‐establish populations until solutions to population decline are identified and take effect (e.g. EA 2002; Kaeding & Boltz 2004; Al‐Chokhachy et al. 2009).…”

“…Over the past 50 years, incubators have become increasingly used in conservation programmes to improve salmonid ova survival and redistribute or re-establish populations until solutions to population decline are identified and take effect (e.g. EA 2002; Kaeding & Boltz 2004;Al-Chokhachy et al 2009). The Vibert and Whitlock-Vibert boxes are widely used in-stream incubators, with total sales since the 1970s exceeding 1.5 million (Boit-Vibert 2010), although results are rarely published.…”