Review of trap-and-haul for managing Pacific salmonids (Oncorhynchus spp.) in impounded river systems

Abstract

High-head dams are migration barriers for Pacific salmon Oncorhynchus spp. in many river systems and recovery measures for impacted stocks are limited. Trap-and-haul has been widely used in attempts to facilitate recovery but information from existing programs has not been synthesized to inform improvements to aid recovery of salmonids in systems with high-head dams. We reviewed 17 trap-and-haul programs regarding Pacific salmon to: (1) summarize information about facility design, operation and biological effects; (2) identify critical knowledge gaps; and (3) evaluate trap-and-haul as a current and future management tool. Existing programs are operated to address a range of management goals including restoring access to historical habitats, temporarily reducing exposure to dangerous in-river conditions, and reintroducing ecological processes upstream from dams. Information gathered from decades of operation on facility design criteria and fish handling protocols, and robust literature on fish collection and passage are available. While many aspects of trap-and-haul have been evaluated, effects on population productivity and sustainability remain poorly understood. Long-term and systematic studies of trap-and-haul outcomes are rare, and assessments can be confounded by concurrent management actions and broad ecological and climatic effects. Existing data suggest that performance and effectiveness vary among programs and over various time scales within programs. Although critical information gaps exist, trap-and-haul is an important management and conservation tool for providing Pacific salmonids access to historical habitats. Successful application of trap-and-haul programs requires long-term commitment and an adaptive management approach by dam owners and stakeholders, and careful planning of new programs.

Capacity of Two Sierra Nevada Rivers for Reintroduction of Anadromous Salmonids: Insights from a High‐Resolution View

“…2017; Pearse and Campbell 2018) such that re‐establishment of anadromous steelhead could potentially emerge simply from diverting these downstream migrants to the lower river via a fish collector at the head of the reservoir and providing means for upstream passage to the adult steelhead that eventually return (Kock et al. 2021). A fish collector at the forebay next to the dam would probably be less effective due both to the propensity of migrants to stop in the reservoir and the large size of the forebay, which reduces the effectiveness of fish collectors (Kock et al.…”

Fate of translocated American eel (Anguilla rostrata) in the lower Ottawa River and passage behavior at a multichannel barrier

“…Trap-and-transport programs involve capturing fish downstream of a barrier and releasing them upstream to improve habitat access and are widely used around the globe for a variety of species including eels (Kock, Ferguson, Keefer, & Schreck, 2020). For instance, implementation of a trap-and-transport program greatly increased the number of short-finned eel (Anguilla australis) and New Zealand longfin eel (Anguilla dieffenbachii) elvers upstream of two dams on the Waikato River, New Zealand (Jellyman & Arai, 2016).…”

“…Trap-and-transport of American eel has also been used at a large scale within the St. Lawrence River system, Canada, where 3.9 million eels were transported beyond dams and released in the upper watershed from 2006-2010 (Threader, Blimke, & Groman, 2010). The success of trapand-transport can vary across barriers and species, in part because trap-and-transport can be stressful and have sublethal consequences for individual fish (Kock et al, 2020). Posttransport consequences can include increased disease susceptibility, injury, downstream fallback, and mortality (Colvin, Peterson, Sharpe, Kent, & Schreck, 2018;Kock et al, 2020;Naughton et al, 2018), compromising the effectiveness of trap-and-transport programs.…”

“…The success of trapand-transport can vary across barriers and species, in part because trap-and-transport can be stressful and have sublethal consequences for individual fish (Kock et al, 2020). Posttransport consequences can include increased disease susceptibility, injury, downstream fallback, and mortality (Colvin, Peterson, Sharpe, Kent, & Schreck, 2018;Kock et al, 2020;Naughton et al, 2018), compromising the effectiveness of trap-and-transport programs. In a trap-and-transport context, fall back is typically assigned to fish expected to continue upstream migration after release above a barrier that instead move back downstream of said barrier (Frechette, Goerig, & Bergeron, 2020;Kock et al, 2020).…”

“…Posttransport consequences can include increased disease susceptibility, injury, downstream fallback, and mortality (Colvin, Peterson, Sharpe, Kent, & Schreck, 2018;Kock et al, 2020;Naughton et al, 2018), compromising the effectiveness of trap-and-transport programs. In a trap-and-transport context, fall back is typically assigned to fish expected to continue upstream migration after release above a barrier that instead move back downstream of said barrier (Frechette, Goerig, & Bergeron, 2020;Kock et al, 2020). A means to minimize fallback associated with trap-andtransport is to increase the distance of release sites from downstream barriers (Kock, Ekstrom, Liedtke, Serl, & Kohn, 2016;Naughton et al, 2018), though the effectiveness of this strategy for American eel has received limited attention.…”