Requirements and boundary conditions for fish passes of non-sport fish species based on Chilean experiences

Abstract

Most artificial fish passes have been developed in Northern temperate rivers and are designed to serve large, migratory sport fish species (mostly salmonids). Experience in construction and maintenance of fish passes show that salmon-criteria are not adequate for flat-land rivers and non-sport fishes. Consequently, over the last decade, design criteria have changed to take requirements of target species into account. Extrapolation of these concepts to rivers in the Southern Hemisphere with different hydrological conditions and fish community composition is not straight forward. This review focuses on requirements for an adequate hydraulic design of passes for non-sport fish species bodied (\15 cm) threatened by small hydropower dams (with a typical head of 3-5 m). First, fragmentation of fish populations due to river obstructions that impede longitudinal movements is introduced from the perspective of environmental sustainability, taking the Chilean indigenous freshwater fish species as a study case. Subsequently, relevant properties of fish passages are reviewed, and experimental issues for maintenance in captivity and determination of swimming abilities in the laboratory are presented. Following dimensional considerations controlling scales for an adequate hydraulic design of fish passes, involving fluid, flow, fish, and pass properties are discussed. Finally, we postulate that successful passage design should consider habitat connectivity as the key concept for preservation of this highly threatened native fish fauna.

Hydropower Development, Riverine Connectivity, and Non-sport Fish Species: criteria for Hydraulic Design of Fishways

“…‘Non‐sport fish’ is a term used to describe freshwater species with small body size (<150 mm total length when adults), which is the case for most native species in temperate regions of the Southern Hemisphere (e.g. Boubée et al ., , for New Zealand species and Link and Habit, , for Chilean species). Because of their small body size, they are generally not commercially important, but several are endemics and have high conservation value (Habit et al ., ).…”

Fish‐Net: Probabilistic models for fishway planning, design and monitoring to support environmentally sustainable hydropower

“…Absent of a biological imperative to migrate to distant spawning locations, resident non‐recreational fish may not make the potentially stressful journey upstream through technical fishways. Thus, we follow Link and Habit () in recommending nature‐like bypasses to ensure habitat continuity for these species where there is sufficient space for a low‐gradient structure. Some commentators have suggested that nature‐like bypasses are also an appropriate solution for migratory fish, but they often fail in this regard due to poor attraction (Bunt et al., , ; Noonan et al., ; Kemp, ).…”

“…This is especially true of small‐bodied, non‐recreational species (e.g. adults <150 mm TL; Link & Habit, ), whose relatively weak swimming abilities are consistent with their diminutive stature (Bestgen, Mefford, Bundy, Walford, & Compton, ; Ficke, Myrick, & Jud, ; Laborde et al., ; Leavy & Bonner, ; Nelson, Gotwalt, Simonetti, & Snodgrass, ; Nikora, Aberle, Biggs, Jowett, & Sykes, ). Several of these species support culturally and economically important capture fisheries (e.g.…”

“…Providing effective passage for non‐recreational fish is increasingly seen as a priority in diverse biogeographical settings, including South America (e.g. Link & Habit, ), North America (e.g. Pennock et al., ), Europe (e.g.…”

Moving beyond fitting fish into equations: Progressing the fish passage debate in the Anthropocene

“…Fish passage research remains largely entrenched in the early paradigm of salmonid biology. This long‐standing focus has resulted in the same approach being perpetuated all over the globe, for all species, in all geographical contexts, rather than taking a step back and rethinking whether it is the right approach in a particular location (Link & Habit, ; Mallen‐Cooper & Brand, ; Wilkes, Baumgartner et al, 2018). Despite the significant differences between the requirements of salmonids and most other fishes (Figure ), including those from the tropics and temperate Southern Hemisphere, the knowledge, techniques, thinking and solutions developed from studies of salmonids have been widely transferred to fish passage design and management elsewhere (Silva et al, ).…”