The effectiveness of spawning habitat creation or enhancement for substrate-spawning temperate fish: a systematic review

Abstract

Background: Habitat is the foundation for healthy and productive fisheries. For fish that require substrate for spawning, lack of appropriate spawning substrate is inherently limiting and a lack of access to suitable spawning habitat will lead to population collapse. To ensure management resources are being allocated wisely and conservation targets are being achieved, there is an increased need to consider the effectiveness of techniques to enhance or create habitat that has been lost. The aim of this systematic review was to assess the effectiveness of techniques currently used to create or enhance spawning habitat for substrate-spawning (including vegetation-spawning) fish in temperate regions, and to investigate the factors that influence the effectiveness of habitat creation or enhancement. Methods: Searches for primary research studies on the effect of spawning habitat creation or enhancement for substrate-spawning fish were conducted in bibliographic databases, on websites and an online search engine, through evidence call-outs, social media, and Advisory Team contacts, and in the bibliographies of relevant reviews. All articles were screened at two stages (title and abstract, and full-text), with consistency checks being performed at each stage. Relevant articles were critically appraised and meta-data and quantitative data were extracted into a database. All included studies were described narratively and studies that met the criteria for meta-analysis were analyzed quantitatively. Review findings: A total of 75 studies from 64 articles were included in this systematic review and underwent data extraction and critical appraisal. The majority of these studies were from North America (78.1%) and a large percentage (63.7%) targeted salmonids. We conducted a meta-analysis using data from 22 studies with 53 data sets. Available evidence suggests that the addition or alteration of rock material (e.g., gravel, cobble) was effective in increasing the abundance of substrate-spawning fish compared to controls, with a taxonomic bias towards salmonids (5/6 data sets). The addition of plant material (e.g., large woody debris) with or without physical alterations to the waterbody (e.g., excavation) was also effective in increasing substrate-spawning fish abundance on average compared to controls. Egg life stages (i.e., nests, redds, zygotes or developing embryos) were associated with larger increases in abundance with habitat creation or enhancement than age-0 life stages (i.e., alevin, fry, young-of-the-year). We found

Making up the bed: Gravel cleaning as a contribution to nase (Chondrostoma nasus L.) spawning and recruitment success

“…Finally, hatched larvae need to emerge successfully from spawning gravel, so infiltration of fines into the stream bed during early ontogeny can reduce emergence success and affect subtle endpoints, such as larval size at emergence (Nagel, Pander, Mueller, & Geist, 2020). Measurements to improve spawning success by restoration of spawning grounds have been widely discussed in the scientific literature (Taylor et al, 2019) and are used to support fish populations by many organizations such as local fishing associations and regulatory authorities. Primary target species mostly comprise salmonids such as brown trout (Salmo trutta L.; Pulg et al, 2013;Sternecker, Wild, & Geist, 2013;Zeh & Dönni, 1994), European grayling (Thymallus thymallus L.; Zeh & Dönni, 1994) and salmon (Cramer, 2012;Mih & Bailey, 1981).…”

“…Measurements to improve spawning success by restoration of spawning grounds have been widely discussed in the scientific literature (Taylor et al, 2019) and are used to support fish populations by many organizations such as local fishing associations and regulatory authorities. Primary target species mostly comprise salmonids such as brown trout ( Salmo trutta L.; Pulg et al, 2013; Sternecker, Wild, & Geist, 2013; Zeh & Dönni, 1994), European grayling ( Thymallus thymallus L.; Zeh & Dönni, 1994) and salmon (Cramer, 2012; Mih & Bailey, 1981).…”

The relative effectiveness of seed addition methods for restoring or re-creating species rich grasslands: a systematic review protocol

“…Grey literature, will be searched in the search engines BASE (https ://www.base-searc h.net/) and google (https :// www.googl e.ch/), where the first 500 hits will be retrieved and scanned for relevance [33]. Furthermore, we will look for grey literature by asking our stakeholder group and other national and international experts in the field.…”

Fish Spawning Habitat Restoration Challenges and Management Options for the Laurentian Great Lakes

“…However, due to low study validity and limited replication, the efficacy of many of these created spawning shoals could not be confirmed. Taylor et al (2019) classified studies as having low, medium, or high validity, and only high validity studies were included in the review. Internal validity includes study design, replication, control matching, measured outcome, outcome method, intervention application coverage, and confounding factors, and is the measure of how likely a study is to be free from bias.…”

“…Internal validity includes study design, replication, control matching, measured outcome, outcome method, intervention application coverage, and confounding factors, and is the measure of how likely a study is to be free from bias. External validity includes how generalizable or relevant the study is and is captured by the reviewer (Bilotta et al 2014; Collaboration for Environmental Evidence 2018; Taylor et al 2019).…”