The future of stock enhancements: lessons for hatchery practice from conservation biology

By Culum Brown, R. L. Day. 2002

428 citations recorded by the source corpus.

The world's fish species are under threat from habitat degradation and over-exploitation. In many instances, attempts to bolster stocks have been made by rearing fish in hatcheries and releasing them into the wild. Fisheries restocking programmes have primarily headed these attempts. However, a substantial number of endangered species recovery programmes also rely on the release of hatchery-reared individuals to ensure long-term population viability. Fisheries scientists have known about the behavioural deficits displayed by hatchery-reared fish and the resultant poor survival rates in the wild for over a century. Whilst there remain considerable gaps in our knowledge about the exact causes of post-release mortality, or their relative contributions, it is clear that significant improvements could be made by rethinking the ways in which hatchery fish are reared, prepared for release and eventually liberated. We emphasize that the focus of fisheries research must now shift from husbandry to improving post-release behavioural performance. In this paper we take a leaf out of the conservation biology literature, paying particular attention to the recent developments in reintroduction biology. Conservation reintroduction techniques including environmental enrichment, life-skills training, and soft release protocols are reviewed and we reflect on their application to fisheries restocking programmes. It emerges that many of the methods examined could be implemented by hatcheries with relative ease and could potentially provide large increases in the probability of survival of hatchery-reared fish. Several of the necessary measures need not be time-consuming or expensive and many could be applied at the hatchery level without any further experimentation.

Subfields: Ecology, Global and Planetary Change, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/6ae6ac20a757f5fec09925659e08bbc3c7848cbb

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Citations in the corpus

Hatchery tank enrichment affects cortisol levels and shelter-seeking in Atlantic salmon (Salmo salar) (2013, background): “In fish reared for conservational stocking, behaviour adapted for natural environments are critical for stocking effectiveness (Brown and Day 2002; Salvanes and Braithwaite 2006).”
No place like home: an experimental comparison of reintroduction strategies using snakes (2010, background): “When combined with captive-breeding programmes, head-starting can also be used to arrange for multiple releases of numerous individuals with less stress on wild donor populations (Brown & Day 2002).”
Environmental enrichment reduces maladaptive risk-taking behavior in salmon reared for conservation (2011, background): “adaptive value in the wild by improving predator avoidance (Lima and Dill, 1990), and therefore help reducing one of the main sources of post-release mortality (Jepsen et al., 1998; Brown and Day, 2002).”
Efficiency of markers and methods for detecting hybrids and introgression in stocked populations (2009, background): “A common management strategy to maintain or improve freshwater fisheries is the extensive release of cultured fish (Brown and Day 2002).”
Responsible genetic approach to stock restoration, sea ranching and stock enhancement of marine fishes and invertebrates (2017, background): “For example, hatchery-reared individuals can develop behavioral deficits, such as in predator avoidance or appropriate foraging behaviours, that lead to poor survival in the wild (Brown and Day 2002).”
Quality of hatchery-reared juveniles for marine fisheries stock enhancement (2007, background): “In fish, behavioural differences between hatchery-reared and wild juveniles are well-documented (for recent reviews see Huntingford, 2004; Brown and Day, 2002).”
Innate antipredator responses of Arctic charr (Salvelinus alpinus) depend on predator species and their diet (2003, methodology): “Although these methods have been shown to work in fish, they have not yet been utilized on a large scale for conservation purposes with salmonids (Brown and Day 2002).”
Less is more: social learning of predator recognition requires a low demonstrator to observer ratio in Arctic charr (Salvelinus alpinus) (2004, background): “Training fish in predator avoidance on a hatchery scale would probably be best achieved using social learning, as it would mean more efficient training (Suboski and Templeton 1989; Brown and Laland 2001; Brown and Day 2002).”
Environmental enrichment and prior experience of live prey improve foraging behaviour in hatchery-reared Atlantic salmon (2003, background): “Exposure to live prey in a social context (Brown & Laland, 2002) in combination with enclosure enrichment prior to release should be incorporated into pre-release training protocols (Suboski & Templeton, 1989; Brown & Laland, 2001; Brown & Day, 2002).”
Stock enhancement as a fisheries management tool (2003, background): “…1994; Stoner, 1994; Stoner and Davis, 1994; White et al., 1995; Crowe et al., 1997; Kellison et al., 2000; Van der Meeran, 2000; Brown and Laland, 2001; Brown and Day, 2002) or increased vulnerability to fishing (Dibden et al., 2000) compared to wild fish, need to be identified and minimized.”
Learning about Danger: Chemical Alarm Cues and Threat‐Sensitive Assessment of Predation Risk by Fishes (2011, background): “A commonly stated goal of predator training is that it may allow us to ‘teach’ threatened or commercially important species raised in hatcheries to recognise potential predation threats prior to stocking (Brown & Day 2002; Brown & Laland 2003; Bischof & Zedrosser 2009).”
The mangrove-based coastal and nearshore fisheries of Bangladesh: ecology, exploitation and management (2004, background): “…production and husbandry practices (e.g., effective breeding numbers, husbandry, nutrition, behavioral training, etc.; Masuda and Tsukamoto, 1998; Brown and Day, 2002) to the production of the most competent, high-quality fishes from endemic stock (Cross, 1999; Burke et al., 2000) in the…”