Hatcheries and Fisheries
Fish are a primary indicator of the health of an ecosystem. The Sacramento-San Joaquin Delta is not only the largest estuary on the Pacific Coast of the Americas, but it also supplies fresh water to two-thirds of California’s population. In the Delta, the relationship between fish and people is significant; the activities of fisheries and hatcheries are just one facet of this relationship.
What is a hatchery?
A hatchery is a man-made facility where fish and other aquatic species are bred, hatched and raised to stock lakes, streams, and ponds. They can serve several different purposes; some are an attempt to conserve vulnerable fish populations, while others safeguard recreational fisheries or support the commercial fishing industry. [1]
Fish hatcheries can be managed by the state, local tribes, commercial enterprises or even private individuals. [2]
What is a fishery?
The classification of a fishery is a bit more complex. Simply put, it is a defined area where fish are caught for commercial or recreational purposes [3]. Each fishery is characterized by the people involved, the species or type of fish, the body of water, the method of fishing, the class of boats engaged and the purpose of the activities. [4] The terms of a fishery are agreed upon by governing bodies and the fisheries active participants.
There are many different types of fisheries determined by its purpose, including [3]:
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Fishing for profit with the catch sold via auction or through direct trade.
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Typically large commercial vessels that catch massive quantities of fish, often through destructive methods such as trawling.
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People fishing for leisure and personal use who do not sell their catch.
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Applies to indigenous communities which have a traditional connection to the areas they fish, with the catch used for personal, domestic, ceremonial, educational or non‐commercial needs.
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Typically small vessels that operate with many fishers
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Typically fishing close to shore for local consumption
How is water usage by people impacting fisheries?
Water consumption is having a devastating impact on fisheries. The combination of water extraction, damming, and diversion has led to widespread degradation of aquatic habitats, putting immense pressure on fish populations. Unsustainable water consumption is disrupting critical habitats and increasing mortality, decreasing reproductive success, and accelerating extinction threats for a wide number of species.
Diversion for irrigation, industrial use, or urban consumption can lead to dramatic reductions in the water volume and flow variability that are critical for maintaining biodiversity in freshwater ecosystems. A good example of the way river diversions can destroy a fishery is the Aral Sea. From 1960 to 1995, 94% of the Aral Sea’s river inflows were diverted, causing a 75% reduction in the sea’s water volume. The result? Twenty of the twenty-four endemic species have gone extinct, destroying 60,000 jobs that were once supported by these local fisheries. The economic consequences of water mismanagement can be severe. [7]
Reduced flow combined with the effects of climate change increases river temperatures, often to levels that are inhospitable – or lethal – for many fish species, particularly salmonids such as salmon and steelhead. When water flow is reduced, especially in the summer months, and temperatures rise due to the loss of snowpack caused by global warming, these species face heightened thermal stress. Increased water temperatures can have detrimental impacts on fish survival, particularly during critical life stages like spawning. Inadequate access to cool, oxygen-rich waters increases mortality rates, decreases reproductive success, and limits population growth.
Over-extraction of water and modification of freshwater habitats has contributed to a global decline in freshwater biodiversity. Between 1970 and 2016, the global population of freshwater species has declined by 84%, with freshwater fish exhibiting the highest extinction rates among all vertebrate groups. According to the International Union for Conservation of Nature (IUCN), more than 30% of freshwater fish species are at risk of extinction, largely due to habitat destruction, water diversion, and water quality degradation [5]. The impact on biodiversity is particularly pronounced in regions where water is overexploited for agriculture, industry, and urban development, leading to the loss of critical fish habitats and the extinction of species that are unable to adapt to the changes in water availability and temperature.
“At least 100 native fishes in California are either in decline, headed towards extinction, or are already extinct, representing 81% of California’s highly distinctive inland fish fauna.”
[15] In addition to flow modifications, water usage often leads to pollution from agricultural runoff and industrial discharges. Poor water quality, combined with altered flow patterns, further stresses aquatic ecosystems and impairs fish health. Eutrophication – a result of excessive nutrients from fertilizer runoff – can lead to oxygen depletion in waterways, creating "dead zones" where fish cannot survive. Contaminants in the water such as heavy metals and pesticides can also accumulate in fish tissues, posing risks to fish populations and human consumers.
Why do we need hatcheries?
Historically, hatcheries were seen as a response to overfishing and habitat degradation. Today, they are a necessary intervention to combat the pressures fish populations face due to climate change and unsustainable water use [13].
One of the primary reasons hatcheries have become so essential in California is their role in compensating for the loss of natural habitats due to human activities. Dams, urbanization, and industrial development have severely impacted the ability of once-abundant valuable fish such as salmon and steelhead to access their natural spawning and rearing habitats. For example, the construction of large dams in California’s Central Valley has blocked access to important spawning grounds on both the valley floor and in myriad tributary streams along the western slope of the Sierra. Hatcheries help mitigate these effects by breeding and releasing fish in controlled environments, ensuring that fish populations can exist even when many of their natural habitats have been altered or destroyed.
Used as a supplemental measure to prevent depletion and reduce the risk of extinction, hatcheries help boost population numbers for both commercial and recreational fisheries. This can ensure that fish populations can continue to provide economic and ecological benefits [8]. Hatcheries in California produce millions of salmon annually for release into rivers and estuaries, contributing to the state’s recreational and commercial fisheries and supporting local economies.
As climate change accelerates the warming of our waterways, the survival of cold-water dependent species like salmon are at particular risk. Hatcheries can serve as a temporary response to this and related challenges, producing fish that can be released into environments where natural conditions are unable to support wild runs. This is crucial for species listed under the federal Endangered Species Act (ESA), including certain runs of Chinook and Coho salmon. Special “conservation hatcheries” can be established to breed, reintroduce and sustain these threatened fish in today’s highly altered environments.
It is, however, important to note that hatcheries are not a perfect solution. Without proper water management strategies that account for the needs of at-risk populations, extinction cannot be prevented – only delayed.
Are hatcheries a successful conservation strategy?
To a degree yes, but not as successful as some proponents claim. Hatcheries produce fish stocks using an agricultural model. There are clear benefits, particularly in preventing the extinction of endangered species, supporting fish populations, and boosting commercial and recreational fisheries. There are also obvious pitfalls, including reducing genetic diversity, inbreeding, and low survival rates for released fish. With the amount of investment we have put into hatcheries, the incentive to construct a positive narrative is clear.
Hatcheries have proven a critical tool in the conservation of endangered fish species, particularly salmon. Salmon runs have crashed in California, with returning populations declining from 600,000 fish in 1952 to fewer than 50,000 in 2022. However, the situation would be even worse without the hatcheries. California’s salmon have been under assault since the mid-19th Century; Gold Rush operations, huge canning enterprises, dams, and water diversions have all taken their toll over the decades. Despite the collapse of wild populations due to overfishing, dam construction, and water diversion, hatcheries have prevented California’s salmon from "blinking out" entirely.
While hatcheries have undoubtedly helped preserve some fish populations, their effectiveness is limited by several factors; nor do they provide a comprehensive solution to the broader environmental challenges facing native fish species. Here is a simplified explanation of the pros and cons associated with hatchery programs:
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Hatcheries help maintain a minimum population that supports commercial and recreational fisheries, while also providing a buffer against the severe impacts of habitat loss, overfishing, and water diversions.
By propagating fish in controlled environments and releasing them back into their natural habitats, conservation hatcheries are helping restore populations that were pushed to the brink of extinction. [12]
Hatcheries provide a means of reintroducing fish to habitats that are no longer capable of sustaining wild populations due to human-induced changes like pollution, invasive species, or altered river flows. This allows fish to reclaim and reoccupy areas where they might not have been able to survive without human intervention.
Hatcheries can help preserve the genetic diversity of a species, particularly when wild populations are small and at risk of inbreeding. This is especially important for species like steelhead, which have a high degree of genetic diversity. Through careful management, hatcheries can maintain a broad genetic spectrum, which can be critical for the long-term health of the population.
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While hatcheries can preserve certain genetic traits, they also pose risks to genetic diversity. In some cases, hatchery fish can mate with wild fish, causing genetic introgression—the mixing of hatchery and wild genes—which can reduce the overall fitness and adaptability of wild populations.
For many salmonid species, hatchery practices can lead to reduction in size, age, and other traits critical for survival in the wild. This is particularly concerning for species like Chinook, where hatchery fish tend to be smaller, have fewer eggs, and are less adapted to the natural environment.
Hatchery fish in California's Central Valley have contributed to genetic introgression, particularly with fall-run Chinook salmon, which now make up 90% of the biomass and are crowding out wild runs. [12]
The survival rates of hatchery fish can be low once they are released into the wild. Factors such as poor river conditions, predation, and competition with wild fish can dramatically reduce their chances of survival.
Hatcheries often release fish at too young an age for optimal survival, and the fish are often released into rivers that do not have optimal conditions for them, including low flows and high temperatures. This results in higher mortality rates and undermines the effectiveness of hatcheries in sustaining wild populations.
Hatcheries rely on a small number of spawners to produce large numbers of fish, which can lead to inbreeding and reduced genetic health, affecting the fitness of the fish produced.
Hatcheries alone cannot address the root causes of fish population declines, such as habitat destruction, water diversion, pollution, and climate change. While they can temporarily boost fish populations, hatcheries do not restore the natural systems that fish rely on.
While hatcheries have produced some clear success stories, a sobering baseline reality remains: fisheries before human intervention were far more expansive and vibrant than they are today. In fact, nearly 40% of North American fishes – 700 species – are facing an imminent threat of endangered status. More than two-thirds of our native fish species are listed as threatened or endangered under the Endangered Species Act [14]. Hatcheries do not address the underlying environmental issues like habitat loss, climate change, and pollution that brought us to our current dire state. Ultimately, hatcheries should be seen as one part of a broader conservation strategy that includes habitat restoration, sustainable fisheries management, and efforts to mitigate environmental stressors. For hatcheries to truly be successful, they must be integrated into a more comprehensive approach that supports long-term ecosystem health and species resilience.
What is sustainable population size?
Sustainable population size refers to the number of individuals in a population that can be maintained over time without depleting the population or causing long-term damage to the ecosystem. In the context of fisheries, it is the size of a fish population that can produce enough offspring to replenish itself while still allowing for responsible harvesting. This concept is critical for maintaining healthy fish populations and ensuring the long-term viability of fisheries [9].
A sustainable fishery requires that the target fish species have healthy, abundant, and productive populations. These populations must be able to reproduce at a rate that matches or exceeds the rate of fishing. This is often determined through stock assessments, which look at the size, age, and reproduction rates of the fish population to determine whether it is healthy enough to sustain fishing pressure. Sustainability is not only about the fish population itself but also about maintaining the integrity of the entire ecosystem. A sustainable fishery ensures that fishing activities do not lead to ecosystem degradation, which could further reduce the capacity of the environment to support fish populations [10].
How does fish passage at dams work and why is it necessary?
Fish passage at dams refers to the methods and infrastructure that allow fish to safely navigate around or through a dam to access upstream or downstream habitats for spawning, feeding, or migration. Fish passage is necessary because many fish species, particularly anadromous species like salmon, steelhead, and shad, rely on unobstructed access to both upstream spawning grounds and downstream feeding areas to complete their life cycles. When dams block these migratory routes, it disrupts fish populations and can lead to declines in fish numbers or even local extinctions [11]. Without effective passage, fish populations can become fragmented and unable to reach spawning habitats or feeding grounds, leading to dramatically reduced numbers or even species extinction. This is why providing safe, effective fish passage is a critical element of dam management and fish conservation.
Fish passage systems are designed to allow fish to bypass or safely navigate around a dam. They include:
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Also called fishways or fish passes, are structures built to help fish move upstream and over a dam. They consist of a series of steps or pools that mimic natural river conditions and allow fish to "jump" or swim through them. While effective for some species, fish ladders may not be ideal for all fish.
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Mechanical systems that lift fish from the base of the dam and transport them upstream to the other side of the dam. Fish elevators are typically used in situations where fish ladders are not effective, such as with larger or more complex dams. They are often used as a supplement to other methods, but they can be costly to build and maintain.
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Facilitate downstream migration. Fish screens are installed at the base of a dam to prevent fish from being pulled into turbines or other infrastructure. These screens keep fish out of dangerous areas and direct them toward bypass systems where they can safely travel downstream.
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In some cases, fish that cannot navigate around a dam are trapped and physically transported past the dam using trucks, barges, or other vehicles. This method is typically used for fish that are unable to pass through fish ladders or other systems due to size or other factors. This method is labor-intensive and can be stressful for the fish. It's generally seen as a last resort measure when other passage options are not feasible or effective.
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A type of fish ladder that uses a series of vertical slots with pools to help fish move past dams. This design provides a more continuous flow of water and lessens turbulence, making it easier for fish to swim through.
Fish passage at dams is necessary to allow migratory fish species to complete their life cycles and ensure the health of river ecosystems. Effective fish passage systems—such as fish ladders, elevators, and by-pass systems—are critical for the survival of species like salmon and steelhead, whose populations have been threatened by barriers like dams. These systems help preserve biodiversity, protect ecosystems, support local economies, and fulfill cultural and legal obligations to safeguard fish populations. However, challenges remain in optimizing and maintaining these systems, especially in the face of changing environmental conditions and the growing pressures on freshwater ecosystems.
Are fisheries protected under California law?
Yes, fisheries are protected under California law through a combination of state regulations, federal laws, and environmental protections that govern fish populations, their habitats, and the fishing practices that impact them. These laws aim to ensure the sustainable use of fishery resources, protect endangered species, and maintain healthy ecosystems.
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The primary body of law that governs the management of fish and wildlife resources in the state. It includes provisions related to the protection of fisheries, including regulations on fishing seasons, limits on catch sizes, and the establishment of protected areas or “no take areas” where fishing is prohibited to preserve spawning habitats and protect fish populations from depletion
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Under CESA, fish species that are at risk of extinction can be designated as endangered or threatened; several runs of Chinook salmon, Coho salmon, and steelhead are salient examples. These species are given special protections, including restrictions on their harvest, habitat protections, and recovery efforts such as hatchery programs.
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A federal law that regulates water quality standards in the U.S. California enforces CWA provisions under its own State Water Resources Control Board and Regional Water Quality Control Boards. The CWA aims to protect the quality of water bodies that are essential to fish populations, including rivers, lakes, and estuaries. The CWA sets standards for water pollution, temperature, and other factors that affect the health of fish habitats.
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Requires that proposed projects (including water management and development projects) undergo environmental reviews to assess potential impacts on fish habitats. This is a key tool for ensuring that new development does not harm existing fisheries.
Despite these efforts, challenges such as climate change, habitat loss, and overfishing continue to threaten the long-term health of California’s fisheries. Ongoing conservation and management efforts therefore remain critical. Additionally, the type of legal protections in place are self-executing, meaning the responsibility for following standards is not held accountable by an external body.
How much do hatcheries cost?
The federal government has invested a substantial amount of money into hatcheries. Over the past 20 years, funding for salmon hatcheries totals around $2.2 billion dollars. In other words, taxpayers are paying between $250 to $650 per returning adult fish, yet annual salmon numbers continue to decline, suggesting that the effectiveness of hatcheries in reversing the collapse of salmon populations remains limited. [12]
While hatcheries are an expensive intervention, they are an essential part of recovering salmon populations that have been devastated by habitat destruction, overfishing, and climate change. It is important to consider that plummeting fish populations have taken a significant toll on both California’s fishing industry and the local indigenous communities which depend on the fish for subsistence and cultural cohesion. Any money devoted to recovering salmon would serve as a remedy to injustice and an investment in a public trust resource that benefits all Californians.
[1] https://sanctuaries.noaa.gov/education/voicesofthebay/glossary.html#h
[2] https://www.fws.gov/story/national-fish-hatchery-system-supports-aquatic-conservation
[4] https://sanctuaries.noaa.gov/education/voicesofthebay/glossary.html#f
[7] https://www.canr.msu.edu/csis/uploads/files/taylor%20w%20etal%202007.pdf
[9] https://www.fisheries.noaa.gov/topic/population-assessments/fish-stocks
[12] Hawley, S., & Duncan, D. J. (2023). Cracked: the future of dams in a hot, chaotic world.
[13] Kurlansky , M. (2020). Salmon: A Fish, the Earth, and the History of a Common Fate.
[14] http://www.fishhatcherychiller.com/species-conservation/