Fishing affects the environment by removing target species, catching animals that were not intended to be caught, disturbing some marine habitats, and using fuel that produces emissions. The scale and type of impact vary with the species, fishing gear, location, ecosystem, and management. “Fishing” is not one uniform practice, and fishing is not the only pressure that can deplete fish populations.
What are the main environmental effects of fishing?
- Pressure on fish populations: Harvest removes animals from a stock. If removals outpace the stock’s ability to replenish, its population can fall and rebuilding may be needed.
- Bycatch and discarded catch: Fishing gear can catch or entangle non-target fish and other animals, including marine mammals, sea turtles, and seabirds. Some animals are released or discarded; some die, and some mortality may go unobserved.
- Habitat disturbance: Gear that contacts the seabed can disturb seafloor habitats and the communities living there. The effect depends on the gear and the habitat.
- Fuel emissions: Fishing vessels burn fuel and release carbon dioxide. Bottom trawling may also disturb carbon stored in seabed sediments, but the scale of that contribution is debated.
- Food-web changes: Removing predators or prey, or catching non-target fish, can alter relationships among species and affect ecosystem and fishery productivity.
These effects should be assessed separately. A stock’s status alone does not show how much bycatch a fishery causes, what habitat its gear affects, or how much fuel it uses.
What do “overfishing” and “overfished” mean?
NOAA Fisheries distinguishes the terms. Overfishing describes a harvest rate: fishing is removing fish faster than the rate that produces maximum sustainable yield. Overfished describes a stock’s condition: its population is too low to produce that yield reliably. Maximum sustainable yield is the largest long-term average catch that can be taken under prevailing environmental and fishery conditions.
The terms are related, but they are not synonyms. A stock can be overfished because of earlier fishing pressure, while other factors—including habitat degradation, pollution, climate change, or disease—can also affect its population and recovery. NOAA’s definitions and U.S. status figures appear in its Status of Stocks 2024 report.
Recommended Free Tools
#1 Best Overall
What the latest cited U.S. figures show
At the end of 2024, NOAA reported 23 U.S. stocks on its overfishing list and 42 on its overfished list. One stock was rebuilt during 2024, bringing the total NOAA reported as rebuilt since 2000 to 51. These are U.S. figures, not global totals. NOAA manages 522 stocks or stock complexes, but status was known for only subsets: 372 had known overfishing status and 263 had known overfished status.
NOAA also reported that approximately 91% of U.S. stocks or stock complexes did not exceed annual catch limits in 2024. That indicates compliance with catch limits; it does not prove that every environmental impact was avoided.
How does bycatch affect marine life?
Bycatch is broader than fish that are thrown back. NOAA Fisheries defines it as “discarded catch of marine species and unobserved mortality due to a direct encounter with fishing vessels and gear.” The agency’s definition includes animals that are caught and discarded as well as mortality that is not observed. Usage of the term may differ among jurisdictions.
Depending on the fishery, bycatch can include unwanted or prohibited fish, dolphins, whales, sea turtles, or seabirds caught on hooks or entangled in gear. The outcome varies: some animals survive release, while others are injured or die. Bycatch can add mortality to non-target fish populations, slow rebuilding, change the availability of prey, and harm animals that are protected or vulnerable.
Fisheries estimate and monitor bycatch in different ways. NOAA describes observers, electronic technologies, required logbooks, and voluntary surveys as tools for tracking it. Estimates and monitoring matter because managers need to understand what is caught—not only the intended catch—to assess a fishery’s effects.
How does fishing gear change the type of impact?
Gear affects which animals are caught and whether fishing contacts habitat. The table describes documented impact pathways, not a universal ranking: the outcome depends on the target species, location, gear design, bottom type, and rules in force.
| Gear or fishery feature | Potential environmental effect | What changes the impact |
|---|---|---|
| Bottom trawls | Contact with the seabed can disturb seafloor habitats and benthic communities. Trawling also involves bycatch and fuel use. | Gear, target species, seabed type, habitat sensitivity, and management. Sandy-bottom fisheries are not equivalent to fisheries operating over sensitive habitats. |
| Hooks and lines | Non-target animals, including seabirds or marine mammals, can be caught on hooks. | Species and location, fishing practices, and measures to reduce unwanted catch. |
| Other gear | Bycatch and habitat effects vary; the impact cannot be inferred from the gear category alone. | The actual fishery, affected species, habitat contact, monitoring, and management rules. |
A 2023 review by Hilborn and co-authors, citing Steadman and co-authors’ 2022 estimate, says bottom trawling accounts for 26% of global marine fisheries catches. That is a share of catch attributed to bottom trawling—not a share of all environmental harm. The review discusses seabed disturbance, bycatch, discards, fuel-related carbon dioxide, and possible carbon release from disturbed sediments. It notes debate about the magnitude of some effects, particularly the sediment-carbon contribution.
How does fishing affect habitats, emissions, and climate?
Seafloor disturbance
Bottom trawling is designed to catch species near or on the seabed, so its gear contacts the bottom. That contact can disturb habitat and benthic communities, but sensitivity is not the same everywhere. The consequences depend on the habitat and the gear used; one species or fishery example should not be treated as representative of all trawling.
Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteWindows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallVessel fuel and sediment carbon
Vessel fuel use is a source of carbon dioxide emissions from fishing. A separate, more uncertain question is how much carbon may be released when trawling disturbs seabed sediments. The 2023 review discusses this possibility while noting that the magnitude of sediment-carbon effects remains contested. These are distinct issues: the established fuel-use pathway should not be conflated with the debated scale of sediment-carbon release.
Rank #4
Climate change as an interacting pressure
Climate change affects ocean conditions, fish-stock productivity, and where stocks occur. NOAA notes that changing conditions can also alter fisheries’ interactions with bycatch, protected species, and other ocean users, with consequences for fishing-dependent communities. Climate change is a pressure on fisheries and marine ecosystems; it is not an impact caused by fishing.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How can fisheries reduce environmental impacts?
Management can reduce impacts, but a rule’s presence does not guarantee a particular outcome. Measures and results differ by fishery and jurisdiction. NOAA describes several tools used in U.S. fisheries:
- Stock assessments and reference points: Estimates of stock status help managers set harvest guidance and evaluate whether populations need rebuilding.
- Annual catch limits and accountability measures: Limits constrain catch, while corrective measures can address an overshoot.
- Rebuilding plans: Plans can set steps for restoring stocks that are overfished.
- Bycatch monitoring: Observers, electronic recording or transmission technologies, logbooks, and surveys can help track what is caught or entangled.
- Gear changes and devices: Modifications can reduce unwanted catch. Turtle excluder devices are one example used in relevant fisheries.
- Gear restrictions and habitat protections: Rules can limit where or how gear is used to reduce contact with sensitive habitat.
NOAA’s Summer Flounder and Sablefish species information illustrate that gear and habitat rules are fishery-specific; a measure appropriate for one fishery is not automatically suitable for another.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Scan for outdated or missing drivers - takes under a minute3Repair Windows errors before they cause bigger problemsHow can you assess a fishery’s environmental impact?
No single label, species name, or stock-status figure captures all the effects. To compare fisheries meaningfully, look for information about the specific source and fishery, and consider these questions:
- What is the stock’s condition and harvest pressure? Check a dated assessment for the relevant jurisdiction. Look for whether the stock is overfished, subject to overfishing, or neither—and whether status is known.
- What bycatch occurs? Ask which non-target species are caught, whether protected or vulnerable animals are involved, how mortality is estimated, and how the fishery is monitored.
- Does the gear contact habitat? Find out whether it touches the seabed and what kind of habitat is present. “Bottom trawl” alone does not establish the sensitivity of the area affected.
- What is known about fuel and emissions? Separate vessel fuel emissions from claims about carbon released from disturbed sediments, whose magnitude remains debated.
- What management measures are in place, and are they monitored? Look for catch limits, rebuilding plans, observers or electronic monitoring, gear rules, and area closures, along with evidence of implementation.
- Are changing ocean conditions affecting the fishery? Shifts in distribution or productivity can change stock assessments, bycatch interactions, and management assumptions.
These questions also explain why a seafood species alone is not enough to determine environmental impact: sourcing, gear, location, stock condition, and management all matter.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
