An evidence-led descent / Global marine fisheries

OVERFISHING

What the calm surface does not show.

01 / Surface

Descent through overfishing evidence

02 / Continuous descent Eight signals below the surface

Arrival at the disturbed seabed

03 / Seabed

What left these marks?

Reverse ascent from the seabed to the ocean surface

04 / Ascent

03 / Field notes

Overfishing is not one image. It is a chain of consequences.

Documentary photography, measured data and direct source links connect fishing pressure to population decline, bycatch and habitat disturbance. Every headline figure retains its year, scope and limitation.

Fishery biologists and deckhands sorting a trawl catch into baskets
Biologists and crew work through a large tow aboard the F/V Excalibur. Photo: NOAA Fisheries · source page ↗
A mixed deepwater trawl catch on the deck of a vessel
A deepwater survey tow containing fish and invertebrates. Photo: NOAA Fisheries · source page ↗
A scientist disentangling a loggerhead sea turtle from a gillnet
A NOAA scientist disentangles a loggerhead turtle from a coastal gillnet. Photo: NOAA PIFSC · source page ↗
A rosy rockfish swimming above deep-sea coral and sponge habitat
Rosy rockfish among corals and sponges at Rittenburg Bank. Photo: NOAA · source page ↗
01

Global scale / FAO 2025

35.5% of assessed marine fish stocks are overfished.

FAO’s most detailed global assessment covers 2,570 stocks. The same report shows that strong, science-based management produces much better outcomes—decline is not inevitable.

2,570
stocks assessed
64.5%
biologically sustainable
35.5%
overfished
Read the FAO assessment ↗
02

Food webs / Science 1998

The catch can move down the food web before it disappears.

Pauly and colleagues found a decline in the mean trophic level of species groups reported in FAO landings from 1950 to 1994. Later research showed that both depletion of upper levels and the addition of lower-trophic fisheries can shape this pattern.

Landings data describe what fisheries report; they are not a complete census of every organism in the ecosystem.
Pauly et al., Science, 1998 ↗
03

Bycatch / NOAA Fisheries

A net does not understand the word “target.”

Bycatch includes discarded catch and unobserved mortality caused by direct encounters with fishing vessels and gear. It can include fish, marine mammals, sea turtles, seabirds, corals and sponges, and can impede population recovery.

Entanglement Discard mortality Lost juveniles
Understanding bycatch, NOAA ↗
04

Seabed / PNAS 2018

Some extraction also changes the place recovery must happen.

Amoroso and colleagues mapped bottom-trawl footprints across 24 continental shelves and slopes. Bottom trawlers land roughly 19 million tonnes each year; 14% of the study's 7.8 million km² area was trawled, with strong regional variation.

19m t
landed annually
14%
of the 7.8m km² study area trawled
86%
of the study area not trawled
Amoroso et al., PNAS, 2018 ↗

04 / Verified briefing

What is measured before anything is simulated.

Select a lens. These figures come from institutional publications or peer-reviewed research; the interactive experiment that follows uses illustrative indices rather than a real stock forecast.

Biological threshold / NOAA + FAO

A rate can be too high before a population looks empty.

NOAA distinguishes overfishing, an excessive harvest rate, from overfished, a population whose size is already too low. FAO's 2025 assessment classified 35.5% of 2,570 assessed marine fish stocks as overfished.

2,570stocks assessed
64.5%biologically sustainable
35.5%overfished
Stock share and production-weighted landings are different metrics.
01Threshold
Return to field notes ↑

ILLUSTRATIVE TEACHING MODEL · NORMALISED INDICES · NOT A REAL STOCK FORECAST

Part II / An ecological experiment

THE LAST
CATCH

An ocean does not become empty overnight.
It disappears through decisions that each feel small.

01 — Extraction

YOUR CURSOR
IS NOW A NET.

Fish move in uneven migration streams.
Hold and drag to remove them.

Catch removed 00 BYCATCH 00

02 — The decision

PRESSURE IS
A CHOICE REPEATED.

A click is easy to ignore. A sustained extraction is not.
Choose what happens next.

03 — Bottom trawling

THE DAMAGE
OUTLIVES THE CATCH.

Hold and drag across the lower seabed.
Habitat scars remain after the vessel has passed.

Habitat scars00
Non-target catch00

04 — Global evidence

35.5%

of assessed marine fish stocks are overfished

CAUSE 01Industrial scale

Capacity increases extraction.

CAUSE 02Bycatch

Non-target life is removed too.

CAUSE 03Habitat loss

Recovery space is disturbed.

05 — After

THE OCEAN DID NOT
BECOME EMPTY AT ONCE.

IT DISAPPEARED
ONE CATCH AT A TIME.

BEFORE INDEX100
AFTER INDEX12

Generated by this teaching model; not a measured fish-stock result.

Continue to reflection

Part III / After the catch

The simulation ends. The consequence would not.

A few minutes compressed extraction, bycatch and habitat disturbance into one screen. Real populations recover over biological time, and not every loss returns when fishing stops.

Pause before leaving

06 / Three questions

What changed when the catch became a decision?

REMOVAL EXTENDS BEYOND THE TARGET

Bycatch can include discarded fish, marine mammals, sea turtles, seabirds, corals and sponges. A catch is therefore also a decision about what the gear cannot perfectly select.

07 / Recovery is designed

No single button rebuilds a fishery.

Evidence from 288 assessed fisheries found cumulative benefits when management interventions were combined. Select the three interventions highlighted by the study; this is not a recovery probability.

Melnychuk et al., Nature Sustainability, 2021 ↗

Build an evidence stack

0 / 3 MEASURES
NO MEASURES SELECTED

Choose measures to compare what each contributes. Outcomes remain fishery-specific.

08 / Before the next choice

A seafood label is the beginning of a question, not the end of one.

01Species

What exactly is being sold?

02Stock or capture area

Where did it come from?

03Gear

How was it caught?

04Management

What evidence supports the claim?

These questions do not make every purchase simple. They make hidden decisions more visible—and create a reason to demand traceable evidence.