Colin Simpfendorfer
@sharkcolin.bsky.social
Shark scientist since 1986. Passionate about sharks and rays, and their conservation and management. Lapsed academic.
I just spent part of my morning summarising literature on the sandbar shark. Now i need a nap I was so bored. #yawnshark
January 25, 2026 at 2:36 AM
I just spent part of my morning summarising literature on the sandbar shark. Now i need a nap I was so bored. #yawnshark
Oh to have lived 50 million years ago during peak elasmo diversity!
January 22, 2026 at 9:36 PM
Oh to have lived 50 million years ago during peak elasmo diversity!
Reposted by Colin Simpfendorfer
We don’t need new frameworks — we need to connect and implement the ones we have.
Fisheries management, trade rules, compliance, and demand must align to reduce fishing mortality at scale.
Implementation is the bottleneck.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Fisheries management, trade rules, compliance, and demand must align to reduce fishing mortality at scale.
Implementation is the bottleneck.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
January 22, 2026 at 3:35 AM
We don’t need new frameworks — we need to connect and implement the ones we have.
Fisheries management, trade rules, compliance, and demand must align to reduce fishing mortality at scale.
Implementation is the bottleneck.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Fisheries management, trade rules, compliance, and demand must align to reduce fishing mortality at scale.
Implementation is the bottleneck.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Reposted by Colin Simpfendorfer
Decline is not inevitable.
Where fishing mortality has been reduced — through catch limits, retention bans, or spatial protection — shark and ray populations are stabilizing or recovering.
Recoveries documented for wide-ranging and restricted-range species @charlie-huveneers.bsky.social
Where fishing mortality has been reduced — through catch limits, retention bans, or spatial protection — shark and ray populations are stabilizing or recovering.
Recoveries documented for wide-ranging and restricted-range species @charlie-huveneers.bsky.social
January 22, 2026 at 3:35 AM
Decline is not inevitable.
Where fishing mortality has been reduced — through catch limits, retention bans, or spatial protection — shark and ray populations are stabilizing or recovering.
Recoveries documented for wide-ranging and restricted-range species @charlie-huveneers.bsky.social
Where fishing mortality has been reduced — through catch limits, retention bans, or spatial protection — shark and ray populations are stabilizing or recovering.
Recoveries documented for wide-ranging and restricted-range species @charlie-huveneers.bsky.social
Reposted by Colin Simpfendorfer
Gaps in catch limits, compliance, and enforcement mean fishing mortality stays high even where policies exist.
Where management is complete, risk is lower and recovery is possible.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Read the paper here: rdcu.be/eZ9n9
Where management is complete, risk is lower and recovery is possible.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Read the paper here: rdcu.be/eZ9n9
January 22, 2026 at 3:35 AM
Gaps in catch limits, compliance, and enforcement mean fishing mortality stays high even where policies exist.
Where management is complete, risk is lower and recovery is possible.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Read the paper here: rdcu.be/eZ9n9
Where management is complete, risk is lower and recovery is possible.
@hollieboothie.bsky.social
@sharkcolin.bsky.social
Read the paper here: rdcu.be/eZ9n9
Reposted by Colin Simpfendorfer
Overfishing is compounded by under-management
Fishing mortality is the primary driver &
management completeness (for guitarfishes & requiem sharks) stands at ~49% globally.
@sammsherman27.bsky.social
@vanderwright.bsky.social
Read the paper here: rdcu.be/eZ9n9
Fishing mortality is the primary driver &
management completeness (for guitarfishes & requiem sharks) stands at ~49% globally.
@sammsherman27.bsky.social
@vanderwright.bsky.social
Read the paper here: rdcu.be/eZ9n9
January 22, 2026 at 3:35 AM
Overfishing is compounded by under-management
Fishing mortality is the primary driver &
management completeness (for guitarfishes & requiem sharks) stands at ~49% globally.
@sammsherman27.bsky.social
@vanderwright.bsky.social
Read the paper here: rdcu.be/eZ9n9
Fishing mortality is the primary driver &
management completeness (for guitarfishes & requiem sharks) stands at ~49% globally.
@sammsherman27.bsky.social
@vanderwright.bsky.social
Read the paper here: rdcu.be/eZ9n9
Reposted by Colin Simpfendorfer
What’s driving the decline?
The crisis isn’t just fishing — it’s invisible fishing.
Much shark & ray catch is under-reported, aggregated, or mislabeled, masking real mortality & delaying management.
What we don’t measure, we don’t manage.
@cgmull.bsky.social
@nathanpacoureau.bsky.social
The crisis isn’t just fishing — it’s invisible fishing.
Much shark & ray catch is under-reported, aggregated, or mislabeled, masking real mortality & delaying management.
What we don’t measure, we don’t manage.
@cgmull.bsky.social
@nathanpacoureau.bsky.social
January 22, 2026 at 3:35 AM
What’s driving the decline?
The crisis isn’t just fishing — it’s invisible fishing.
Much shark & ray catch is under-reported, aggregated, or mislabeled, masking real mortality & delaying management.
What we don’t measure, we don’t manage.
@cgmull.bsky.social
@nathanpacoureau.bsky.social
The crisis isn’t just fishing — it’s invisible fishing.
Much shark & ray catch is under-reported, aggregated, or mislabeled, masking real mortality & delaying management.
What we don’t measure, we don’t manage.
@cgmull.bsky.social
@nathanpacoureau.bsky.social
Reposted by Colin Simpfendorfer
Sharks & rays are sentinels of ocean health.
- Global abundance has been fished down by 65%,
- Now 37.5% of species are threatened,
- The current extinction rate is 25–250 times greater than the background fossil record, with greatest losses in tropical coastal seas. #BiodiversityTargets
- Global abundance has been fished down by 65%,
- Now 37.5% of species are threatened,
- The current extinction rate is 25–250 times greater than the background fossil record, with greatest losses in tropical coastal seas. #BiodiversityTargets
January 22, 2026 at 3:35 AM
Sharks & rays are sentinels of ocean health.
- Global abundance has been fished down by 65%,
- Now 37.5% of species are threatened,
- The current extinction rate is 25–250 times greater than the background fossil record, with greatest losses in tropical coastal seas. #BiodiversityTargets
- Global abundance has been fished down by 65%,
- Now 37.5% of species are threatened,
- The current extinction rate is 25–250 times greater than the background fossil record, with greatest losses in tropical coastal seas. #BiodiversityTargets
Time for a rethink! Thank you science.
@iucnshark.bsky.social @nickdulvy.bsky.social @sharks-int.bsky.social
@iucnshark.bsky.social @nickdulvy.bsky.social @sharks-int.bsky.social
January 22, 2026 at 2:52 AM
Time for a rethink! Thank you science.
@iucnshark.bsky.social @nickdulvy.bsky.social @sharks-int.bsky.social
@iucnshark.bsky.social @nickdulvy.bsky.social @sharks-int.bsky.social
And to be fair, we had a hint about this from a previous paper, but it was for a single animal and so I, like many others, dismissed it as a one-off.
"The critically endangered bowmouth guitarfish (Rhina ancylostoma) in the open ocean with an associated tuna school"
dx.doi.org/10.1007/s125...
"The critically endangered bowmouth guitarfish (Rhina ancylostoma) in the open ocean with an associated tuna school"
dx.doi.org/10.1007/s125...
The critically endangered bowmouth guitarfish (Rhina ancylostoma) in the open ocean with an associated tuna school - Marine Biodiversity
Marine Biodiversity -
dx.doi.org
January 22, 2026 at 2:52 AM
And to be fair, we had a hint about this from a previous paper, but it was for a single animal and so I, like many others, dismissed it as a one-off.
"The critically endangered bowmouth guitarfish (Rhina ancylostoma) in the open ocean with an associated tuna school"
dx.doi.org/10.1007/s125...
"The critically endangered bowmouth guitarfish (Rhina ancylostoma) in the open ocean with an associated tuna school"
dx.doi.org/10.1007/s125...
I always thought these animals lived close to the seafloor in coastal areas. But it turns out they occur they are observed in the open ocean a lot. This is totally mind blowing and makes me think that everything that we thought we knew about this species is just a tiny sliver of what we need to know
January 22, 2026 at 2:52 AM
I always thought these animals lived close to the seafloor in coastal areas. But it turns out they occur they are observed in the open ocean a lot. This is totally mind blowing and makes me think that everything that we thought we knew about this species is just a tiny sliver of what we need to know