L16- Fisheries Controversies

Background on fishery controversies:

• fishing is a heterogenous global industry

• is important for global food security

• has significant environmental impacts

• is a source of controversy as it encompasses many aspects/rights

Fishing controversies:

1. atlantic cod

2. proportion of world’s fish stocks overfished

3. carbon cost of fisheries

4. fishing down food webs

5. seaspiracy documentary

Atlantic cod controversy

• started with a post from a restaurant:

  

  • was posted in multiple news headlines

is the atlantic cod controversy credible?

• source→ CEFAS quote (UK government fisheries laboratory), is reliable

  

• but what do we know about cod?

  • mature at 3 years old, fully mature at 6 years old

  • don’t often see cod above 13 years old

• so what is the truth?

  • there are fewer than 100 above 13 but there are found 21million adult cod

• mythbuster (website) and more or less (radio show looking at numbers behind the headlines- discredited this

atlantic cod controversy reactions

• these stories matter because of their reactions e.g. 2 different takes to the same headline→ invited ridicule and anger from fishing industry

  

atlantic cod controversy conclusion

• accuracy matters in conservation messaging

  • simplifying matters is important but over exaggerating loses credibility

  • nature is based on facts

proportion of world’s fish stocks overfished controversy

• starts with headlines from WWF:

  

is the proportion of world’s fish stocks overfished controversy credible?

• UN Food and Agricultural Organisation→ authoritative providers of stats on global fisheries, actually found was 34.2% at this time

  • UN FAO are criticised as Ray Hilborn was accused of being an overfishing denier→ using particular characters to discredit stats they don’t like

• evidence from UN FOA:

  • fish stocks underfished, fished to maximum sustainable limits, overfished→ target for fisheries is maximum sustainable yields

    

  • get this evidence from SOFIA FAO report:

    • unsustainable levels was 31.4%

    • 2022 report- increased

    • sustainably exploited stocks are the aim, which the paper included in their 85%

proportion of world’s fish stocks overfished controversy conclusion

• the truth is already bad enough

  • is tempting to have attention-grabbing headlines but are misleading and can lead to conflicts that miss the point, can sometimes be effective

carbon cost of fisheries controversy:

• guardian article→

  

  • numbers-

  

is the carbon cost of fisheries controversy credible?

• look at study story links to→ is high profile, numbers seem to add up

• look at the science

the science of trawling and carbon costs:

• constant organic carbon falling in the oceans

• is mineralised into co2→ dissolves into seawater or hits seabed and gets buried in sediment in a carbon sink

• trawling disturbs the sea bed through use of heavy gear→ releases carbon

• closing off bigger areas of trawling will increase amount of carbon sequestered→ reason to increase coverage of MPAs in paper

what do other authors think of the carbon cost controversy?

• see lots of author corrections in this paper:

  

  • paper does not believe their numbers

  • objections:

    • the model of organic carbon mineralisation the original paper uses assumes reactivity of carbon in the sediment is the same as the carbon at the surface but we don’t know enough to say this, experiments suggest sediment carbon has 2-3x lower impacts than the model used

    • 60% of evidence reported no sig effect of fishing on sediment organic carbon, 10% has less in no trawling areas though

    • evidence is mixed but is not strong to show that bottom trawling always releases carbon

why does the carbon cost of fisheries controversy matter?

• this matters as the paper was used to support carbon credits→

  • offsetting co2 in this area by buying in MPAs that prevent trawling will create imaginary reductions in co2

  • air travel emits lots of carbon directly into climate- can quantify this but trawling is uncertain

carbon cost of fisheries controversy conclusion

• even high profile publications require scrutiny

  • need extraordinary evidence for extraordinary claims, cannot simplify ocean systems

fishing down food webs controversy:

• as time goes on (left to right), fisheries used to fish high tropic fish, removing large fish and leaving simpler systems of small trawling fish and jellyfish now

  

• early paper→

  

is the fishing down food webs controversy credible?

• evidence:

  • has happened generally, assigned trophic level of fish caught, tracked through time

    

  • hypothesis is logical→ initial feeling is it feels right but need to think through it→ having multiple working hypotheses

expected vs observed fishing in the food web:

• what we expect- fishing down the trophic level→ where you fish is red, has happened in 9/48 ecosystems

  

• what we actually see- fishing through the food web→ start by targeting large predatory fish, over time catches remain high, target others, mean trophic level declines whilst high tropic level fishing is still increasing, happens 2x more than fishing down the food web

  

• expected vs observed:

  

why is this type of fishing in the food web happening?

• high tropic level fish should be the most valuable but data shows there is no relationship between price of fish and trophic level it is found at:

  

• are fishing for profits

• fishing down the food web is not a general phenomenon

fishing down the food web controversy conclusion

• making sense of controversies

  • media can make simple stories and fisheries (food) is more emotive than other topics but these can lead to conflicts

Seaspiracy controversy

• does more harm than good, dont mislead or sensationalise there are things we cna do that are better e.g. pushing for legeslations

• pauly (believes in fishing down the food web) and hilborn (known as an overfishing denier) agreeing (don’t ever agree)

How to counteract controversies:

• think critically, challenge ideas, data has power but limitations too

• fact-check conservation- support those that separate truth from lies