Thanks for the comprehensive reply! Strongly upvoted.
Secondly, I read your reply from Michael St Jules, though affirming that âmicroplastic ingestion rarely causes mortality in any organismâ canât be farther from the truth. As an example from what we already debated, this is what led to the seabird numbers (as there are dozens of studies proving that plastic debris is their cause of death, as you had also pointed out). An example of study here: https://ââwww.nature.com/ââarticles/ââs41598-018-36585-9 .
The statement you quote refers to microplastic ingestion, but the study you link does not contain âmicroplasticâ, so it may be focussing just on larger pieces of plastic:
There is a 20.4% chance of lifetime mortality from ingesting a single debris item, rising to 100% after consuming 93 items. Obstruction of the gastro-intestinal tract is the leading cause of death. Overall, balloons are the highest-risk debris item; 32 times more likely to result in death than ingesting hard plastic.
However, based on the other studies you linked, I agree the statement âmicroplastic ingestion rarely causes mortality in any organismâ was misleading. I was quoting a page from Our World in Data which has meanwhile been modified, and no longer seems to discuss impacts on wildlife. However, they now have a FAQ on microplastics which reflects uncertainty about the effects on mortality, rather than confidence in the absence of effects (emphasis mine):
One challenge of microplastics is that their small size makes them easier to (consciously or not) ingest. Ingestion of microplastics could have detrimental impacts on wildlife health. The small size of these particles make them difficult to track and monitor; evidence on the impacts and behaviour of microplastics are therefore currently very limited.
I have added to the comment replying to Michael the following. âUpdate on 29 December 2023: Nathalie Gil pointed out some studies have concluded microplastics increase mortalityâ.
microplastics are debris of 0,5mm or less, so this fits the size with a lot to spare
Nitpick, microplastics have a diameter of less than 5 mm (which makes your point even more valid).
I am roughly aware of Brian Tomasikâs numbers on fishing as I work to fight against it myself.
Besides often having numbers, another common thread of Brianâs posts is that the impact of reducing fishing may be quite unclear due to indirect effects. To illustrate, here is the summary of How Wild-Caught Fishing Affects Wild-Animal Suffering:
Fishing imposes agonizing deaths on 1-3 trillion fish per year, as well as many other marine animals. However, (over)fishing has many other indirect effects on wild-animal suffering. This piece surveys reasons why the harvesting of wild fish might reduce as well as increase the suffering of oceanic creatures. The net impact is extremely unclear. Moreover, the sign of net impact may depend on what kind of fish is eatenâfor example, catching big piscivorous fish may reduce zooplankton populations, while catching small zooplanktivorous fish may increase zooplankton populations. If you do buy fish, itâs plausible though not completely clear that unsustainable kinds are bestâe.g., overfished species, those caught with bottom trawling, etc. That said, I would probably err on the side of not eating fish, especially because wild-catch fishing may increase the amount of fish farming in the future.
I guess wild animals have net positive lives, although it is quite unclear, so I think we had better minimise fishing and plastic pollution.
Just to be dead clear, I still am in complete alignment with you regarding the impact of fishing x plastics for the oceanâs ecosystem, as a fighter for the end of fishing myself. I just wanted to shed a light on why not to de-prioritise the efforts on fighting plastic pollution for the protection of the ocean.
Makes sense! I have added the following at the top of the post. âDisclaimer: plastic pollution may well kill way more animals besides seabirds and sea mammals. There are 6.20*10^14 wild fish and 1.00*10^20 wild marine arthropods, but only 6.75*10^11 wild mammalsâ.
Thanks for your reply, Vascoâall clear and comprehensive. Iâd only dispute the claim from How Wild-Caught Fishing Affects Wild-Animal Suffering: âfor example, catching big piscivorous fish may reduce zooplankton populations, while catching small zooplanktivorous fish may increase zooplankton populations.â - this does not consider the full balance of the trophic chain, and the fact that if you remove big piscivorous fish, you are in fact on the SHORT TERM increasing the population of zooplankton, however, this have many complex effects, one example: the decrease in the Caribbean shark population is met by an increase in its prey, the grouper fish. The expanding grouper population takes parrotfish, normally responsible for clearing coral of algae, in greater numbers. This could explain why algae now dominates many degraded reefs in the Caribbean. It also shows how the systematic elimination of one speciesâa key link in a complex web of relationshipsâcan destabilize the entire ecosystem. When it comes to wild animals, no impact is so straightforward and isolated as weâd like to measure. This is my pet critic with EA, as the difficulty in measuring the clean direct impact of efforts in wildlife conservation can be hindering funds to these efforts, however, in the larger sense, the strategy to leave the ocean alone to rebalance its ecosystems is about saving all life on Earthâtherefore the investment on ocean conservation has strong direct links to Existential Riskâours and of all life on Earth. Perhaps this is a conversation to another topic/â thread...!!
Thanks for the comprehensive reply! Strongly upvoted.
The statement you quote refers to microplastic ingestion, but the study you link does not contain âmicroplasticâ, so it may be focussing just on larger pieces of plastic:
However, based on the other studies you linked, I agree the statement âmicroplastic ingestion rarely causes mortality in any organismâ was misleading. I was quoting a page from Our World in Data which has meanwhile been modified, and no longer seems to discuss impacts on wildlife. However, they now have a FAQ on microplastics which reflects uncertainty about the effects on mortality, rather than confidence in the absence of effects (emphasis mine):
I have added to the comment replying to Michael the following. âUpdate on 29 December 2023: Nathalie Gil pointed out some studies have concluded microplastics increase mortalityâ.
Nitpick, microplastics have a diameter of less than 5 mm (which makes your point even more valid).
Besides often having numbers, another common thread of Brianâs posts is that the impact of reducing fishing may be quite unclear due to indirect effects. To illustrate, here is the summary of How Wild-Caught Fishing Affects Wild-Animal Suffering:
I guess wild animals have net positive lives, although it is quite unclear, so I think we had better minimise fishing and plastic pollution.
Makes sense! I have added the following at the top of the post. âDisclaimer: plastic pollution may well kill way more animals besides seabirds and sea mammals. There are 6.20*10^14 wild fish and 1.00*10^20 wild marine arthropods, but only 6.75*10^11 wild mammalsâ.
Thanks for your reply, Vascoâall clear and comprehensive. Iâd only dispute the claim from How Wild-Caught Fishing Affects Wild-Animal Suffering: âfor example, catching big piscivorous fish may reduce zooplankton populations, while catching small zooplanktivorous fish may increase zooplankton populations.â - this does not consider the full balance of the trophic chain, and the fact that if you remove big piscivorous fish, you are in fact on the SHORT TERM increasing the population of zooplankton, however, this have many complex effects, one example: the decrease in the Caribbean shark population is met by an increase in its prey, the grouper fish. The expanding grouper population takes parrotfish, normally responsible for clearing coral of algae, in greater numbers. This could explain why algae now dominates many degraded reefs in the Caribbean. It also shows how the systematic elimination of one speciesâa key link in a complex web of relationshipsâcan destabilize the entire ecosystem. When it comes to wild animals, no impact is so straightforward and isolated as weâd like to measure. This is my pet critic with EA, as the difficulty in measuring the clean direct impact of efforts in wildlife conservation can be hindering funds to these efforts, however, in the larger sense, the strategy to leave the ocean alone to rebalance its ecosystems is about saving all life on Earthâtherefore the investment on ocean conservation has strong direct links to Existential Riskâours and of all life on Earth. Perhaps this is a conversation to another topic/â thread...!!