Figured I’d flag that it seems pretty likely to me that aquatic noise reduces populations (and unlikely that it increases them), both fish and invertebrates, by increasing mortality and reducing fertility. See this thread with Perplexity AI (I haven’t carefully verified the accuracy, though). So, reducing aquatic noise increases wild animal populations in expectation, which is plausibly bad if their lives are bad on average. There could be tradeoffs with average welfare, but I’d be at best clueless about whether reducing aquatic noise is good or bad overall for aquatic animals in the near term.
it seems pretty likely to me that aquatic noise reduces populations (and unlikely that it increases them), both fish and invertebrates, by increasing mortality and reducing fertility.
What about trophic cascades? Maybe the populations most directly affected and reduced by aquatic noise were essential for keeping overall wild animal populations down?
Do you think aquatic noise is like some specific forms of fishing that determinately reduce overall populations? Is it because you think it directly affects/​reduces all populations (unlike some other specific forms of fishing) such that trophic cascades can hardly compensate?
I’d guess aquatic noise reduces populations across trophic levels. There’s some evidence across different animal size groups. It also seems a priori more likely that smaller animals, like zooplankton, will have the largest population-relative direct effects at a given noise volume because the force will be larger relative to their body and organ sizes (but they may be closer or farther from noise sources), and since they feed other animals up the food chain, higher trophic levels would have less available food, too.
Speculating pretty wildly: maybe larger primarily herbivorous species would be least affected or could increase in populations due to reduced competition for food with smaller herbivores. That could actually mean increasing the average welfare of aquatic animals.
Interesting. I think it might be useful to have more studies on this. For example, one uncertainty is about net welfare across time, i.e if it decreases the net population or if some other group of animals fill in to consume the available resources. Also since it mentions that anthropogenic noise increases cortisol by 90-120x in fishes, I wonder how we should trade off against the stress this causes animals in short term vs the population reduction.
The section Invertebrates in the article documents some studies that suggest that invertebrates are not directly affected by noise, unless the source is less than a meter away
It does look like most studies suggested small or no effects after less than 10 meters away, but I wonder how much they focused on eggs, larvae and zooplankton, which are plausibly more sensitive. For example, from this study (discussion):
Experimental air gun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar (~3–4 dB drop within 15–30 min) and net tows (median 64% decrease within 1 h), and caused a two- to threefold increase in dead adult and larval zooplankton. Impacts were observed out to the maximum 1.2 km range sampled, which was more than two orders of magnitude greater than the previously assumed impact range of 10 m. Although no adult krill were present, all larval krill were killed after air gun passage.
This might be an outlier study, though. I had Perplexity attempt a systematic review here.
Figured I’d flag that it seems pretty likely to me that aquatic noise reduces populations (and unlikely that it increases them), both fish and invertebrates, by increasing mortality and reducing fertility. See this thread with Perplexity AI (I haven’t carefully verified the accuracy, though). So, reducing aquatic noise increases wild animal populations in expectation, which is plausibly bad if their lives are bad on average. There could be tradeoffs with average welfare, but I’d be at best clueless about whether reducing aquatic noise is good or bad overall for aquatic animals in the near term.
What about trophic cascades? Maybe the populations most directly affected and reduced by aquatic noise were essential for keeping overall wild animal populations down?
Do you think aquatic noise is like some specific forms of fishing that determinately reduce overall populations? Is it because you think it directly affects/​reduces all populations (unlike some other specific forms of fishing) such that trophic cascades can hardly compensate?
I’d guess aquatic noise reduces populations across trophic levels. There’s some evidence across different animal size groups. It also seems a priori more likely that smaller animals, like zooplankton, will have the largest population-relative direct effects at a given noise volume because the force will be larger relative to their body and organ sizes (but they may be closer or farther from noise sources), and since they feed other animals up the food chain, higher trophic levels would have less available food, too.
Speculating pretty wildly: maybe larger primarily herbivorous species would be least affected or could increase in populations due to reduced competition for food with smaller herbivores. That could actually mean increasing the average welfare of aquatic animals.
Interesting. I think it might be useful to have more studies on this. For example, one uncertainty is about net welfare across time, i.e if it decreases the net population or if some other group of animals fill in to consume the available resources. Also since it mentions that anthropogenic noise increases cortisol by 90-120x in fishes, I wonder how we should trade off against the stress this causes animals in short term vs the population reduction.
The section Invertebrates in the article documents some studies that suggest that invertebrates are not directly affected by noise, unless the source is less than a meter away
It does look like most studies suggested small or no effects after less than 10 meters away, but I wonder how much they focused on eggs, larvae and zooplankton, which are plausibly more sensitive. For example, from this study (discussion):
This might be an outlier study, though. I had Perplexity attempt a systematic review here.