[ALittleLight]

This reminds me of a passage in the book Sapiens, where the author muses that there may have been prehistoric tribes where grandparents told tales of when mammoths were so plentiful hunters would take them every month, and the grandchildren would smile and nod. The grandchildren would in turn grow up and tell their grandchildren that there were once beasts called mammoths, and these grandchildren too would smile and nod...

[CalRobert]

The shifting baselines problem comes up a lot; it related to fish catches

It's described more here - https://oceana.org/blog/daniel-pauly-and-george-monbiot-conv... and aptly illustrated here - https://oceana.org/sites/default/files/285468/catch_of_the_d...

https://en.wikipedia.org/wiki/Shifting_baseline

[gnat]

Daniel Pauly is amazing. We hosted him for a conference here in NZ a few years ago. Such a mind!

What is your connection to shifting baselines and fishing policy? My father (former commercial fisherman) is part of a recreational fishing group arguing that the goal of fish policy should be abundance not short-term profit. http://legasea.co.nz

[CalRobert]

I don't have a strong connection to it, I just know that it's an apt illustration and we have photos for it - I doubt fishers today would turn away giant groupers. It's also discussed in a book I just read, Whittled Away, about Ireland's horrendous wildlife and fishery management (while pretty, virtually the whole island has been stripped of its wildlife to turn it in to livestock grazing). In short, there used to be a hell of a lot more fish, of different species, and the stocks we want to return to are levels from an already diminished time. Though it's got a lot to do with the EU's common fisheries policy, which was similarly awful, but has been improved somewhat since, with at least a ban on deep sea trawling.

[powercf]

Excellent article.

I especially like "We have to get rid of this notion that the past is a provider of anecdotes and the present is a provider of knowledge". This way of thinking is pervasive everywhere, including on HN. But we shouldn't be so quick to dismiss the accounts of our ancestors because they seem exagerated when we compare them to our experiences today.

[varjag]

Same happens with climate change. Obligatory apt XKCD:

https://xkcd.com/1321/

[benj111]

This is interesting, thanks for the links, but.....

It isn't science its basically relying on peoples unreliable memory. Should I believe my uncle Bob, when he tells me he used to catch fish bigger than he was using a homemade hook, and some twine?

So at the moment I'm struggling with what this is. History? Probably. A tool for deciding public policy? Probably not.

I'm not denying the phenomena, just that as it stands theres a severe lack of facts in the linked articles.

[nosuchthing]

https://sites.uw.edu/bevanseries/2018/02/28/data-is-in-the-e...

"Dr. McClenachan used photographs taken between 1956 and 1985 to document the loss of the large trophy fish in the Florida Keys, and compared them with photographs that she took in 2007. She found a major shift in species composition across reef communities through time, with larger predatory fish being fished first, followed by a steep decline in the sizes and weights of fish caught more recently. Historically, catches were dominated by large sharks and goliath groupers, but today, the catches are almost exclusively small snappers. Interestingly, Dr. McClenachan found that the cost of fishing trips did not decrease, meaning customers paid approximately the same price for a ~20 kg trophy fish as they do for a ~2 kg trophy fish now, some 50 years later."

[benj111]

Thanks. I still have issues though.

We don't know how representative those picture were. The 1950s pictures have survived over a half century, they were taken at a time when photography was harder work than today. I could go fishing, photograph my meagre catch, and put it on instagram for the world to see easily.

Plus these seem to be tourist photos? Maybe its a symptom of (inexperienced) amateurs going to Florida Keys spending big bucks for the experience, whereas in the 50s it was actual fishermen going out to catch big fish, and the very best would take photos of their catch.

Again I'm not denying the phenomenon, just how much we can actually rely on it to tell us something useful. You can't from this array of photos definitively state that populations of x,y and z have dropped i%.

[NeedMoreTea]

Isn't that conclusion 100% the wrong way round?

If it were so difficult for photos to survive half a century wouldn't it be hard to show catches tended to bigger? After all the ancient 1950s photos of large catches have been lost through not surviving such unimaginable eons. Sorry for the tone, but seriously, by 1950s photography was not the rare and specialist thing it was in the 1910s. Sure, it might be just the unrepresentative ones that survived into modernity, but...

With millions of photos being taken daily today, shouldn't it be trivial to find some examples of enormous catches among them? Yet we don't find them. Yeah, yeah, I know, absence of evidence is not evidence of absence.

Reports of 2m, 100kg cod are from history, today both size and catch has plummeted.

[benj111]

My point was more that today I have a phone in my pocket permanently, digital photos are free so ill take a picture of anything. In the 50s there were financial and convenience barriers to photography, however small.

Plus these photos have survived. My modern photo of an un notable thing probably wont survive, a picture of a notable thing probably will.

[Cthulhu_]

Aren't there trading / sales logs, like, official records from back then?

[est31]

You will also love this twitter thread: https://twitter.com/drmegafauna/status/1088716741700710401