What you want to look for are stock assessments. For example, for the species closest to home, under the Pacific Fisheries Management Council:
https://www.pcouncil.org/groundfish/stock-assessments/archived-stock-assessments/
Three rockfish species that might be good to look into for your purposes are widow, yelloweye, and bocaccio, but these will have shorter-term data than any of the cod data. Also, NOAA NMFS Technical Reports on individual stocks often have long appendices with lots of data. For the Canada side of things, I just Googled in “Canadian cod stock assessment” and got this:
https://publications.gc.ca/collections/collection_2011/mpo-dfo/Fs70-6-2005-024-eng.pdf
Note that Canada divides up its cod into multiple stocks based on region, and it’s the Newfoundland one in this assessment that had the most famous collapse. The US does the same – of the US cod stocks, the Georges Bank one is probably the most relevant to you – it’s the second one at:
https://www.nefsc.noaa.gov/sos/spsyn/pg/cod/ (note links to .cvs data for each figure). Also, some relevant synthesis papers that come to mind as potential pointers to data sources are: https://www.nature.com/nature/journal/v423/n6937/abs/nature01610.html https://www.nature.com/nature/journal/v406/n6798/abs/406882a0.html https://www.sciencemag.org/content/325/5940/578.short https://www.esajournals.org/doi/abs/10.1890/1540-9295(2005)003%5B0078:THOORM%5D2.0.CO%3B2 https://www.sciencemag.org/content/293/5530/629.short
Three of these are from NCEAS working groups, so they might have archived the data with NCEAS. The big caveat for all of this, as I mentioned earlier, is that any catch data confounds abundance and harvest effort – for example, as Alan said, zero catch doesn’t mean zero fish, it means the fishery was closed.
Another thought might be to look into the North Sea cod/herring/mackerel system, where there is an explicit model with the right kind of bifurcation in mind based on cultivation effects (herring and mackerel preying on cod recruits but being the prey of adult cod can drive alternative stable states) – there are a couple of recent statistical modeling papers aimed at trying to detect alternative states in the system that might indicate data sources, including abundance data that isn’t confounded by effort:
https://www.pnas.org/content/106/1/197.short https://www.esajournals.org/doi/abs/10.1890/09-1500.1
For cod more generally, both cultivation effects (originally modeled in the Walters & Kitchell paper referenced in the second North Sea paper linked above) and Allee effects (I think the Rosenberg Frontiers paper linked among the synthesis papers talks about this) are hypothesized to be potential drivers of alternative states. Competition cultivation effects are hypothesized to occur in rockfish too, which was the basis for one of my papers.
But, really, Loo Botsford will have the most knowledge of anyone on campus about which fisheries have the most reliable data – also, might he, Alan, and Matt know of some time-series cod data sources for the cod/salmon biocomplexity project?
- MB