Shifting baselines: how healthy are our recovering fisheries?

A typical haul of Murray cod in Renmark, 1898.
A typical haul of Murray cod in Renmark, 1898.

One of the problems when assessing the health of fisheries is that we get used to how they are now or how they were when we started fishing them, we don’t view them in the context of their historical abundance. The baseline shifts, so instead of comparing the abundance of fish to the long term abundance of the stock, each generation redefines what “natural” or “healthy” fish stocks are as they continue to decline each generation. Daniel Pauly first introduced the idea of shifting baselines in fisheries management, showing that shifting baselines can mask drastic declines in fish stocks over the long term (his TED talk on the topic is worth watching if you aren’t acquainted with the idea). It can also effect how anglers think about fish stocks that are recovering, especially stocks that have drastically declined with only a small fraction of the pre-fished biomass remaining.

There are a number of fish stocks around the country that are well well below historical levels. Two that are most pertinent when it comes to how shifting baselines affect how we perceive fisheries that are in the process of recovering are the Southern Bluefin Tuna fishery and the Murray cod fishery.

In the case of Southern Bluefin tuna, less than a decade ago it was estimated that the stock was at a mere 5% of pre-fished spawning biomass. Thats LOW! In the last decade, reduction in quotas have seen the stock bounce back slightly. The stock is now estimated to be at 9% of pre-fished spawning biomass, with the biomass of 10+ year old fish increasing from 5 to 7% between 2011 and 2014. This is great news, there are signs that Southern Bluefin are making a comeback!

Southern Bluefin Tuna at the Tsukiji Fish Market. Photo by Nate Grey, used under the creative commons licence.
Southern Bluefin Tuna at the Tsukiji Fish Market. Photo by Nate Grey, used under the creative commons licence.

The problem comes from some within the angling and commercial fishing communities, seeing and experiencing this recovery first hand thinking that everything it now hunky dory, that quotas should be increased and bag limits upped (potentially stalling or slowing the recovery that has really only just begun). The low abundance of the fish now perceived as normal, the small recovery as a “boom”. This is shifting baselines in action. Southern Bluefin stock still aren’t in great nick, they are still ONLY at 9% of pre-fished spawning biomass. So while the fishing has improved and it seems that the fishing is the “best its ever been”, thats only because as a community, we’ve forgotten how good it was a generation ago, 30-40 year ago. The baseline has shifted. We have forgotten what we have lost. We have forgotten how good our fishery should be.

The same goes for Murray cod. Its estimated that Native fish populations in the Murray Darling basin are at less than 10% of their original levels. This is potentially a vast over-estimate, with scientist such as Paul Humphries suggesting that the real figure is likely closer to 1%, thats REALLY low (you can check out a video about his genius pub crawling “Stuffed Murray cod in Pubs” project here). You only have to look back at the commercial catch data and historical accounts to realise that our current Murray cod fishery is a sick emphysemic shadow of what it once was. A large commercial fishery for cod was established in the 1860s, with 75% of fish being sold at the Melbourne markets being Murray cod. Catches peaked in 1918, after which there was a decline in catches and populations to the point where by the mid 1930s the fishery had become uneconomic for many participants. Further declines followed, with commercial catches dropping by 85% between the mid 1950s and the closure of commercial cod fisheries in the early 2000s, suggesting a drastic decline during that 50 year period, on top of the declines that had already happened previously. To give you some an idea of the historical abundance of Murray cod, in 1862 a group of six men would send 2-3 tonnes of Murray cod  to Melbourne a WEEK, all caught from the Murray river around Deniliquin. In 1926 on the Murray at Echuca, it was reported that the average catch for recreational anglers had been between 18-23kgs per angler every few hours in the preceding decades but had begun to substantially decline. To a modern cod fishermen, those numbers are almost unbelievable! Even with all the technological improvements that have been made over the years, which have made catching cod “easier”, those sort of average catch rates are something most cod anglers will never get close to experiencing. It would now only be a tiny handful of extremely lucky people who have experienced an absolutely red hot, “once in a lifetime” day on the water who would know what Murray cod fishing was once like. It used to be like that ALL OF THE TIME.

"A couple of cod"
“A couple of cod”
Unloading the days catch
Unloading the days catch

Over the last decade progress has been made. Wonderful programs like the Native fish strategy (which had its funding cut in 2012), stocking programs, work by the various government fisheries organisation (e.g. Victorian DEPI, NSW DPI), work by scientist and hard work by community and angler groups to improve habitat and fish populations have started to pay dividends. It appears that in some areas Murray cod (and trout cod in some, which is even more exciting) are making a comeback. Once again, you often hear “fishing has never been better”. Again, thats only because we have forgotten how good things were in the past. We are coming off such a low baseline, a baseline many now perceive as normal, that even very modest improvements in the stock make it appear like the stock is “booming”. That most definitely isn’t the case, something history makes abundantly clear.

Why is this important? Because as anglers, we owe it to our children to pass on healthy ecosystems, environments and fish stocks. We owe it to ourselves to fight for healthy fish stocks and improved fishing opportunities. If we forget about the past, we run the risk of doing a really really bad job of that. So while its great that the stocks of Southern Bluefin and Murray cod have started to recover, we shouldn’t be satisfied with these short term improvements. Doing so we sell ourselves short. WAY WAY WAY short. If we take the time look back at history, we can see that the fisheries that exist today are still only a mere shadow of their former selves. We have a lot of work to do to get back to something we can be happy with and we shouldn’t lose sight of that.

Fighting for that improvement is something that will be of huge benefit to anglers. Think of what the small improvements in fish stocks have done to improve angling in the examples used for this piece. Now think about what angling would be like if instead of being at 9 or 10%  (or 1%) of pre-fished levels fish stocks were instead at 20, 30, 40, 50 or 60% of pre-fished levels? Thats the sort of fishing we need to be imagining, thats what we owe ourselves and our children. We may never get back to average catch rates of 18-23kgs an hour, but we might one day be able to achieve half that. That would be something we could be proud of. So while we should be excited about and welcome the small improvements that are happening, we need to remember that the job of improving these fisheries has only just begun.

This doesn’t apply just to Murray cod and Southern Bluefin, but to a range of different species, including Mulloway, Bigeye tuna, Striped marlin, Yellow belly, Trout cod, Silver perch, Macquarie perch, Australian bass, Estuary perch and many others, all of which have suffered significant historical declines. A number of our fisheries can and should be a lot better than they currently are.

If we want great fisheries for all these species, its important we don’t forget what we have lost, that we don’t forget how abundant they once were. Remembering the past is an important part of building a better future.

Thanks for reading!


Thanks to Simon Kaminskas for kindly providing the historical Murray cod photos and to Kurt Kiggins for unwittingly inspiring this post.

Further reading: A really interesting article on recreational fishing causing fisheries collapses in Canada. Once again, shifting baselines come into play, this time in the traditional sense, masking long term declines of fish stocks.

Hamish Webb, Dan Firth, Graham Fifield and Lee Georgeson have been fishing the south-east Australian region since 1987. Since then they’ve become avid sportfishermen who are constantly looking for new ways to challenge themselves. They are all scientists and conservationists who are passionate about the long-term sustainability of the ecosystem in which they live. They promote understanding and appreciation of the complex socio-political, economic and environmental issues surrounding fish, fishing and fisheries, while never losing sight of the various motivations that keep them coming back. In English, that means they love all things fishing and have a damn good time on the water, and that’s all that really counts in the end!

12 thoughts on “Shifting baselines: how healthy are our recovering fisheries?

  • June 13, 2015 at 10:38 pm

    This shows the Abundance of the Earth if the systems are healthy. .. and it shows our cultural disconnection with our home and its effects

  • June 15, 2015 at 7:31 am

    Great article.

    With my passion for all things historical when it comes to native fish, I too have spent years trying to enlighten people as to what we once had with native fish, and what a pale pale sick shadow of it we now have.

    And in my own way, I too have been trying to sound caution when one environmental flow environment or one stocking leads to supposedly the “best fishing ever” — and point out that we have a long long way to go to even remotely approach our original native fish populations.

    The Shifting Baseline effect is real and very scary. It, and the related phenomenon Inter-generational Amnesia, has struck particularly hard when it comes to upland native fish — Macquarie perch and trout cod.

    There was a time when almost every upland stream and river in the southern MDB abounded with Macquarie perch and trout cod, to very high altitude. Local anglers loved them. Trout were then introduced, almost invariably without local people’s permission or agreement, and in many cases (notwithstanding that *some* (not all) streams were also affected by dams, sand-slugging and mining/sheep-dip pollution), these trout introductions and subsequent continual trout stockings extirpated upland native fish populations. (For those who want to argue, please don’t! — there’s a mountain of black and white newspaper article evidence for this in the National Library’s Trove that makes arguing pointless.) What’s interesting is when the trout were first introduced, the current generation of local anglers hooked on upland native fish hated them. But when upland native fish disappeared, the next generation were quite happy to fish for trout and thought quite positively about them — because by then there was nothing else to fish for in upland streams, and because they had never known anything else.

    Over the decades, we got the point where — horrors of horrors — most fishermen and even most fishery deparment personnel had started to believe (and publicly claim) that our upland rivers and streams had never had large sporting native fish in them.

    Fortunately, some good historical research by William Trueman (I suggest the 2007 version over the 2011 version) and also the old records now available through TROVE, tell the story:

    — almost every upland stream and river in the southern MDB abounded with Macquarie perch and trout cod, to very high altitude

    — these could and should have been the jewel of freshwater fishing in SE Australia

    — introduction of trout and constant restocking of trout, especially after bushfires, DID have a lot to do with their loss

    — amazingly, the memories of these fish/this fishing was mostly forgotten rather than being passed down, as you might assume.

    Yep, it’s worth thinking about.

    A final thought is that anglers in 1915 probably thought fishing was hunky-dory in all regards, tuna, kingfish, salmon, snapper, etc. and in the freshwater, lowland natives (Murray cod, silver perch, golden perch), and even our upland natives too, Macquarie perch and trout cod. No doubt an angler from 1915 would be really shocked if he knew where these fish and and fisheries had got to by 2015. A question we must ask ourselves is, if we don’t finally learn from history and the Shifting Baseline effect, would we be similarly be shocked by where things will in 2115?

  • June 15, 2015 at 11:43 am

    On another note, I agree with your point (and Paul Humphries) about wild Murray cod stockings probably being closer to 1% of pre-European levels, not 10%.

    The 10% thing is hopelessly optimistic–based on fairly recent commercial catch data, I undestand–and with my historical insights, I never believed it.

    We’re down to way less than 10%.

    Incidentally, I sent you guys a fascinating scientific on just this issue, and how important it use to use historical data (however patchy and difficult) to extend stock estimates and catch estimates beyond just the last few decades of recorded commercial catch data.



    • June 15, 2015 at 11:47 am

      sorry, that should be “wild cod numbers”, not “wild cod stockings”

  • June 16, 2015 at 10:05 pm

    One thing is for certain: if you look at fishing in isolation as the cause for decline in fish stocks there is no way you’ll come to any other conclusion.

    • June 17, 2015 at 9:38 am

      Hi Bruce

      My intention certainly wasn’t to blame declines solely on over-fishing. The use of catch data from the past was simply used to illustrate how much stocks have declined and what fishing used to be like.

      In terms of native fish, the decline in stocks was caused by a myriad of factors, including over-fishing, de-snagging, changed river regulation and changed flow regimes, dams, cold-water pollution, siltation, introduced pest species, reduced water quality, habitat degradation and other factors. The declines happened because of all those factors and the inter-play between all of them. Discussing that is a topic for another post and teasing apart the relative importance of each of those is a devilishly difficult thing to do (which was one of the reasons I tried to avoid it here).

      My point is simply that these fish used to be very common and that if we want to have really good fisheries for them again, that its important that we remember that and set our sights at achieving something “good” in terms of their historical abundance, not just “good” in terms of their abundances now which are low. Of course, many rivers and other ecosystems have changed markedly since the “pre-fished” era, we will never get back to a “pre-fished” abundances of any of the species listed. Thats completely fine. I haven’t got into what proportion of pre-fished abundance could be deemed “good” because thats something that we will need to work out over time as we try to rebuild stocks and learn more about the reasons for declines and the best ways to restore stocks of fish (the number achievable and the best strategies are also likely be different for different species, e.g. rebuilding Mulloway stocks will be very different to rebuilding Southern bluefin stocks, both of which will be very different to rebuilding MDB native fish stocks).

      If you look at the strategies that have started to work for Murray cod, that have lead to them bouncing back in a number of areas, a mixed strategy which addresses a number of the issues that caused the declines (habitat restoration, improved flow regimes etc etc etc), seems to be the ticket. Those strategies seem to be working and we are learning more about how to improve those all the time. We will get better at it as time goes on.

      The point of the blog was simply to point out that if we want to improve recreational fisheries, remembering history is an important part of doing that. That its important that we have an idea of the upper potential/productivity of our fisheries.

      Thanks for your comment!!


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