Sunday, January 11, 2015


Climate change has been in the news quite a bit lately.  

Globally, 2014 was the warmest year ever recorded, and there’s no reason to believe that 2015 won’t be pretty warm as well.

The ocean is warming as well as the air, and that can’t help but have an effect on fish. 

One group of researchers has determined that warming waters will have a significant impact on Atlantic cod off the northeastern coast, as they lose thermal habitat—that is, waters become too warm—on parts of Georges Bank and much of the Mid-Atlantic Bight.  In addition, increased water temperatures in the Gulf of Maine are likely to lead to lower cod recruitment and make the fish more vulnerable to high fishing mortality rates.

“There has been mounting evidence that over extended periods of time, even small increases in water temperature can significantly affect species composition, distribution, and abundance of fish communities…It has been projected that with warming, the geographical distribution of cold-water species will shift toward the poles and to deeper waters where temperatures are cold, causing a general reduction of cold-water species while expanding the ranges of warm-water species.”
Rutgers University has gone a step farther.  Its School of Environmental and Biological Sciences has created the OceanAdapt website, which allows people to see the changes in the centers of abundance for various species, in terms of both depth and latitude, as the shifts described by Rhode Island Sea Grant take place.

There’s no question that a warming ocean is creating new challenges for fisheries managers.

Unfortunately, one of the biggest challenges has nothing to do with the warming ocean itself.  Instead, it is taking the form of fishermen who fight against needed regulations, and now have added climate change to a list of excuses--which already includes predation, pollution and habitat change--used to try to evade responsibility for declining fish stocks.

While there is no question that warming waters are bringing change to fish distribution, those changes are not consistent across all species.  And rather than absolving fishermen from responsibility for declining stocks, they actually increase the need for more intense, and more restrictive, regulation of existing fisheries.

The National Marine Fisheries Service recently described a study that investigated how four popular fish stocks have responded to a warming ocean.  The stocks involved were black sea bass, scup, summer flounder and the sourthern New England/Mid-Atlantic Bight stock of winter flounder.  The study incorporated data collected between 1972 and 2008 by NMFS’ northeastern trawl surveys.

It turns out that the fish don’t all react in the same way.

Winter flounder exhibited no northward movement at all.  

The other three stocks did show northward movements, but the reasons for those movements were not all the same.

The researchers found that, in the case of two of the stocks,

“Northerly shifts in scup and black sea bass are linked to increases in temperature and are more tied to climate than fishing.”
However, in the case of summer flounder

“The fish were not shifting northward with warmer conditions, but simply re-colonizing their former habitat areas.”
That was happening because of

“…a decrease in fishing pressure and an expansion of the age structure…
“Fishing typically removes the larger fish from a population.  Large, older summer flounder are typically found further north, and as exploitation reduced the number of summer flounder in the 1980s and 1990s, larger fish were preferentially harvested by the fishery.  The remaining summer flounder population, dominated by smaller fish, subsequently became centered further south.  The northward shift of the stock in recent decades was linked to an increase in the number of larger, older fish as the population has rebuilt.”
Thus, as the study advises,

“multiple factors specific to individual species need to be considered when developing management regulations for living marine resources.”
NMFS, in announcing the study, noted that

“climate change can have major impacts on the distribution of fish, but the effects of fishing can be just as important and occur on a more immediate time scale.”
If we extend that thought to the cod discussed earlier in this essay, we can look at a study entitled “Reconciling overfishing and climate change with stock dynamics of Atlantic cod (Gadus morhua) over 500 years”, which appeared in the Canadian Journal of Fisheries and Aquatic Sciences in 2011.

In that article, the researcher reported that a population model that only considered fishing impacts on cod population trends between 1505 and 2004 failed to accurately predict historical fluctuations in the stock.  A model that relied only on climate failed almost as badly.  

However, a model that considered both factors tracked historical changes in the cod population with reasonable accuracy.

When the model is applied to fairly recent times—roughly the last 200 years—the finding was that

This model suggests temporal differentiation between fishing and climate effects, including (i) declines during the Little Ice Age (18001880) caused by lower productivity, (ii) collapses in the 1960s caused by overfishing, (iii) collapses in the late 1980s caused by both, and (iv) rebuilding now hindered by depensatory effects of low numbers.”
Based on that finding, it is folly to attempt to separate climate change from overfishing when we look at stock declines.  While both are detrimental to healthy stocks, together they create a sort of synergy that makes it even more difficult to conserve and rebuild fish populations.

Although conducted on the other side of the Atlantic, the conclusions drawn in the paper “Fishing, climate change and north-east Atlantic cod stocks,” written by three members of the Marine Biological Association of the UK in 2007, probably provide good guidance for the maintenance of our western Atlantic cod stocks as well.  The authors found that

“Cod stocks in the north-east Atlantic, especially the North Sea, have been impacted upon heavily owing to sustained overfishing by modern fleets.  It seems unlikely that global climate change warming is the primary factor causing the decline in fish numbers, but evidence suggests that this phenomenon may be exerting additional pressures on already overexploited stocks by further reducing recruitment rates that are already low due to reduced [spawning stock biomass].  Indirect effects of climate change on the availability of prey for juvenile fish are predicted to be detrimental to the recovery of fish stocks, and current climate conditions are likely to drive this decline in suitable prey supply for the foreseeable future.  Temperature effects on cod growth, reproduction and recruitment will cause significant effects that require consideration when making stock assessments and catch forecasts…
There is a need to take precautionary measures to give stocks a chance to rebuild.  Although climate change appears to be one of the factors responsible for non-recovery of cod in the North Sea, fisheries are no longer sustainable at the present level of fishing effort.  Future policy must take both factors into account when deciding upon sustainable catch quotas…  [emphasis added]”
Thus, there is no scientific justification for using climate change as an excuse to allow overfishing.  To the contrary, climate change probably amplifies the problems that overfishing causes, and makes the adoption of conservative annual catch limits even more important than it might have been before.

That’s not what a lot of the folks up in New England want to hear, but it is true nonetheless.


  1. lack of effort isn't going to help anything at this point...and that's what I took away from this tripe. Looks like you've cherry picked some pretty good data but in the end, you like many others fall back on the old stand-by: overfishing.
    "Instead, it is taking the form of fishermen who fight against needed regulations, and now have added climate change to a list of excuses--which already includes predation, pollution and habitat change--used to try to evade responsibility for declining fish stocks."
    Really? Have you been paying attention to, oh, the last 15 years? I love how no one wants to talk about 2005-2010 when the cod were making an honest comeback. Since catch-shares went into effect there are no fish, no boats in business and plenty of experts on why. Fucking joke and if this is the shit your going to pump out you sir should be ashamed. It's lazy and ignorant. Finger pointing at its best.

  2. So please supply me with some solid science that indicates that overfishing is not causing the problem, and hasn't been a primary contributor to the current state of .the cod stocks. Not opinions, mind you, but peer-reviewed studies backed by statistically valid data.

    Because I can't find any.

    I've been paying attention to New England cod stocks for a very long time, and I suggest that the reason that no one is talking about the cod "making an honest comeback" in 2005-2010 is because it wasn't happening. Concentrations of bait over inshore structure may have made the cod more available to fishermen, but outside of a now-discredited stock assessment made during that period, which placed too much emphasis on a couple of tows which happened to capture a disproportionately high numbere of fish, there isn't much scientific support for the notion that there was a significant increase of cod over a broad area. Increases in abundance on some local grounds, yes.

    Which is why its disingenuous to blame catch shares. Yes, the big boats did hit the inshore grounds pretty hard, and out-competed less efficient operations, but the overall number of fish caught was constrained by their quotas. In fact, if I recall correctly, the overall cod quota wasn't landed in recent years.

    New England fishermen need to wake up to the reality that they have been killing too many fish. But I have little reason to believe that they will voluntarily change their ways. Even now, with the Gulf of Maine stock collapsed, we see the New England Fishery Management Council still adopting the least risk-averse measures; after NMFS recommended a 200 mt quota for 2015, the Council instead adopted a quota nearly twice that--if I recall correctly, 386 mt--which was the most that could be legally caught.

    That sort of management is why the cod are gone, and until fishermen admit that they are the biggest part of the problem, things are only going to get worse.

  3. Spoken like someone who is on the outside looking in. Let me ask you a you think fishermen are making decisions for themselves? Are you under the impression that a fishermen just gets in his/her boat and goes fishing? I have no peer reviewed data...thank god. I don't think the peers have a very good track record as of late. As far as stock assessments are concerned, they have never and will never be accurate. If you'll remember the 'peers' were falling over themselves to celebrate the end of overfishing in 2011...Now since you have been paying close attention, why don't you tell me what has happened since.
    the idea that it is disingenuous to blame catch shares, but the problem is over-fishing is an oxymoron. Take away daily limits, rolling closures and base-line leasing restrictions and then claim that you have stopped overfishing (which is what the catch-share junkies have done)? Desk jockies selling numbers on paper. Tell me I'm wrong? They are all of a sudden re-instituting rolling closures and daily limits.
    Stop taking the easy way out. Because in a few short years the fleet has been reduced by a huge percentage and things have just gotten worse because of catch shares.

  4. The single most important tool to end overfishing and rebuild stocks is exactly the one that the New England Fishery Management Council worked so hard to avoid for so many years. Hard quotas. Catch the annual quota, and you tie the boats up to the dock. It is the tool that the Mid-Atlantic Fishery Management Council used to rebuild summer flounder, black sea bass and scup--and please don't tell me that I'm looking in when it comes to those fish, because I held a Council seat at the time. If fishermen had been responsible, and the New England Council did what was required to end overfishing and rebuild the stocks, catch shares would never have been imposed; doing so was a desperation measure. Keep harvest low enough to allow rebuilding, and it doesn't matter whether the quota is caught by a dozen boats taking big trips or fifty boats landing smaller numbers of fish. It's the total dead that matters. Eliminating closures was a mistake (yet the Council is still talking about opening up areas). The trip limit is to keep people from directing on cod, but will probably lead to a lot of regulatory discards. That's not going to fix the problem.

    Data and good assessments will. They may not be perfect, but they're better than what went before. What happened in 2011? Folks were too eager to show progress, and didn't question two tows that fortuitously captured far more cod than any of the other tows in the series. So instead of questioning what seemed to be outliers, they included them into the model and came up with a bad result, which made the stock look healthier than it was. Essentially, they acted like fishermen instead of scientists, and assumed that fish were abundant just because they happened to catch a lot of them in one place. Once that error was corrected last year, the unpleasant reality emerged.

  5. Hilarious to me how petrified all the know-it-alls are to get a little egg on their face. " If fishermen had been responsible" Oh...I had no idea you were on the must be so proud of all the great things you've accomplished. The 'total number dead' is what matters? Wrong. Without daily limits, the fish were targeted when they were the most vulnerable. Massive spawning schools were wiped out by the offshore fleet. To stop the hemorrhaging the catch share junkies cut the tac...but what good is catching 70% less of a stock that's at 30%?
    fishermen are directed by management. We fish when we are told, how we are told and what we are told to fish for. The fact that the hand outs (quota) was based on years that the fish were in dire straights, therefore rewarding the guys that still hammered the troubled stocks is a whole different conversation. And, unless your council seat happened to be on a boat, you are just regurgitating to someone who watched the whole thing transpire first hand. So while you might think that 'data' is teaching the managers about protecting the stocks, it does not. It clearly leads to an economic disaster for the industry and a crash in stocks. And who will rebuild? who's going to be left to harvest when things come back? It's not going to be the little family fisherman with the small environmental footprint. It's going to be your 'dozen boats making big trips'.
    Those dozen boats leasing all of the quota from the little guys that were run out is much worse than some cod discard. Remember, the discard numbers are based on the idea that all those fish go over dead...which is ridiculous. We'll just let the tagging program prove that. guys would naturally try to avoid discards to avoid unnecessary effort...vs. guys benefiting from loading up.

  6. Yes, I'm proud of what I the Mid-Atlantic Council did when I was there. Despite a lot of resistance, it made the hard decisions necessary to restore summer flounder, scup and black sea bass. Thanks to the positions taken and management approach taken at that time, the Mid-Atlantic currently presides over no overfished stocks, and none are subject to overfishing. It's a pretty big contrast to what we see in New England, where hard choices were generally avoided and fish stocks suffered as a result.

    If you're objecting to fish being targeted on important spawning grounds, I'm not going to disagree with you about that, but catch shares aren't to blame. Those grounds should be places off-limits ton fishing with any gear that could interact with cod, as some grounds already are. Doesn't matter to a cod whether the boat that kills it is large or small; having the quota landed by a smaller number of larger boats likely reduces dead discards substantially and leads to less overall mortality in the end.

    And it's a little disingenuous to try to defend bad practices in the fleet by arguing that fishermen are directed by management. Who writes the management plan? The New England Fishery Management Council. And who holds most of the seats on the Council? Fishermen. And those fishermen have historically adopted the riskiest measures available to them in order to maximize short-term income. Restrictions contained in Magnuson rein them in a little, and the regional office could and sometimes does reject portions of management plans, but the excesses that have historically plagued the groundfish stocks can be traced directly to the Council, made up primarily of people with a financial interest in the fishery, mismanaging the resource.

    In many ways, this discussion is a microcosm of what has plagued New England all along--folks who have no peer-reviewed data, stock assessments, etc. trying to manage a fishery by the seats of their pants, always more concerned with the immediate health of the fleet rather than the long-term health of the resource. The result is out there for all to see in the form of depleted stocks, but still they insist on arguing that the data is bad and fishermen know best. Yet the state of the stocks make it clear that's not true.