While the die-off probably wasn’t that significant, there are larger forces at work
Photos of large quantities of dead stripers began to circulate around the internet mid-week last week. Yes, it was pretty disturbing. While there is no definitive estimate, certainly the number of expired fish was well over a thousand. The die-off occurred in central CT in the Blackhall River, a tributary of the Connecticut River in Old Lyme.
Why did it happen? Well, right off the bat it was pretty obvious… to me anyway. It just got really freak’n cold, really freak’n quickly. If you want to get technical it was “cold shock”, according to Dave Simpson of the CT Dept. of Energy and Environmental Protection, which results in a “cascade of physiological and behavioral responses and, in some cases, death”. Completely understandable, because I’m pretty sure I went through cold shock as well last week, although fortunately it didn’t kill me.
According to Simpson, the die-off was likely the result of fish getting caught by solid ice and shallow depths due to the sudden temp drop and a new moon that caused exceptionally low tides. Apparently striped bass aren’t as resilient as the killies, white perch and other fish that live in that part of the river during this time of the year. I can tell you first hand, you can put killies in a toilet bowl and they will survive. But moving on, yeah, certainly there have been other documented cases of striped bass die-offs due to cold-shock in the past, in fact there was a smaller scale one in the same area just last year.
Such die-offs certainly aren’t good, given the declining striped bass stock, especially since the great majority of those fish were dinks. In other words they hadn’t yet had a chance to reproduce. But given the vastness of the coastal striped bass stock, it certainly wasn’t catastrophic. During the season, we kill thousands of schoolies weekly in the Chesapeake Bay and upper Hudson River (remember that “producer areas” have an 18” size limit), and of course there is the release mortality along the rest of the coast. The reality is that, at least theoretically, “cold shock” deaths and similar events are included in the stock assessment under a “natural mortality” value M (note: there was some discussion on social media about whether or not managers took into account such events. The answer is of course yes, but not as the events occur, just overall in this M value.) But I can’t help but believe the recent occurrences (there were reportedly some bass die-offs in Massachusetts as well) are a precursor of things to come, as climate change disrupts historical weather patterns and makes long-term weather forecasting a far more difficult task. Certainly these crazy temperature changes aren’t “normal”.
I’ll admit that way-back-when, when I first started hearing about global warming I was stoked. I don’t really like cold weather. For one, every time I ski, I break something. And while there is a certain charm to pulling yellow-perch out of a hole in the ice, or putting on a 5/4 wetsuit, or making a roaring fire, I do prefer the alternative. Yet every time I spend more than a few days in Florida or Southern California, I kinda want to leave. In other words, I’m a New Yorker through and though. The point is that if things were going to warm up, and I didn’t have to suffer though freezing-ass winters, or the terribly “slow” people in the south, it would be a good thing!
Unfortunately, it hasn’t worked out that way. The science is pretty clear these days that “global warming” or more aptly “climate change” has been more about extreme weather patterns than warmer winters. Global warming has had and likely will continue to have cascading effects on climate patterns which have resulted in extremes on either end. As I’m writing this, it’s 45-degrees out. Last week on this day it was 6-degrees. And last week we had a 30-degree temperature drop in just a few hours! If that doesn’t say extreme weather patterns I don’t know what does. And of course, you’d have to have been living on the moon to not have noticed all the storms, flooding and extreme tides we’ve been having.
I suspect none of this is really news to readers. However, what is becoming increasingly obvious is its effect on fisheries. Not just in this isolated case but everywhere. I’ve written about recent science here and elsewhere indicating that shifting climate is a likely causing all of these poor striped bass young of the year indices in the Chesapeake. Of course it isn’t just stripers. The glaring example is cod in New England. I’m not going to claim for a minute that overfishing wasn’t responsible there, but climate change is almost unquestionably a contributing factor as the Gulf of Maine temps have shown a historical increase of 3 to 5-degrees. It is not unreasonable to speculate that such a temp change would change/weaken the GOM ecosystem. Yes, large-scale fishing on that weakened stock probably pushed it over the edge. That fishery has pretty much collapsed, and is taking local fishing communities down with it. With new far stricter regulations on groundfish, assuming they stay in place long enough to make a difference, it may get better one day, but it will likely never be the fishery it used to be.
Herring and mackerel have reportedly moved north. There really isn’t a winter party boat fishery for them anymore (although some would argue that large scale fishing on them is the culprit). In my neck of the woods, spot and croaker are regular baits now. Black drum are a new occurrence here also. And I’m not sure what’s going on with all these cow-nosed rays, but I’ve never seen so many. Being that I’ve spent two decades here, much of that on the water, I feel like I can say with some authority that things are definitely changing rapidly. Fishermen are perhaps the most attuned to such changes. Even the staunches conservative/tea-party fishermen I know believe in and understand climate change. Rarely will you find a real fishermen who is a “global-warming-denier”.
So yes, ecosystem dynamics are shifting. The result is that not only are fish moving, there are increased stressors, which have been and likely will lead to increased natural mortality (M). This is pretty well recognized by managers, and one would think that if this is the case, managers would adjust. While there is some movement to that effect, they have yet to fully adjust to the changing conditions (at least on the East Coast). Because, well, for one, the system moves as slow as molasses. And such ecosystem management, as opposed the current single-species model, is extremely complicated. Yes, plans are being developed, and some Councils are way ahead of the game, especially on the other coast, but it sure as hell isn’t happening quickly. Our Council has been working on an Ecosystem “Guidance Document” for a couple of years. It should provide useful information/direction, but it is just that, a “guidance” document. In other words it won’t require us to do anything. And, well, history has been pretty clear that unless there’s a legal mandate, it usually doesn’t happen, particularly when the result would be politically unpopular catch reductions. But I suppose we shall see.
I admittedly tend to over simplify things, likely because I’m not near as smart as the pointy-heads who work on this stuff daily. But it would seem pretty darn reasonable to adjust natural mortality (M) values in the models based not only on the proven stressors involved in climate change but the suspected ones. I mean for Christ sake, given the obvious shifts why aren’t we proceeding with caution? Well, I suppose I know the answer to that. Because of course natural mortality vs. fishing mortality equals total mortality we would likely need to reduce the later, and as mentioned, that is never politically popular.
Circling back to striped bass and last week’s die-off. Is it another nail in the coffin of the striped bass stock? Probably not. We’re doing that pretty well on our own, without such die-offs. That said, we are indeed likely to see an increase in such events, and there will likely be other natural stressors on the striped bass stock resulting from such extreme weather patterns moving forward. Not just die-offs but a continued increase in natural mortality due to climate change, and other factors beyond or control. It would be nice if managers would try and take this into account, by adding precautionary buffers etc. Maybe they will… One day. But we certainly aren’t there yet.