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new theory on striper decline

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dogboy

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this morning on NPR's morning edition- a NOAA researcher posits the theory that the weather is the driving cause

 

the atlantic multi-decadal inversion (AMI)- or something like that

 

warm wet springs leading to healthy phytoplankton populations result a few years later in healthy striper numbers

 

this gradually changes to conditions less favorable to little critters, and after a lag, the striper numbers drop

 

we appear to be five years into a bust cycle right now

 

i did not catch how long the cycle needs to play out

 

all the more reason to outlaw catching them in nets and culling out the smaller (now dead) fish

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Atlantic Weather May Be Key Culprit In Fish Decline

 

 

by Christopher Joyce

 

 

January 25, 2011

 

 

During the 1980s, wildlife managers said striped bass like this one were overfished. Now, it appears that a weather pattern known as the Atlantic Multidecadal Oscillation may have been a contributing factor to the declines.

 

 

January 25, 2011

 

 

The striped bass is in trouble again.

 

 

During the 1980s, wildlife managers said these big, full-bodied fish - favorites of anglers along the East Coast - were overfished. So they laid down severe catch limits. The population recovered, and fishing resumed in what is considered one of conservation's great success stories.

 

 

But now catches are down again, and some biologists say the problem may not be overfishing this time: It could be the weather.

 

 

Nearly 70 percent of the country's striped bass come to the Chesapeake Bay to lay their eggs, including inlets like this one, where the Choptank and Tred Avon rivers meet.

 

 

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Maggie Starbard/NPR Nearly 70 percent of the country's striped bass come to the Chesapeake Bay to lay their eggs, including inlets like this one, where the Choptank and Tred Avon rivers meet.

 

 

Brad Burns, who started fishing for striped bass in 1960, says he and his fellow anglers, Stripers Forever, are singing the blues about striped bass.

 

 

"What we hear from people that go striped bass fishing - the general trend very decidedly is down," Burns says.

 

 

Stripers live in the ocean as well as in estuaries and some rivers. Burns says members have been reporting fewer fish for the past five years. As for the cause?

 

 

"Well I don't know," he says, "and I don't know that anybody does."

 

 

A New Theory On Fish Levels

 

 

But Bob Wood thinks he might. Wood is a biologist with the National Oceanic and Atmospheric Administration. He studies his fish in a boxy little building on the Maryland shore of the Chesapeake Bay. In the semi-darkness, you can make out several vats with bubbling oxygen hoses. Each vat is home to striped bass or white perch, two species that spawn in the bay. This is where Wood's team studies the fish to figure out why striper numbers go up and down.

 

 

They thought they had the 1980s crash figured out: "The striped bass crashed because of overfishing," says Wood, "and then it recovered because we closed the fishery."

 

 

But now Wood has a new idea that's just taking shape. "This research, at first glance, seems to call that into question," he says.

 

 

This idea focuses not so much on fish but on the weather, and especially the Atlantic Multidecadal Oscillation, or the AMO. The AMO is a mashup of wind and ocean currents, a flip-flop that happens every 35 years or so in the North Atlantic.

 

 

Bob Wood (left) and Ed Martino are researchers at NOAA's Cooperative Oxford Laboratory in Oxford, Md. They think a weather pattern in the North Atlantic called the Atlantic Multidecadal Oscillation is responsible for wide swings in fish populations.

 

 

"Circulation changes in a way that warms the entire basin," Wood explains. "And you can imagine if you warm the entire North Atlantic basin, you're changing the weather because the air and circulation patterns above the ocean are affected."

 

 

Ed Martino, a fisheries scientist who works with Wood at NOAA, says when the AMO shift happens, it affects the local weather along the Atlantic Coast.

 

 

"You are talking about differences in temperature and precipitation, and therefore river flow or salinity, ultimately all affecting the base of the food chain," says Martino. "It's the way that the climate affects the microscopic plankton." Plankton are tiny plants and animals in the water, and that's what young stripers eat.

 

 

Understanding The Weather-Fish Relationship

 

 

Here's how Wood and his team think the AMO is messing with fish food. When it's in a warm phase, springtime along the East Coast actually tends to be wet and cool - more rain, more water, more food. In the years following that phase, striper numbers tend to go up. Then the AMO flips - drier springs, less rain, less food. After a lag, it looks like striper numbers start to decline.

 

 

Wood says the past 100 years of fishing records show that very trend. And currently?

 

 

"It hasn't been so good in say the last five years," Wood says. "And it just so happens this is also the time when the Atlantic Multidecadal Oscillation seems to be switching phase."

 

 

Wood suspects it's switching into a "bad for stripers" phase, and he thinks it was also a down cycle that caused the striper crash in the 1980s. When that cycle ended, stripers recovered - not just owing to the fishing limits but because the weather bcame more favorable.

 

 

Janet Nye, who studies fish stocks for the Environmental Protection Agency, thinks this research could help fisheries managers.

 

 

"We would be able to say, 'OK, for the next 35 years or so we're pretty certain that the AMO is going to be more positive or warm,' and we would be able to say, 'These are the fish that respond favorably to that - you might be able to fish those more,' " she says.

 

 

Conversely, fish less in a down cycle, Wood says. "If we know that there is this cycle coming up," he says, "a trend that we are beginning to enter, we can keep that in our heads as we set limits."

 

 

If Wood's research is correct, it may take tougher catch limits to bring striper numbers back up again.

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Yet another contributing factor,

 

BUT NOT THE SMOKING GUN OR SOLE CAUSE !!!

 

Myriad factors are at play - bunker reduction fishery, farm run off in Ch. bay, disease, recreational fishing, commercial fishing, by-catch in the bunker and herring trawling fisheries, etc., etc., etc..

 

Step one - Stop killing spawning aged fish so they can make as many young as possible. cwm40.gif

Bait is for old men and little boys... real men plug.

 

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Does anyone know whether there are places in striper spawning regions where fish are captured for artificial rearing of fry for release? It seems in the Pacific Northwest that this is common and successful. I wonder if it is happening or would work for stripers?

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I don't think this is only due to over-fishing. Other factors are clearly at play. There seems to be a relatively large number of big fish around,but not smaller fish. Look at the quality of our water, changes in weather patterns, etc. There's a lot that we don't yet understand.

ASMFC - Destroying public resources and fisheries one stock at a time since 1942.

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Interesting theory. I found this chart of the Atlantic Multidecadal Oscillation.

 

It is interesting that the cooler period seems to align with the slow striper years in the 70's and 80's and the warmer ones with the rebound. Since we are still in the warm part of the cycle, it doesn't explain why the spawn rate in the Chesapeake has dropped so much in the past few years.

 

Whatever the contributing factors are, we should be taking steps now to leave as many breeding fish as possible out there.

525

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Same deal as the Pacific Decadel Oscillation in the Pacific - the sardine/anchovy cycles are the most pronounced and studied result. Supposedly the oscillation in the North Atlantic isn't as pronounced. There's a ton of stuff available - just use Google and you'll get buried in it.

 

As far as other "contributing" factors, that seems to be an open question at this point. Ref the sardines/anchovy cycling, both species are fairly quick growing, early maturing, plentiful and fecund that I don't think anyone knows if fishing on 'em during the down years makes much of a difference or not (as far as the subsequent "recovery" is concerned.

 

The NPR piece points out one of the biggest problems with our fishermen management system - that is passed off as a fisheries management system - that we have today. If all you've got is a hammer, you treat everything like it's a nail, and if all you can do is manage fishermen, by God you're gonna justify your professional existence by managing fishermen, whether it has an effect or not, and the hell with trying to find out otherwise.

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View Post

 

Step one - Stop killing spawning aged fish so they can make as many young as possible. cwm40.gif

 

 

maybe it is time for a slot limit like they have in Maine

 

daily bag limit is, i think, 2 fish- one under 26 inches and one over 42 inches

 

(lengths are approximate)

 

unless you catch the bigger one first, in which case you can't take the small one

 

or something like that anyway

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View PostI don't think this is only due to over-fishing. Other factors are clearly at play.

 

Fishing is the one we can control. Scratch that, fishing is the one we have a responsibility to control. When the other things are addressed, we can start fishing them harder, but right now, while they are being fished into oblivion, it's our responsibility to manage our direct impact by reducing fishing mortality across the board.

 

TimS

Show someone how to catch striped bass and they'll be ready to fish anywhere.
Show someone where to go striped bass fishing and you'll have a desperate report chaser with loose lips.

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View PostRef the sardines/anchovy cycling, both species are fairly quick growing, early maturing, plentiful and fecund that I don't think anyone knows if fishing on 'em during the down years makes much of a difference or not (as far as the subsequent "recovery" is concerned.

 

That makes them the polar opposite of striped bass Nils - they are slower growing, not nearly as fecund, later maturing and an apex inshore predator. They have exactly nothing in common with converter species like sardines/anchovies....other than they all have scales.

 

There aren't any apex predators that you can fish the **** out of while they are declining - it doesn't work that way. Sure, you can fish squid, sardines and anchovies - they are designed to be converters, they were built to be food. Plentiful, fecund, fast growing, mature quickly - that's bait. Striped bass are almost exactly the opposite - it's no secret what happens when you maintain crushing pressure on an apex predator in decline. We've done it before, we are doing it now, you'd think we'd have learned from the past.

 

TimS

Show someone how to catch striped bass and they'll be ready to fish anywhere.
Show someone where to go striped bass fishing and you'll have a desperate report chaser with loose lips.

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Although Im no expert on the issue, it seems like there's a multitude of factors in play. I think most of the comm guy's are as concerned as the rec's about striper mortality and managing the resource. There's unethical parties in both sectors of our fishing community. I don't understand why adjusting the catch limits/reg's is such a slow process. Every year we loose more of our beach access to a ridiculous little bird. What's their management plan? Is there one? It just seems like it's a complete hands off, "don't go near them" mentality. As rec's we should be screaming for a one fish limit per angler. I mean, can anyone pose an argument as to why your "family need's" 2 striper's a day? It's not even heathy to consume that much striper for pete's sake!

 

All in all, nothing will change if everyone along the atlantic coast isn't on the same page. The dragger in NC seems to be the hot topic solely because it happened in a highly visible spot. I previously didn't know what the law's were regarding dragging trawler's, but it inhibited a terrible waste of our resource. It took this to realize that system was ridiculous? Why weren't those commercial fisherman requesting a change when they saw how many "released" fish were belly up? I mean we can go on and on here, and to an even higher degree with the BFT. 1 fish at 28 until the stock's rebound again....just my opinion

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here on Long Island there is no doubt that stripers are over fished. when the regulations for fluke went up to 21.5 inches more people started fishing harder for stripers and I am not talking surf fisherman. this past summer there were huge pods of bunker just off the beaches with all big bass on them (20 plus lbs) you had to see the size of the fleet that was ambushing these bass these fish did not stand a chance people who normally would be fishing for fluke became instant striper experts with their snag hooks and keeping anything and everything.

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We don't know what effect reducing or eliminating fishing mortality is going to have in the face of any major ocean oscillation decline. It could be that no matter how much fishing effort is reduced, the normal striped bass haunts will be barren of striped bass until the cycle swings back in the other direction and the so-called recovery will proceed at the same rate regardless. That being the case, the only rational response would be to allow fishing unabated 'cause the fish are going to be gone anyway.

 

It could also be that a highly reduced resident population could be maintained and that resident population could hasten the recovery. In that case, reduce or stop fishing.

 

The problem is that we don't know. The bigger problem is that I doubt anyone is particularly interested in looking for the answers. It's the same with habitat degradation. Want more stripers? Fish less, and totally ignore the impact of those 40 million people living in the Chesapeake watershed. But does fishing less make a difference, or is the environment in its crippled state producing as many fish as it can regardless of how many are caught? We don't know and the guys in control of the purse strings - who have built careers on managing fishermen and not on managing fish - don't appear to be real anxious to find out.

 

The argument that we should manage fishermen because that's all we can manage doesn't make a lot of bottom line sense until/unless we know what the realative impact of fishing is.

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