Impact of oyster over harvesting on condition of fish in Calcasieu Estuary

[MathGeek]

We've managed to complete a draft of the paper. It still has some revising to go, but it seemed like a good time to offer to email a copy to interested parties here who are willing to give the paper a read and email feedback to us.

If you would like a copy of the paper to read, send me a PM, including your real name and your email address. Please understand that we do not want the paper distributed beyond those we email it to directly, because we do not yet have approval for public release, and the paper is still in the revision process. Also please understand that we would prefer comments on the draft stage to be emailed privately rather than discussed in a public forum. Public discussion will be appropriate after publication.

The abstract is below. Smalls, Duckbutter, and W, I am particularly interested in your feedback. Assistance that proves particularly useful will be recognized in the acknowledgements section if the party providing it agrees. Smalls, if you agree, we'll add you to the acknowledgements for helping out with the survey.

From 2009 to 2011 the Calcasieu Estuary of the Louisiana Gulf Coast was subject to heavy oyster harvesting pressure and stocks of the eastern oyster (Crassostrea virginica) were significantly reduced, especially on the east side of Calcasieu Lake. To study potential impact in fish, creel surveys were performed over three week periods in spring 2011 and 2012 at the Calcasieu estuary. Weights and lengths were measured for red drum (Sciaenops ocellatus), spotted seatrout (Cynoscion nebulosus), black drum (Pogonias cromis), and gafftopsail catfish (Bagre marinus). Relative condition factors were calculated relative to expected weights for each species. A normal relative condition factor is 1.00. In each species, the relative condition factor was significantly below 1.00 for both years, and the condition factors tend to be lower in 2012 than in 2011. Furthermore, the more strongly benthic feeding species, black drum and the gafftopsail catfish, show the lowest relative condition factors. Though there are other possible contributors to the decrease in relative condition factors reported here, consideration of possible contributing factors and the fact that benthic species are most strongly affected suggests that increased harvest pressure on oysters is likely a strong contributor to the decrease in relative condition factor.

[Gottogo49]

Cool, can you also do a study on the effect on closing off the marsh on the East side of the lake. I know it was done to protect the marsh but wouldn't wind levees also help. How does Sabine Lake compare to Calcasieu in terms of oystering and marsh blocking/erosion? Not trying to high jack your thread or disapprove of your study at all. Just some quick thoughts. Thanks for all the good work on your paper.

[MathGeek]

Originally Posted by Gottogo49

Cool, can you also do a study on the effect on closing off the marsh on the East side of the lake. I know it was done to protect the marsh but wouldn't wind levees also help. How does Sabine Lake compare to Calcasieu in terms of oystering and marsh blocking/erosion? Not trying to high jack your thread or disapprove of your study at all. Just some quick thoughts. Thanks for all the good work on your paper.

Sabine has a lot more oysters, since TX hasn't allowed oystering in a long time, and LA has not been open to oystering in several years either. I'd have to double check, but if I recall correctly, I don't think Sabine has near the "marsh blocking" infrastructure (weirs and levees) as Calcasieu.

Studying the hypothetical negative impacts of the weirs on the fish in Calcasieu is a tough experiment. One could measure the fatness of the redfish on the lake side and on the marsh side, say on the same two days of the month for a number of months. But even if one found that the redfish on the marsh side were, say 15% fatter (on average), one could conclude that there is more food per redfish on the marsh side, but estimating how much fatter the fish on the lake side would be if the food in the marsh were available to all the fish in the lake would be challenging.

Everyone seems to agree that closing the weirs is giving up some short term productivity in the lake to retain the long term productivity of the marsh, which can then be accessed from the lake when the tides and salinity allow the weirs to be open.

If I really wanted to access the productivity of the marsh behind the weirs, I think I'd look into the legality of carrying a kayak or canoe back there: boat to weir, carry canoe over to marsh side, catch the fish. On the other hand, I don't think I'd work that hard. Calcasieu is at some risk of decline if the marsh and the oysters are not taken care of, but it is still one of the top ten fishing places on earth.

[Smalls]

Originally Posted by MathGeek

Sabine has a lot more oysters, since TX hasn't allowed oystering in a long time, and LA has not been open to oystering in several years either. I'd have to double check, but if I recall correctly, I don't think Sabine has near the "marsh blocking" infrastructure (weirs and levees) as Calcasieu.

Last I checked, Sabine does not have as deep a channel as the Calcasieu does, so salinities are not as big an issue there as they are here. I believe to a certain extent that there is still a pretty good natural salinity barrier there. I would have to check that to be sure, though. Either way, the calcasieu ship channel has been dredged since the 40s. Seventy years of dredging and saltwater intrusion requires some form of man-made blockage. Whether it was the best method at the time, is debatable. This was the 80s though. They didn't know the things we know now. There are some reports out there, I would have to pull them up, that show the sabine-calcasieu watershed has some of the highest land loss rates in the coastal zone. Ill have to pull that report and post some figures from it.

Anyway, sorry for hijacking again, MG. Just trying to add to the discussion a little bit. This has actually given me an idea for the future though. May have to run it by you, see what you think of it.

Sent from my SAMSUNG-SGH-I847 using Tapatalk 2

[MathGeek]

Originally Posted by Smalls

Last I checked, Sabine does not have as deep a channel as the Calcasieu does, so salinities are not as big an issue there as they are here. I believe to a certain extent that there is still a pretty good natural salinity barrier there. I would have to check that to be sure, though. Either way, the calcasieu ship channel has been dredged since the 40s. Seventy years of dredging and saltwater intrusion requires some form of man-made blockage. Whether it was the best method at the time, is debatable. This was the 80s though. They didn't know the things we know now. There are some reports out there, I would have to pull them up, that show the sabine-calcasieu watershed has some of the highest land loss rates in the coastal zone. Ill have to pull that report and post some figures from it.

Anyway, sorry for hijacking again, MG. Just trying to add to the discussion a little bit. This has actually given me an idea for the future though. May have to run it by you, see what you think of it.

I don't see any hijack. There is a discussion in our paper about whether our observations of reduced fish condition is more likely due to oyster reductions or saltwater intrusion and/or weir management. We think the evidence points more to oyster reductions, but it is not definitive. A lot of shallow channels can also lead to saltwater intrusion like has occurred to the (formerly) brackish marshes surrounding Terrebonbe Bay. Fortunately, neither Sabine nor Calcasieu has all those shallow channels leading to higher salinity open water. I've seen the reports on the land loss on the Sabine and Calcasieu basins, as well as the conversion of brackish to salt marsh.

So by all means continue contributing to the discussion.

[Gottogo49]

Thanks for your insights.

[CajunSteelsetter]

Say smalls, when did you start working on cool projects like this?? You know you got some cheap labor around here if you need someone to go tromp through da marsh and take some measurements yeah? As long as I get some street cred. lol

On a serious note, it does seem like an extremely interesting study. I believe we both know some mutual acquaintances that would be very interested in this data as well.

[Smalls]

Oh I agree on the Channels, MG. Have that same issue in the Vermilion Bay area. There are a lot of oil and gas exploration canals in that area. We have some in this part of the world, but more around the Rockefeller Area.

However, I think you are spot on with attributing it to oyster reduction and not saltwater intrusion. The main species affected in the study were Black Drum and Gafftopsail Catfish, if I remember correctly. Those are two species you don't see often in the marshes, which are the main places you see the effect of saltwater intrusion, especially the east side marshes. That is why the wiers were constructed in the first place, because of the saltwater intrusion into that marsh, which degraded several tens of thousands of acres. That degradation of marsh actually did lead to an increase in shrimp and crab production, because these species feed on dying marsh. This is what led to the increased harvest numbers a lot of people here have referred to in the 80s and early 90s.

Would it be right to contribute the decreased body size of Trout and Red Drum to the wier management? Possibly, although I do not know the figures for how many days the wiers were opened or closed for the past decade, I do know there was some damage done to them during the storms that led to them remaining open for some time. Only this year did they return to the original operating plan outlined in the late 80s. So the jury is still out on that, in my opinion. You have to look at it from a Holistic management point of view. An estuary is much more than a marsh or a lake.

[Smalls]

Let me add a little to my last post. Was rushed and had to post it or lose the whole thing.

Estuaries require a holistic management approach. This means that you can't just manage part of it, you have to manage all of it. This is true of any natural resource, but especially in estuaries because there are multiple parts to the system. You have a lake, surrounding marsh, and a freshwater input. The problem we have in calcasieu lake is, first and foremost, a heavily altered estuary. The ship channel has been dredged since the 40s (maybe earlier, can't remember). The calcasieu river has had the saltwater barrier for a long time (pretty bad if you have to have a saltwater barrier that far up a system; that's how bad things are), so you don't have the freshwater input that you normally would because you have so much saltwater pushing up the system. You have the wiers and levees that (to a certain extent) cut off the marsh from the lake. They are not completely cut off though. So a degraded system.

Then you've got the actual resources. Everyone has issues with how the fishery is managed (wier management, creel limits, etc.) and why the wiers are operated the way they are. As i've stated time and time again on these boards, you cannot look at the wiers as simply being a salinity control structure. They control salinity in order to preserve the marsh. The marsh is preserved for several reasons. Marshes provide several benefits. As far as the general population is (or should be concerned), they provide storm protection. For the sportsmen, its a haven for wildlife and fisheries. In the case of marshes associated with a rich (but degraded) estuary such as Calcasieu Lake, it is the lifeblood of the lake as far as fisheries are concerned. The marshes serve as the nursery for crabs, shrimp, and fish.

So if you don't control the salinities, and water levels as we have seen this year, you lose marsh. If you lose marsh, you lose the nursery and thus the resource.

I know there are a lot of people that will say we had a great resource and great harvests before the wiers and then they dropped off. As I stated in my last post, that is because the marsh was dying. Shrimp and crabs feed on detritus. So an increased population of crustaceans was most likely due to the death of the marsh. It may impact the harvests short term, but long term, it will be beneficial to the system.

A bit repetitive as I have said these things before, but I felt it needed to be in one place.

[Gottogo49]

Great discussion, I am not a biologist but I have fished Calcasieu for about 50 years. Personally, I have not seen a large deterioration of the Calcasieu lake shore line. Some losses for sure - I used to duck hunt on the island in Turners. There is a rock wall underwater near Deatonville where the lake shore used to be. I don't see the losses in the marshes because they are mostly private and I don't have access to them. What concerns me some is that Calcasieu used to be a shrimp producing machine. Opening day of shrimp season was a crazy event. All the boat launches were overflowing, boats were everywhere, it was hard to drag without dodging someone else. I really don't want to see that again but what happened to all the shrimp? Back in those days there were no weirs. It wasn't just a one year event. The lake survived many years without weirs. Some years were better than others but there were a lot more shrimp in the lake back then. Just my observations. It may be just a coincidence that shrimping deteriorated about the time that the weirs were installed. This may all be a mute point if they put a salt water barrier in the ship channel at Cameron like one option that is proposed. Just my opinion, opinions are like AHs, everyone has one and mine is more important to me than it is to anyone else. HaHa!

[Smalls]

Let me clarify what I meant by degrading. I didn't necessarily mean shorelines eroding away. I meant the general health of the system. Go back far enough (late 19th century, early 20th century, before the ship channel was dredged) and this is a completely different ecosystem compared to what it was naturally. Turner's Bay, Prien Lake, and Lake Charles all had Cypress in them. They were freshwater swamps. Calcasieu Lake was a thriving estuary that was probably brackish at best, maybe salt at different periods.

Then the calcasieu river was straightened and dredged deeper, allowing more saltwater into the system. Now you've got a saltier system, who's major freshwater input is not nearly as effective anymore.

So by deteriorated or degraded, I mean health, the salinities. The marsh has greatly changed. Back in first half of the century, the marshes were predominately fresh and intermediate on the east side of lake. Think cutgrass, bulrush, sedges, lilies in the deeper areas. Similar to what the northeast part of the Cameron-Creole is now, if anyone is familiar with that area or lacassine for something many are familiar with. Much of the marsh in this part of the state was that way. Add the saltwater super highway that is the ship channel, and salinity, and likely water levels (although probably not significantly), increased. Freshwater plants are poor tolerators of salt, and died off from the stress. This was over time now.

With a dying marsh, you get detritus (dead biotic material). This is what shrimp and crabs feed on. The more you have, the more shrimp and crabs you will produce. Simple enough, right?

So this would most likely explain the better than average shrimp and crab harvests before the wiers. Once the wiers and levees were constructed, it cut off a lot of that ingress and egress out of the marsh, but has saved that marsh from dying off. Sure, the marsh was able to transition from fresh and intermediate communities to brackish and saltmarsh species, but if it hadn't, Big Lake would be Giant Lake. That marsh would be open water.

So my hypothesis would be that the decrease you saw is due to a change in what was happening in that marsh. It could be due to a lot of other factors, something MG has pointed out with his study with oysters and body index.

As far as a saltwater barrier, we may get to see, at least somewhat, what this system was like before 1900.

Some will say salinity is not a big issue. Me being a vegetation guy, I say it is, especially dealing with fresh and intermediate wetlands.

P.S., I know i'm a little long winded, my appologies for that.

[PaulMyers]

Mr Smalls and MathGeek, first off I want to thank each of you for the insite you bring to this discussion.

I have always thought that the most of the people that remember the "good old days" just weren't looking far enough back. The river used to run through Calcasieu Lake before the ship channel was cut. Also the fact that the ship channel hasn't always been dredged to 42', in the early days it was much shallower.

If the Salt Water Barrier in Westlake would have been built at the mouth of the Calcasieu River none of these conversations would be taking place at all.

I can remember when I was young there were fresh water marshes south of the Salt Water Barrier. We.used to catch bass, brim and white perch behind our camp on the river at the end of Bagdad Rd in Westlake. In the front of the camp we could sometimes catch specks, reds and flounder the same day we caught the freshwater fish in the back.

[Smalls]

Originally Posted by PaulMyers

Mr Smalls and MathGeek, first off I want to thank each of you for the insite you bring to this discussion.

I have always thought that the most of the people that remember the "good old days" just weren't looking far enough back. The river used to run through Calcasieu Lake before the ship channel was cut. Also the fact that the ship channel hasn't always been dredged to 42', in the early days it was much shallower.

If the Salt Water Barrier in Westlake would have been built at the mouth of the Calcasieu River none of these conversations would be taking place at all.

I can remember when I was young there were fresh water marshes south of the Salt Water Barrier. We.used to catch bass, brim and white perch behind our camp on the river at the end of Bagdad Rd in Westlake. In the front of the camp we could sometimes catch specks, reds and flounder the same day we caught the freshwater fish in the back.

Thanks for pointing those things out Paul. It really shows some of the changes that have occurred in a short period of time. And I agree with you on the barrier position
If it was at the mouth, things would be a lot different today.

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[mstulb]

I completely agree that the shrimp population has decreased noticably over the past few decades. Testominals from Shrimpers I have met in Hackberry and Cameron and my own observation have led me to this conclusion. Not only a decrease in the amt of shrimp but small baitfish also. Cant prove that the instalation of the wiers was the cause but....

This theory was somewhat proved when Rita hit us in SW LA blowing a giant hole in the corner of the lake allowing a natural in-flow & out-flow of bait and shrimp. The birds were working in the lake chasing shrimp almost year round and we had one of the best fall/ winters on shear #' of large sow trout. Not necesarily best for size for sheer numbers. You could probably ask any guide on the lake what the lake looking like months after Rita. The lake absolutely Full of schooling trout.








QUOTE=Gottogo49;494785]Great discussion, I am not a biologist but I have






fished Calcasieu for about 50 years. Personally, I have not seen a large deterioration of the Calcasieu lake shore line. Some losses for sure - I used to duck hunt on the island in Turners. There is a rock wall underwater near Deatonville where the lake shore used to be. I don't see the losses in the marshes because they are mostly private and I don't have access to them. What concerns me some is that Calcasieu used to be a shrimp producing machine. Opening day of shrimp season was a crazy event. All the boat launches were overflowing, boats were everywhere, it was hard to drag without dodging someone else. I really don't want to see that again but what happened to all the shrimp? Back in those days there were no weirs. It wasn't just a one year event. The lake survived many years without weirs. Some years were better than others but there were a lot more shrimp in the lake back then. Just my observations. It may be just a coincidence that shrimping deteriorated about the time that the weirs were installed. This may all be a mute point if they put a salt water barrier in the ship channel at Cameron like one option that is proposed. Just my opinion, opinions are like AHs, everyone has one and mine is more important to me than it is to anyone else. HaHa![/QUOTE]

[Ray]

There is a ship channel in the Sabine. It is just as deep as the one here.
They have more fresh water, cause the Sabine, Neches and ICW run down to the Gulf from there. Lot more fresh water from East Texas.

There is a lot of erosion along the banks of Big Lake. The island is gone in front of Grand Bayou. At one time, you could not go straight into it.
Also, the marshes are probably 70% gone behind the levee. If it wasn't for the levee, it would be a lot worse. There are huge ponds back there that were once small ponds.
Oilfield canals don't help either.
Boudreaux Lake used to be about 20 acres. It is now about 300 acres in size.
The ponds in the reserve have gotten 10 times bigger in the past 30 years.
They built that levee around the lake a long time ago, but didn't put the weirs up. That helped, but it just slowed the erosion down.
Cameron Parish can disappear, or we can have more shrimp. Cameron Parish is hurricane protection for Calcasieu Parish. No Cameron Parish, no Calcasieu Parish.
I remember when the lake was a lot deeper. On opening weekend of Shrimp season, the lake was full. Texas boats, big ones came into Big Lake the first week, then went back to Texas when their waters opened up.
There was also green grass at the mouths of Grand and Lambert. When we pulled out nets up, we would shake the grass and the Shrimp would fall out on to the culling board.
There is a big lake behind Tboys weirs, where a great marsh used to be.

If you think Hurricane Rita busted the levee's, I got some good desert land to sell you in the middle of Big Lake.

[Smalls]

Originally Posted by Ray

There is a ship channel in the Sabine. It is just as deep as the one here.
They have more fresh water, cause the Sabine, Neches and ICW run down to the Gulf from there. Lot more fresh water from East Texas.

There is a lot of erosion along the banks of Big Lake. The island is gone in front of Grand Bayou. At one time, you could not go straight into it.
Also, the marshes are probably 70% gone behind the levee. If it wasn't for the levee, it would be a lot worse. There are huge ponds back there that were once small ponds.
Oilfield canals don't help either.
Boudreaux Lake used to be about 20 acres. It is now about 300 acres in size.
The ponds in the reserve have gotten 10 times bigger in the past 30 years.
They built that levee around the lake a long time ago, but didn't put the weirs up. That helped, but it just slowed the erosion down.
Cameron Parish can disappear, or we can have more shrimp. Cameron Parish is hurricane protection for Calcasieu Parish. No Cameron Parish, no Calcasieu Parish.
I remember when the lake was a lot deeper. On opening weekend of Shrimp season, the lake was full. Texas boats, big ones came into Big Lake the first week, then went back to Texas when their waters opened up.
There was also green grass at the mouths of Grand and Lambert. When we pulled out nets up, we would shake the grass and the Shrimp would fall out on to the culling board.
There is a big lake behind Tboys weirs, where a great marsh used to be.

If you think Hurricane Rita busted the levee's, I got some good desert land to sell you in the middle of Big Lake.

x2

Most of what I said, but in shorter form. Thanks for the info on the Sabine though, I knew I had that somewhere, but wasn't sure of it. Actually just looked back on a report I have from 2003 i think. Stated that they had actually intended to extend (or deepen) the Sabine-Neche Ship Channel to Beaumont. Haven't looked that up, but did they actually do this?

Also, because of the intracoastal, the two basins are actually connected. Gum Cove ridge used to serve as a barrier between the two, but the intracoastal bisected that. Now their hydrologies are directly affected by one another. So I imagine there isn't much difference between the two, although since it has 2 major inflows as opposed to one, the Sabine probably trends somewhat fresher, as you said. So I can believe that.

[MathGeek]

Originally Posted by Smalls

x2

Most of what I said, but in shorter form. Thanks for the info on the Sabine though, I knew I had that somewhere, but wasn't sure of it. Actually just looked back on a report I have from 2003 i think. Stated that they had actually intended to extend (or deepen) the Sabine-Neche Ship Channel to Beaumont. Haven't looked that up, but did they actually do this?

Also, because of the intracoastal, the two basins are actually connected. Gum Cove ridge used to serve as a barrier between the two, but the intracoastal bisected that. Now their hydrologies are directly affected by one another. So I imagine there isn't much difference between the two, although since it has 2 major inflows as opposed to one, the Sabine probably trends somewhat fresher, as you said. So I can believe that.

A good document describing the hydrologies of the Sabine and Calcasieu basins is here: http://lacoast.gov/reports/static/HILCP_3.pdf

While I agree that the intracoastal waterway connected the two hydrologies, I disagree that they are the same. Here are some major differences:

1. The Sabine-Neches ship channel skirts around the west side of Sabine Lake and actually creates a much different salinity gradient in Sabine than in Calcasieu. There are many times when Sabine is actually has lower salinity in the middle of the lake than at the north end.

2. A lot more fresh water, and a more consistent supply of fresh water flows through Sabine. I doubt spotted sea trout catches regularly occur nearly as far north in the Sabine system as in the Calcasieu.

3. The pollution related water quality issues of each system are unique and dominated by the point and non-point sources local to each system. The intracoastal creates a much greater salinity exchange than it creates a pollution exchange. Most pollutants are heavier and more likely to get bound up with the mud in comparison with salt.

4. Over time, I expect the better protection of the oyster beds in Sabine will both improve water quality as well as improve fish habitat. Oysters remove nitrogen and phosphorus and filter feeding allows light to penetrate deeper into the water.

[Smalls]

Good points. And I owe you a big thank you for posting that document. Been trying to get my hands on that for my thesis. I have the first half of it, which covers the Mermentau Basin, but could not get my hands on this part of it which covers Sabine-Calcasieu.

[Gottogo49]

Thanks guys, good discussion. No one getting their dander up.

[redaddiction]

Originally Posted by Gottogo49

Thanks guys, good discussion. No one getting their dander up.

Thanks everyone for all the info.