Redfish and Specks Benefit from Limited Weir Closings

[T-TOP]

Originally Posted by MathGeek

There is a lot of truth here, in that the high salinities are the main problem in recovery of the oysters after the major overharvesting event on the E side in 2010.

Reducing salinity is one key issue to the future of the oyster reefs in the estuary.

But it was over harvesting rather than salinity that created the original problem back in 2010. Oyster harvesting was closed in most of the state due to the oil spill, and tremendous harvest pressure was concentrated on Big Lake.

Addressing the salinity issue will likely allow the oysters to return to historical levels.

But keeping harvests at a modest and sustainable level is also key to long term productivity of the system.

I think things are going in the right direction with the harvesting issues. Side note, LWF built a reef south of the old jetties that had never been harvested (15 acres) it basically died last year. No dredging had been done. I'm sure you have looked at the assessments the sample stations in the lake show zero oysters on them. It seems it would have to be the salinity levels stopping oysters from coming back not dredging. FYI i would like to see the oyster dredging stopped.

[MathGeek]

Originally Posted by T-TOP

I think things are going in the right direction with the harvesting issues. Side note, LWF built a reef south of the old jetties that had never been harvested (15 acres) it basically died last year.

Yes, salinity levels at the S end of the lake are high enough to cause a problem with no harvesting. The reefs at the N end of the lake are in better shape. Most of the LDWF sampling stations for the stock assessments are near the S end of the lake, because this is where most of the commercial harvesting occurs. There is a line running east-west near the middle of the lake N of which harvesting is closed even when the S end of the lake is open. Because the N end is closed to harvest, LDWF has less interest in rebuilding or assessing stocks in this area.

Originally Posted by T-TOP

No dredging had been done. I'm sure you have looked at the assessments the sample stations in the lake show zero oysters on them. It seems it would have to be the salinity levels stopping oysters from coming back not dredging. FYI i would like to see the oyster dredging stopped.

Right. Since there has been no dredging on the E side since 2010, dredging on the E side is not the current problem.

But note that LDWF is more interested in rebuilding reefs S of the line where oystering is allowed, rather than N of the line where reefs would be protected. Since salinity levels are lower the further N you go, it would make more sense to restore oysters N of the line. Restoring reefs S of the line in the higher salinity areas suggests that the purpose of reef restorations is focused on harvest, not habitat and ecosystem services. See the attached figure.

[MathGeek]

Originally Posted by BloodKnot

MG,
I am a pro-weir big lake guy. So I appreciate your thoughts and research.

Do you or anyone have an knowledge if the weirs affect the oysters any? Not sure if weirs being closed for a long period hurt the oysters, which would indirectly negatively affect the fish.

Just wanted to get your 2 cents on that.

That's a great idea worthy of consideration.

Other than overharvesting and dredging, the biggest enemies of oysters are the oyster drill, the black drum, and overly low and high salinities.

Is it possible that opening or closing the weirs somehow impacts (for better or worse) one of the key predators so that predation pressure is increased or decreased? Sure, but this is likely a second order effect that may vary depending on the time scale. For example, suppose opening the weirs pulls a lot of the drum off of the oyster reefs to feed at the weirs, thus reducing predation pressure. This is good in the short term, but could also have the effect of increasing the drum population in the longer term.

One big issue for the oysters at the S end of Big Lake (east side) is the additional stress from high salinities. The weirs may have a small effect here, but in the long run, improvement requires smaller coupling between the lake and the Gulf.

[Jrchip1]

Very Very Interesting !!!

[Jrchip1]

I will sum it up, as it's those who want "Immediate Gratification" , that often do long term damage. EXAMPLE.....disappearance of SE LA Coastline in order to maintain salinity levels. SE LA also raises cane at the suggestion that Diversions would be beneficial. Face it people....every wave takes some coastal mud with it, with nothing to replace it. Can't have your cake and eat it too. Need to adjust priorities....

For Example Atchafalaya Delta, Wax lake Outlet...both are low on Specs most of the time BUT...it is doable to catch them, just requires more effort. AND...that place is both gaining acreage, though much in the form of "Spoil Banks", and it is a Waterfowl Mecca.

["W"]

Oyster fisherman have the strongest hand on the lake by far

Almost untouchable


Don't understand how they control so much power with the state but they do. !

[slickfish]

Originally Posted by "W"

Oyster fisherman have the strongest hand on the lake by far

Almost untouchable


Don't understand how they control so much power with the state but they do. !

They provide a more important service to the surrounding areas than a part time fishing guide. Who do you think they are going to listen to duck?

["W"]

Originally Posted by slickfish

They provide a more important service to the surrounding areas than a part time fishing guide. Who do you think they are going to listen to duck?

Dude S T F U

How about to shove a stick of dynamite up your aZZ and light it !!

Tell your mom I said HI

[slickfish]

Originally Posted by "W"

Dude S T F U

How about to shove a stick of dynamite up your aZZ and light it !!

Tell your mom I said HI

I'll let you tell her yourself when we come down at the end of the month. I'll come find you.

["W"]

Originally Posted by slickfish

I'll let you tell her yourself when we come down at the end of the month. I'll come find you.

305 big lake rd 337 789 9002

No need to look ill go to you !!

Only coward like you talk s h it behind a screen name becaus your to yellow to face someone !! Your mom let's you play on the internet everyday !! Grow some balls and post your name and # ?!!

O wait cowards like you can't because your mom would be mad if she had to pay for you to be stitched up

[dmtfish]

Someone educate me here... Since when do oysters die in high salinities? Are the oysters in BL different from other gulf oysters?? The best oysters I have eaten came from old project areas where we collected data and the salinity was 25 ppt +. Its been my experience that high temps and low salinities are the cause for poor oyster production

["W"]

Originally Posted by dmtfish

Someone educate me here... Since when do oysters die in high salinities? Are the oysters in BL different from other gulf oysters?? The best oysters I have eaten came from old project areas where we collected data and the salinity was 25 ppt +. Its been my experience that high temps and low salinities are the cause for poor oyster production

Yea I agree I never heard that high salinity hurt oysters because west cove has always been thick and we have a few deep reefs in channel that are full of oysters

I think the problem we have on east side of ship channel and behind old jetties is settlement from dredging and erosion depositing on reefs and smothering them out . Crabbers have 2inchs of slit in traps some days along wash out and 9 mile

This this is more of our problem than salinity

[capt coonassty]

Originally Posted by dmtfish

Someone educate me here... Since when do oysters die in high salinities? Are the oysters in BL different from other gulf oysters?? The best oysters I have eaten came from old project areas where we collected data and the salinity was 25 ppt +. Its been my experience that high temps and low salinities are the cause for poor oyster production

"Crassostrea virginica appears to have a higher tolerance of salinity fluctuation than other oyster species (Berquist et al. 2006). The optimal salinity for growth and reproduction is 10 - 28 ppt (Wilson et al. 2005). Larvae will not settle and metamorphose into spat when salinity is less than 6 ppt (Wilson et al. 2005). Adult C. virginica can live in salinities up to 35 ppt (Buroker 1983)".

But one of the problems with higher salinity waters is predation. When salinity is higher oyster drills become more numerous and predation rates are higher.

[T-TOP]

Originally Posted by capt coonassty

"Crassostrea virginica appears to have a higher tolerance of salinity fluctuation than other oyster species (Berquist et al. 2006). The optimal salinity for growth and reproduction is 10 - 28 ppt (Wilson et al. 2005). Larvae will not settle and metamorphose into spat when salinity is less than 6 ppt (Wilson et al. 2005). Adult C. virginica can live in salinities up to 35 ppt (Buroker 1983)".

But one of the problems with higher salinity waters is predation. When salinity is higher oyster drills become more numerous and predation rates are higher.

I will add to this about high salinity levels.

Perkinsus marinus a parasite that causes Dermocystidium Marinum (also known as Derma)= this parasite kills oysters.

The critical environmental factors which favor the proliferation of the parasite are high
water temperatures and high salinities. Thus infections are more intense in the late summer, on
the seaward side of estuaries and during droughts.

Also when you control the salinity going in the lake the sediment will also be controlled it goes hand and hand really.

Most of this info that I post is in the oyster assessments that are on the LDWF website. Very informative for a person that is interested in these issues.

[dmtfish]

Originally Posted by T-TOP

I will add to this about high salinity levels.

Perkinsus marinus a parasite that causes Dermocystidium Marinum (also known as Derma)= this parasite kills oysters.

The critical environmental factors which favor the proliferation of the parasite are high
water temperatures and high salinities. Thus infections are more intense in the late summer, on
the seaward side of estuaries and during droughts.

Also when you control the salinity going in the lake the sediment will also be controlled it goes hand and hand really.

Most of this info that I post is in the oyster assessments that are on the LDWF website. Very informative for a person that is interested in these issues.

Thanks TTOP

[Duck Butter]

Originally Posted by T-TOP

I will add to this about high salinity levels.

Perkinsus marinus a parasite that causes Dermocystidium Marinum (also known as Derma)= this parasite kills oysters.

The critical environmental factors which favor the proliferation of the parasite are high
water temperatures and high salinities. Thus infections are more intense in the late summer, on
the seaward side of estuaries and during droughts.

Also when you control the salinity going in the lake the sediment will also be controlled it goes hand and hand really.

Most of this info that I post is in the oyster assessments that are on the LDWF website. Very informative for a person that is interested in these issues.

add to this and what capt coonassty said, there are a few oyster reef restoration projects (several miles of them) around the state that are showing the same thing. One at Vermilion Bay SW Pass are not growing oysters due to too much freshwater. At Grand Isle the water is too saline too long and they are getting hammered by drill snails. The project in St Bernard Parish though seems to be the perfect mix as they are growing oysters 'like gangbusters' per the manager

add: some of the reefs are enclosed so there is no predation from black drum to account for either

[MathGeek]

Originally Posted by T-TOP

I will add to this about high salinity levels.

Perkinsus marinus a parasite that causes Dermocystidium Marinum (also known as Derma)= this parasite kills oysters.

The critical environmental factors which favor the proliferation of the parasite are high
water temperatures and high salinities. Thus infections are more intense in the late summer, on
the seaward side of estuaries and during droughts.

Also when you control the salinity going in the lake the sediment will also be controlled it goes hand and hand really.

Most of this info that I post is in the oyster assessments that are on the LDWF website. Very informative for a person that is interested in these issues.

Right. It is not the high salinity that directly kills the oysters. It is this parasite and the oyster drills. But in practice, these issues are making it difficult to reestablish oyster reefs in higher salinity waters in Louisiana right now. Moving further inland (lower salinity) gives a higher probability of successful reef establishment

[Smalls]

Where's Michael Jackson and his popcorn when you need him?!?!

[BloodKnot]

Anger management class list: Ray Rice, Adrian Peterson, W,...

[Bobbynofish]

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