Oyster Overharvesting in Calcasieu Estuary in 2010- 2011: References needed

[MathGeek]

We've completed the data analysis from our creel survey data from 2011 and 2012 relating to the Calcasieu Estuary. The data and other background suggests that the dominant factor most likely responsible for the decline in the condition factor of fish and slow growth is the overharvesting of oysters from Calcasieu Lake in the 2010-2011 oystering season. We're writing up our results now and hope to have a draft ready to submit for publication in a few weeks.

We've found a number of relevant LDWF press releases and also the info and reports at the CCAL site and popular press, as well as a relevent LSU Master's Thesis by Steven Beck. The purpose of this post is to request pointers to additional references or study results regarding the overharvesting of oysters in Calcasieu Estuary at any time from 2005 to the present, but especially in 2010-2011. Certainly pointers to references related to other possible causal factors would be appreciated as well.

["W"]

Originally Posted by MathGeek

We've completed the data analysis from our creel survey data from 2011 and 2012 relating to the Calcasieu Estuary. The data and other background suggests that the dominant factor most likely responsible for the decline in the condition factor of fish and slow growth is the overharvesting of oysters from Calcasieu Lake in the 2010-2011 oystering season. We're writing up our results now and hope to have a draft ready to submit for publication in a few weeks.

We've found a number of relevant LDWF press releases and also the info and reports at the CCAL site and popular press, as well as a relevent LSU Master's Thesis by Steven Beck. The purpose of this post is to request pointers to additional references or study results regarding the overharvesting of oysters in Calcasieu Estuary at any time from 2005 to the present, but especially in 2010-2011. Certainly pointers to references related to other possible causal factors would be appreciated as well.

1st season they went to dregging it was over harvested

[Duck Butter]

It has been very difficult to get any actual data from LDWF especially since the oil spill, they have been issued a gag order from their attorneys. You can sometimes go to lsu.edu in the natural resources department and look at theses and dissertations under the students' major professor. They sometimes have them as a .pdf file under their profile. Sending you a PM

[MathGeek]

Originally Posted by "W"

1st season they went to dregging it was over harvested

My understanding is that dredging became legal in 2005. Certainly, dredging has a negative impact on the reef structure and benthos that make the reef their home. However, are you aware of any hard evidence or published assertions from reliable sources suggesting over-harvesting prior to 2011?

As much as I respect your opinion, I don't think I can cite "W at Salty Cajun said so" in a scholarly paper.

[MathGeek]

Originally Posted by Duck Butter

It has been very difficult to get any actual data from LDWF especially since the oil spill, they have been issued a gag order from their attorneys. You can sometimes go to lsu.edu in the natural resources department and look at theses and dissertations under the students' major professor. They sometimes have them as a .pdf file under their profile. Sending you a PM

LDWF has been very tight with the info. We've gotten a couple of letters in legalese from their attorneys in response to requests for info. Thanks for the hints and the PM.

[Duck Butter]

Originally Posted by MathGeek

My understanding is that dredging became legal in 2005. Certainly, dredging has a negative impact on the reef structure and benthos that make the reef their home. However, are you aware of any hard evidence or published assertions from reliable sources suggesting over-harvesting prior to 2011?

As much as I respect your opinion, I don't think I can cite "W at Salty Cajun said so" in a scholarly paper.

I got a chuckle out of that

[TNP]

Originally Posted by Duck Butter

I got a chuckle out of that

Is there any data??

[capt coonassty]

Try shooting an email to Dr. Megan LaPeyre with LSU RNR, she should be able to point you to something your looking for.

[Gerald]

Not sure if this will help.....

The picture were taken on 4-21-10 along the south bank of the lake.

This was just 2 of the many many oyster dredging boat that I saw that day. There must have been 30 or 40 boats working the SW part of Big Lake and West Cove areas. There was steady traffic going and coming from Cameron that day.

[Duck Butter]

Originally Posted by TNP

Is there any data??

Who knows? Not sure about Calcasieu Lake, but there is data from the other side of the state but its probably the cultch data where they seed em on that side. LSU has a good coastal program so it would make sense for them to have better data on that side. Sabine Lake on the other hand is supposed to be home to an incredible oyster reef, one of the last remnant natural reefs and Texas has made it known that no harvest will take place on this reef and La has also agreed to it on our side, but not with the passion that TX had. Oysters seem to really be political. The secretary of LDWF gave a talk a couple weeks back and he wanted so bad to tell it like it was but kept talking about a gag order that was issued since the oil spill.

[MathGeek]

Thanks for the tips and pointers and encouragements. Found the hard data I need here:

http://www.wlf.louisiana.gov/sites/d...ent-report.pdf

and

http://www.wlf.louisiana.gov/sites/d...assessment.pdf

These are the official state oyster stock assessments.

The graph below shows the decline in oysters on the east side of Calcasieu Lake (Area 29).

[Duck Butter]

Wow, what does the E sack and E seed exactly mean? and how did assess the stock? Thanks

Looks like it rebounded fairly quick after 2006

[MathGeek]

Originally Posted by Duck Butter

Wow, what does the E sack and E seed exactly mean? and how did assess the stock? Thanks

Looks like it rebounded fairly quick after 2006

E. Sack means sack oysters (> 3") on the east side; E. Seed means seed oysters (<3") on the east side. The stock assessment documents explain the sampling methods, but I only found these documents this morning so I have not yet studied them sufficiently to be able to adequately summarize the methods.

[MathGeek]

I also found some hard numbers on the average number of vessels landing oysters each month for the area 29 and area 30 combined (E and W Calcasieu Lake). Along with the illegal harvesting on the E. side (see LDWF Press releases from March 2011), the increase in pressure has contributed to the reduced stocks.

[MathGeek]

The dearth of oysters suggests it would be good to keep every black drum you catch until the oysters come back. Big bull drum can devour 2-4 dozen oysters per day, and even the smaller black drum can wreak havoc on the seed oysters and the spat.

All the fisheries in Big Lake benefit from healthy oyster reefs, and in the areas where oystering will be closed, the drum are the biggest enemy of a quick return of healthy oyster reefs.

[Ray]

It's not the dredges that are over harvesting, it is the number of licenses.
Before dredging, there was probably 75 or so boats.
After the dredging was made legal, the number was over 200 licenses.
It is too easy to dredge.
The tong fishermen caught their 15 sacks a day.
But trippling the number of boats really hurt.
They let them dredge, hoping that they would roll more oysters, making them grow better and kill the mussels.
But easy money brought in too many more boats.

[CharlieFoxtrot]

Can the speckled trout fishing slowdown during 2013 trace back to the oyster over harvesting ?

["W"]

Originally Posted by CharlieFoxtrot

Can the speckled trout fishing slowdown during 2013 trace back to the oyster over harvesting ?

Probably, how West Cove has any oysters left amazes me!! Zero seeding and months of dredging

[MathGeek]

Originally Posted by CharlieFoxtrot

Can the speckled trout fishing slowdown during 2013 trace back to the oyster over harvesting ?

Prolly not. Numbers may have been down in 2013, but body condition was way up. Been looking over the data the past few days with a colleague. There was lots of bait in 2013, and the specks were fat, happy, and growing fast.

Bull reds were real skinny and growing slow, as were bull drum, like 80% of their normal weight. Most fish below 80% of expected weight at a given length do not survive.

Gafftops were down too. Juvenile redfish were also fat and happy. Raping the oyster reefs hurts the more benthic feeders (gafftops, bull reds, drum) more than it hurts the juvenile redfish and the specks. With the closing of the pogey plant (Omega Protein), we're looking for there to be a lot more Gulf Menhaden around in 2014, so look for both specks and redfish to be fat and happy.

Remember that population and body condition are a teter tot. A lot of skinny, hungry fish means they are easy to catch. Smaller numbers that are fat and harder to catch is actually a good thing, because they will be more likely to grow to trophy sizes and have higher fecundity rates.

Trout are healthy and in balance in 2013. I am worried much more about the redfish and the drum. At 80% body condition, fecundity rates will be very low.

[CharlieFoxtrot]

MathGeek, with the ongoing increase in redfish population, do you feel that it affects the 80% theory ?