Tidal Fish Forum banner
1 - 20 of 24 Posts

·
Registered
Joined
·
106 Posts
Discussion Starter · #1 ·
Had a conversation with a friend this weekend about placing a moritorium on harvesting crabs and oysters. He claims oysters reach full maturity in a year and it is fruitless to place any moritorium on harvesting them because of this. Do oysters die off after a year or what? He claims what has to be addressed is the polution thats killing them. He got this information from a book about the bay called "swimmers" or something near that. I agree about the polution but I think giving them a chance to exist with no harvesting for a few years can help bring them back. If they only live a year then maybe Im wrong. But the real question for me is about the life span.
Bob
 

·
Registered
Joined
·
3,679 Posts
I am pretty sure that oysters reach maturity after something like 18 to 24 months.

The problem is that they die of disease before they get much older. Hypoxic water doesn't do them any good either.
 

·
Registered
Joined
·
7,566 Posts
I am making it my mission to rid TF of this type of oyster mis-information. Oysters do not necessarily die after a year...or two years...or three years....or longer....from disease or otherwise. Like all things in the wild, some get eaten, some die of various diseases, but some also press on and continue to grow for many years, becoming much larger and stronger in the process and filtering many times more water. That is, unless they're scraped off the oyster bar by harvesters and never given that chance.

I have seen, first hand, how well oysters do and how large they grow in some pretty awful water (Severn River, Pax River, mid-Bay, etc.) IF they are left alone. The longer they live, the more water they filter, and the more chances they have to create more offspring that share whatever genetics allowed their parents to resist disease/poor conditions for so long. Like many marine animals, I suspect that as oysters grow larger, they also produce more egss/sperm than smaller, younger oysters, but I don't know that for certain. Hopefully, a true oyster expert will chime in here.
 

·
Registered
Joined
·
3,679 Posts
I stand corrected. I should have said

The problem is that they FREQUENTLY die of disease before they get much older. Hypoxic water doesn't do them any good either.

One of the disturbing results of opening up the lower Rappahannock River after it was closed for like 10 years was a lack of large mature oysters.
 

·
Registered
Joined
·
805 Posts
All you can eat fresh oysters for 14.55. with lots of shimp, samon, clams and my favorite..frog legs! All on Rt. 60 in Chesterfield, Va. Had some last friday.
 

·
Registered
Joined
·
7,566 Posts
I stand corrected. I should have said

The problem is that they FREQUENTLY die of disease before they get much older. Hypoxic water doesn't do them any good either.

One of the disturbing results of opening up the lower Rappahannock River after it was closed for like 10 years was a lack of large mature oysters.
Thanks Tom. Fair enough. My follow-up question about the Rapp, though, is why open it to harvest if the oysters are doing so poorly? Do we do that for any other struggling species ("ah, what's the use...Condors fly into utility lines often enough that we might as well let hunters take them early in their lives").

I have been told that oyster recovery can be more of a challenge farther down the Bay, in saltier water, since the diseases are more prevalent there, but I've also been told that in areas where oysters overcome the disease, the higher salinity really allows for better reproduction. I believe that this is what happened in Lynnhaven, right? A number of organizations carpet bombed the place with spat. Many oysters did not make it, but enough did to eventually lead to a real population explosion that well exceeded expectations. If the few adult oysters are harvested just as they reach maturity, however, the chances of ever establishing a disease-beating population seems nil.
 

·
Registered
Joined
·
3,621 Posts
Windbreaker,

This is a good conservation thread, thanks for starting it.

Tom,

We have never met, but I think you are involved in VA fisheries issues, correct? I have not met Goose or Crow either. I know were Goose lives from his posts and I fish the Severn sometimes, and I think Crow is involved in MD fisheries issues. I hope to meet all of you as well as others on this thread and a lot of other Tidalfishers someday.

The posts on this thread in some ways reflect the different perspective between MD and VA, with the MD portion of the Bay having more freshwater influence and lower salinity and the associated differences in oyster survival. I fundamentally agree with the point Goose made. I think we should be doing everything possible to promote viable populations of native oysters that have disease resistance, but it seems like that may be a more realistic approach in MD waters than it is in most of the VA portion of the Bay and tribs.

New posting on MD DNR page today, seems appropriate to note it in this post:

DNR Biologists Complete Annual Oyster Surveys

DNR Biologists Complete Annual Oyster Surveys
5th Consecutive Year of Good Native-Oyster Survivorship
--------------------------------------------------------------------------------

Oxford, Md. - Maryland Department of Natural Resources fisheries biologists recently concluded the 2008 oyster survey, an annual assessment of the health and population of oyster bars in Maryland's portion of the Chesapeake Bay. Since 1939, each fall biologists use a dredge to monitor natural oyster bars, seed production and planting areas, dredged and fresh shell plantings and oyster sanctuaries.

"Preliminary results from 2008 indicate that reproduction was poor throughout most of the bay, with the exception of the lower eastern shore areas of Tangier Sound, Honga River, and the Little Choptank River," said Mitch Tarnowski, DNR fisheries biologist. "In general, mortalities and oyster disease levels appear to be relatively low again this year."

During the late 1950's, biologists starting seeing the effects of Dermo (Perkinsus marinus) and MSX (Haplosporidium nelsoni) diseases on the bay's oyster population. While not harmful to humans, these parasitic organisms infect oysters and have lead to the death of up to 90 percent of oysters in some areas. Both diseases thrive in higher salinities, so mortality is much higher in the lower parts of the Bay.

Typically, disease causes the greatest problems during years with higher than average salinity brought about by lower than normal stream flow. With higher salinity in the bay between 1999 and 2002, MSX, Dermo and oyster mortality was higher than average. The relatively wet years between 2003 and 2006 translated to reduced disease pressure and lower oyster mortality.

As part of the 2008 survey, biologists assessed more than 1,800 oysters collected from 282 oyster bars. The dry summer of 2007 did not result in high disease levels similar to previous dry years. Dermo increased in 2007, but remained below normal in both prevalence and intensity. MSX increased in frequency, but for the fifth straight year observed oyster mortality remained low.

"Oyster mortality in 2006 and 2007 were the two lowest years since the 1980's. It's too early to know if this is a trend, but this is a very positive development that we will be monitoring carefully," said Mike Naylor, Director of DNR's Shellfish Program.

--------------------------------------------------------------------------------

January 13, 2009 Contact: Olivia Campbell
410-260-8016 office I 410-507-7525 cell
[email protected]

Edit: Goose, our emails crossed in the ether
 

·
Registered
Joined
·
3,679 Posts
Yes I am involved with fisheries down in VA. I live in Poquoson which is about 5 miles south of the mouth of the York River.

They opened the lower Rap due to pressure from the watermen. It was done in stages. Part of the reason was so that they could really determine if the long closure was really allowing the disease resistant oysters to survive to older ages. The results were not that encouraging. I picked most of this up at meetings that I attended (for other matters) where oysters was on the agenda. VMRC does audio minutes of the Commission meetings. If you go back over the past two years or so you can see what staff and the public had to say. Here is a link to thier calendar.

Calendar 2009

Go on the right hand side and pick last year. Take a look at the draft minutes with audio minutes for each month and you can find the agenda items of interest. I recommend downlaoding the .mp3 files so that you can fast forward through the boring parts.

One thing that I believe is that viable oysters in the lower bay really requires changes in salinity over the course of the year. Saltwater to kill one parisite and fresh water to kill the other. The James river has few dams to stablize the flow. That is why I think that it does so well.
 

·
Registered
Joined
·
3,621 Posts
Brian,

You are located near the mouth of the Bay, correct? Please tell us more about the photo you posted--I see a lot of oyster shell in the intertidal zone, is that your property, where is it located?

It looks like there would be tailing redfish on that shell bar in the grass at high tide!
 

·
Registered
Joined
·
3,967 Posts
My neighbor and I share Bay Point at the mouth of Lyons Creek. This year we finished our shoreline
restoration project. 5 years and thousands of bushels of shells and plenty of natural strike, we are
both proud of it. Well over 2000 ft of shoreline and all the shells placed in the grass by hand.


 

·
Registered
Joined
·
3,679 Posts
I think know where that is. . . Is that right at the point almost dead center in the top photo?

I wondered why all of the pvc poles are out there. I kayak past that point on a regular basis during the warmer months. I will have to remember to go cast some grubs up in there at high tide. I usually spend my time across the creek fishing the back side of cow island.

To boot I bet you don't have a problem with erosion undercutting the grass beds.
 

·
Registered
Joined
·
7,566 Posts
Brian, your pride is well justified. That's a terrific thing that you've done for the Bay. Thanks!

P.S.: This is a very informative thread. ...great topic.
 

·
Registered
Joined
·
1,358 Posts
Kudos to Brian... That is nothing short of incredible. We all thank you for your hard work.

How long have some of the oysters survived Brian? It really makes you wonder what is really going on.
 

·
Registered
Joined
·
235 Posts
I too would be in favor of a moratorium on wild oysters and increased oyster aquaculture. Can you imagine if most or all of the docks in Lynnhaven had 200 oysters (a couple cages) on the end? Not only would owners be able to enjoy a wonderful oyster dinner whenever they want in the winter, but the cleaning and conservation power would be nothing short of awesome.
My parents live on the bay and grow a couple crates of oysters at a time. It's not too difficult and I find it rewarding and delicious!

Also, in terms of growth, I do not know the exact numbers on wild oysters, but those grown in float cages develop much faster than wild ones and are big enough to eat within a year. I have read that this increased growth rate is because they are suspended in the water and have better access to food than if they were sitting on the bottom.

Great Thread,
Ed
 

·
Registered
Joined
·
3,967 Posts
Tom, yes you are correct. I am the last house on left when you are exiting
Lyons Creek. The cove with the 25' Grady on a lift. Next time you are out
pull in and say hello.
Ware Fisher, I will respond to your Private message shortly. Floats work good
but I prefer to hang them from my dock in cages, they do not foul and are
easier to manage.
OneMoreCast, 5-6 years is as long as I have seen. Out of a hundred maybe
5 or 10 will make it that long. I only raise debbies (diploids) that reproduce.
A lot of people raise sterile triploids because they grow faster, but I see no
benefit to the bay if they are not also spawning.
The purpose of all of the shells (substrate), is to give the oysters something
to strike on. And yes Tom, it does help reduce erosion and runoff. Here are
a couple of pictures from 2 years ago.


 

·
Registered
Joined
·
5,348 Posts
Hey Brian. Thanks for your good work down there. We doing a bunch of stuff up here in Solomons also.

Tell me about the shoreline piece. Our oysters do well in the intertidal zone, except in a very cold winter when they may be caught on the low tide mud in 10 degree weather. (This is going to happen tomorrow night.)

So we grow our oysters in floats in at least 3 feet of water so that does not happen. Are you expecting to take a hit down there as well?

Congrats on your success and the overall Lynnhaven success story. Are your shoreline oysters protected from harvest?
 
1 - 20 of 24 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top