Belated Report From the SJ Freshwater Fisheries Forum

[Dave B.]

My apologies for the delay in getting this post up, things have been rather hectic of late. As well let me apologize in advance for the length of this post. It's likely to run long but I want to share as much info as possible gleaned from the forum on Sat.

For the presentation on the entire course of events at Pequest including the current status there we had the pleasure of having Mr. Jeff Matthews the hatchery superintendant both presenting and handling the Q & A afterwards along with Lisa Barno our Freshwater Fisheries Bureau Chief.

The current status of the fish at the hatchery is full negative testing for the bacteria (Aeromonas salmonicida) that causes the disease. Contrary to many rumors only a portion of the facility was infected or tested positive for the bacteria. After the initial round of antibiotic treatment in late Sept/ early Oct the bacteria was again detected via testing in certain raceways in early Dec prompting a second round of treatment. Since late Dec there have been zero positive test results in either fish or water. The staff test the water at regular intervals (I believe weekly) and also do lethal sampling of an average of 60 fish per raceway on a monthly basis. The lethal sampling is necessary to test for the presence of the bacteria within the fishes organs, specifically the kidneys, as this pathogen is known to survive there at times despite treatment.

The current status of the various stocks at Pequest range from raceways wherein the fish and water tested positive but without an actual outbreak in the fish, to raceways where only the water tested positive, to raceways where both the fish and water have tested negative from the outset. The Division is acting on the assumption that any raceways wherein the fish tested positive at some point that these fish are potential carriers despite having now tested consistently negative for over 2 months. These are the fish slated for those 1 time high volume stockings you see listed on the Div. website.

The fish residing in raceways wherein the raceway had at some point in time tested positive but without any positive results in those fish at any time are to be stocked in the normal non-trout put & take waters of the state that are still on the proposed stocking list.

All of the above fish are brooks and browns, which traditionally are more susceptable to this disease. The remaining fish which reside in raceways that have never tested positive for the presence of the bacteria are what will be stocked in our usual trout maintenance/production waters including our major streams. These fish are all rainbows. There will be no brooks or browns available for those waters.

Rainbows it seems are naturally far less prone to contracting this disease even when exposed to the bacteria that causes it. However this seems to have had no relation to our rainbows consistently testing negative, they simply happened to be on some of the upper raceways where the initial water supply enters the system.

On the subject of the disease and the causal bacteria, this pathogen has been known to fisheries expets since the early 1890's. It's definitely not something new or exotic. Nor is it something that is isolated to the northeast, US or even North America. It exists virtually worldwide. There are a number of slight variants in other parts of the world but the strain we're dealing with is the simple, common strain well known to hatchery operators across the continent. In fact the US Fish and Wildlife Service has combatted it many times in their numorous hatcheries across the country, as have nearly all state hatcheries at some point. We've been very fortunate that our staff at Pequest have been able to keep it out of the system for nearly 35 years.

This bacteria is considered primarily a salmonid problem, due in part to the fact that it can only survive in temps below 74`F. Above that is dies. Also it has a very short lifespan outside of a host environment, my apologies but I don't recall the exact time frame for that but I believe it's around 5-7 days tops. It has been documented in many other fish species including some saltwater species such as cod but these incidences appear to be statistically very low.

One key factor in every major outbreak is stress of some sort. Obviously the ultra-high density environment of a fish rearing facility causes a level of stress to the fish. As well it's a prime setting for an outbreak insofar as one infected fish can go unnoticed while the disease progresses within it until the boils burst and pour clouds of bacteria into the flow immediately infecting all the fish in the raceway.

Regarding the fish which have already been euthanized this was accomplished simply by injecting CO2 into the water of the affected raceway. Those raceways already emptied have been undergoing a 2 step sanitization and sterilization process and will remain empty for some tiime. Likewise as other raceways are emptied during the spring stocking period they will be cleansed as well.

One other note on the bacteria before I move on, this pathogen does not and cannot cross over into humans so anyone with a personal health concern can rest easy. This fact has been confirmed by both state and federal health agencies. The simple fact of it's 74`F death would preclude it's survival in a human at 98.6`F.

Moving on, regarding this year's fall stocking I asked Lisa what the current proposed plan was. At present they plan to hold out 5,000 rainbows from the current stock of clean fish for the fall. These will be supplemented with approx. 23,000-24,000 yearlings. Those yearlings will unfortunately only be about 7 inches at stocking time in Oct making them sub-legal fish but the thinking is that at least there'll be some fish in the water in addition to the 5,000 13-15 inchers to provide some action for anglers. There will be no winter stocking however due to a shortage of available fish.

We do have trout fry in the nursery building at present that are clean and disease free so we will have fish for next spring's stockings. In addition the Division plans to acquire both brook and brown eggs from NYDEC via their Rome,NY hatchery. The biologists there have been selectively breeding furunculosis resistant brooks and browns for some 20 years now and have developed strains which are proven to be consistently disease resistant even when exposed and stressed. We won't see any of those fish in our waters until the spring of 2016 though but the plan is to gradually phase out our present strains of brook and brown trout and phase in the new ones. We will gradually develop our own broodstock from the inititial round of fish just as they did when the Pequest facility first opened. This eliminates the need for outside fish or eggs and greatly minimizes the risk of pathogen contamination.

As for the hatchery itself, despite being a 'State-of-the-Art' facility upon which many other states have fashioned their facilities after, there are obviously some further steps that can be taken to minimize the risk of pathogen contamination as we've just experienced. The greatest factor obviously is birds. They are almost certainly responsible for this current problem. There are steps in planning to increase the bird exclusion measures already in place. They currently have a network of wires strung above the raceways to keep the raptors out, especially the ospreys, and there are electric wires strung on insulators an inch or so above the edges of the raceways to keep the herons out. Yet these birds manage to find ways around these measures, particularly the ospreys. They've been seen swooping in from the sides just beneath the wires, snatching a fish and continuing out the other side. The Div is considering full netting over the raceways among other things, they just have to make allowances for both feeding and access come stocking time.

Almost forgot, regarding stocking allocations. I asked Lisa about the numbers and she informed me that the pre-season allocations will remain unchanged for all normal trout stocked waters but the in-season weekly allocations will be reduced by 20%. The reason behind this is that given the number of fish available in the various categories, at normal allocations they had enough fish to get through Tue of week 4 but by reducing each week's allocation they were able to provide a full four weeks of stocking. Also if you check the list you'll notice that the ponds and lakes that normally would not get stocked on week 1 will be getting fish that week this year. With regards to those waters getting those huge numbers of one-time stockings such as the lower Rahway, Farrington Lk, etc, they hope to be able to get those fish out sometime in early March so that folks can have a shot at them before the season closes on the 17th. Regarding whether or not those waters will be closed to angling I do not know, didn't think to ask but I will try to find out. Personally I can't imagine that happening but one never knows.

I'm sure there are subjects I've missed and items I forgot. Any questions I may not have answered, ask and if I know the answer I'll be glad to offer it up. Hopefully I've been able to clarify and put to rest some of the rumors and speculation that has been flying around.

One more item, here's the link to the Powerpoint presentation used by Jeff Matthews. It includes some images of the boils and lesions the disease causes on the fish.
http://www.njfishandwildlife.com/pdf...esentation.pdf

Dave, Thank you for your informative post.....I looked through the PP presentation and now I know what the disease actually looks like....I actually have seen and caught a few rainbows the past few months that looked similar to some of those in the photos.....If I continue to catch infected fish from time to time, what should I do w/ the fish. release it back in the river?...... I didn't know much about this as I now do.....Again, thanks for taking the time posting this....good job...

[surfrod]

Originally Posted by iceehot6766

Dave, Thank you for your informative post.....I looked through the PP presentation and now I know what the disease actually looks like....I actually have seen and caught a few rainbows the past few months that looked similar to some of those in the photos.....If I continue to catch infected fish from time to time, what should I do w/ the fish. release it back in the river?...... I didn't know much about this as I now do.....Again, thanks for taking the time posting this....good job...

Thanks, Dave, for the GREAT summary (even though I was there for most of Jeff's presentation)

One statement:
"Rainbows it seems are naturally far less prone to contracting this disease even when exposed to the bacteria that causes it. However this seems to have had no relation to our rainbows consistently testing negative, they simply happened to be on some of the upper raceways where the initial water supply enters the system."

I thought Lisa had said that there were no plans to change the strain of Rainbows because, as you said, they are naturally resistant, however, I thought she said this was also proven since some *had* been exposed yet did not contract the disease? Just for kicks, if you're sending her follow up questions, can you clarify that? Obviously no big deal because the fact is they didn't contract the disease. but am just curious...

Tight lines,
Rob S

[UglyStick]

Dave - great re-cap, thanks for taking the time to post it. This is actually very good news considering what could have happened.

[Skunk City]

I think that answers a lot of the important questions guys were asking about the whole ordeal. Good stuff, thanks.

[FASTEDDIE29]

Informative and insightful. Thanx for the report! Everything will work out! There's still healthy fish to catch in our big waters. That's a positive!

[Almaink]

Thank you Dave, all my questions where answered, except one, is there any warning about eating the treated fish? I know most fish have consumption warnings now about how much a pregnant woman for example can eat. I wish they would say something about the safety aspect of eating these treated fish.

[Polelock]

Thanks for the info Dave.. I have confidence the Divison is doing all they can...

I have the same question as Almaink.. What about eating these fish? They are treated with Aquaflor.

MSDS Sheet for it..
http://www.fws.gov/fisheries/aadap/0...lorfenicol.pdf

[surfrod]

Originally Posted by Almaink

Thank you Dave, all my questions where answered, except one, is there any warning about eating the treated fish? I know most fish have consumption warnings now about how much a pregnant woman for example can eat. I wish they would say something about the safety aspect of eating these treated fish.

The state is treating using Aquaflor and here is the FDA's statement:
"According to the FDA, losses due to furunculosis associated with Aeromonas salmonicida are significant in hatchery-reared salmonids, including those at state and federal hatcheries producing fish for native species restoration programs.

The agency said it reviewed “extensive data” on the antibiotic’s effectiveness against furunculosis and its safety for treated fish and the environment. FDA also said it found that freshwater-reared salmonids fed AQUAFLOR are safe for human consumption when the product is administered according to label directions."

http://www.aquaflor-usa.com/secondar...runculosis.asp


AQUAFLOR® Approved for Controlling Mortality Due to Furunculosis in Freshwater-Reared Salmonids

Efficacy studies show that AQUAFLOR is highly effective

KENILWORTH, N.J., Nov. 6, 2007 — AQUAFLOR® (florfenicol), the fast-acting in-feed antibiotic developed by Schering-Plough Animal Health Corporation, has been approved by the U.S. Food and Drug Administration (FDA) for control of mortality in freshwater-reared salmonids due to furunculosis associated with Aeromonas salmonicida.

“AQUAFLOR has been shown in clinical field trials to be highly effective for the treatment of furunculosis, which is a serious disease concern in salmonid species. Furunculosis outbreaks often times result in substantial losses,” says Dr. David Erdahl, Fisheries Biologist and Branch Chief of the U.S. Fish and Wildlife Service’s (USFWS) Aquatic Animal Drug Approval Partnership Program in Bozeman, Montana.

“This is the first new oral antibiotic available for the treatment of furunculosis in 20 years, and represents an important new management tool for fisheries programs throughout the country,” says Erdahl.

USFWS conducted the efficacy studies demonstrating the effectiveness of AQUAFLOR to control mortality due to furunculosis. AQUAFLOR administered in feed to either fingerling Coho salmon or fingerling Chinook salmon with naturally occurring furunculosis significantly reduced mortality compared to untreated controls. For instance, in a study with Fall Chinook Salmon fingerlings, mortality in fish treated with AQUAFLOR was reduced by over 80 percent. No adverse reactions to treatment were reported in any of the studies.

Outbreaks of furunculosis associated with Aeromonas salmonicida, a Gram-negative bacterium, can cause rapid onset of high mortality. Sub-acute or chronic forms of the disease lead to lower mortality and the formation of external “boil like lesions” or furuncles.

According to the FDA, losses due to furunculosis associated with Aeromonas salmonicida are significant in hatchery-reared salmonids, including those at state and federal hatcheries producing fish for native species restoration programs.

The agency said it reviewed “extensive data” on the antibiotic’s effectiveness against furunculosis and its safety for treated fish and the environment. FDA also said it found that freshwater-reared salmonids fed AQUAFLOR are safe for human consumption when the product is administered according to label directions.

AQUAFLOR has been shown to be effective for several other diseases in aquaculture, such as coldwater disease (associated with Flavobacterium psychrophilum) in freshwater-reared salmonids and enteric septicemia in catfish (ESC) associated with Edwardsiella ictaluri. Earlier this year, its sister product, AQUAFLOR®-CA1 (florfenicol), received a conditional approval for the control of mortality in catfish due to columnaris disease associated with Flavobacterium columnare.

Studies show AQUAFLOR does not lead to reductions in feed consumption or growth. AQUAFLOR also has a short, 15-day withdrawal period in freshwater-reared salmonids.

AQUAFLOR is the first in-feed antibiotic in aquaculture and the second for all food-animal species to be classified by the FDA as a Veterinary Feed Directive (VFD) drug. VFD is a category established in 1996 to help the agency more closely control new therapeutic products, primarily antimicrobials, and their use in food animals. The VFD classification applies only to new in-feed therapeutics approved by FDA after 2000. Aquaculturists may obtain VFD drugs through normal feed distribution channels, but they will be required to obtain a signed Veterinary Feed Directive from a licensed veterinarian.

For more information on AQUAFLOR and AQUAFLOR-CA1, producers should contact their extension specialist, veterinarian, diagnostician or feed company representative. Information also may be obtained at www.AQUAFLOR-USA.com or by calling Schering-Plough Animal Health 1-800-521-5767.

[UglyStick]

Originally Posted by Polelock

Thanks for the info Dave.. I have confidence the Divison is doing all they can...

I have the same question as Almaink.. What about eating these fish? They are treated with Aquaflor.

MSDS Sheet for it..
http://www.fws.gov/fisheries/aadap/0...lorfenicol.pdf

I don't want to speak for Dave, but to boil down all the tech info on the drugs, by the time the trout are stocked there would be no drug left in their systems since everything used has a relatively short wash-out period - thus, no worries from that perspective.