MD Scientists: Harvests Not Stressing Menhaden Populations

[Q]Four Js originally wrote:
You know funny thing about all this, things like toooo many rockfish as Mr june has suggested......................... I have to wonder how in the world did the menhaden and rockfish survive BEFORE we rec and omega started fishing for them. June I boat out of Deltaville and have seen first hand three and four of your steamers working the Rapp river from the mouth to the Whitestone bridge. Omega has big talk about the 200 jobs in Reedville but seems to have feelings about the many Charters that fish the river and make their liveing there. I have seen them drop nets right on top of the charters. I have to wonder if Omega is leading by example ie WE will get ours and to he!! with the rest. June be assured the I will be out this year and I have added a new peice of equiptment to my boat............a video camera. Maybe if we as rec anglers get a lot of video and get it to the right news people the rest of the state will become aware of whats really going on.
[/Q]
So, the sportfishing for charters on the Rappahannock has been bad, huh?

I stand corrected on the growth rate. I guess it is non-linear during that first year. That still does not change the fact that the 400 billion age 0 fish was counted in the early spring when they were on the order of 1/2 inch long.

The distribution of harvest numbers that was given to me indirectly from NOAA was:


2004 Coastwide (preliminary)
age 0 1%
age 1 14%
age 2 72%
age 3+ 12%

2003 Coastwide
age 0 9%
age 1 18%
age 2 64%
age 3+ 9%

Here are the percentages for previous years (From the ASMFC report).


Year -- Age 0 -- Age 1 -- Age 2 -- Age 3-plus
1990 14.28% 6.15% 71.97% 7.60%
1991 27.85% 32.65% 29.88% 9.63%
1992 19.47% 35.43% 38.75% 6.34%
1993 4.26% 23.78% 61.68% 10.29%
1994 5.94% 18.40% 59.58% 16.09%
1995 3.46% 32.48% 40.88% 23.18%
1996 3.09% 19.15% 62.19% 15.57%
1997 2.53% 24.79% 42.63% 30.05%
1998 7.23% 18.36% 53.66% 20.75%
1999 18.36% 28.51% 42.68% 10.45%
2000 11.83% 17.37% 51.80% 19.00%
2001 3.44% 6.50% 55.22% 34.85%
2002 22.19% 26.36% 32.35% 19.10%

So it looks like the industry did good at catching a high percentage (>80%)of older fish in 2001, and 1996 and caught a higher precentage (>30%) of age 0-1 fish in 2002, 1999, 1995, 1992 and 1991. On average over the 14 year period between 1991 and 2004 67% of the harvest was age 2 and older and 33% was age 0 and 1.

In 2004 -- 87% of the coast wide harvest was before the end of the 2nd year which in accordance with the ASMFC menhaden fact sheet is prior to when the majority of those fish have a chance to spawn. During the 1991 through 2004 time period pre spawn (not completed they end of year 2) fish made up 83% of the harvest. That is a lot of prespawn fish.


I wonder what the population estimates were for 2004 and how many age 2 fish you left to spawn that year. And folks wonder why there is poor recruitment. If Omega was trying to help recruitment they would not be targeting the prespawn fish.

As far as striped bass are concerned. There are plenty of other predators in the bay. Flounder, bluefish, grey trout, red drum, blue crabs, herons, seagulls, osperys, to name a few. It will be interesting to see the analysis from the studies as to which species eats more or what. Also not all striped bass leave the bay at age 7 (28 inches) a certain fraction stays year round. Also those age 5 through 7 make up 20% of the coast wide popluation most of those age classes stay in the bay. Depending on the year class a good percentage of that 80% of the age 5 and less striped bass you are quoting are age 0/1 fish which do not eat those 3" to 6" inch menhaden. For instance in 2004 38% of the striped bass were age 1 fish.

Sam

[Q]manfromva originally wrote:
Hey Junebug,
I had no idea that there were so many menhaden. I guess all of omega's conservation efforts have paid off since the early 80's.

Agreed. Omega harvests 2 out of every 1,000 menhaden in the total population annually.

They use to catch 300,000 to 400,000 metric tons a year. I'm glad to see that they are limiting themselves to just over a 100,000 now.

Wrong. Omega (actually under it's former name Zapata Protein) never harvested anything close to that amount. Moreover, you're referring to a time when striped bass stocks were depleted, and menhaden vessels numbered in the 30-40 range, not less than a dozen.

With those numbers you gave in the Billions
You should help omega out and let them know where they are. Heck I might even quit my job and go cast netting for them like the old timers use to since there are so many.

The juvenile survey in Virginia in 2005 produced roughly 20x the previous 5 year average, so you should, indeed, have success cast netting.

As for the pollution factor...I guess the low oxygen levels and large algae blooms have been figments of everyone's imaginations.

Perhaps your own imagination. See my post from this morning on the main Chesapeake board.

[/Q]

Junebug, don't Menhaden stay primarily near the surface? Or, at the very least, can't they easily cope with doing so if DO levels go down? If so, then I don't see how the dead zones would stop Menhaden from swimming north. In fact, Menhaden have regularly swam into even very bad dead zones that extended to the surface in some areas, as was evidenced by massive Menhaden die-offs in the 80s and even moderate one last Summer.

These dead zones are obviously a huge problem, but I do not think they are the reason for the lack of Menhaden in the Bay. Dead zones can kill Menhaden, but where is your evidence that the Menhaden come up the Bay in reduced numbers due to dead zones (or is this not your contention)? I believe that something else (i.e. - Omega) is keeping the Menhaden from coming up the Bay in historical numbers (by historical, I mean only 15-25 years ago).

Another point: You regularly blame increased Striped Bass stocks as causing Menhaden depletion in the Bay, yet have not, to my knowledge, reconciled this with (1) the huge stocks of mostly larger Striped Bass that patrol coastal waters, where the Menhaden stocks are supposedly healthy and (2) the fact that Bluefish were at record levels and Weakfish were much more numerous when the Striped Bass population was down in the 80s. Are you saying that these massive schools of chopper Blues didn't do AT LEAST as big a number on Menhaden as Striped Bass do today?

I think we all agree that increased populations of predators put increased strain on forage, and declining water quality further strains the entire ecosystem --the latter is a situation that MD, VA, PA and NY -- and every citizen thereof -- need to more seriously address, otherwise the Omega debate will soon be moot. However, that does not mean that, knowing all of the other stress factors on the Bay population, it is wise policy to say, “oh well, since there are many issues at play, let's just continue to allow 100,000 tons of critical forage to be removed from an already strained Bay forage base.”

[Q]goose70 originally wrote:
Junebug, don't Menhaden stay primarily near the surface? Or, at the very least, can't they easily cope with doing so if DO levels go down? If so, then I don't see how the dead zones would stop Menhaden from swimming north. In fact, Menhaden have regularly swam into even very bad dead zones that extended to the surface in some areas, as was evidenced by massive Menhaden die-offs in the 80s and even moderate one last Summer.

These dead zones are obviously a huge problem, but I do not think they are the reason for the lack of Menhaden in the Bay. Dead zones can kill Menhaden, but where is your evidence that the Menhaden come up the Bay in reduced numbers due to dead zones (or is this not your contention)? I believe that something else (i.e. - Omega) is keeping the Menhaden from coming up the Bay in historical numbers (by historical, I mean only 15-25 years ago).

Another point: You regularly blame increased Striped Bass stocks as causing Menhaden depletion in the Bay, yet have not, to my knowledge, reconciled this with (1) the huge stocks of mostly larger Striped Bass that patrol coastal waters, where the Menhaden stocks are supposedly healthy and (2) the fact that Bluefish were at record levels and Weakfish were much more numerous when the Striped Bass population was down in the 80s. Are you saying that these massive schools of chopper Blues didn't do AT LEAST as big a number on Menhaden as Striped Bass do today?

I think we all agree that increased populations of predators put increased strain on forage, and declining water quality further strains the entire ecosystem --the latter is a situation that MD, VA, PA and NY -- and every citizen thereof -- need to more seriously address, otherwise the Omega debate will soon be moot. However, that does not mean that, knowing all of the other stress factors on the Bay population, it is wise policy to say, "oh well, since there are many issues at play, let's just continue to allow 100,000 tons of critical forage to be removed from an already strained Bay forage base."

[/Q]
You raise some interesting issues.

However, here is the bottom line question for you: Say you have a leak in your swimming pool, as the result of two cracks. One crack leaks around a gallon a day; the other crack leaks around 1,200 gallons a day. Assuming you're interested in repairing these leaks, which leak would be the focus of your attention and efforts?

Hey look everybody - Junebug went back into the discussion and deleted a couple of his earlier posts!
You may remember this yourself - one item Junebug has struck from the record: a graphic depicting the max exent of the deadzone.

http://www.cbf.org/site/PageServer?pagename=resources_facts_deadzone#mainstem

As I remember events, Junebug claimed the deadzone was preventing menhaden from migrating up the Bay. Junebug, why did you see fit to delete your remarks on this subject? Must have deleted those posts by accident, right? [grin]

Junebug, I agree 100% that by far the greatest effort and expense needs to be towards reducing nitrogen/phosphate input into the Bay. The problem is that even if a huge effort would begin immediately, it would likely not yield results for a decade or more. And realistically, this will be a slow process compounded by the continued massive influx of people into the watershed (which for misguided reasons, our gov't officials celebrate and encourage).

But once again, that doesn't mean that we sit by and don't tackle the smaller -- but also important -- issues simultaneously. Rudy Giuliani attacked NY City's crime/corruption by first tackling the little issues, like graffiti and squeegeemen, to show that a change for the better COULD happen. He found that eliminating those little things not only energized others to take on the bigger problems, but it actually made a noticeable difference, by itself, in the overall reduction in crime/corruption. When a company with seemingly insurmountable problems hires my firm to defend it and fix the problems internally, we immediately tackle the things that can be fixed quickly and cheaply, then move up the task list. By the time we reach the most difficult/expensive problem, it’s been isolated and often is no longer as critical and expensive as it once was. Unburdened by its smaller problems, the company is in better shape to deal with (and, in the meantime, endure) the bigger issues. I don’t see why the Bay isn’t fundamentally the same.

junebug,
I thought you were a menhaden expert. you should know what menhaden do for the bay.

Juveniles primarily feed on zooplankton, but adults are mainly herbivores, but retain the ability to feed on zooplankton. The adults are very adaptable and will feed on several species of phytoplankton, as well as suspended organic plant detritus. Atlantic menhaden are an ecologically critical fish species. They consume and redistribute a significant amount of energy within and between the Chesapeake Bay and other estuaries, and the coastal ocean. This is due, in part, to their tremendous numbers, individual growth rate, filter feeding capacity, and seasonal movements. An adult fish can filter up to a million gallons of water every 180 days. A healthy Atlantic menhaden population has the potential to consume up to 25% of the Bay's nitrogen in 1-year.

Less nitrogen in the bay would mean less algae blooms which in turn (and here it is) less oxygen depleted water.

thanks again for the graph...

the information above can be found at:

<http://www.chesbay.org/forageFish/menhaden.asp

[Q]manfromva originally wrote:
junebug,
I thought you were a menhaden expert. you should know what menhaden do for the bay.

Juveniles primarily feed on zooplankton, but adults are mainly herbivores, but retain the ability to feed on zooplankton. The adults are very adaptable and will feed on several species of phytoplankton, as well as suspended organic plant detritus. Atlantic menhaden are an ecologically critical fish species. They consume and redistribute a significant amount of energy within and between the Chesapeake Bay and other estuaries, and the coastal ocean. This is due, in part, to their tremendous numbers, individual growth rate, filter feeding capacity, and seasonal movements. An adult fish can filter up to a million gallons of water every 180 days. A healthy Atlantic menhaden population has the potential to consume up to 25% of the Bay's nitrogen in 1-year.

Less nitrogen in the bay would mean less algae blooms which in turn (and here it is) less oxygen depleted water.

thanks again for the graph...

the information above can be found at:

<http://www.chesbay.org/forageFish/menhaden.asp
[/Q]
Interesting that you cite Chesapeake Bay Ecological Foundation materials. The CBEF is on the record as supporting a culling of striped bass in the Bay. Read for yourself:

...By the conclusion of the three-day workshop, however, scientists determined that research conducted thus far has not indicated any link between the abundance of menhaden in the Bay and the incidence of mycobacteriosis in striped bass.

Furthermore, preliminary scientific models prepared by Commission scientists indicate that the increased occurrence of undernourished striped bass in the Bay may be the direct result of an overabundance of this species - not the result of concurrent, sustainable commercial menhaden harvests.

Because predator species like striped bass feed heavily on prey species such as menhaden, scientists have increasingly developed methods to estimate the cumulative effects on menhaden populations by predators. Based on these preliminary studies, scientists indicate that the consumption of juvenile menhaden by striped bass is significant. In fact, when compared to the number of these menhaden harvested by commercial menhaden fishermen, these studies estimate that striped bass conservatively consume an order of magnitude more menhaden than harvested by fishermen.

"It would appear that striped bass populations may have exceeded their natural carrying capacity within the Chesapeake Bay as early as the late 1990s," notes Niels Moore, marine scientist and graduate of the Virginia Institute of Marine Sciences. "Indeed, the striped bass stock, which has continued to grow despite reaching 'fully recovered' status in 1995, may have now ballooned to a disproportionate, and potentially unsustainable, size within the Bay."

Marine conservation organizations and others also assert that fishery regulators may need to reduce striped bass populations in order to preserve the Bay's natural ecosystem. According to the Asbury Park Press, Jim Price of the Chesapeake Bay Ecological Foundation states, "We need to kill more of these fish," and adds, "I want to see the Bay get back into balance."

http://www.menhaden.org/news_pr_102504.htm

junebug,
This is what is listed on there site now. your report was from october 2004. What was said a last years meetings. I think it was something along the lines of a cap on menhaden landings. Here is what the CBF is listing on it's site about striped bass now.
<http://www.chesbay.org/stripedBass/

"Striped Bass are the largest species of the Pecichthyidae family and can be found along the Atlantic Coast from northern Florida to the maritime provinces of Canada. Spawning however takes place almost entirely in the Hudson River and the Chesapeake Bay. They are voracious piscivores and grow rapidly as a result. Historically their diet is seasonal, comprising of bay anchovy and Atlantic menhaden in the summer and fall, and juvenile spot and Atlantic croaker throughout the winter. During the early spring their forage almost entirely consists of white perch with blueback herring and alewife becoming available to them in late spring and early summer.

In the late summer and fall months, it is extremely important for the bass to store up body fat. Besides giving the fish reserves to live off of during the lean winter months, the body fat in males assists in the development of gonads for spawning. The Spring and Fall seasons are also when Striped Bass attain most of thier growth for the year. This past fall, surveys showed alarming results in the general condition of the striped bass population. Judging from the data collected, there may be several factors influencing this. One of the most obvious was the lack of Atlantic Menhaden that normally dominate their diet this time of the year."