MD Scientists: Harvests Not Stressing Menhaden Populations

Hey Junebug,
Just wondering what numbers they were using. It could be very deceiving using metric tons. Here are a few numbers to look at that sound far worse than 100,000 metric tons.

Using a 100,000 metric tons
a metric ton is = to 2204.62 lbs
therefore that would equal 220,462,000 lbs caught in a year (less than the average of the last five)
minus the 1 % bycatch of 2,204,620 lbs (which sounds like a lot put that way)
equals 198,415,800 lbs left of pure menhaden
if each fish weighed 1.5 lbs that would equal
132,277,200 menhaden landed
at 1 lb of course it would be 198,415,800 menhaden landed
if each fish weighed .5 lbs that would equal 396,831,600 menhaden landed

Now if 70% comes out of the chesapeake bay as Omega says and they each weighed in a 1 lb(remember 198,415,800 menhaden)
then the total menhaden harvested in the bay would be
138,891,060.
That's just omega..not including predation, disease, and natural causes.
Sounds liike localized depletion to me.
when was the last time you saw that much bait in the bay

Now if we let omega set their quota at 131,000 metric tons
that equals 288,805,220 lbs
minus the 1% bycatch
2,888,052.2 lbs
leaving 285,917,167.8 lbs left
If the 70% still applied saying that they actually could catch that much in year and each fish weighed 1 lb
It would equal 200,142,017.46 menhaden landed.


Feel free to correct me if my numbers are in error. Remember also that the atlantic menhaden fishery only lands 25% of the total menhaden landings in the U.S. The gulf takes the other 75%

Name any other species that can survive that much pressure.

JB, here is a little counter propaganda,

Virginia Assembly Rejects Menhaden Conservation Measures
January 27, 2006 PDF Print Version

Richmond, VA - In a stunning decision yesterday, the Chesapeake Subcommittee of the House of Delegates voted to reject a cap on the industrial harvest of menhaden from the Chesapeake Bay as mandated by the Atlantic States Marine Fisheries Commission (ASMFC). The measure, adopted last fall by the ASMFC, would have capped the effort of the menhaden fleet at an average of the last five year’s harvest while studies were conducted to determine if the commercial operations are causing localized depletion of the important forage fish.

“The decision by the Virginia state legislature sets up an unnecessary confrontation with the federal government and puts the continued operation of the entire menhaden industry at risk,” said John Bello, chairman of Coastal Conservation Association Virginia (CCA VA).

Under the Coastal Cooperative Act, the ASMFC has little choice but to certify the state of Virginia as out of compliance with its menhaden plan and proceed with a closure of the entire fishery. The potential closure would not take effect before July 1, but if it is instituted at that time, the Virginia legislature will be out of session and unable to prevent the shutdown of the fishery.

“It is disappointing that the industry and the subcommittee apparently were not concerned that their decision puts all the employees of the reduction industry and the bait fishery at risk. In our testimony before the subcommittee we stressed the consequences of rejecting this basic conservation measure,” said David Nobles, chairman of CCA Virginia’s Government Relations Committee. “It is frustrating that they chose to ignore the realities of the situation.”

CCA VA supports the harvest cap which was designed to allow the reduction industry to continue operations while scientists develop a clearer picture of the impact of the harvest on the health of the Bay’s ecosystem. Evidence has indicated that the intense harvest of menhaden in the Bay is creating a localized depletion of the primary forage fish for a host of species important to commercial and sport fishermen. The Chesapeake Bay is the spawning ground for at least 80 percent of all Atlantic striped bass and that species in particular has shown signs of malnutrition and disease that could be linked to insufficient numbers of menhaden.

“We have maintained since the beginning of this debate that the intent of the harvest cap was not to put the industry out of business,” said David Hickman, executive director of CCA VA. “The cap would have allowed them to catch almost 106,000 metric tons per year, which is the average of the last five year’s harvest. The industry felt it could not live even with that modest restriction. Now the legislature and the industry leadership have chosen a course of action that will either weaken fishery management by the ASMFC or result in the closure of the reduction fishery by the federal government. Neither of those options is good for the resource or for the citizens of Virginia.”

CCA will ask the ASMFC to initiate the process of enforcing the cap at the Commission’s meeting in February.

###

Coastal Conservation Association is a national organization of 90,000 members in 15 state chapters. CCA’s mission is to advise and educate the public on conservation of marine resources. The objective of CCA is to conserve, promote and enhance the present and future availability of these coastal resources for the benefit and enjoyment of the general public.

hey junebug,
I really don't like to keep bugging you but here is another little tidbit of information.

But as filter feeders an adult menhaden 3 years and older can filter 4 gallons of water per minute or over 100 million gallons in 180 days. And that is just one menhaden

Now talk about localized pollution

so let me know if my math is right

if a omega takes 70% locally of their average 100,000 metric tons

minus their bycatch and each fish weighed 1.5 lbs
132,277,200 menhaden and let's they can each can filter 1920 gallons of water a day (I calculated an 8 hour day since they may have some child labor laws that won't let them filter for a full 24 hours)(8x60x4)
that would equal 254,171,124,000 gallons a day
(remember this is only one third of what they really can filter)

someone care to add up how much water just omega's share of menhaden can filter in 180 days....because even if they weren't caught they may not stay here due to migration

[Q]manfromva originally wrote:
hey junebug,
I really don't like to keep bugging you but here is another little tidbit of information.

But as filter feeders an adult menhaden 3 years and older can filter 4 gallons of water per minute or over 100 million gallons in 180 days. And that is just one menhaden

Now talk about localized pollution

so let me know if my math is right

if a omega takes 70% locally of their average 100,000 metric tons

minus their bycatch and each fish weighed 1.5 lbs
132,277,200 menhaden and let's they can each can filter 1920 gallons of water a day (I calculated an 8 hour day since they may have some child labor laws that won't let them filter for a full 24 hours)(8x60x4)
that would equal 254,171,124,000 gallons a day
(remember this is only one third of what they really can filter)

someone care to add up how much water just omega's share of menhaden can filter in 180 days....because even if they weren't caught they may not stay here due to migration
[/Q]
Omega catches alot of fish... what's your point? Your posts ignore the fact that scientists estimate the total menhaden population at over 400 BILLION. Thus, commercial fishermen only remove approximately only 2 out of every 1,000 menhaden from their population. Need those extra 2 fish, as well, do you?

As for water filtration, yep, menhaden collectively 'filter' alot of water. Again, what's your point?

Oh yes here we go again. 2 fish out of 1000

Here is the CALCULATED population distribution for 2004 as per the ASMFC technical committee report.

Age -- Billions of fish
0 -- 406.8
1 -- 2.51
2 -- 0.67
3 -- 0.36
4 -- 0.095
5 -- 0.014
6 -- 0.003

Those numbers are at the beginning of the year when those 406 Billion age 0 fish are about 1/2 inch long. Most of those get eaten before they reach 6 inches long and 3 onces in weight.

During that same year the commercial harvest of the standing stock at age was:

0 -- 0.04%
1 -- 8.43%
2 -- 38.8%
3 -- 37.7%
4 -- 18.0%
5 -- 3.57%

Furthermore the 406 Billion fish is back calculated in the model based on a constant annual natural mortality of about 98%. Also that year 22% of the fish harvested were age 0.

Thus the Menhaden industry harvested about 40% of the (edit AGE 2) fish before they had a chance to spawn and another 40% (Age 3) before they could spawn a second time. The industry does harvest a significant number of these fish. To state otherwise is just Junebug spinning the numbers the Omega way in order to downplay the impact. Those two year old fish if left to live another year would contribute in a major way to the spawning stock and help in filtering the water in the Chesapeake Bay ecosystem.

Sam

From the ASMFC Fact sheet.

"One-year old menhaden are about six inches long and weigh two to three ounces, three year old menhaden are nine to ten inches long and weigh about 0.5 pound, and menhaden six years and older are about one foot long and weigh about one pound."

Thus your age zero fish don't reach 6 inches until the end of the year, not the middle as you claim. The baitfish that are caught in the middle of the summer are 2 to 3 inches long.

From the ASFMC stock assessment document, the table with the population numbers has the following as a heading:

"Table 7.3 Estimated numbers of Atlantic menhaden (in billions) at start of fishing year from forward-projecting statistical age-structured model"

The start of the fishing season for the snapper rigs is March. How big is an age 0 menhaden in March? That is where I came up with a 1/2 inch number. I don't know the exact growth rate but if it should be pretty linear during the first year and those fish would be 3 inches long in the summer and 6 inches long in December.

With respect to forage. Maybe an 18 inch striped bass will eat menhaden up to 6 inches or so. But those 26 to 50 inch fish will certainly eat a 9 inch (age 3) menhaden. Bluefish and trout will eat any size as they chop them up first.

With respect to math I corrected the wording in the last paragraph above.

Here are the numbers for the 2002 biomass and harvest at age from the ASMFC report in Billions of fish.

Age -- (spring Biomass) -- Harvest during the year
0 -- 406.8 -- 0.178
1 -- 2.51 -- 0.211
2 -- 0.67 -- 0.259
3 -- 0.36 -- 0.136
4 -- 0.095 -- 0.017
5 -- 0.014 -- 0.0005

The math to get the percentage of the standing stock harvested and the percentage of the harvest at age is pretty simple, unless you are trying to put the Omega spin on it. Did my spread sheet program add or divide something incorectly?

No matter how you stack it Omega harvest a reasonable fraction of age 1 and above fish. They harvest a substantial fraction of the age 2 and above fish. To boot most of that harvest is in Virginia's waters of the Chesapeake Bay. Many believe that the Chesapeake Bay ecosystem needs more of those age 2 and 3 menhaden swiming and filtering the water to be healthy.

Sam

[Q]Sam Whitefoot originally wrote:
From the ASMFC Fact sheet.

"One-year old menhaden are about six inches long and weigh two to three ounces, three year old menhaden are nine to ten inches long and weigh about 0.5 pound, and menhaden six years and older are about one foot long and weigh about one pound."

Thus your age zero fish don't reach 6 inches until the end of the year, not the middle as you claim. The baitfish that are caught in the middle of the summer are 2 to 3 inches long.

From the ASFMC stock assessment document, the table with the population numbers has the following as a heading:

"Table 7.3 Estimated numbers of Atlantic menhaden (in billions) at start of fishing year from forward-projecting statistical age-structured model"

The start of the fishing season for the snapper rigs is March. How big is an age 0 menhaden in March? That is where I came up with a 1/2 inch number. I don't know the exact growth rate but if it should be pretty linear during the first year and those fish would be 3 inches long in the summer and 6 inches long in December.

With respect to forage. Maybe an 18 inch striped bass will eat menhaden up to 6 inches or so. But those 26 to 50 inch fish will certainly eat a 9 inch (age 3) menhaden. Bluefish and trout will eat any size as they chop them up first.

With respect to math I corrected the wording in the last paragraph above.

Here are the numbers for the 2002 biomass and harvest at age from the ASMFC report in Billions of fish.

Age -- (spring Biomass) -- Harvest during the year
0 -- 406.8 -- 0.178
1 -- 2.51 -- 0.211
2 -- 0.67 -- 0.259
3 -- 0.36 -- 0.136
4 -- 0.095 -- 0.017
5 -- 0.014 -- 0.0005

The math to get the percentage of the standing stock harvested and the percentage of the harvest at age is pretty simple, unless you are trying to put the Omega spin on it. Did my spread sheet program add or divide something incorectly?

No matter how you stack it Omega harvest a reasonable fraction of age 1 and above fish. They harvest a substantial fraction of the age 2 and above fish. To boot most of that harvest is in Virginia's waters of the Chesapeake Bay. Many believe that the Chesapeake Bay ecosystem needs more of those age 2 and 3 menhaden swiming and filtering the water to be healthy.

Sam
[/Q]
You're wasting my time.

Your statistics are, once again, wrong.

For starters, regarding the size of an age-0 menhaden, consult Table 2.1 from the most recent stock assessment. It indicates that a mid-year newbie is around 134 mm in length (5.3"), so by the end of summer it is, indeed, about 6". This is, of course, common knowledge to anyone familiar with menhaden on the Bay.

Your statistics also reflect (incorrectly, I would add) old harvest data. Recent harvests have been 90-95% age-2 or greater.

As for predation by striped bass - the principle predator in the Bay currently - they must reach about age-5 before most are physically capable of consuming an age-2 menhaden. According to the most recent striped bass assessment, over 82% of the striper population is age-4 or less. Furthermore, as you should know, the larger striped bass are migratory and only stay in the Bay for relatively short time periods. During their Spring migration into the tidal flat areas of Maryland, their principle prey isn't even menhaden.

Lastly, you bring up the "filtering" issue. You're chasing the proverbial red herring again. Kindly provide reference to any scientific studies that indicate more populations of large menhaden are needed in the Bay (and no, MSSA anti-Omega diatribes don't count).