Menhaden Math

[Kevin Smith]

While sitting at home today I came across this article, which may be old news, but seems to explain the importance of menhaden to stripers, trout & bluefish. This is not the entire article but this seems like very interesting reading as we struggle with low numbers of weakfish and some unhealthy stripers inside the bay.

It would also be interesting to get some opinions about the accuracy of this data and this source? All comments from TFer's welcome?

Finfish Fisheries Depend on Menhaden

In the Chesapeake Bay and along the entire East Atlantic Coast,
menhaden play a significant role in the diets of larger predator fish such
as weakfish, bluefish and striped bass. In a study by Kyle Hartman and
Dr. Steve Brandt, at the University of Maryland Chesapeake Biological
Laboratory, the stomach contents from striped bass, bluefish and weakfish
in the Chesapeake Bay were collected and analyzed on a bimonthly basis.
Using regression techniques, the live weight or biomass of each of the
individual prey species in the stomachs was estimated so that the relative
importance of each of them could be determined.xiv

The study found that regardless of season, menhaden constituted an
important food source for many recreationally and commercially valuable
fish species. These include:

Striped Bass: Menhaden are the most important prey species for striped
bass that are two years and older. Seasonally, these fish relied almost
completely on menhaden for their diet in November and December.
During January and February, this importance dropped only slightly.
During the spring and early summer, young spot, older white perch and
various marine worms become a larger share of the striped bass diet.
Although menhaden constituted a smaller portion of the diets during the
mid-late summer months as compared to winter, they still contributed
25 to 50 percent.

Weakfish: Menhaden also are an important part of the weakfish diet,
slightly lower in importance than they are to striped bass. Still, age 0
weakfish rely on menhaden for approximately 60 to 90 percent of their
diets in July through December; age 1 and 2 weakfish rely on menhaden
for 50 to 60 percent during this same time period. During the spring
months, menhaden generally constitute less than 15 percent of age 1
and 2 weakfish diets.

Bluefish: Menhaden represent a significant portion of the bluefish diet,
constituting nearly 31 percent of the diet of age 0 bluefish after
September and October and up to 88 percent of the diets of age 1 and
age 2 bluefish. At other times of the year, blue crab, bay anchovy, and
7 other finfish constituted the major portion of the diets of all ages of
bluefish.

Moreover, the timing of the availability of menhaden to these diets for
their growth and survival cannot be overemphasized. Menhaden became
increasingly important in diets of older and larger predators, particularly
in the second half of the year. Much of the growth of striped bass and
bluefish occurs during these latter months. According to Hartman and
Brandt, “Atlantic menhaden are likely of considerable importance to
annual production of striped bass and bluefish because much of the
annual growth of these predators occurs when menhaden dominate their
diets.” In the September to October and November to December sampling
periods, menhaden composed over 60 percent of older (age 2+) diets. This
is not only important for growth, but also as a nutritional source to prepare
striped bass for the winter months and the following spawning season in
the spring. Reductions in this important food source during these critical
months could have a significant impact on the numbers and availability
of economically important finfish such as striped bass, weakfish and
bluefish, thus affecting fishing participation.

http://www.menhadenmatter.org/menhaden_math.pdf

Kevin
Weekend Mistress

[Bob Allen]

Hartman and Brandt: "This (Menhaden) is not only important for growth, but also as a nutritional source to prepare striped bass (for winter)

that other stuff they found in the stomachs does not provide the nutrients , vitamins, oils that are necessary. Eating clams, crabs, croakers, bay anchovies , flounder, trout is NO substitute for the nutrients provided by Menhaden to the Striped Bass population.

Rockfish and others must be fed...humans are guilty of taking the major forage base for all other species...the industrial harvest of Menhaden inside Chesapeake bay MUST stop; it will stop. The Bay will recover and come back to a more normal ecosystem as soon as commerical exploitation ceases..

Ask your congressperson to supportr lesgislation now in the US Congress to prohibit the wholesale removal of Menhaden from inside Chesapeake Bay.

Bob
Allen