Interesting speaker at RISAA tonight

[MikeToole]

Not sure if I'm reading this right but from the meetings I've been to on this topic. When Pennsylvania gets heavy rain in the Susquehanna basin this washes large amounts of nitrogent and phosphorus from fertilizers into the bay. This increase in nitrogent and phosphorus, called "nutrients", causing algal blooms which reduces sunlight in the water causing a reduction in the amount of oxygen in the water. This reduction in oxygen causes fish kills and reduces the amount of plant life. You will often see posting about dead zones in the Chesapeake caused lack of oxygen. Often getting worse in the summer as temperature also comes into play.

One problem being that the seasonal rains and heavy fertilizer use both occur in the spring. Since 1987 this has been a focus area for bay protection. Actions such as bans on detergents with phosphorus in them and improved sewage treatment are helping but it is still a big issue.

[MAKAI]

I read that a menhaden can filter the phytoplankton in up to five gallons of water a minute. This helps prevent algae blooms.
The clearer water means sunlight can penetrate deeper which promotes the growth of oxygen producing plants.

According to the U.S. Department of Commerce fishery statistics, Omega protein landed 1.5 BILLION pounds of menhaden in 2007.

Thats a lot of water clearing biomass removed.

Menhaden is used for health supplements, fertilizer,animal feed,lipstick and industrial lubricants.

Connect the dots, it's not good for the bass.

Menhaden help put oxygen in their nursery and provide their natural perfect food.

Last spring I was catching high 40 inch fish in skinny water on 12# test outfits. They pretty much were one run and done. Poor anorexic fish had no fight in them. That is not the way it should be. There may be many but their overall health sucks. Refugee fish, we as a group so much miss the bigger picture on this. It would take a miracle to cure all the issues this fish is about face. Too bad, for we are Legion, and could be heard.

[DZ]

Interesting - I remember that same theory coming to light when the stocks started to tank in the late 70s early 80s.

Another theory at the time was sun spot activity.

DZ

[RIROCKHOUND]

Originally Posted by MAKAI

I read that a menhaden can filter the phytoplankton in up to five gallons of water a minute. This helps prevent algae blooms. The clearer water means sunlight can penetrate deeper which promotes the growth of oxygen producing plants.

The speaker was David Bengtson, nice guy and knows his stuff!

As far as the other stuff, if you dig into the science behind the filtering claim, it turns out adult (the size that are captured commercially) filter large plankton (i.e. zooplankton) the small algae and phytoplankton pass right through their gill rakers... so this argument is not really accurate... Google Seagrant Menhaden symposium, there is a lot of info in that report. I'm not sure on the science for this next line, as it comes from my head, BUT there is a leap there that if there is a ton of pogies, eating all the zoo plankton, then there are less of them to prey on the algae and phytoplankton, and maybe you'd still have low-oxygen events and such.

that being said, I am 100% Omega and the reduction boats catching billions of lbs/year... but putting the devil moniker on the bait boats probably isn't that fair, especially when they are catching a targeted, monitored quota like they do in RI

Paul,
NAO is a cycle (or a quasi-cycle) not an anomaly...
we can have long chats about it at some point. it doesn't just impact fisheries. But I bet it also has a huge impact on fish that spawn offshore and then migrate inshore i.e. pogies!

[Mr. Sandman]

I'm with DZ and others...Back in the early 80's there was "direct proof" that heavy rain in the upper chesapeake bay region would cause run off from farmlands that contributed to fish kills. This problem was largely addressed as an element to the moratorium if I remember correctly. I recall that farms had to install protection so that runoff directly into the water was avoided.

Now they are saying heavy rain contributes to the population? Hmmm. I would question that. We had a hell of a lot of rain last year and the YOY index was no record breaker.

[MAKAI]

Digging a little deeper into the science I found this note, in a report to the VMRC by Drs Nathan Smith and Cynthia Jones, regarding isotope values in Menhaden.
" Previous studies of menhaden diet based on stomach contents indicated phytoplanktivory, but while they may consume phytoplankton, zooplankton may be much more important than previously reported"

Seems to me I must have read a previous study.
Ahh, more nebulosity.
I will get my shovel and dig some more.

[MakoMike]

Originally Posted by MAKAI

I read that a menhaden can filter the phytoplankton in up to five gallons of water a minute. This helps prevent algae blooms.
The clearer water means sunlight can penetrate deeper which promotes the growth of oxygen producing plants.

Living algae, like all plants also produces oxygen during photosynthesis, it only consumes oxygen (again like all plants) when it dies and begins to decompose.