zebra mussels

For an updated article on zebra mussels, check thr following site:

http://enn.com/news/enn-stories/2001/08/08222001/mussels_44691.asp

I heard on the radio friday tha sheephead eat Zebra Mussels? Any truth to that?

Hook

excellent information John!! thanks for the link…….

as for sheepies… they have been documented feeding on Zebes in a visual study conducted in lake Champlain in New York… some of our fellow “boarders” have also mentioned see them being “puked” up by larger sheepies that they have landed……

John,

Thanks for the information. I jig the wingdams in both Pool 3 and Pool 12 quite a bit and often pull up zebra mussels in pool 12 but I’ve never seen one in pool 3. Even when I’ve snagged old pieces of metal in pool 3, they’ve come up clean. Pool 12 is a different story. It’s not at all uncommon to snag zebra mussels on the wingdams down there. Has anybody else found zebra mussels on Pool 3? I heard Prairie Island nuclear power plant caused a minor fish kill last year when they were trying to clean zebra mussels from some pipes so they must be in pool 3 but I’ve never seen one. In the little bit I’ve fished pool 4, I’ve seen them there a couple of times. I meet some zebra mussel research divers that were returning to the Prescott ramp on pool 3 a couple of years ago and it sounded like they were trying to determine why pool 3 didn’t have many zebra mussels but some other pools do.

Also, I understand that once the zebra mussels reached the great lakes and the inland water ways, they spread very rapidly. Their introduction is blamed on ballast water being dumped into the great lakes. I assume ocean going vessels have been dumping ballast water in the great lakes for decades. Was it just one unfortunate instance that resulted in the introduction of the zebras or did something else occur that allowed their introduction?

Thanks for sharing your technical expertise,

Boone

Zebs have a unique life cycle that can explain why they are abundant in one pool and not some pools further upstream. Eggs hatch into a intermediate form know as a veliger, it is microscopic and it drifts with river currents for up to 8 days before settling out onto a solid substrate (clams, rocks, boat hulls, docks, etc) and attatching by small threads of protien called bysal threads. The veligers can be very abundant in the water column during the summer period (July and August) and a cup of water can hold up to 100 individuals. With this type of life cycle, there is usually a spawning population, and then a settling area a distance downstream. In the settling area, zebs can be very dense – up to 90,000 per sq yd. To populate upstream pools, veligers must somehow get upstream (and they do not swim against the current). This can only be done by transport of some type. So, upstream pools never benefit from drifting veligers- the bottom line with this type of life cycle is that downstream pools will generally have much higher populations than upstream pools.

As far as the introductions by ballast water is concerned – I have no idea what changed with respect to shipping and why the transport of veligers did not occur earlier. It is just sad that it all could have been prevented by exchanging ballast water out on the open ocean – but then, that would have cost money by running the pumps and cut into profits I suppose.

As far as most researchers can determine – the first veligers were introduced sometime in the late 1980’s. Maybe prior to that time – all the ships were loaded with cargo. It is my understanding that the reason they fill their holds with ballast water is for the ship to ride more smoothly when it is empty.

Hope this helps.

I for one have not had the dis-pleasure of dealing with the Zebs in pool 3. I do have a buddy who is a commercial diver who works at P.I. and said that there are very few Zebs in 3. Pools 4 on down have been making him a lot of money. It is not easy work either! You guys and gals that have tried to walk on some of Pepin’s beaches know of what I speak! One other note, why doesn’t the Corp of Engineers get in on the act, and put up a sign on the lock to drain all bilge water before entering???

EYE GUIDE,

that’s not a bad idea. But what about live wells?