Pond Boss Forums GENERAL QUESTIONS Help Brackish Pond questions...

Hi All...

I have a smallish, semi-natural, 30x30x20d brackish pond that the previous homeowner put in when they built. My land backs up to a saltwater marsh on Cape Cod MA. There is an eel grass marsh that they decided to connect to the pond via a buried PVC pipe. So, when the tide is high enough the marsh floods and flows into the pond.

I think the theory was that the salt water would keep the plant life and algae at bay. It doesn't.

My question is what can I do with this... I've yet to find a fountain or fish that can tolerate the environment. I think for any fish that could tolerate the salt, carp?, I would need to aerate. But the saltwater implies a stainless pump (I think) and these are outrageously expensive.

I'd like some sort of fish, for visual interest, and to cut down on the cattails and the like around the edge.

Any ideas for aeration/fountains or fish for this envieonment?

thanks,
-Tom

Blue Gill outnumber the RedEars except in brackish waters here in the south. They seem to thrive in sorta salty environs.

I think HSB can handle brackish water as well.

Welcome to the forum danap!

Any idea if you have any fish in there presently? Any idea how brackish your water is? Technically, brackish water contains between 0.5 to 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (ppt or ‰). Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time.

As is the case with many "salt" ponds, the salinity levels fluctuate greatly! Any idea on the maximum depth your pond contains? There really are not many species that can thrive in environments such as this...

Most "freshwater" species such as bass and sunfish tolerate salinities up to about 10 ppt, but some species are less or more tolerant than others. Without knowing the salinity range your pond experiences, I would recommend some fish that are highly tolerant of a wide range of salinity levels.

These fish species would be:

Mummichog, Fundulus heteroclitus is a species of killifish and is highly tolerant of salinity level fluctuations. It would probably be the ideal forage fish for this pond. You should be able to easily collect them with a minnow trap in the waters around your pond as they are native to your area.

Sheepshead Minnow, Cyprinodon variegatus is another species of killifish highly adapted to changing salinity levels. It too is found in your area naturally and can be caught the same as the mummichog.

Rainwater Killifish, Lucania parva is another species of killifish, can you tell killifish dominate the brackish water? It too is adapted to the changing salinity levels of a "salt" pond. It is also native to Massachusetts and should be easily caught with the other species previously mentioned.

Striped Killifish, Fundulus majalis is the last species of killifsh that is adapted to this environment and is native to your area as well. It is the largest of the mentioned species and can be collected in the same manor.

OK, those species can be used to build your food chain. I could collect a couple hundred of as many of the species as you can find and introduce them to your pond. Give them about a year to multiply and then look at these species to add to your fishery.

As Theo said, hybrid striped bass(HSB) has the striped bass as their parent species. Striped bass are anadromous and therefore adapted to full sea water all the way to completely fresh water. Their hybrid has taken on these characteristics and where stocked have been found to migrate with their parental species into oceanic water without any issues. So HSB could definitely be an option to stock. However, I would check with Massachusetts before stocking as many east coast states are now banning the stocking of HSB into waters that drain into the Atlantic for fear they will cross back with striped bass and cause genetic loss.

White perch is another species you can consider. They are very similar to striped bass, in that they are anadromous and can tolerate full sea water to complete freshwater. They are one of the few species that is naturally found in "salt" ponds so they should do quite well in your pond.

Now, this is where the tricky part comes... Just how salty is your water?

These species are "freshwater" fish, but are more tolerant of higher salinity levels than most.

Yellow perch are very salinity tolerant, I catch them in salinities into the mid teens in the Potomac River.

Channel cats are also tolerant to fairly high salinities. In the spring when heavy rains comes, channel cats are often caught well into the upper Chesapeake Bay where later in the summer bluefish and cobia can be caught!

Redear sunfish are probably the most tolerant of higher salinities and pumpkinseed sunfish are as well for more so than bluegills.

I have also caught brown bullheads or as they call them in New England, hornpouts are very tolerant of higher salinities.

Carp are only tolerant to about 10 ppt and 15 ppt for short periods. Koi are just fancy colored carp so should have the same tolerance to salinity as carp.

Now, there are some "saltwater" fish that can tolerate lower salinities. The issue you run into is many of these species are highly migratory and cannot handle the cold winter water temps. Species like croaker, spot and red drum from the family Sciaenidae are all tolerant of lower salinities and in Texas where waters stay warm enough, red drum have been introduced with some success into freshwater impoundments. You could perhaps catch fish from the wild, put them in your pond in the spring but know they will not survive the winter cold water months. Even needlefish can survive and spawn in pure freshwater and can be found far up the Mississippi and are native to Massachusetts, but again they cannot survive cold water temps.

My recommendation is to try to find out what the maximum and minimum salinity levels are of your pond. Once you know that, you can better choose what species will live in it. However, any of the killifish species I mentioned should do fine along with the white perch. HSB should also survive, if the pond is deep enough to maintain sufficient DO levels and to not have winter die offs.

Salt ponds are a harsh environment! There is a natural salt pond on the preserved next to my father's place on the Chesapeake Bay. The fish life in it is limited to killfish and immature white perch with some hogchockers and rarely immature summer flounder.

Consider cutting the PVC pipe connection off from your pond? This should eventually allow the pond to become mostly freshwater and allow more species to survive in it... There isn't a species of fish out there that is going to cut back on cattails, you'll have to manually remove them or spray them with the correct herbicide. All the species I mentioned that should be adapted are not overly colorful, but some are rather interesting to watch. They should help keep your pond mosquito larvae free as well...

wow... thanks for the input all! I appreciate the time and thought put into my question.

I will endeavor to find out just how salty the pond is. I guess that's a good obvious first step.

I do occasionally see 'minnows' racing around the edge that must get flushed in from the marsh. I never see dead fish, but the minnow activity is infrequent so I think they either die off or get eaten by something eventually.

I *think* the pond is ~20ft deep. The sides are very steep, and I can only walk into it 4-5 feet before I'm chest high. I had been thinking it needed aeration to support any real lifecycle.

I'll do some tests and see where that goes.

thanks!

denap,welcome to the forum.Try to get a little more info on the size and depth of your pond and start a post under areation.They be some pretty smart folks who check in there regularly.