Freshwater plants blacklist - the impact of invasive species like water hyacinth

Discussion in 'Ponds' started by mydummyname, Oct 4, 2010.

  1. mydummyname

    mydummyname Balala shark

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    ok, i'm not sure where to post this, mods please move this to an appropriate area on the forum if neccessary.

    now we on the forum are always asking, why do they have a blacklist for this or that plant (or fish species) and we say we need the people who make up the black list to justitfy why a plant or animal is on the blacklist.

    so i watched an interesting programme on SABC2 this morning about invasive plant species, in particular the water hyacinth.

    according to the people interviewed, water hyacinth is the worst or most invasive water plant (weed) on the planet, and in south africa as well.

    it will have an impact on the drinking water of south africa, in that it forces out the natural or indiginous SA species of plants which are beneficial to our waterways, it also fouls up the water, the smell and taste of the water is negatively affected as well. it also works its ways into sewarage and waterways and even treatment plants.

    when the water hyacinth covers the entire sureface of a water area, and it will cover the entire surface, it blocks out the sun, and keeps the water temperature below 18deg celcius. we know that this will have an effect on our beloved tropical fish.

    and even more, it will, and is already affecting our drinking water in a negative way.

    because of the low temperatures and frosts that we experience in south africa, introducing natural enemies (insects) to deal with water hyancinths have been ineffective because the bugs die of the cold more easily than the water hyacinth does.

    removal by hand has almost no impact.

    use of pesticides also destroy our natural indiginous plants and insects etc.

    here are a few links with info:

    http://web.wits.ac.za/academic/science/apes/research/water/waterhyacinth.htm

    http://www.dwaf.gov.za/wfw/

    http://www.iol.co.za/dwaf-to-blame-for-roodeplaat-dam-1.413815

    please guys, if you do have any of these plants in your ponds, do not get rif of them by just throwing them in the dirtbin or in the drain, rather bury them or someting.

    please feel free to add anything i may have missed or gotten wrong.
     
    Last edited: Oct 4, 2010
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  3. larch

    larch

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    To be fair saying that all blacklisted species are as invasive as the water hyacinth is a bit unfair. How many imported fish and plant species that we keep in our own aquariums have become such a massive problem in our local water ways like the water hyacinth?

    Hyacinth is a good indicator of bad water quality as they thrive in polluted water, so the fact that they have a impact on the drinking water is pretty mute at the moment. We need to remove the water pollutants before we can remove the plants. You dont cure a patient of illness without finding the cause.

    We have indigenous tropical fish in South Africa?

    The real problem is here, you solve this you solve everything else:

    Source: http://www.news24.com/SouthAfrica/News/Govt-labour-to-address-water-crisis-20100928

    Improve water quality, monitoring and management and the rest will follow.
     
  4. OP
    mydummyname

    mydummyname Balala shark

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    hi boet, i think you are misunderstanding me, i'm not saying all species are as invasive as water hyacinth, but that water hyacinth is considered to be the most invasive.

    water hyacith is not THE MAIN PROBLEM with our water, i agree fully with you there, but it will and does have a very bad impact on the water as well.

    ;)
     
  5. TankMaster

    TankMaster Apistogramma

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    You see, being invasive may not be the only reason why some plants are blacklisted.

    Cannabis is not invasive but it is illegal? Some water plants fall into the drug category as well.

    Some plants may spread diseases in ideal climate conditions that we have. Some are just blacklisted because the authorities feel like or they are endangered.

    Take the shrimp argument into consideration. Okay, they do breed fast but they are at the bottom of the food chain and most catfish will eat them in nature. They may not seem invasive to busy systems but given the ideal, isolated region, they can multiply fast . . .. even this does not make them invasive because they don't cause harm to plants or other animals. They are merely a food source for most fish. Some shrimp may be endangered so this might be the reason why all are blacklisted . . . A case of specific shrimp being unidentifiable when compared to invasive/ quick breeding species.

    Anyway, let's cross our fingers for shrimp being removed from the blacklist.

    TM
     
  6. OP
    mydummyname

    mydummyname Balala shark

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    i doubt it bro...


    fresh water shrimp.. now that would make for a way cool setup!!
     
  7. larch

    larch

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    But you see people are going at this the wrong way you will never be able to remove water hyacinth's from our local dams till the water quality is improved. And that is what annoys me they are basically pissing in the wind, because they aren't treating the cause they are treating the issues. Remove the cause and the issues will clear themselves up.

    Water hyacinth's grow so nicely in our damns because of the high levels of nutrient found in the water because of agricultural runoffs and raw sewage being dumped into our rivers and dams take those away and you will basically starve the plant.

    Tank Master has a point, I doubt any type of shrimp would survive in our native waters there is just to many predators and other variables that needs to be looked at. And I think the people who draw up this list dont really go out there and do their research properly and do case studies to see what will actually survive in our waters.
     
  8. Vis

    Vis Gerhard

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    I think there is something to remember. If everything should be on the BL I do not know.
    One would have to consider that one single sprout do have the potential of wiping out a whole
    eco system. Can we really afford to take that chance because we like it in our tanks?
    Do not think invasive plants get in in bucket loads.
     
  9. Henk Hugo

    Henk Hugo

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    You really dont have a clue do you? What about the native shrimps?
     
  10. larch

    larch

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    As far as I know we have 2 fresh water species of shrimp: The Common Shrimp and the Black Shrimp dont ask me for their scientific names because fisherman rarely use those (The vaal river is full of shrimps, we sometimes use them as bait) but here is some pictures:

    [​IMG]

    Now back to my original point, was there ever an impact study done to see what would happen to the local population of shrimp if an alien species managed to survive in our waters which I doubt would happen because:

    1. Brightly colored shrimp in our local waters, wouldn't stand no chance against predators. Their natural color is no conducive to hiding from predators like fish and birds, they might as well have a bright red x painted on them.

    2. Our local shrimp have already built in mechanisms and survival tactics to avoid and escape predators invading species wont and their is a lot of predators out there like the Great white pelican, you see them at most of the bigger dams while fishing.

    3. River and dam conditions, have you ever swam in a local river and dam in the middle of winter? The water can easily drop between 15 - 10 most imported shrimp species wont even survive those temperatures, not to mention the over polluted rivers and dams.

    Now everything above I mentioned is pretty much speculation on my part at this point and speculation cant replace proper studies. But at this point it is better than DEAT just stamping everything that might have a 0.001% chance of surviving in our waters without doing proper research. Which costs money and resources something they dont have. So they take the easy way out.
     
    Last edited: Oct 5, 2010
  11. OP
    mydummyname

    mydummyname Balala shark

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    i agree, just because the govt is not doing their part to get our water systems in the right condition, it doesnt mean that we have a right to make the problem worse. two wrongs will never make a right and if it all really goes to pot and the eco system fails, we might not even be able to sustain our hobby in the future. this is not just about us here in South Africa. our tropical hobby fish come from various parts of the world, and they have the same problems over there with invasive species. but fixing it should start somewhere. why not with us?

    what if our water problem gets so bad that water is rationed or not available in the future? THIS IS ENTIRELY POSSIBLE - RECENT STUDIES HAVE SHOWN THAT SOUTH AFRICA MAY RUN OUT OF DRINKING WATER IN 15 YEARS TIME.

    then, no-one will think about keeping fish but about where they gonna get their next drink of water from.

    added to this, if there is no drinking water, there is no food, coz you cant feed livestock or grow crops if there is no water.

    the possibility of this happening is real guys.

    if you dont have water to drink, i guarantee there will be no water for fishkeeping.

    ---------- Post added at 09:10 ---------- Previous post was at 08:10 ----------

    we have native shrimps?

    lol
     
  12. TankMaster

    TankMaster Apistogramma

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    Okay, Larch has a very well rounded argument here but I noticed arguments about Blacklisted stuff becomes really heated.

    As enthusiasts, we know for a fact that shrimp numbers grow and drop daily, since they are on the menu. If one had to get rid of Red Cherry Shrimp in the local river system, they will last about a day or 2 because of their bright color.

    In fact, the reason why they might be blacklisted is because they are on the menu. What I mean is, if there is an invasive species that relies solely on shrimp for their diet, they will eventually multiply uncontrollably with the abundance of food.

    Remove the food, and you remove the fish . . . . .you also indirectly strike an imbalance in the river ecosystem!!

    As far as invasive fish and plants go, there is nothing that can be done. Blacklisting stuff is just going to make people want it more. It's already in our freshwater systems and cannot be eliminated without killing off our native species too.

    Just be grateful that we don't have silver carp and big heads in our water!

    TM
     
  13. OP
    mydummyname

    mydummyname Balala shark

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    ag, i dont think its really heated? the thing is when we have these discussions people get educated (especially me lol) and that is the important thing, we are always learning something..

    i saw that program about the bug head carp! they totally destroying the fish and plankton life in the rivers of the USA!! freaking flying fish!!
     
  14. larch

    larch

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    I dont view these as heated debates rather constructive debates, if you dont get to talk or debate on a taboo subject like blacklisted species then you dont get to inform others or yourselves. And hell I learned a view things while researching the subject.

    Well for the most part the Vaal river is over populated with our local variety using a casting net you can catch hundreds of them in a single throw. So even if on the off hand chance some lucky shrimp survives it still has to compete with the local variety.

    The problem with that is that the invasive species need to survive beyond that point to start multiplying before we can get to that point, and most of the fish and invertebrate species on the blacklist wont survive our winters due to our cold temperatures in our local rivers and dams.

    It depends really if we are talking about removing hyacinth then no local species would be affected because they dont really feed on water hyacinth hence they have become a problem. Now if we start talking about carp then it is a different story because local fish like yellow fish and barbel feed on the young and fry. Not to mention birds and crocodiles.

    I agree with you 100% on that, but you have to look at all the invasive species that have become a issue in our waters. How many of those species come from fish tanks and pets shops? Things like carp and bass weren't introduced through those methods but years and years ago by people who wanted better sports fish. Hence I think the whole blacklist needs to be reviewed from scratch and each fish/invertebrate needs to be handled on a case by case study to see if they would survive in our water.

    And to add on to my previous statement about water pollution being the main issue I found this on the Friends of Rietvlei website and makes for an interesting read:

    http://www.friendsofrietvlei.co.za/WaterHyacinth.html

    Nitrates and phosphates come from raw sewage that gets dumped into our water table by the local municipality who cant handle the current sewage loads. Even worse mines who want to cut prices and corners and not treat mine water...
     

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