Learn | Aquatic life
Leeches: Are they really so menacing?
Many of our clients complain when they notice leeches in their ponds. The complaints are based on fear, but are they really justified? In the following article, we will clarify the role of leeches in the aquatic ecosystem and learn about some of the advantages of having leeches in your pond. You’ll see, they really aren’t so terrifying! In total on Earth, there exists close to 700 different species of leeches. All are carnivores but not all are hematophagy (who are nourished by blood), many only eat worms, molluscs, insect larvae, and other little organisms that populate the aquatic environment. Of those that enjoy blood, few enjoy human blood. In Canada, only one leech species will chase your baby toe in the water: Macrobdella Decors, or the medicinal leech of North America. Other leech species that feed on blood will choose frogs, snails, turtles, and ducks over your tender flesh any day. In Europe, there are many species of bloodsuckers that prefer human blood. The most famous of these being Hirudo Medicinalis which is now close to extinction but was once used widely in medical practices across Europe for treating many human ailments.
Since human blood is not always easy to find (few of us stroll in the water for the simple pleasure of feeding our friends (Macrobdella Decors), this last evolutionary period brought frogs to thrive in our ponds. Frogs are the second favourite food for our leech friend. We generally find frogs in many water environments today, calm waters either warm or cold are normal homes to many species of frogs. Better than baiting leeches with bottled contraptions of rotting meat; consider going to the source of the problem by reducing (in a food chain sort of way) the leech population. Back to the frogs, if frogs are abundant, leeches will be too. Reduce frogs, reduce leeches.
Who eats frogs you ask? Small-mouthed bass eats frogs and tadpoles and they are suited to warmer pond water. Before you leap to the natural conclusion about fragile frog populations, introducing a few bass into your pond won’t eliminate all frogs, nor all leeches, it will simply help control a problem situation. And barbequed bass tastes great!
Leeches also tend to use the accumulation of muck and debris at the bottom of your pond as a habitat and hiding place from fish. The best way to banish leeches from your pond is to remove this habitat. Meticulous care in removing falling leaves and debris using an aquatic lake rake, adding muck digesting bacteria and making sure there is proper water circulation and or aeration, will deter leeches and with nowhere to hide the leeches will be picked off by your fish population.
Leeches are a wonder of nature that deserves our admiration. To avoid attracting our attention and for efficient latching, the leech injects us at the precise moment of attachment, with an anaesthetic and an anticoagulant. Even though they do not transport any disease, care (cleaning and covering site) must be taken after the leech detaches, since blood can continue to flow for up to 10 hours afterwards. Isn’t that amazing! So what are you to do when a hungry leech attaches onto your leg? Don’t panic! If you are patient, you can let the leech take breakfast (it never overeats!) then it will detach itself as quietly as can be, and go and hide at the bottom of the pond for weeks or months. Remember, you won’t feel any pain from the leech, only a heat sensation at the dinner site. The pain comes when you try to rip off the leech from your skin. If you cannot wait for the Macrobdella Decors to finish eating, carefully dislodge it with the odour of a burning cigarette or sprinkle salt on it.
Leeches are not detested by everyone. Their analgesic, anaesthetic, and anticoagulant virtues have made many micro-surgeons happy; to such a point that a company in England specialises in the commercialization of these little critters. So just remember, there is only one kind of leech in all of Canada that wants your blood, if it finds you it won`t hurt, in fact, it is inviting you to become a part of its food chain. Just stock your pond with small mouthed bass, and eventually, you’ll get your blood back! Happy pondering!