In the dew of little things

Wildlife-swimming tours are big business. Now you can travel to Scotland to swim with basking sharks, take a boat ride off the northern coast of Western Australia and get in the water with majestic whale sharks, or spend a few days in Tonga being totally blown away by close encounters with humpback whales.

Swims such as these truly are wild, and provide completely unforgettable experiences. However, there is an untapped market in wildlife swimming that can, with a bit of expectation management and a squinted sideways glance, provide encounters just as exhilarating as those with the megafauna superstars. Well, almost.

I’m not talking about anything as large and dangerous as a shark, nor even as big as a beaver or platypus.  I’m talking about the wildlife that inhabits almost every lake and river suitable for swimming- the aquatic invertebrates. Below are some examples of the elegant creatures you may encounter:

Aquatic invertebrates – the microfauna superstars

Just the idea of aquatic invertebrates, those creepy-crawly things in the water, is enough to keep some swimmers doing laps, but even pools are not as devoid of life as their caretakers would like. I often see backswimmers tumbling in the turbulence of my arm strokes as I pass overhead. And like most things we’re a bit nervous about, they’re not so bad once you get to know them.

One of the best things about swimming in lakes and rivers is that they are full of life that it forever changing; daily, through the seasons, or on some other timescale beyond the ken of a swimmer. Invertebrates constitute a large, and readily accessible component of this life. In fresh water, insects and crustaceans are the main kinds that we will encounter, but with a bit of searching in the right spot, you might also come across small jellyfish, freshwater sponges, small mites, flatworms, and amazing little creatures called hydra that are related to jellyfish but are attached to weed and dangle their tentacles in the water to catch prey.

Larval dragonfly – the lions of weed beds

Anyone who has kept a larval dragonfly in an aquarium with other insects will appreciate the drama that exists in the underwater world.  Dragonflies are the lions of the weed beds. Perfectly camouflaged, they sneak slowly up on their prey, either by crawling slowly or by underwater jet propulsion. Once in range, their bottom jaw shoots out with the speed of a striking snake and grasps the unsuspecting prey in specially modified teeth.

Bloodworms – nature’s eco-filter system

One of the best groups of filterers are the bottom-dwelling larvae of non-biting midges, which make contributions far beyond their minute size. Bloodworms, as they’re collectively known because of their bright red appearance, build small tubes less than 1 mm in diameter through which they filter water. In doing so, they trap dissolved nutrients and small particles of carbon. Recent research has demonstrated that the millions of bloodworms living in small lakes can filter the equivalent volume of the lake in scales of days to weeks.

What is more, the global contribution of bloodworm filtration is so vast that it can mediate some of the factors contributing to climate change. The humble midge isn’t so humble after all!

Midges are just one group of invertebrates living in fresh waters, and filtration is just one of the services that aquatic invertebrates provide. Countless other species help break down organic matter, farm bacteria, burrow through the sediments, graze bacteria, and otherwise maintain our aquatic ecosystems like minute gardeners tending their little patch of river bed.

Indeed, almost everything living in the water contributes to the health of the ecosystem in some way. In fact, councils use the aquatic bacteria, insects, and small crustaceans in water treatment plants.  They are also key players in sewage treatment; cleaning water after we’ve finished with it so that it is of a suitable quality for release to the environment.

The Roger Deakin way

“For in the dew of little things, the heart finds its morning and is refreshed.” That is Khalil Gibran’s way of saying stop and smell the roses. For outdoor swimmers, this means occasionally slowing right down in order to get to know the aquatic creatures in your local swimming hole. While larger aquatic invertebrates can be observed with a pair of goggles, smaller ones can be caught with a small net and placed in an aquarium. This is something Roger Deakin did to familiarise himself with the residents of his moat, and it is something that everyone can do.

The mindful swim

I’ve written mostly about the invertebrates living in fresh water, but there is also fascination in fish, frogs, salamanders and tadpoles. Marine and intertidal areas have a whole suite of animals from limpets and crabs, to anemone and fish. And don’t forget to lift your gaze to the things above the water; the birds flying overhead, or the otters along the shore. Aquatic environments are alive, and their inhabitants are well worth taking an interest in if for no other reason than you’re guaranteed to make each swim even more interesting, mindful even.

Author Peter Hancock recently achieved 1000 days of swimming. Read about his experience here.