Saturday, April 13, 2013

Ottawa River Deep Ecology (oil on canvas 12 x 24) commissioned by DFO


13 April finds me deciding that this painting is finished. It is always chancy to reconstruct a scene, especially when photographic reference is hard to come by. People who commission paintings often have no idea how much reference is needed! I often keep wondering for weeks after a
painting is finished, whether I should further develop one part or another, especially in cases like this, where I don't have any comparable scene for reference. I would love to take up scuba diving and then I could go down there to see for myself - but since Fred and I have always relied on Muskrats for the underwater parts of our unionid surveys (collecting the shells they leave in piles where they feed by the water) I have not recently broken the surface of the mysterious  underwater world that is so important to my imagination. As a child, before I learned to swim with my head above water I felt at home inside it, with my eyes open and my nose held closed.

The fresh water mussel researcher at Fisheries and Oceans Canada asked me if I would paint an Ottawa River scene with a Sturgeon over a mussel bed, and I supposed that there would be enough photographic reference to do that, so I agreed. However, the people who photograph live mussels have focused on individual mussels, and though I searched intensively and badgered people by e-mail, including the "Unio-L" e-mail list, and the most I found from the Ottawa River were of fishermen with their catches and before and after shots of groups of divers. However, I found a few good photos of Sturgeon, both in and out of the water.

I know that the Ottawa River has a logging history, so I painted an old waterlogged White Cedar lodged among the rocks of the bottom. The rare mussel called the Hickorynut, Obovaria olivaria, was to be featured in the painting, so I acquired photos of live individuals from researchers, and also photos of living Ligumia recta (the dark ones with pale grey mantle fringes) and Lampsilis, which are gold with green rays. The pearly purple pair of opened valves directly beneath the belly of the Sturgeon is our most common fresh water mussel in eastern Ontario, Elliptio complanata, and the live ones are slim vertical shapes, mostly in the background.

In my painting, the umbos of the two Obovaria that are in traveling position are eroded into round white spots by the acidic water of the Ottawa River, which flows off the granitic Canadian Shield. The large one that is half buried with its opening facing out is in position for feeding. Water flows in through the fringed siphon hole and out through the smooth one, and bits of organic material collect on its gills, trapped by mucous and drawn into the digestive system.

Obovaria olivaria is listed as a Species At Risk, and one reason given for its rarity is its dependence on only one kind of fish as the host for its young - the ancient Lake Sturgeon (Acipenser fulvescens), whose kind is older than the Dinosaurs.

In the Ottawa River, Obovaria had been known only from a few specimens since the 1880's, but in the 1990's, concern for the status of native freshwater mussels became acute as Zebra Mussels wiped out native mussel populations all across southern Ontario and Quebec.

The the post-Zebra Mussel rediscovery of Canadian O. olivaria (now often referred to in government publications as the "Olive" or simple "Hickorynut") began on 18 October 1999, when Fred and our daughter Jennifer found one fresh shell on a bouldery tidal St. Lawrence River shore, 1.7 km west of Deschambault.

Then on 29 April 2000, 580 km west of the Deschambault site, during a very low-water spring, Fred and Robin Mellway found shells in the muddy claybelt Blanche River at Judge and Belle Vallée, and again along the Ottawa River at nearby Notre-Dame-du-Nord. These were 300 km upstream of previous Ottawa River records.

On 18 August 2001, with the river low from drought, Isabelle Picard, Jean-Francois Desroches, and Fred made the big break in collections upstream of Ottawa, finding shells at Portage-du-Fort, Rapides-de-Sable, Chenal-de-la-Culbute (near the Highway 148 Waltham Bridge), and a living individual at Rivière Coulonge below Hwy 148 (see the sketch). We've been back to several of these sites at times of normal water levels, without seeing any Obovaria shells.

In 2005, André Martel and Jacqueline Madill checked a location, where, on 2 September 1962, Joyce and Francis Cook had picked up an old eroded Obovaria shell on the shore of the Ottawa River at Crown Point, west of Ottawa. André and Jacqueline found no shells on the shore, or by diving in adjacent shallow water.  Then, 
Hickorynuts were found by SCUBA diving farther out in the river, at depths of 1.5 and 6 m, in an extensive underwater area of pure sand covering nearly 3 square kilometres. The Hickorynuts were scattered among abundant mussels of other species, at a density of 0.01 -0.05 individuals per square metre, so the population of this Species At Risk in these sandy shoals was estimated at 10,000-30,000 individuals. This is a substantial population, and similar habitats elsewhere in the Ottawa River have not yet been explored.

Hickorynuts are typically found on sandy substrates in deep water (compared with other species of mussels), at depths usually exceeding 2 to 3 m, with a moderate to strong current. It seems that they are not brought up to the shore by Muskrats except when there have been exceptionally low water levels.

In 2010 Isabelle found a shell at Plaisance, and in 2011 Fred found shells at Petrie Island, showing that the species also occurs downstream of Ottawa.

Between the clusters of known populations there remains the great length of the unsearched Ottawa River, and the very important question of whether the fluctuations in water level due to hydro dams would suppress the populations of a deep water species as much as they do those of shallow water mussels. Maybe Obovaria is thriving in all the hydro impoundments between the Saint Lawrence and Notre-Dame-du-Nord (and, who knows, maybe up into the interior of Quebec?), and nobody has ever looked in deep enough water in the impoundments. The long unimpounded stretch of the river between Lac des Chats and Des Joachims, past the aptly named Deep River where I did a painting in early spring, is also mostly unsurveyed.

We've had reports of "no mollusca" along the dammed shores in Ontario from MNR personnel and personal surveys, but since we need drought to find Obovaria shells along natural rivers, maybe there's just no way shells could become visible at the edge of a hydro impoundment, with little current, constant water level fluctuations, and barren shores inhospitable to Muskrats. 




3 comments:

  1. If you're on the shores of a sandy river in northern Ontario or Quebec, or along the Ottawa or St Lawrence rivers, at times of low water, you can look out for compact heavy shells, and send the specimens or clear photos of them to me , Isabelle Picard , Jackie Madill , or Todd Morris . Those who are SCUBA diving for whatever reason can also look out for Hickorynuts. The recent range extensions suggest that there must be other Sturgeon-inhabited rivers, including tributaries of lakes Huron and Superior, where the species occurs.

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  2. Having grown up on the Ottawa River in the area of Dunrobin Shore, I can say that you have done an excellent job of recreating a river bottom scene including the colour of light that I remember from our daily swims and dives off the edge of a "drop off" in front of our cottage. The shore was rocky - big circular domes of rock with sharp tops - I think they have been studied along that area as they are quite unusual. Anyhow, once you waded further out, the bottom dropped away and there was a sudden drop off. There was a large boulder just on its edge, so we would stand on that, wearing our masks and fins, then dive forward and down and stay down as long as we could before heading back to the surface. As it happened, there was sand on the bottom and a mussel bed and the odd boulder and sunken pulp log (there were always waterlogged pulp logs on the bottom). As for sturgeon, I never saw a live one, but one time my dad discovered a tangled mass of line and hooks with several dead sturgeon hooked to it, floating on the water near our cottage. He reported it to the police or MNR - this is a long time ago, so I'm not sure who came to investigate (MNR, I think). I remember the sturgeon as being very large - a child's eye view - but I do think they were whopping big compared to any fish I'd previously seen hauled from the Ottawa River. Anyhow, excellent work on piecing together this scene from relatively sparse reference material, Aleta!

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  3. Excellent work folks; Aleta, I simply love your painting of the underwater scene in the Ottawa River; the sturgeon, the log, the mussels, the rock, all look as when we are scuba diving in that river. Also, Fred, you have put together an excellent summary of the events surrounding the observations of the Olive Hickorynut mussel in our region.
    A+
    André L. Martel
    CMN-MCN

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What do you think of this painting, and what do you know about the subject that I have painted?