Posts Tagged ‘Fred Schueler’


In the tiny hamlet of Oxford Mills, Friday evenings are Mudpuppy Night. The open water below the old mill dam offers an unusual opportunity to encounter Ontario’s aquatic salamanders in winter habitat. Dr. Fred Schueler, who has surveyed the mudpuppy population at Oxford Mills for a number of years, shares his expertise with visitors. You can learn more about the event at his website linked here. It is reported:

Since 1998 Mudpuppy Night in Oxford Mills’has been taking observers to the only place in Ontario where Mudpuppies have been repeatedly observed in large numbers throughout the winter, the longest-running winter hempetological outing in Canada.


Seabrooke and I had been trying to coordinate an outing for much of the winter and finally made it to Oxford Mills on the evening of February 21st. It drizzled for much of the day, but late in the afternoon the rain stopped and the sun came out just in time to set. We joined an intrepid group from the Kingston Field Naturalists who had made the long drive to attend.

The mudpuppies can be seen on the rocky bed of the river, highlighted by Fred’s flashlight. A few are gently netted and placed in a cooler so that visitors can get a better look at them.

This was a return visit for Seabrooke and I. We first attended Mudpuppy Night in 2011. You can find additional photos of the mudpuppies at my earlier blog post linked here.


Mudpuppies are amazing. This information is provided on the Mudpuppy Night website:

Mudpuppies, Necturus maculosus, are foot-long permanently aquatic Salamanders. They retain the gills and smooth skin of larvae as adults, and go undetected in many water-bodies because of their secretive habits. Mudpuppies are slow and cautious, though they can swim nearly as fast as a fish on occasion. In May females deposit 50-150 eggs on the underside of a flat rock. The female guards the eggs, and attends the larvae after they hatch.

About 25 years ago herpetologists realized that Mudpuppies are active, and feed actively, all winter, because they can be caught in baited minnowtraps in the winter but not in the summer. Mudpuppies were long famous for having more DNA in each cell than just about any other animal, and this winter activity has shown that the abundant DNA provides Mudpuppies with the array of temperature-adjusted enzymes they require to remain active in water from 0°-32° C. Mudpuppies are fairly common in the Ottawa River and its major tributaries, north to the Arctic Watershed, and the Canadian range extends through southern Quebec, Ontario and Manitoba.


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As we lingered on the shore of Beaver Dam Lake, encountered on the Marble Rock Trail, we noticed strange, alien shapes in the water. They looked a bit like big masses of eggs, but autumn isn’t egg season.

The largest of the blobs was about a foot long or more. The masses seemed to be anchored to branches or debris in the water. A closer look shows that the mass surface was divided into segments with star-like white markings discernable.


That evening, I sought out more information about the blobs. Dr. Fred Schueler of Pinicola kindly came to my aid and quickly identified the mystery mass as Pectinatella magnifica, a freshwater bryozoan. Please visit Pinicola.ca for a wonderful photo of a Pectinatella magnifica mass out of the water, glowing like Einstein’s brain with the sun shining through it (Page 17). It is part of a very useful guide ot freshwater species. About Pectinatella magnifica, this information is offered:

Our conspicupous Bryozoan is the vast jelly colonies of Pectinatella magnifica, filter-feeding colonies, up to two metres in diameter, that disintegrate into floating dot-like statocysts to pass the winter, and germinate into new colonies in the spring. Colonies are always composed of clearly recognizable rosettes of zooids on the surface of the jelly mass. In the water the surface appears white
from the zooids’ lophophores, and brownish when the lophophores collapse when the colony is lifted out of the water. As water temperatures fall below 20°C in the fall the zooids form into statoblasts which are saddle shaped with a single row of flattened barbed spines.


The Encyclopedia of Life offers this information:

Bryozoans, also known as ectoprocts, are a family of small filter feeding invertebrates that live as colonies in aquatic habitats. Of the several thousand species of bryozoans, almost all live in marine environments. A set of exceptions are the 19 species in class Phylactolaemata which are found exclusively in freshwater lakes and resevoirs (Ruppert et al 2004). Pectinatella magnifica, the magnificent bryozoan, is one of these unusual freshwater bryozoan species, conspicuous in that it forms the largest colonies of the fresh water bryozoans (Wilcox 1906).

While most bryozoan colonies form as an encrusting layer on algae, pilings, or other submerged surfaces, a Pectinatella magnifica colony lives on the surface of a gelatinous mass. When starting a colony, an individual animal (called a zoid) hatches from a hard seedlike “statoblast” and buds to form a small number of identical individuals. This founding clump of zoids secrete a watery fluid that hardens to form a firm gelatinous core upon which the colony spreads as the zoids reproduce (first asexually and then sexually as the colony ages ) into visible rosettes of 10-18 individuals across the surface. Before the gelatinous skeleton of a young colony hardens, colonies may fuse their masses together and form mosaic colonies from more than one genotype (Henchman and Davenport 1913). An early study found that young colonies can propel themselves across the slippery surface of their gelatinous substrate by creating water currents with coordinated beating of the ciliated tentacles on their crown-shaped lophophore organ, a specialized filter feeding apparatus common to all bryozoans (Wilcox, 1906; Davenport 1899). Pectinatella magnifica colonies can grow large, more than two feet (60 cm) across, and are found as a somewhat slimy translucent brown mass usually attached to an underwater substrate but sometimes free floating (Van Der Waaij 2009; Wikipedia 2013).


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On Friday night, Seabrooke and I went to see mudpuppies! We hummed and hawed about getting together, because the weather forecast wasn’t promising. In the end, we decided to give it a shot, and we were glad we did. The bad weather held off, and it was a brisk but calm evening.

Mudpuppy Night takes place every Friday evening from Thanksgiving to March in the little hamlet of Oxford Mills, where mudpuppies gather in shallow water below the dam. They have been studied by Biologist/Artist team Fred Schueler and Aleta Karstad for many years, and the public is invited to share this rare opportunity to see usually-secretive mudpuppies up close.


When we arrived, we joined Fred and his daughter Jennifer, and fisheries biologist Naomi Langlois-Anderson and her three young children. In addition to head-lamps, Fred had a bright flashlight that helped to illuminate the searchers. We gathered at the ice-ledged creek edge while Naomi, Fred and Jennifer waded into the water. A mudpuppy was quickly caught and released in a white bucket of water. Immediately, many hands darted out, seeking a chance to hold and admire the mudpuppy.


Here’s Seabrooke, taking her turn. What a thrill, to hold one of these beautiful salamanders in your hands! The water is icy cold. It’s amazing that the mudpuppies thrive in this frigid environment. Soon, several more mudpuppies joined the first in the bucket.

Mudpuppies are large aquatic salamanders with bushy reddish gills behind their heads. The gills are larger and bushier in warm, oxygen-poor water, and smaller in cold water with a higher oxygen content. Their bodies are and olive brownish colour, with bluish black spots. They have short legs with four toes. They can swim, but are primarily bottom-walkers.

These mudpuppies may travel up Kemptville Creek from the Rideau River and are stopped in their progress by the dam at Oxford Mills. Mudpuppies often form large groups in the fall, from late September to November, when the normally solitary males join the females. After courtship, the male deposits his sperm package (spermatophore), which the female picks up with her vent. She stores the sperm in her cloaca until spring.


There are five or so species of mudpuppies in eastern North America, but only Necturus maculosus maculosus is found in the Great Lakes region. Mudpuppies live in permanent rivers, reservoirs and lakes. In clear waters, they tend to be nocturnal, hiding beneath rocks and ledges during the day. In habitats with good vegetative cover, they may be active both day and night.

Mudpuppies eat a variety of aquatic creatures including crayfish, small fish and their eggs, worms and insect larvae. They have a strong sense of smell and will also eat carrion. Enemies of mudpuppies include water snakes, fish and herons, and of course, people. They may be caught on baited hooks by ice fishermen, and it is reportedly common practice to throw mudpuppies out on the ice to die. They are very sensitive to pollution, and are also susceptible to the chemicals used in lamprey control programs.

It was an entertaining and educational outing. Thank you to Fred and Jennifer and Naomi for this wonderful opportunity to see these neat amphibians. Below, here I am, all bundled up, holding a mudpuppy under the close supervision of a junior naturalist.


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