Wednesday, September 27, 2017

Field Trip - Boardman River Fish Weir, Traverse City, MI

Coho and Chinook Salmon are not native to the Great Lakes.  They were introduced into the Great Lakes in the 1960s by the Michigan Department of Natural Resources (DNR) in an attempt to solve two problems.

The native population of Lake Trout was nearly extinct due to a combination of overfishing and predation by non-native Sea Lampreys.  Also, populations of a non-native fish the alewife exploded in the Great Lakes.  Alewives frequently experienced seasonal die-offs as they exhausted food supplies.  Their bodies would then wash up on Great Lakes beaches making them inhospitable.  Both Sea Lampreys and Alewives were introduced to the Great Lakes when the Welland Ship Canal.

By introducing Salmon, the DNR hoped to revive the Great Lakes sport fishery and reduce Alewife populations to an acceptable level.   The introduction was a wild success.  Today, Salmon remain a popular sport fish in the Great Lakes.

Great Lakes Coho and Chinook Salmon sped most of their lives swimming in the open waters of the lakes.  At the age of three, they return to rivers to spawn. After these salmon spawn they die just like all Pacific Salmon species; Atlantic Salmon live after after spawning and return to the ocean.

When salmon were first introduced in the Great Lakes this caused a huge problem in Traverse City.  Four dams spanned the river preventing salmon from migrating far upstream (one of these dams has been removed and two others are slated for removal).  This meant that when the salmon spawned and consequently died they did so within the city limits of Traverse City.  Saying that the resulting smell was unwelcome is an understatement!

The solution was to build a harvest facility to collect salmon from the river before they could spawn and die.  This facility, known as the Boardman River Weir, consists of a weir that blocks passage upriver, a fish ladder that leads to a series of survival tanks, and a building that contains sorting tables and other equipment for processing the fish.

The weir allows water downstream, but blocks fish from traveling upstream
The fish ladder is staggered to allow salmon to rest before swimming up each spillway.

The holding tanks and fish ladder a fenced off to prevent people from taking salmon.

Inside the building, processing tables are used to sort salmon for shipping to distributors.  Tubes lead to a recovery tank so trout, steelhead, and Atlantic Salmon collected in the weir can be returned to the river.

Carbon Dioxide and Oxygen are used as an anesthetic to calm the fish so they can be handled for processing.  The basket on the right is used to lift the anesthetized fish up onto the sorting tables.

The number of salmon (and other species) collected are recorded and posted so the public can see what is happening.  Windows look in on the processing facility

During the fall salmon run, staff from the Michigan DNR is on site to answer questions and give tours of the facility.  We are lucky enough to know several of the DNR employees at the weir and we were allowed to stay inside the fence taking photos as long as we wanted.

Once in the holding pens salmon just cruise around as there is nowhere further upstream for them to go.  Occasionally one will jump up out of the water, sometimes even landing on the concrete walkway.
The weir spans the entire river, blocking passage upstream upstream, but allowing water through

Despite the barrier, a small number of salmon jump over the weir and continue upstream.

Debris has to be removed from the weir periodically so water can flow through.  If the water flows over the weir salmon will be tempted to jump over instead of entering the fish ladder.

The view of the facility from the weir.

While we were watching several fish attempted to make their way up the fish ladder.  Some of the fish had an easy time; others struggled to make it upstream.  The staggered spillways ensure that there is an area of slack water at each level, allowing tired fish to rest before ascending to the next level.

This salmon just swam up the ladder

This salmon jumped up the spillway to the next level.

The bright sunlight made it easy to see the salmon as they swam around the holding pens.

Unfortunately not every salmon that makes it up the fish ladder survives until harvest.  Some salmon are simply too exhausted and beat up by their journey.  When that happens the dead fish are removed from the pen and disposed of.

DNR employee Francis Majszak gaffs a dead salmon and removes it  from the holding pen at the Boardman River Weir.

This dead salmon had a surprise.  That's a juvenile Sea Lamprey attached to its tail fin.

A closer view of the juvenile lamprey.  Because the Sea Lamprey is an invasive species it was destroyed rather than being returned to the river.

If you would like to learn more about the Boardman River Weir, the brochure shown below can be downloaded from the Michigan DNR.  The fish weir typically remains in operation through October.  It's only a 2 hour drive from Mid-Michigan and is a great place to visit while in the Traverse City area, especially when combined with a fall color tour of the Old Mission Peninsula, Leelanau Peninsula, or Sleeping Bear Dunes National Lakeshore.

Tuesday, September 26, 2017

Native Species Profile - Witch Hazel

While most wildflowers in Mid-Michigan are either done blooming or close to the end, one species has just begun to bloom and will continue to do so for another four to six weeks.  Witch Hazel (Hamamelis virginiana) is an understory shrub that reaches heights of 10 to 20 feet.  This species is found in deciduous and evergreen forests and savannas throughout the eastern United States and Canada.  In Michigan it is found throughout the Lower Peninsula, but is less common in the UP.

Witch Hazel flowers - note long, narrow petals

Witch Hazel flowers are yellow and have four narrow petals, four short sepals, four stamen, and a pair of pistils.  The petals measure about 3/4 inch long and are typically curved or twisted.  These flowers are one of the last nectar sources of the year and are pollinated by a number of insect species including moths, bees, flies, and wasps.  After pollination, the tree develops small brown seed pods that measure roughly 2/3 to 3/4 inch long.  These pods are roughly shaped like acorns and are divided into four sections.  These seed pods often remain on a tree for a year or more.

A wasp-mimic fly pollinating Witch Hazel flowers

Witch Hazel flowers - note four-part seed capsule at lower right of image

Witch hazel leaves are roughly oval, ovate (egg-shaped with a wider base than tip), or obovate (egg-shaped with a wider tip than base) in shape with wavy margins.  The leaves can measure up to five inches long and three inches wide.  They are arranged alternately on the plant's branches.

Oval-shaped leaves of Witch Hazel - note wavy margins of leaf.

Yellow fall leaves and flowers of Witch Hazel appear at approximately the same time.
Witch Hazel leaf - note obovate shape and wavy margins

While Witch Hazel can have a single trunk, it typically branches out right at ground level.  The branches are rarely straight.  Instead they undulate back and forth giving the Witch Hazel a wavy appearance.
A stand of Witch Hazel can be mistaken for no other species.

Undulating branches of Witch Hazel

Witch Hazel is a host plant for approximately twenty species of moths.  Most of the caterpillars are small and inconspicuous.  Exceptions to this are the caterpillars of the Pyreferra genus - these caterpillars are usually lemon yellow and white striped.

Pyreferra caterpillar on Witch Hazel leaf

Basic Information

Witch Hazel
Hamamelis virginiana 

Height:  10-20'
Habitat:  deciduous and evergreen forests, oak and pine savannas
Flower Color:  yellow
Bloom Time:  late September - November

Tuesday, September 19, 2017

30-Minute Nature Fix (Mill Pond Park - 18 SEP 2017)

Going outside is good for you.  Studies show that even as little as 30 minutes of outdoor activity a week has been proven to have health benefits such as reducing stress and lowering the risk of heart disease.  During the school year, I spend my days teaching kids about science and nature.  Unfortunately, out of necessity, most of this teaching takes place in the classroom.  My job teaching about nature means that I have less time to enjoy nature.  (This is what is known as a paradox: a statement or proposition that seems self-contradictory or absurd but in reality expresses a possible truth.)

I try to find time every day to get out and enjoy nature.  Sometimes this means spending time in the garden watching the bees feeding on nectar.  Yesterday I was able to stop at Mill Pond Park after giving a presentation to the local garden club.  I only had 30 minutes.  How much can you see in 30 minutes?

Quite a bit, if you are inclined to look!

Mill Pond Park - my path is highlighted in red

Painted Turtles taking advantage of the late summer sun to bask.

Reeds growing in the remnants of the old mill pond.

Swamp Milkweed seeds are ripe and ready to fly away.

So are the seeds of cattails!

White Water Lily leaves are changing color as they use up their chlorophyll.

Wood Nettle - llok close and you can see the needle-like hairs that give the plant its sting.

The fluffy seedheads of Virgin's Bower cause the plant to also be known as also known as Old Man's Beard.

This Virgin's Bower is not quite as far along as the previous photo.

A few Spotted Joe-pye Weed flowers are still in bloom.

Most Goldenrod species are in full bloom, attracting pollinators like this wasp.

Purple Loosestrife is an invasive species, but pollinators love it.
Sun shining through White Oak leaves.

This patch of Common Goldenrod was attracting the attention of dozens of wasps and Locust Borer beetles.

That's it.  My walk through the park is over.  Not bad for 30 minutes!

Monday, September 18, 2017

Late summer pollinator bonanza

With the first day of fall occurring this Friday (22 SEP), insects that feed on pollen and nectar have limited food sources available.  Those plants that are still in bloom are covered with bees, wasps, flies, beetles, moths, ants, and more. 

Here is a short video of some of the Showy Goldenrod growing in our yard.   This is just one plant, every goldenrod in our garden was seeing this level of pollinator activity.

Thursday, September 14, 2017

Tree ID

One of the first lessons that I teach third grade students is how to classify leaves.  They learn to differentiate between needle-leaf and broadleaf species; then they learn how to tell the difference between simple leaves and compound leaves.

If you are scratching your head right now.  It's easy.  A needle-leaf tree has leaves shaped like...wait for it... a needle!

In contrast, a broadleaf tree is any tree that is not a needle-leaf.  Instead a broadleaf tree has broad (or wide) leaves.

Broadleaf trees can be further divided into simple leaves and compound leaves 

Simple leaves are those that have one leaf on one stem.  The shape and size of the leaf do not matter; if the leaf has only one part it is a simple leaf.  That leaf can have smooth edges, serrated (toothed) edges, or edges that are divided into lobes.  See, it's simple!

In contrast, compound leaves are not simple.  Instead of having one leaf on one stem, compound leaves have one stem with multiple leaflets.  These small leaflets are each distinct from one another - meaning that they are not connected to each other, but only to the stem that they share.

To make this leaf classification activity more memorable for students, I have collected dozens of real leaves.  These leaves have been pressed, allowed to dry and them laminated on a sheet of 8.5" x 11" cardstock.  Unfortunately, due to class sizes, I often need as many as ten different sets of leaves for student groups to work with.  This means that sometimes I do not have enough real leaves to go around.  So to fill out my leaf sets, I pick one real leaf of each species and create a color scan. 

Here are my scans of the leaves of forty different species that can be found here in Mid-Michigan.  Please feel free to save and print these images as needed.