Friday, April 29, 2016

(3) Lake St. Clair Delta acts as Native Mussel Sanctuary

--- third and last in a series ---

In The Voice, October 2, 2014, Jim Bloch wrote a story titled, “Written off as doomed, native mussels survive zebra mussel invasion.” Excerpts:

“The causes of the decline and extinction of fresh water mussels are among the same conditions that led the St. Clair River to be classified as an environmental area of concern in 1985: Habitat destruction, pollution, commercial exploitation and invasive species.

Lake St. Clair and delta

“In the case of the Great Lakes, invasive species in the form of zebra mussels and quagga mussels came close to wiping out native mussels, already in a perilous state when the invaders arrived in the late 1980s and early 1990s.

“ ‘Come the late 1980s and early 1990s, all the native mussel populations crashed in Lake St. Clair, Lake Erie and the Great Lakes in general,’ said [Dr. David T.] Zanatta.”

“Average density of native mussels before the arrival of zebra mussels was two per square meter in Lake St. Clair. By 1990, zebra mussel density was at 1,600 per square meter.”

“By 1994, there were almost no native mussels left in the lake, with zebra now at 3,000+ per square meter.”

“ ‘But there was reason for hope,’ said Zanatta. ‘Remnant populations of native mussels were beginning to be found in coastal wetlands in western Lake Erie in the late 1990s.’ ”

"In addition, zebra mussel populations started showing dramatic declines between 1994 and 2001 in Lake St. Clair, even though their sheer numbers remained staggering."

“ ‘In my master’s work, we found that there was a large native mussel refuge in the St. Clair Delta,’ said Zanatta, referring to samplings he participated in 1999-2001.”

“...’There are 37 species known historically from Lake St. Clair. We’ve recorded 22 species actually in the lake in the last decade despite all sorts of pretty negative impacts.’ ”

“In expanded research funded through the Great Lakes Restoration Initiative, Zanatta found that the St. Clair Delta and western Lake Erie ‘were the most healthy areas of the lakes in terms of native mussel abundances.’ “


From the abstract of Distribution of native mussel (unionidae) assemblages in coastal areas of Lake Erie, Lake St. Clair, and connecting channels, twenty-five years after a dreissenid invasion, a journal article by David T. Zanatta, et al. published in 2015 (excerpts):

“Despite the invasion, unionids have survived in several areas in the presence of dreissenid mussels.”

Thompson Bay, Presque Isle, Pennsylvania

“We...documented species abundance and diversity in coastal areas of lakes St. Clair and Erie. The highest-quality assemblages of native mussels (densities, richness, and diversity) appear to be concentrated in the St. Clair delta, where abundance continues to decline, as well as in in [sic] Thompson Bay of Presque Isle [Pennsylvania] in Lake Erie and in just a few coastal wetlands and drowned river-mouths in the western basin of Lake Erie. The discovery of several new refuge areas suggests that unionids have a broader distribution within the region than previously thought.”


From the abstract of Characteristics of a refuge for native freshwater mussels (Bivalvia: Unionidae) in Lake St. Clair, a journal article by D.J. McGoldrick, et al., last updated January 29, 2016 (excerpts):

“The Lake St. Clair delta ...  provides an important refuge for native freshwater mussels (Unionidae) wherein 22 of the ~35 historical species co-occur with invasive dreissenids.”

“Zebra mussel infestation of unionids in the delta appears to be mitigated by dominant offshore currents, which limit densities of zebra mussel veligers [planktonic larvae] in nearshore compared to offshore waters …”

“Glycogen concentrations in the tissues of a common and widespread species in the delta (Lampsilis siliquoidea) suggest that zebra mussels may be adversely affecting physiological condition of unionids in a portion of the Lake St. Clair delta. Physiological condition and community structure of unionids within the delta may also be influenced by differences in food quantity and quality resulting from the uneven distribution of water flowing from the St. Clair River. The delta likely supports the largest living unionid [?] includes several species that have been listed as Endangered or Threatened in Canada and/or the state of Michigan, making it an important refuge for the conservation of native unionids.”


Round Goby

Why no mention, you might ask, of quagga mussels? Don’t know. Maybe Lake St. Clair and the delta are too warm and shallow for them.

And why haven’t the zebras wiped out the bottom of the food web in Lake St. Clair, as the quaggas have done in lakes Huron and Michigan? Possibly the abundance of nutrients like phosphorus in Lake St. Clair (and western Lake Erie) can produce phytoplankton such as algae faster than the zebras can devour it, leaving plenty for tiny animals that become food for an invasive fish, the round goby, now thriving and the favorite prey of some of the popular game fish in Lake St. Clair.

In any event, this saga is far from over. The balance will work out over decades, altered from time to time by further agents of change.

Tuesday, April 26, 2016

(2) Mussel Invasion, Alewife Collapse Doomed Salmon in Lake Huron

Alewife, a herring, average 10 inches in length
-- second in a series --

Researchers have found that Lake Huron cannot provide a salmon sport fishery any longer because the alewife population on which the salmon fed has crashed. It seems likely that the same sequence is repeating itself in Lake Michigan.*

The best course now may be to restore native species like lake herring, lake trout, walleye and whitefish.

Scientists studying the subject are Sara Adlerstein-Gonzalez, Yu-Chun Kao and Edward Rutherford.

Alewives, a herring species, invaded the Great Lakes 60 or 70 years ago through the Welland Canal. They became the main food source for the salmon, steelhead, brown trout and hybrids that have been introduced in Lake Michigan and Lake Huron over the past 50 years.

The new study is the first attempt to use a food-web modeling approach to assess the various factors behind the 2003 collapse of Lake Huron alewives and the implications for future fish populations there. The total weight or ‘biomass’ of alewives in Lake Huron plunged by more than 90 percent between 2002 and 2003, and the exact causes of the collapse are still debated by anglers and biologists.

Some researchers have suggested the alewife collapse was mainly due to too much predation by Chinook salmon and native lake trout. Others say it likely resulted from a drop in food availability tied to the explosive spread of zebra and quagga mussels starting in the late 1980s.

The computer simulations in the new study show that the collapse was caused by a combination of predation and food limitation—and that predation alone would not have caused the crash. The spread of the non-native mussels, coupled with declining levels of the nutrient phosphorus entering the lake from rivers and streams, were essential factors, according to the new study.

Predation peaked in the 1980s, then remained constant until the alewife population crashed in 2003. Filter feeding by staggering numbers of invasive mussels reduced nutrients, including phosphorus, which had already been depleted in farm runoff as a result of improved agricultural practices.


[Chinook] Salmon are declining at an alarming rate [in Lake Michigan] according to biologists and the Department of Natural Resources.

“Because there’s less prey, the capacity to support the current Chinook salmon just isn’t there,” [Jay] Wesley said. “So one way we can address that is to lower the Chinook stocking.  That will help reduce predation pressure on the remaining prey.”

As for invasive mussels, biologists are hoping they’ll reach a peak, allowing algae and plankton back into the water…

*****     *****     *****

Saturday, April 23, 2016

(1) Alien Mussels Dominate Lake Bottoms, Scramble Ecology

--- first in a series ---

Hello, invasive zebra and quagga mussels. Goodbye: introduced salmon, invasive alewives, native Diporeia, diatoms and on and on.


Invasive quagga mussels have out competed their cousins, zebra mussels, at the bottom of Lake Huron and Lake Michigan. Quaggas tolerate colder, deeper water and thrive on mud bottoms. Zebras prefer to attach themselves to less abundant hard surfaces.

Both are efficient filter feeders and prolific breeders. Small quaggas can filter a quart of water daily. Billions of them cover the bottoms Lake Huron and Lake Michigan.

Diatoms are single cell plants, a form of algae, that make up part of the quagga’s diet. Diatoms envelop themselves in a hard shell of silica taken from the water.

The process is useful to mussel researchers as a marker of or proxy for total algal density, i.e. an extrapolation of the quantity of all algae in the water.

Diatom blooms occur in the spring. As the plants absorb silica and sink to the bottom, a reduction or drawdown of silica in the water is measurable. Less silica means more diatoms; more diatoms implies more algae in general.

In 2008, EPA researchers found that silica in the water was 80% lower than 30 years earlier, indicating a similar reduction in algae and coinciding with the proliferation of quaggas, which began in 2004 in Lake Michigan.

“By filtering out the algae, the mussels are robbing other organisms of the food they need to survive. Of particular concern is the plight of Diporeia, a tiny shrimplike creature that was one of the pillars supporting the base of the Great Lakes food web. Nearly every fish species in the Great Lakes relies on Diporeia at some point in its life cycle. But Diporeia populations have crashed in lakes Michigan and Huron, and the change is already impacting Great Lakes commercial fisheries and the sport-fishing enterprise.”

It’s worth noting, however, that in Lake Huron, where the salmon/alewife-heavy ecology crashed first, native species like lake trout have rebounded and invasive gobies have entered the picture.

*****     *****     *****

Thursday, April 21, 2016

‘Pure Michigan’ Implies Clean Water

The State of Michigan’s tourism ad campaign, ‘Pure Michigan,’ implies (among other things) clean water. It is an illusion, but a widely accepted illusion, especially outside Michigan where it has attracted visitors. The ad campaign doesn't mention frequent beach closings or the PCB- and mercury-laced fish, but tourists have seemed willing to overlook such shortcomings.

Nevertheless, you can only push your luck so far. What had been a catchy phrase and a phenomenal success in promoting tourism, ‘Pure Michigan’ became diluted and cheapened when a political cabal in Lansing started renting out the phrase to the likes of Kroger.

Steadily over recent years, the very concept that suggested a clean, healthy and pleasant locale to visit was undermined and ultimately trashed by a cadre of exploiters and abusers, unrelenting in their quest for lower business taxes and less government, including less environmental regulation.  

They put greed and special interests ahead of public health and a clean environment.

The Flint water debacle is the most recent example. Administrators from the Michigan Department of Agriculture (having been given a tail, “...and Rural Development”) or MDARD were put in charge of the Michigan Department of Environmental Quality (MDEQ), obviously to deflect enforcement action away from agricultural polluters, particularly the big factory farms that have appeared in the past decade or two.

Other departures from the purity proclaimed in the tourism ads are plain. Instead of improving the suffocating, chemical-laden air in southeast Detroit, the Lansing cabal was smiling on plans to increase toxic emissions from a steel plant and an oil refinery, prior to the disaster in Flint.

Ancient, corroding pipelines throughout the state have gone uninspected; or have been inspected, found to be deficient and then ignored. Under the Granholm Administration, one such line ruptured, polluting wetlands, tributaries and the Kalamazoo River itself.

In 2014, either reckless, inattentive permitting or wink-and-a-nod permitting on the part of MDEQ concerning a huge construction site near East Grand Traverse Bay resulted in sediment clouding the bay and threatening pristine aquatic habitat after rain. MDEQ had allowed the construction contractor to strip the vegetation off 160 acres all at once.

Citizen reports of excessive pathogens and nutrients running off industrial-scale livestock feeding operations, supported by water samples, have been routinely ignored by MDEQ, which pleads lack of staff and budget, following reductions required by the governor and colleagues in the legislature.

In 2011, false reports concerning court-ordered sewage sludge production at the Detroit wastewater treatment plant, bearing upon pollution of the Detroit River and Lake Erie, went undiscovered by MDEQ, although an amateur (this writer) could find them.

Health risks associated with toxins and pathogens in Michigan’s numerous, polluted Areas of Concern are marginalized in MDEQ’s rush to be rid of the stigma that inhibits profit.

So much for ‘Pure Michigan.’

Friday, April 15, 2016

Lake Erie: Making Political Hay While the Sun Shines

The 2012 Great Lakes Water Quality Agreement Protocol and Lake Erie Ecosystem Priority (LEEP) require Canada, the U.S. and the International Joint Commission (IJC) to examine the decline of water quality in Lake Erie and arrange fixes.

One result of that effort has been a tenfold increase in political happytalk among the state and provincial authorities assigned to grapple with the problem. Is their optimism warranted? How many of them will still be in office when the results are in?

The pending Lake Erie Protection and Restoration Plan agreed to by leaders in Ontario, Ohio and Michigan is an ambitious, 10 year venture to eliminate 40% of the phosphorus overload by which Lake Erie is impaired. We haven’t been told yet precisely how this vision will be implemented.

A lot of residents, business people and farmers invested in the western Lake Erie watershed are heartened by such talk.

Nothing wrong with setting a very high bar as long as everybody understands the odds are long. It’s irresponsible to build great public expectations based on politically inspired pipe dreams that nobody in authority really believes will be met.

False hope is destructive.