Learn more about declining Great Lakes prey fish populations

A cross-basin overview reviews status and trends of prey fish from 1978 to 2016.

The research vessel Sturgeon conducts prey fish trawl surveys on the Great Lakes. Photo: Great Lakes Fishery Commission

The research vessel Sturgeon conducts prey fish trawl surveys on the Great Lakes. Photo: Great Lakes Fishery Commission

There were massive changes in the Great Lakes fish communities during the 20th century. During that time proliferation of sea lamprey, alewife, and smelt occurred. In the mid-20th century the collapse of native fish communities, such as lake trout and ciscoes occurred. In the late 20th century there was stocking of trout and salmon; the invasion and proliferation of zebra mussels, quagga mussels, spiny waterfleas, and round gobies; declines in Diporeia (small, shrimp-like crustacean), alewife, and rainbow smelt; and the oligotrophication of Lakes Huron, Michigan, and Ontario because of low phosphorus inputs and the cropping of phytoplankton by quagga mussels. An oligotrophic lake has a deficiency of plant nutrients, usually accompanied by an abundance of dissolved oxygen.

Given this scenario questions are asked on how similar or different are the changes in fish communities across the Great Lakes and what could be causing these changes? Michigan Sea Grant and Michigan State University Extension recently held an educational session at the Michigan Fish Producers Association Annual Conference. At the conference Chuck Madenjian of the U.S. Geological Survey Great Lakes Science Center discussed this topic and reviewed data prepared by his colleague Owen Gorman with other contributors from U.S. Geological Survey, Ohio Department of Natural ResourcesNew York Department of Environmental ConservationPennsylvania Fish and Boat Commission, and Ontario Ministry of Natural Resources and Forestry. Here is a summary of his presentation on Great Lakes prey fish:

Assessments of Great Lakes prey fish stocks have been conducted annually by the U.S. Geological Survey since the 1970s using bottom trawl surveys. The focus of the surveys has been on the prey species cisco, bloater, rainbow smelt, alewife, and round goby. Total prey fish (alewife, rainbow smelt, bloater, and cisco) biomass declined during 1978-2016 in Lakes Superior, Michigan, and Huron. Lake Ontario is now different based on a new correction factor and prey fish biomass was not available for Lake Erie.

Coregonids

There was a synchronous decline in coregonid (whitefish, cisco or lake herring, bloater, kiyi) biomass in Lakes Superior, Michigan, and Huron during 1978-2016 with peak biomass occurring during 1989-1992. Lake Huron showed a coregonid rebound during 2008-2012. Predation does not appear to be the primary driver of bloater dynamics during 1978-2016. Some fishery biologists believe predation on bloaters by salmon and trout is more important nowadays than during the 1980s and 1990s, but most of the diet data do not support this contention. There may be population-intrinsic factors (sex ratio); changes in climate patterns; changes in trawl catchability over time due to changes in bloater behavior or increased water transparency in Lakes Michigan and Huron.

Alewife

In Lakes Huron and Michigan there was a synchronous decline in alewife biomass during 1978-2016. Alewife is the dominant prey fish in Lakes Huron, Michigan, and Ontario. It is rare in Lakes Superior and Erie. Predation has been the primary driver of alewife dynamics in Lake Michigan since the 1960s and it is likely the main driver of alewife dynamics in Lakes Huron and Ontario as well.

Rainbow smelt

Rainbow smelt had a synchronous decline in Lakes Superior, Huron, Michigan, and Ontario during 1978-2016. Lake Superior peaked earlier than the other lakes in 1978. In these four lakes, rainbow smelt was an important prey species before the mid-1990s and is now a minor prey species. Predation appears to be the primary driver of rainbow smelt dynamics in Lake Superior but not in Lake Michigan.

Round goby

Round goby biomass increased in Lakes Michigan, Huron, Erie, and Ontario during the 1990s or 2000s, then peaked, perhaps even decreased somewhat, and appears to have leveled off in all four lakes. Further increases in round goby biomass are not expected. Round gobies in Lake Superior are mainly limited to harbors. Round goby populations in Lakes Michigan, Huron, Erie, and Ontario now appear to be under some degree of predatory control as they are fed upon by smallmouth bass, lake whitefish, burbot, lake trout, brown trout, yellow perch, other fish and birds. There are relatively high annual mortality rates (> 60% each year) in open waters of Lakes Michigan, Huron, and Erie.

Great Lakes net-pen aquaculture—real and perceived risks to the environment

Michigan Sea Grant addresses environmental issues surrounding net-pen aquaculture in the Great Lakes at recent Annual No-Spills Conference.

Great Lakes net-pen aquaculture—real and perceived risks to the environment

In the last several years there has been a great deal of discussion about net-pen aquaculture in the Michigan waters of the Great Lakes. Much of the attention about Great Lakes net-pen aquaculture is the generation of large quantities of fish waste from these fish production operations as well as the consequences if these fish escape into the environment. The main issue with fish waste is the release of phosphorus which is the growth limiting nutrient for primary production in freshwater ecosystems. Although some phosphorus is necessary to drive the freshwater food chain, concern arises when excess amounts of phosphorus are available which can result in significant algal blooms and other aquatic plant growth. In addition there is a concern about fish diseases and genetics, which may be the consequence of the interaction of fish raised in Great Lakes net pens and native fish in the surrounding environment.

Discussing environmental issues

To address these concerns Michigan Sea Grant was invited to speak at the 28th Annual No-Spills Conference in January 2018, to discuss environmental issues surrounding net-pen aquaculture in the Great Lakes. Currently there are seven net-pen aquaculture operations that exist in northern Lake Huron on the Canadian side of the lake. These operations are sustainably producing more than 5,000 tons of rainbow trout per year with some being sold in retail markets in Michigan. They provide 340 direct and indirect jobs with a $100 million contribution to the Canadian economy. These net-pen aquaculture operations take up a small footprint in the environment; one of these operations that produces 500,000 pounds of rainbow trout per year would fit into an average size Michigan marina.

Fish disease risks and genetic dilution can be minimized

For Great Lakes net-pen aquaculture to be environmentally sound it must have practices that prevent disease transmission and escapement of fish into the wild, as escapees could affect the genetic integrity of surrounding fish populations. These operations must also be non-polluting with minimal and recoverable impacts. With regards to fish diseases, the commercial aquaculture industry is highly regulated and is held to the same standards as state and federal hatchery programs. Fish disease risks are minimized and prevented through regulation, biosecurity, and best management practices.

In 2014 the state of Michigan stocked more than 20 million fish, produced from gametes collected from wild fish. This equated to 325 tons of fish stocked, 9 different species, 370 stocking trips, 732 stocking sites, with 100,000 miles of travel from several fish hatcheries. In comparison Canadian net-pen operations in Lake Huron typically stock one cohort, certified as specific pathogen free, then raise the fish to harvest and truck them one way to a fish processing facility. The net results are that Michigan hatcheries have a much higher risk of disease transmission than the current system for growing trout in Canadian net pens.

The Great Lakes already have rainbow trout which are non-native to the region. They were introduced by fishery management agencies years ago and many of these fish are now naturalized, spawning on their own in local rivers, with additional enhancement from government fish hatcheries. Rainbow trout produced in Great Lakes net-pen operations can be female triploids which are sterile and will not reproduce should they escape into the environment. So the risk of genetic dilution can be eliminated by use of these female triploid rainbow trout.

Low phosphorus, digestible fish diets help minimize phosphorus waste

During the height of the Great Lakes net-pen aquaculture discussion there were media reports that a typical net-pen operation with 200,000 fish would produce as much waste as a city of 65,000 people. In reality a city of 65,000 people would produce 21 times more fecal matter than a 200,000 fish net-pen operation. This same city would produce 5 times more phosphorus compared to the net-pen aquaculture operation. The city would also generate 24 kg/yr of E. coli with none coming from the net-pen operation.

Canadians have had net-pen aquaculture operations in their northern waters of Lake Huron since 1982. To help address the issue of excess phosphorus discharge from freshwater net pens, Fisheries and Oceans Canada completed a study on Freshwater Cage Aquaculture: Ecosystems Impacts from Dissolved and Particulate Waste Phosphorus. Fish receiving digestible phosphorus in specific amounts to meet their growth requirements excrete only small amounts of dissolved phosphorus. Dissolved phosphorus is most often the form of concern in impaired waters. The other form of phosphorus excreted from fish is particulate phosphorus which settles to the bottom sediments. The particulate phosphorus which accounts for the majority of the waste from net-pen operations is transported to the bottom sediments and is not immediately available for uptake into the ecosystem. In sediments it can be consumed by the benthic organisms and enter the aquatic food chain. Both dissolved and particulate phosphorus wastes produced by fish are the results of the diets they consume. The development of low phosphorus, highly digestible diets has been a tool to help minimize phosphorus waste by aquaculture operations.

The Fisheries and Oceans Canada study found that based on net-pen aquaculture production in northern Lake Huron in 2006 contributed about 5 percent of the annual total phosphorus loading to the North Channel. The study concluded that the likelihood of phosphorus additions to the environment from net-pen aquaculture operations resulting in eutrophication to Canadian freshwater environments under the current level of fish production can generally be characterized as “low.” The greatest concerns for phosphorus are in the nearshore areas where excess aquatic plant growth can foul the shorelines. In contrast, offshore phosphorus loading is of less concern and higher phosphorus concentrations may be considered a means to help mitigate declining populations of forage fish and the poor condition of sport and commercial fish species.

Sea Grant Seeks Proposals for Aquaculture Research

Event Date: 12/15/2017
End Date: 3/30/2018

The NOAA National Sea Grant College Program 2018 Ocean, Coastal, and Great Lakes National Aquaculture Initiative federal funding opportunity is now open. 

Depending on appropriations, NOAA Sea Grant expects to have available a total of $7,000,000 to $11,500,000 across fiscal years 2018, 2019, and 2020 as part of the Sea Grant National Aquaculture Initiative (NAI). This federal funding competition is designed to foster the expansion of a sustainable U.S. ocean, coastal, and Great Lakes aquaculture sector by addressing one or more of the following priorities:

  • Supporting the development of emerging systems or technologies that will advance aquaculture in the U.S., including projects that will help stimulate aquaculture production by nascent industries.
  • Developing and implementing actionable methods of communicating accurate, science-based messages and information about the benefits and risks of U.S. marine aquaculture to the public. And
  • Increasing the resiliency of aquaculture systems to natural hazards and changing conditions.
Complete proposals are due from eligible parties to Sea Grant programs on March 2, 2018 at 5 p.m. local time. 
 
Applicants are strongly encouraged to reach out to their Sea Grant Program one to two months prior to the Sea Grant program application deadline to receive guidance regarding proposal development and discuss their proposed project(s). 
 
Proposals from Sea Grant programs are due in grants.gov by March 30, 2018
 
Please refer to the FFO for all planning and formal guidance. 
 

MSU prof seeks crowdfunding support for Great Lakes fish diet research

You can be a part of this important study by donating to support student researchers analyzing stomach samples from Lake Michigan and Lake Huron.

As we all know, the Great Lakes have changed a lot in the last decade or so. Alewife have declined, round goby are increasing, and lake trout and walleye continue to recover. Chinook salmon, the heart of Lake Michigan’s fishery, have fluctuated in numbers in the past few years, and have collapsed in Lake Huron. Our fisheries agencies must make informed decisions regarding stocking and levels to support both fisheries and conservation goals. These decisions are based in part on what those predators are eating. What predators eat is an excellent indicator of ecosystem health, and can help tell us how sustainable the fishery is.

With the tremendous help of recreational anglers, MSU together with state, federal, and tribal agencies have collected nearly 2,000 predator stomachs from around Lake Michigan and Huron. We need help to be able to analyze all of them, particularly those from Lake Michigan. MSU has a wealth of potential help in terms of undergraduate students eager to gain valuable research experience. However, funding is needed to pay these students for their work.

Would you help by contributing to this research effort?

With the help of MSU CrowdPower, any donations made at the website will go directly to the predator diet study. Any donation will help, and all donations are tax deductible.

Want to stay up-to-date on the project? 

We have several other ways to connect including:

Alpena students’ project yields more than 1,000 pounds of invasive frogbit

First- and fifth-grade students remove invasive species from Great Lakes watershed, clean up along the Thunder Bay River — and captured it all on film.

Alpena elementary students work alongside NEMIGLSI network coordinator, Meaghan Gass, to identify and remove invasive European frogbit. Photo: Michigan Sea Grant

Alpena elementary students work alongside NEMIGLSI network coordinator, Meaghan Gass, to identify and remove invasive European frogbit. Photo: Michigan Sea Grant

More than 100 first- and fifth-graders from Alpena Public Schools got their feet wet this fall contributing to an invasive species removal effort in their local watershed. Visiting the Alpena Wildlife Sanctuary and the Maritime Heritage Trail along the shores of Thunder Bay River these students removed more than 1,000 pounds of invasive European frogbit, conducted litter cleanups, and did a little filmmaking to raise public awareness about their project.

Removal of European frogbit, newly found in the Thunder Bay watershed, took center stage as the primary stewardship project for participating students. This invasive plant grows in large, thick mats that block sunlight to the aquatic plants beneath it; therein threatening the health of surrounding plants and aquatic wildlife. Community and conservation leaders – with helping hands from these students – have prioritized removal efforts to help reduce and prevent the spread of this new invader to the local watershed. Student efforts contributed in accomplishing the Huron Pines frogbit challenge, where the collective community (with students) worked together to remove close to 3,500 pounds in 2017.

To get the ball rolling, fifth-graders from Hinks Elementary visited Duck Park where they donned waders and life jackets, grabbed rakes and buckets, and after learning to identify frogbit, started pulling the plant. Two hours later, they had pulled close to 500 pounds of frogbit from the river. Arriving later in the afternoon that same day, fifth-graders from Besser Elementary removed more frogbit, and also conducted an Alliance for the Great Lakes Adopt-A-Beach litter clean up along the Thunder Bay River. Over the course of three hours they picked up more than 12 pounds of trash and removed more than 700 pounds of frogbit. Meanwhile, on the Maritime Heritage trail, first-graders from Lincoln Elementary removed nearly 20 pounds of frogbit and eight pounds of trash along the river.

a picture of European frogbit that grows in thick mats in water

Throughout the day students shared their experience with local media – but also collected their own photos, video footage and interviews using iPads provided through the Northeast Michigan Great Lakes Stewardship Initiative (NEMIGLSI) in order to share their stories. Students provided a public service by removing invasive species and they also learned the importance of raising community awareness on these issues. They hope to produce a short film highlighting the dedication of their class, teachers and community partners to keeping our Great Lakes clean and free of invasive species.

A great example of place-based stewardship education in action, this experience offered opportunity to expand students’ learning beyond the four walls of the classroom while partnering with their community to accomplish this river habitat improvement goal. These enthusiastic students from three different schools collectively engaged in a fun-filled, hands-on learning experience while enhancing the Thunder Bay watershed and Lake Huron habitats within their own local Alpena community.

Teachers from Besser, Hinks and Lincoln Elementary schools facilitated this effort through the NEMIGLSI network and partnership.

Michigan Sea Grant and Michigan State University Extension help provide leadership for the network, which is part of the Great Lakes Stewardship Initiative (GLSI), a larger, statewide partnership. Other NEMIGLSI network partners collaborating with the schools and providing leadership for this project included: Huron PinesHuron Pines AmeriCorpsAlpena Wildlife Sanctuary, and NOAA Thunder Bay National Marine Sanctuary.

Ludington Regional Fishery Workshop

Event Date: 1/13/2018

January 13, 2018

West Shore Community College
3000 North Stiles Road
Scottville, MI 49454

Details

Lodging

There is a block of room secured at the Ludington Holiday Inn Express for the night of January 12th. Double rooms are $75/night and are first come first serve. 

Group Code: MSU
Group Block Name: Fisheries Workshop
Reservations: (231) 845-7311

Michigan Fish Producers Association Annual Conference

Event Date: 1/27/2018

Michigan Sea Grant will be coordinating a daylong, educational program on current issues affecting the Great Lakes commercial fishing industry.

The program will run from 9:00 a.m. through 4:00 p.m. on Saturday, January 27, 2018 as part of the Michigan Fish Producers Association Annual Conference at the Park Place Hotel in Traverse City.

There is no charge for attending this event. For additional information please contact Ron Kinnunen at (906)-226-3687 or kinnune1@msu.edu.

See: MFPA Agenda

DNR seeks comments on Lake Michigan management plan

Event Date: 11/28/2017
End Date: 11/30/2017

November meetings in Manistique, Traverse City, and Grand Haven to share details and solicit input on proposed plan.

DNR seeks comments on Lake Michigan management plan

Fishing in Lake Michigan has had its share of ups and downs. A steady stream of invasive species led to several big changes in the lake. Sea lamprey destroyed the lake trout fishery in the late 1940s, leaving the door open for an explosion of alewife that died off en masse and became the plague of beachgoers in the early 1960s. Stocking of non-native Chinook and coho salmon created a world-class recreational fishery in the late 1960s. Fishery managers have been trying to maintain an optimal balance of predators and prey since salmon declines due to bacterial kidney disease (BKD) in the 1980s. With the explosion of new exotics like quagga mussel and round goby and decreases in open water nutrients over the past twenty years, old assumptions about the lake’s productivity are being revised.

All of this makes management a difficult proposition. States and tribes around Lake Michigan serve on the Lake Michigan Committee, which adopted Fish Community Objectives (FCOs) in 1995. The lake has changed a lot since then, and some key objectives (like total harvest of all salmon and trout species) have fallen below target levels in recent years.

Individual states have worked within the framework of the FCOs. In the past, states have accomplished this on a species-by-species basis. Now Michigan Department of Natural Resources (DNR) is working to develop a more comprehensive and holistic approach to managing the lake.

Visit the Lake Michigan Management plan website to view the draft plan and submit comments online.

What to expect

The agenda for the public meetings includes:

  • Brief overview of management plan and how to comment.
  • Brief overview of zonal management.
  • Describe and discuss stocking options.
  • Have participants pick their most preferred option.

Meeting times and locations

Three meetings are planned:

  • November 28, 2017: 6:30 p.m.-8:30 p.m., Comfort Inn Conference Room, 617 E. Lake Shore Dr., Manistique, MI 49854
  • November 29, 2017: 6:30 p.m.-8:30 p.m., Boardman River Nature Center, 1450 Cass Road, Traverse City, MI 49685
  • November 30, 2017: 6:30 p.m.-8:30 p.m., Loutit District Library, 407 Columbus Ave., Grand Haven, MI 49417

Sea Grant report on Asian carp includes educational resources

Great Lakes conservation groups will find a wealth of resources in this new publication.

By Dan O’Keefe

The Silver Carp is one of four Asian carp species that threaten Great Lakes waters.

The Silver Carp is one of four Asian carp species that threaten Great Lakes waters.

The Great Lakes Sea Grant Network, in support of the Asian Carp Regional Coordinating Committee, just released a report that contains a variety of resources for anyone working on education and outreach related to Asian carp. The report contains sections that provide basic information in addition to helping readers sift through the large amount of information available to find the best outreach products for their audience.

the cover of the report is shown

Understanding the threat

The new report details the four species of Asian carp that pose a threat to Great Lakes waters: Bighead Carp, Silver Carp, Black Carp, and Grass Carp. Each species is a concern, but Bighead Carp and Silver Carp get the most attention because they are filter feeders that eat plankton. This could result in direct competition with native gamefish or indirect effects if baitfish populations are harmed. Scientists are now employing a variety of techniques to learn more about these fish, and the report explains some of the headline-grabbing methods like eDNA monitoring and DIDSON sonar imaging.

Educational resources

The Sea Grant report includes a state-by-state list of fact sheets, articles, brochures, posters, online videos, and other materials related to Asian carp outreach. This is a great place to start if you are looking for materials to distribute at a boat show, club meeting, or other event. In the “Analysis of Education and Outreach” section, the report provides a quick reference chart that organizes materials by audience and message.

PowerPoint Presentation

In addition to a list of available materials, the report includes a set of slides that can be downloaded and used by educators around the Great Lakes region. Slides include basic life history information for each species, potential for economic and ecological harm, control attempts, and an overview of existing research and research gaps. Each slide contains comprehensive presenter notes, and the slide set can be modified to suit your audience.

Lake Michigan’s charter fishing industry is… remarkably stable

It doesn’t make for sensational headlines, but charter fishing has been a consistent part of coastal tourism despite recent ups and downs in fishing success.

Unhooking a Chinook salmon on the deck of a Lake Michigan charter boat. Lake Michigan charter trips and salmon remain a big draw and consistent part of coastal tourism. Photo: Michigan Sea Grant

Unhooking a Chinook salmon on the deck of a Lake Michigan charter boat. Lake Michigan charter trips and salmon remain a big draw and consistent part of coastal tourism. Photo: Michigan Sea Grant

For the past 10 years as a Sea Grant Extension Educator I’ve worked to understand the economic impact of Michigan’s charter boat industry. This has big implications for coastal tourism. In 2016, charter fishing generated $23 million in Michigan’s coastal communities, resulting in 476,361 employment hours. Lake Michigan’s charter fishery is the largest, accounting for around 70 percent of the state’s charter fishing effort according to Michigan DNR. Charter captains in Michigan report their catch and effort to DNR, and Michigan Sea Grant uses this information to calculate economic impacts and investigate trends.

Big salmon are a big draw

Last year was a tough one for fishing. The Chinook salmon is a prized species on Lake Michigan, and charter harvest rate of Chinook salmon fell to the lowest it has been since 1995, when bacterial kidney disease (BKD) wiped out many of the lake’s salmon. According to Michigan DNR, charter harvest in Michigan waters of Lake Michigan ranged from 1.09 to 1.94 Chinook salmon per trip in the early 1990s, ranged from 2.24 to 7.40/trip 1996-2014, and fell from 2.27/trip in 2015 to 1.94/trip in 2016.

This understandably caused a lot of concern among charter captains last year. Angst was compounded by plans to reduce stocking, although the goal of the stocking cut was to prevent a complete crash in the fishery. Some of the debate centered on which species to cut: lake trout or Chinook salmon.

A recent study funded by Wisconsin Sea Grant found that Wisconsin anglers on Lake Michigan are willing to pay more to target Chinook salmon ($140/trip) vs. lake trout ($90/trip). An earlier study on the Lake Huron charter fishery found that the decline of Chinook salmon catch rates was linked to a 51 percent drop in charter fishing effort and resulting economic impacts, although increasing gas prices in the late 2000s were also a factor. During the Lake Huron charter fishing crash of the mid-2000s lake trout catch rates remained high. But what does this all mean for Michigan waters of Lake Michigan?

Consistent economic impacts are the rule

Despite low Chinook salmon catch rates in 2015 and 2016, charter trips and resulting economic impacts did not exhibit the same kind of crash that occurred in Lake Huron around 2004. In fact, Lake Michigan charter trips remained above the post-BKD average of 11,577 trips/year in 2015 and 2016 according to Michigan DNR.

2009 charter economic study found that the economic impact of charter fishing around Lake Michigan averaged $14 million; due to economic factors (e.g., rising gas prices, recession) this fell to $11.6 million in 2009. After adjusting for inflation, this means that Lake Michigan charter fishing generated an average of $15.7 million in Michigan and bottomed out at $12.6 million in 2009. In 2016, Michigan Sea Grant found that Lake Michigan charter fishing generated $15.7 million in economic impacts for Michigan coastal communities. Dead on average, despite the low Chinook salmon harvest rate.

Few fluctuations relative to Huron

The fact of the matter is that Lake Michigan’s charter fishery has been much less volatile than Lake Huron’s, both in terms of harvest rates and economic impacts. While Lake Michigan harvest rate dropped to just under two Chinook salmon per trip in 2016, Lake Huron crashed to fewer than one Chinook salmon every two trips (Michigan DNR data) and economic impacts of charter fishing fell by more than 50 percent.

In other words, anglers could still expect a good chance that their boat would harvest a Chinook on Lake Michigan last year while this was not the case after the decline of salmon on Lake Huron. Other species (including lake trout, coho salmon, and steelhead) play an important role in the charter fishery, too. Many anglers are thrilled to catch any of our Great Lakes trout and salmon, all of which make good eating and top out at an impressive size.

Given the recent troubles with predator-prey balance in Lake Michigan and the high prey consumption of Chinook salmon, we can expect a more diverse mix of predators in the future along with modest Chinook catch rates. The good news is that the economic impacts of Lake Michigan’s charter fishery appear to be quite stable so long as anglers can still expect a reasonable chance at boating a ‘king.’