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. 
 

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

Seafood HACCP Training Course

Event Date: 12/5/2017
End Date: 12/7/2017

A Seafood Hazard Analysis Critical Control Point (HACCP) Training Course that is being coordinated by Michigan Sea Grant, Michigan State University Extension, and the Great Lakes Indian Fish and Wildlife Commission will be held December 5-7, 2017 at Ojibwa Casino Resort in Baraga, Michigan. All fish processors are required to take this training if they are not currently certified.

Hazard Analysis Critical Control Point (HACCP) consists of identifying safety hazards, determining where they occur, monitoring these points and recording the results. HACCP involves day-to-day monitoring of critical control points by production employees. The Seafood HACCP regulation that is enforced by the U.S. Food and Drug Administration is based on the belief that commercial fish processors can understand the food safety hazards of their products and take reasonable steps to control them. Commercial fish processors are required either to obtain formal training for one or more of their own employees or to hire trained independent contractors to perform the HACCP functions.

The HACCP regulation requires processors to keep extensive records of processing and sanitation at their facilities.

Those completing the course will receive a Seafood Alliance HACCP Certificate issued through the Association of Food and Drug Officials that is recognized by agencies regulating fish processors.

For registration information please contact Ron Kinnunen at kinnune1@msu.edu

Michigan Sea Grant’s HACCP safety programming efforts have helped hundreds of businesses

Programs include Hazard Analysis Critical Control Point (HACCP) for Seafood Safety, and Preventing the Movement of Aquatic Invasive Species.

The Magic Springs trout production facility helps contribute to the 40 million pounds of trout production per year in Idaho.

The Magic Springs trout production facility helps contribute to the 40 million pounds of trout production per year in Idaho. Photo: Ron Kinnunen | Michigan Sea Grant

Michigan Sea Grant Extension has served as the North Central Regional Aquaculture Center representative on the planning committee for the National Aquaculture Extension Conference for the last two years. At the recent conference in Boise, Idaho, Michigan Sea Grant coordinated a Great Lakes session and presented on its Hazard Analysis Critical Control Point (HACCP) programming efforts with the commercial fishing, aquaculture, and baitfish industries.

Seafood HACCP is a system for food safety control and is preventive, not reactive. It is a management tool used to protect the food supply against biological, chemical, and physical hazards. HACCPs emphasize process control and concentrate on the points in the process that are critical to the safety of the product. Every fish processor is required to have and implement a written HACCP plan whenever a hazard analysis reveals one or more food-safety hazards that are reasonably likely to occur. A HACCP plan is specific to each processing location and each species of fish and type of fishery product.

Some exceptions

The Seafood HACCP regulation does not apply to the harvest or transport of fish or fishery products, or the operation of retail establishments. Practices such as heading, eviscerating, or freezing intended solely to prepare fish for holding on a harvest vessel are also exempt from the regulation.

Aquaculture practices exempt from the HACCP regulation include harvesting and boxing unprocessed fish on ice for immediate transportation, live fish hauling to various markets, custom processing the fish directly for the consumer who does not resell it, and fee fish operations.

More than 650 benefit from training

Since the inception of the Seafood HACCP regulation, Michigan Sea Grant Extension has conducted 25 three-day Seafood HACCP courses in the Great Lakes region training 653 commercial fishers, processors, and aquaculturists. More than 200 follow-up visits to fish processing facilities have been conducted to assist with the implementation of HACCP plans. The benefits of Seafood HACCP has resulted in fish processors developing value-added fishery products which increases their revenues.

Aquatic invasive species HACCP training offered, too

Several years ago Michigan Sea Grant and Minnesota Sea Grant developed an Aquatic Invasive Species-HACCP (AIS-HACCP) program following the principles of the Seafood HACCP program. Aquatic invasive species can invade and disrupt baitfish and aquaculture operations as they have been identified as a pathway for the spread of AIS. The hazards that have been identified in the AIS-HACCP program include AIS fish and other vertebrates, AIS invertebrates, AIS plants, and fish diseases.

AIS-HACCP training materials were developed and Michigan Sea Grant Extension worked with the baitfish and aquaculture industry representatives on training programs and developing AIS-HACCP plans specific to their operations. Michigan Sea Grant Extension has conducted over 40 AIS-HACCP one-day training programs in the North Central Region of the United States.

What’s the best fish to stock in your Michigan fishing pond?

Stocking the wrong species can lead to problems down the road.

Rainbow trout, such as these, are used to stock cold-water ponds. Photo: Ron Kinnunen

Rainbow trout, such as these, are used to stock cold-water ponds. Photo: Ron Kinnunen

Spring is the time of year to evaluate the type and quantity of fish to put in your farm pond. This is a critical decision as it will dictate the quality of fishing in the pond for years to come. Many make common mistakes when stocking fish into their pond that includes stocking the wrong type of fish species or the wrong combinations of fish species that are not compatible with each other.

Warm-water ponds

If you have a warm-water pond it is best to stock largemouth bass. A common mistake when stocking largemouth bass is to also stock bluegills with them. Many think that stocking the bluegills will provide forage fish for the largemouth bass and enhance their growth. Bluegills have the tendency to overpopulate the pond, monopolize the food supply, and stunt out in growth. Largemouth bass in our northern climate have a difficult time keeping bluegill populations in check. When stocking largemouth bass, it is best to have an established minnow population that they can forage on. These minnows can include fathead and bluntnose minnows.

Bluegills are many times stocked in Michigan ponds as the sole fish species. Several years of good fishing will occur after initial stocking of bluegills but over time they will overpopulate the pond, severely deplete the food supply, resulting in decreased growth rates that are not conducive to good quality fishing. Even as the growth of the bluegills decreases they will still remain very prolific producing even more bluegills which will tax the food supply. As an alternative to stocking bluegills, some will stock hybrid sunfish which is a cross between a green sunfish female and bluegill male. This hybrid cross results in the production of mostly male fish which can reduce reproduction in the early years resulting in larger growth and better quality fishing. But over time reproduction will occur and the quality of the fishery will be reduced.

Cold-water ponds

If you have a cold-water pond, you can stock trout. The best species to stock are brook and rainbow trout. These two fish species can also be stocked together. Avoid stocking brown trout as they are difficult to catch and as they grow they will eat other trout making it difficult to restock your pond. When stocking trout do not stock any other species of fish with them including minnows. Minnows will compete with trout for feed and reduce their growth rates. For trout, there is no need to stock forage fish. There are plenty of natural foods, such as aquatic insects, that inhabit the pond on which the trout can feed.

Avoid cool-water fish

Avoid stocking cool-water fish, such as yellow perch, walleye, and northern pike in ponds. These fish need large open water systems and will not do well in ponds. Yellow perch like bluegills are prolific breeders and can soon overpopulate a pond, monopolize the food source, and stunt out.

And never use grass carp to solve excessive aquatic plant growth problems as it is illegal to possess this fish species in Michigan.

Michigan Aquaculture Internship Program

Event Date: 4/7/2017

Michigan Sea Grant is offering internship funding to undergraduate students interested in pursuing a career in aquaculture. Students who coordinate with a private, state, or federal hatchery to create a summer internship could receive $5,000 for an internship of at least half-time work. Interested students should submit application materials to a sponsoring faculty member at their home institution.

One student will be selected from each institution and forwarded to Michigan Sea Grant by Friday, March 31, 2017, at 12:00 pm (noon). Final funding decisions will be made at Michigan Sea Grant by April 7, 2017.

Farming for Fish? Webinar will explore how to get started

Event Date: 4/10/2017

Webinar series for beginning farmers includes an overview of this fast-growing business sector.

Aquaculture tanks are shown in a recirculating aquaculture facility. Photo: Todd Marsee | Michigan Sea Grant

Aquaculture tanks are shown in a recirculating aquaculture facility. Photo: Michigan Sea Grant

A Beginning Farmer webinar series taking place throughout winter and spring 2017, seeks to assist farmers across the country with starting up and improving their agricultural practices. This series of nine webinars includes “Getting Started with Aquaculture.” The aquaculture webinar will be held 7-9 p.m. April 10, 2017. The cost is $10 for individual webinars, or $45 for access to the entire series.

Aquaculture, or fish farming, is the fastest growing sector of the seafood industry. While global demand for seafood continues to rise, wild catch of fish has not increased and, in some cases, it has decreased as wild fisheries have been overharvested. Michigan is well suited for aquaculture with its vast water resources and increasing demand for local agriculture products. The aquaculture industry in Michigan is currently less than a $5 million industry. A recent strategic assessment of aquaculture in Michigan states that there is potential for growth up to a $1 billion industry. Aquaculture in Michigan can be a way to supply high quality locally produced products.

The Michigan Sea Grant and Michigan State University Extension webinar will introduce a variety of subjects for farmers interested in pursuing the innovative farming techniques of aquaculture. Topics covered will include market demand, types of aquaculture systems, aquaculture facilities in Michigan, and what is needed to start your own facility.

Competitive funding available from NOAA Sea Grant for aquaculture initiatives

NOAA Sea Grant welcomes proposals for two competitive opportunities to advance aquaculture research, address barriers to aquaculture, and expand aquaculture production. Up to $15 million is expected to be available over several years to support projects in two nationwide grant competitions. Learn more about the funding opportunities here or at seagrant.noaa.gov.

Individuals, public or private groups, and state or tribal agencies are welcome to apply through their local Sea Grant program. Interested parties in Michigan should contact Catherine Riseng, Michigan Sea Grant’s research program director, at criseng@umich.edu to discuss the application process.

Biology’s new frontier could have big implications for Great Lakes fish

New research shows that epigenetics play a major role in the domestication of hatchery trout.

Although steelhead are not native to Michigan, they have been spawning naturally in streams including the Little Manistee River since the late 1800s.

Although steelhead are not native to Michigan, they have been spawning naturally in streams including the Little Manistee River since the late 1800s. Photo: Dan O’Keefe, Michigan Sea Grant

Sometimes two fish that look alike can be very different indeed. Take rainbow trout for example. Some live the majority of their lives in freshwater lakes; others are born in rivers but move to the Pacific Ocean to feed on fish and squid. Some reside in desert streams eating tiny invertebrates; others are reared on pelleted diets in aquaculture facilities.

All of these fish are rainbow trout. They can breed with one another and share the same basic physical characteristics – the position of fins, pattern of spotting on the tail, etc. Even so, we recognize the difference and even call them by different names.

The Kamaloops trout is a lake-strain rainbow trout from interior British Columbia. The steelhead grows fast feeding in ocean currents. The redband trout can tolerate warm daytime temperatures in desert streams, and domesticated rainbow trout tolerate crowded conditions much better than wild fish.

None of this will come as a surprise to anglers and fisheries biologists who are familiar with a long list of “strains” of rainbow trout and other fish that have been stocked for their unique characteristics. Hatcheries have even been involved in selective breeding of rainbow trout to create new strains with desirable characteristics. The long-lived summer run Skamania is one example of this.

What is the difference?

In the past, we generally assumed that differences between strains could be understood by looking at genes. For example, it makes sense that the desert-dwelling redband trout would have genes that allow it to survive in warmer water than, say, a steelhead that spawns in Alaskan rivers.

At the molecular level, a gene is a sequence of DNA. The DNA molecule contains a genetic code that essentially provides a blueprint for an entire organism – in this case a rainbow trout. When comparing wild rainbow trout strains, looking at DNA makes sense. Natural selection allows some trout to survive and breed while others die and fail to pass on their genes.

Over the course of many generations, different strains of rainbow trout develop in ways that reflect differences in their environments. We expect to see this reflected in the DNA of wild redband trout and the Alaskan steelhead, but what about fish reared in hatcheries?

Too fast for natural selection

Domestic fish, like domestic cattle and other livestock, are raised in conditions that are more crowded than natural environments. Previous research has shown that even a single generation of captive breeding and rearing can reduce fitness of rainbow trout (steelhead) by up to 40%. In this context, fitness is not a measure of how healthy an individual fish is. Instead, Darwinian fitness relates to the number of successful offspring produced by an individual fish.

For rainbow trout, this means that first-generation hatchery trout are not as good at producing offspring in natural environments as wild-spawned trout are. For example, first-generation hatchery steelhead in the Hood River, Oregon, produced 15% fewer successful offspring than wild steelhead when spawning in the wild but when spawned in captivity, the first-generation hatchery fish produced twice as many successful offspring. In a single generation, the hatchery fish had adapted in ways that made them more successful in artificial environments but less successful in the wild.

Changes in domesticated fish, and other animals, occur so quickly that changes in gene frequencies (DNA) cannot be the only cause. Several generations of very strong selective breeding are needed to create even minor changes in gene frequencies. Researchers working on Hood River steelhead hypothesized that changes were caused, at least in part, by the way that some genes are expressed (as opposed to changes to the genes themselves).

What they found was astounding (see study). After a single generation of captive breeding and hatchery rearing, the expression of 723 different genes was altered in comparison to wild fish. Many of these genes were related to wound healing, immunity, and metabolism. This makes a lot of sense, seeing that crowded hatchery conditions lead to more wounds and exposure to disease.

The new frontier of epigenetics

These changes in gene expression are not limited to first-generation hatchery fish, either. Molecular tags that control the expression of genes can be inherited by the next generation. The Hood River hatchery steelhead experienced “heritable epigenetic modifications” that were passed on to their offspring.

All this may sound rather esoteric, but this is one of the first studies to demonstrate the importance of epigenetics in fisheries management. Put simply, “epi-” means “above” and “epigenetics” refers to all of the factors that control expression of genes. Think of DNA as the computer hardware of your cells and epigenetics as the software or computer programs that control the use of DNA (see Duke University video).

The emerging field of epigenetic research has made a splash in the news over the past few years, but most studies have dealt with human health. It turns out that diet and stress influence human epigenetics, too. Researchers have investigated epigenetic effects on aging, Alzheimer’s disease, obesity, cancer, and a host of other health issues.

Fisheries scientists have only begun to investigate the role of epigenetics. If the Hood River study is any indication, this new frontier could have big implications for how we understand and manage wild and stocked fish populations in the Great Lakes.