News Article | March 30, 2017
Sea lampreys (Petromyzon marinus) have gained a notorious reputation in the North American Great Lakes. Although considered an endangered species in their native territories - Europe and the Pacific Northwest - their presence inspires terror in U.S. waters, threatening local fish populations and the fishing industry. These parasitic eel-like fish thrive at the expense of other aquatic creatures, which have come to fear their gaping jawless mouths. Equipped with razor-like teeth, they attack and kill other water inhabitants, latching onto their prey and sucking the blood out. But that's not all. Lampreys hide even more secrets in their deadly arsenal of evolutionary traits. According to a new study published on March 29 in the journal Proceedings of the Royal Society B, the parasitic fish can change their gender depending on what their environment has to offer. Researchers from the U.S. Geological Survey and Michigan State University set out to investigate how environmental conditions affect growth rates in lampreys. What they discovered instead was utterly unexpected: These "vampire fish" (as they are sometimes called) become male or female as dictated by how much they grow in their larval stage. This sex determination method is unprecedented in nature, making lampreys the first creatures to undergo sex change based on the resources in their environment. In mammals, sex is established at a chromosomal level, while in reptiles gender assignment is governed by the temperature of the eggs. The international science journal Nature reports lamprey larvae start out with undifferentiated sexual organs, developing gonads within a year and metamorphosing into adult fish after several more years. Scientists led by Nick Johnson, a USGS biologist, surveyed the creature's habitats in the Great Lakes area, including their tributaries and nearby situated reservoirs, and - after making sure there were no wild lampreys in the study sites - released between 1,500 and 3,000 larvae to monitor their developmental process. All larvae had been tagged beforehand and so it was easy for the team to recapture them after metamorphosis and observe their sex. The experiment showed the environments with poorer food resources led to slower growth rates in lamprey larvae, which increased their likelihood of becoming male, rather than female. Such unproductive sites, where prey wasn't abundant, resulted in a male lamprey population of 78 percent, whereas more plentiful environments only produced 56 percent males. "We were startled when we discovered that these data may also reveal how sex is determined because mechanisms of sex determination in lamprey are considered a holy grail for researchers," said Johnson. He believes the explanation for this species' gender assignment system lie within larval density, as well as food availability, since a nutrient-rich environment offers better conditions for the fish to produce eggs. The newfound data could help establish new ways to keep the lamprey population in check. These invasive and destructive parasitic fish have taken a great toll on the Great Lakes' ecosystem, decimating native aquatic fauna and disrupting the multibillion-dollar fisheries based in this area. Previous efforts to curtail the species' prevalence involved using pheromone bio pesticides to lure females into baiting sites and collect them before they get the chance to breed. Even though sea lamprey numbers have been reduced by 90 percent, specialists call for even more innovative pest control strategies to protect American lakes from their predatory attacks. "The results of this study could open paths forward to novel technologies that can disrupt or modify gender in sea lampreys," said David Ullrich, chairman of the Great Lakes Fishery Commission. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Management of alewife using Pacific salmon in the great lakes: Whether to manage for economics or the ecosystem? [Manejo de la alosa en la región de los grandes lagos por medio del salmón del Pacífico: ¿manejo del ecosistema o de la economía?]
Dettmers J.M.,Great Lakes Fishery Commission |
Goddard C.I.,Great Lakes Fishery Commission
Fisheries | Year: 2012
The combined destructive effects of overfishing, habitat destruction, and invasive species, especially alewife (Alosa pseudoharengus) and sea lamprey (Petromyzon marinus) led to the loss of the native top predator lake trout (Salvelinus namaycush) from most of the Great Lakes by 1960. Alewife populations then exploded, creating nuisance die-offs. Public demands for action, coupled with control of sea lamprey, allowed fishery managers to consider stocking Pacific salmon to control alewife and establish a recreational fishery. This effort was successful, reducing alewife numbers and creating a recreational fishery that is estimated at $7 billion annually. This fishery management regime may no longer be viable as new invasive species continue to alter the ecosystem. Fishery managers face an interesting dilemma: whether to manage in the short term for a popular and economically important sport fishery or to embrace ecosystem change and manage primarily for native fish species that appear to be better suited to ongoing ecosystem changes. Such dilemmas occur in great lakes around the world as fishery managers seek to balance economic pressure with changes in their respective ecosystems, often brought about by invasive species.
News Article | October 26, 2016
In the bestiary of bizarre ocean creatures, there are few animals stranger than the jawless, finless sea lamprey. These eel-like fish are parasites, latching on to larger fish and boring into their skin with a tooth-lined sucker to feed on the blood of their prey. Sea lampreys are among an elite collection of anadromous fish—saltwater fish that spawn in freshwater—a trait they share with much more palatable species like salmon, striped bass, and sturgeon. As the Great Lakes became increasingly channelized in the mid-19th century to permit shipping from the Midwest to the Atlantic coast, sea lampreys, native to inland lakes in New York and Vermont, invaded. Over the next century, they would decimate native fish populations in Lake Huron, Lake Michigan, and Lake Superior. They are relentless invaders, and tracking their spread has proven to be an exercise in futility, at least for human observers. But a new robotic challenger has emerged. GRACE (short for Gliding Robot Ace) is as unusual among underwater robots as sea lampreys are among freshwater fishes. Eschewing the conventional thrusters or ruddered propellers of most underwater robots, GRACE instead packs a powerful tail fin to propel it forward. This is supplemented by a glider system: By changing its buoyancy, GRACE can propel itself forward by ascending and descending through the water column. This is an exceptionally efficient configuration, giving GRACE an enviable multi-week endurance while patrolling for lampreys around Lake Michigan. Grace 2.0 out for testing in August. GRACE is the brainchild of Dr. Xiaobo Tan of Michigan State University, and he's thinking seriously about developing a powerful, multi-user platform. "We're not just trying to publish a paper," said Dr. Tan, "we want to make something really functional." GRACE's tracking system is built on a standardized acoustic monitoring protocol that is used throughout the Great Lakes, as well as many other marine and freshwater systems to track everything from salmon to bull sharks. Here's how it works: Researchers capture fish of interest and tag them with an acoustic pinger. The pinger responds to signals from a transducer, which provides a rough estimate of location. Add a second transducer and researchers can triangulate the fish's location. This type of system allows researchers to track the movement of tagged fishes as they travel into and out of the lake, and can reveal spawning aggregations, nursery grounds, and population centers. But there are major limitations: the transducers are either static, which limits the range a fish can be tracked; or mounted on a boat, which requires people to continuously monitor the system, limiting the amount of time a fish can be tracked. An autonomous robotic fish, swimming through the lake, constantly monitoring tagged animals, overcomes both those limitations. Dr. Tan's ultimate vision is a swarm of GRACE robots, continuously swimming across Lake Michigan, communicating with each other, and triangulating the location of tagged sea lampreys or other species of interest. It's an incredibly adaptable mobile platform, one that can support a variety of Great Lakes monitoring programs. GRACE supplements the Great Lakes Acoustic Telemetry Observation Systems (GLATOS), a collaborative network of researchers who use acoustic telemetry to monitor fish in the Great Lakes. But GRACE's mobility is the killer application that makes this platform a compelling addition to GLATOS, as GRACE can cover a much greater area than GLATOS, and move with the fish it's tracking. Following schools of fish is where its design really shines. Rather than noisy propellers, which can become mired in seagrass and potentially injure wildlife, GRACE moves more naturally through the lake. "[The design] minimizes impact on the environment." said Dr. Tan. "We don't want a noisy machine." Building a new kind of underwater robot is not without its challenges. Every new component comes with its own host of difficulties. GRACE, now in its second generation, is the product of intensive testing and evolution. "We fail, we try again," said Dr. Tan. "The biggest hurdle is system integration—how to integrate all mechanical, electrical, and software elements and make sure the robot works reliably in real-world environment." Even these prototypes will enter common use for Great Lakes researchers. Though Dr. Tan doesn't foresee full implementation of his vision until at least the third generation of GRACE prototypes, earlier units are shared with the research community, to support other acoustic monitoring programs. GRACE is backed by the Great Lakes Fishery Commission, the National Science Foundation, and the US Geological Survey. Dr. Tan plans to continue adapting and refining its systems, and predicts at least another two years to realize his vision for GRACE. In an ocean of autonomous underwater robots that are often more hype than function, GRACE stands out as one of the few systems driven by proven prototypes over press releases.
News Article | January 7, 2016
Sea lampreys are bad news and the U.S. Environmental Protection Agency has come up with a new way to deal with the invasive species by registering a mating pheromone as a biopesticide. Called 3kPZS, the sea lamprey mating hormone released by males works like an alluring perfume, attracting females onto nesting sites. However, as a biopesticide, it will be used to lure female sea lampreys into baiting sites where they can be collected before they get the opportunity to breed. Researchers have been studying how to use pheromones to manipulate sea lamprey's behavior since the 1990s. The mating pheromone 3kPZS has been tested in baiting sites before and the results of those tests paved the way for it to be registered for official use as part of the EPA's sea lamprey control program. According to Dr. Weiming Li, a Michigan State University professor part of the Great Lakes Commission's Partnership for Ecosystem Research and Management, the field trial carried out to test the effectiveness of 3kPZS showed a boost in trapping efficiency by up to 53 percent. Additionally, baited traps were found to capture twice more sea lampreys compared to traps without baits. Initial trials prior to the registration used pheromones naturally derived from male sea lampreys but a synthetic version will also be manufactured in partnership with private company Bridge Organics. The EPA registration applies to both synthesized 3kPZS and a mixture of solvents and the synthesized pheromone used in the field. U.S. Geological Survey director Dr. Suzette Kimball referred to it as a milestone, the culmination of combined efforts to come up with cutting-edge ways to control the sea lamprey population in the Great Lakes. The Great Lakes area represents a $7-billion fishery industry. Once the biopesticide is registered in both the U.S. and Canada, it will officially become part of the Fisheries and Oceans Canada and U.S. Fish and Wildlife Service's arsenal to control the sea lamprey population. Aside from biopesticides, traps, barriers and lampricides are used. "U.S. EPA registration of the sea lamprey mating pheromone opens the door for use of the pheromone in the commission's sea lamprey control program, which protects Great Lakes fisheries from destruction caused by invasive sea lampreys," said Dr. Robert Hecky, chair of the Great Lakes Fishery Commission. A biopesticide refers to any substance that is naturally occurring and can be used for controlling pests. Others registered include disparlure, a pheromone used for detecting and controlling small gypsy moth infestations. 3kPZS is the first vertebrate biopesticide registered.
News Article | January 29, 2017
The Grass carp one of the four Asian carp species has reportedly entered the great freshwater lakes of Michigan, Erie and Ontario. The invasion of Grass carp poses a serious threat to the lake's aquatic environment reveals a scientific study. Grass carp is an herbivorous fish found in freshwaters which can weigh a maximum of 90 lbs. It is not a naturally occurring fish in U.S. and Europe. The Grass carp was first cultivated in early 1960s in the U.S. to control growth of weed in the waterways. Some escaped through the system and went north, gradually settling down in the Great Lakes. This is not the first time the invasive fish has been spotted in the great lakes. Bighead Grass carp and Silver Grass carp are most feared in the aquatic ecosystem as they feed on microscopic plants and animals in huge quantities. Grass carp as a species is considered to be the most invasive of all fishes and they pose a threat to other fishes in the lakes. Why? As Grass carps "aggressively outcompete" native fish for food and are capable of eventually overtaking the particular aquatic ecosystem. A report has been prepared by American and Canadian experts with help from Fisheries and Oceans Canada, the U.S. Fish and Wildlife Services and the Great Lakes Fisheries Commission, which states that 9 out of 10 Grass carp caught between 2013 and 2016, were found to be fertile. It is believed that the fertile fish were not born in the Great Lakes and eventually made their way into Canada. "Grass carp have been in the Great Lakes for ... probably 30 years or even more but they've been sterile, lately ... we've been seeing recurring incidents of fertile grass carp in the Great Lakes. They're not supposed to be fertile," said Mark Gaden from Great Lakes Fishery Commission. They are known to reside the freshwater lakes for quite some time "humming in the background." Most of these fish were sterile, thus the question of invasion and risk to the ecosystem never arose. However, in recent years, the concern has been growing as more and more fertile Grass carps are being captured. Grass carps reared in hatcheries in some states have to be sterile before they are released into water. "Right now, the sterile fish outnumber the fertile fish. This isn't game over, but we are finding more of these fertile fish," said Becky Cudmore, primary author of the study. The study's analysis points out that Grass carp will eventually become "established" in the lakes of Erie, Huron, Michigan and Ontario in 10 years unless serious action is taken. To reach an established population, the specie has to reproduce over multiple generations. Several options like strict laws regarding bringing Grass carp in the region, along with prevention of release of fertile fish, may help control the alarming situation. Also, nets can be used to block the fish's course to spawning areas during the time of reproduction. "Our assessment is saying that yes, they were showing up before, but now they're starting the invasion process. They have arrived. Now is the time to act," noted Cudmore. Â© 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Lawrence T.J.,Great Lakes Fishery Commission |
Lawrence T.J.,University of Michigan |
Watkins C.,Culture and Conservation
International Journal of Sustainable Development and World Ecology | Year: 2012
Decentralisation policies in least developed countries have emerged in response to failed centralised natural resource governance programmes because high-value natural resources are distributed unequally, with central governments often reaping more than local-level users. Current natural resource governance institutions have been created to remedy the problems that central governments formerly posed. Here, we argue that Uganda's forestry and fishery resources are biologically diverse and thus amenable to current decentralised management programmes, provided that there is compromise between market values and local cultural and subsistence values and uses. We observe, however, Uganda's current institutional arrangement favours the former over the latter and determine that successful natural resource decentralisation requires strengthening local-level natural resource institutions with increased fiscal flow, enforcement, monitoring and judicial powers. A strong and reliable partnership between local-level resource users and the central government is necessary for this to occur. © 2012 Copyright Taylor and Francis Group, LLC.
Li K.,Michigan State University |
Brant C.O.,Michigan State University |
Siefkes M.J.,Great Lakes Fishery Commission |
Kruckman H.G.,Michigan State University |
Li W.,Michigan State University
PLoS ONE | Year: 2013
A sulphate-conjugated bile alcohol, 3,12-diketo-4,6-petromyzonene-24-sulfate (DKPES), was identified using bioassay-guided fractionation from water conditioned with sexually mature male sea lamprey (Petromyzon marinus). The structure and relative stereochemistry of DKPES was established using spectroscopic data. The electro-olfactogram (EOG) response threshold of DKPES was 10-7 Molar (M) and that of 3-keto petromyzonol sulfate (3 KPZS; a known component of the male sea lamprey sex pheromone) was 10-10 M. Behavioural studies indicated that DKPES can be detected at low concentrations by attracting sexually mature females to nests when combined with 3 KPZS. Nests baited with a mixture of DKPES and 3 KPZS (ratio 1:29.8) attracted equal numbers of sexually mature females compared to an adjacent nest baited with 3 KPZS alone. When DKPES and 3 KPZS mixtures were applied at ratios of 2:29.8 and 10:29.8, the proportion of sexually mature females that entered baited nests increased to 73% and 70%, respectively. None of the sexually mature females released were attracted to nests baited with DKPES alone. These results indicated that DKPES is a component of the sex pheromone released by sexually mature male sea lamprey, and is the second biologically active compound identified from this pheromone. DKPES represents the first example that a minor component of a vertebrate pheromone can be combined with a major component to elicit critical sexual behaviors. DKPES holds considerable promise for increasing the effectiveness of pheromone-baited trapping as a means of sea lamprey control in the Laurentian Great Lakes. © 2013 Li et al.
Miehls S.M.,Urbana University |
Dettmers J.M.,Urbana University |
Dettmers J.M.,Great Lakes Fishery Commission
Transactions of the American Fisheries Society | Year: 2011
Yellow perch Perca flavescens exhibit a consistent early life history across most lakes, with hatching in spring followed by a brief pelagic phase that ends with an ontogenetic shift to benthic habitat. This shift occurs with consistent timing and at consistent sizes in most freshwater systems. In Lake Michigan, however, the pelagic phase is prolonged and age-0 yellow perch undergo the transition to benthic habitat at variable sizes, the reasons for which are unknown. We investigated whether prey resources, diet preferences, and physical environment affected the habitat shift of pelagic, age-0 yellow perch. The shift to nearshore benthic habitat between 1998 and 2005 was strongly correlated with the occurrence of onshore wind events, a surrogate for transport by onshore currents. The timing of this habitat shift was not strongly related to prey resources. Abiotic factors structured the habitat shifts of age-0 yellow perch in Lake Michigan, a pattern atypical of freshwater systems but consistent with the patterns seen in marine systems. © American Fisheries Society 2011.
Eshenroder R.L.,Great Lakes Fishery Commission
Transactions of the American Fisheries Society | Year: 2014
The origin of populations of the landlocked Sea Lamprey Petromyzon marinus in Lakes Champlain and Ontario, whether by artificial canals or by natural colonization following the last ice age, is controversial, in part because the related history and ecology had been poorly documented. This situation favored a native classification for the populations in both lakes based mainly on genetics. A native classification for the Lake Champlain population was predicated on either of two erroneous dates of first record, 1841 and 1894, whereas the correct date, 1929, was much more recent and strongly supports a nonnative classification. The detection of the Sea Lamprey in Lake Champlain occurred shortly after the opening in 1916 of the Champlain Barge Canal, which opened the upper Hudson River to fish passage. The case for a native Lake Ontario population did not account for a watershed breach in 1863 between the Susquehanna River, where the Sea Lamprey had been common, and the Lake Ontario drainage. Shortly after this canal-related connection was made, Sea Lamprey populations became abundant, nearly simultaneously, in four locations in the Lake Ontario drainage, suggesting this breach was the entry point for the founding population. The genetic distances between the landlocked populations and the Atlantic Ocean population appear to have been caused by recent bottlenecks rather than long-term residence; a recent genetic bottleneck was detected in the Lake Ontario population. Native classifications rested, in part, on extraordinary ecological scenarios, whereas nonnative classifications are consistent with experience in the upper Great Lakes and with well-known vectors of range expansion (canals, dam openings, watershed breaches). These findings in aggregate favor a nonnative classification of the Sea Lamprey in both lakes. © American Fisheries Society 2014.
Li K.,Michigan State University |
Siefkes M.J.,Great Lakes Fishery Commission |
Brant C.O.,Michigan State University |
Li W.,Michigan State University
Steroids | Year: 2012
Petromyzestrosterol (1), a novel polyhydroxylated steroid, was identified from water conditioned with sexually mature male sea lamprey (Petromyzon marinus), a jawless vertebrate animal. Along with this novel steroid, two known steroids, 7α,12α,24-trihydroxy-5α-cholan-3-one-24-sulfate (3k PZS) and 7α,12α,24-trihydroxy-5α-cholan-24-sulfate (PZS), were isolated. Structures of these compounds were unequivocally established by spectroscopic analyses and by comparison with spectra of known compounds. Electro-olfactogram recordings (EOG) showed that 1 at nanomolar concentrations was stimulatory for the olfactory epithelium of adult females. 3k PZS, known to function as a male sex pheromone, was more stimulatory than 1 for the female olfactory epithelia. The concentration-response curve of 3k PZS was exponential in shape with steep slopes between 10 -10 and 10 -6 mol L -1. The concentration-response curve for 1 was shallower than that for 3k PZS. © 2012 Elsevier Inc. All rights reserved.