ASIAN CARP FRENZY: CARP NOT FIRST NEWCOMER TO RECEIVE COOL WELCOME
ASIAN CARP FRENZY: GOVERNMENT PLANS FEATURE LOTS OF SHOW, LITTLE ACTION
The image of the Asian carp that has captured the public imagination is of fish launching like projectiles out of the water and sometimes on to boats. Projectile fish knocking off boaters create a formidable and provocative image.
The media has generally adopted a militaristic stance in framing the issue of Asian carp. A TIME online article published in 2010 with the headline “Asian Carp in the Great Lakes? This Means War!” began thus: “There are illegal immigrants on the loose in the Midwest. Originally hailing from Asia, they're about 3 feet (90 cm) long and weigh up to 100 pounds (45 kg), and are known to resist capture. Once they establish residency, they can eat you out of house and home.”
Such narratives drive the discourse on non-indigenous species into “linguistic maelstroms of war and pestilence.” The rhetoric of war dramatizes the issue in the media and intensifies audience attention and alertness. Militaristic metaphors capture eyeballs and propel political action.
Consider the terms used for non-native species: introduced species, exotics, invasives, aliens, foreign, non-indigenous, biological immigrants, strangers, pests, unwelcome aliens, conquering hordes, and isolated terrorists. The phenomenon of non-indigenous species in the Great Lakes has been called a plague, a menace, an alien invasion, biological pollution, a slow never-ending wildfire, and herpes for the Great Lakes.
Such rhetoric has a tendency to conflate human and nonhuman immigrants and to assign each with negative qualities based on the logic that because some undesirables are immigrants, it follows that individuals or species are undesirable because they are immigrants. Declaration of war against non-native species seems a satisfying response to a public whipped up by media frenzy. However, we must consider whether declaring war against a perceived common enemy is satisfying merely because it allows us to displace our anxieties about social, economical, and environmental change.
The psychological consequences of militarism are serious in the context of both human and non-human immigrants. A nativist plant movement in Nazi Germany spawned overmilitaristic anti-invasive species rhetoric and the “mania for native plants” may have translated to increasing antagonism towards certain foreigners.
Ongoing debate today centers on the role that the caustic rhetoric against immigrants may have played in inciting recent tragic events around the world (e.g. the Norway killings). The rhetoric of war has the effect of shutting down debate and narrowing options for consideration, often to most extreme and violent ones. In the case of floral and faunal species, it begs the questions: On whom are we declaring war? What are the goals of such a war? What will be its “Mission Accomplished” moment? And most importantly, is this the most serious threat that faces our ecosystems and against which all available resources must be marshaled?
Recent critiques have questioned the dangers of invasive species, raising doubts about whether the spread of non-indigenous species will in fact result in global homogeneity of species and ecosystems. Moreover, the distinction is not always as clear as the rhetoric would suggest, between “native species,” which originated in a location or arrived there by “natural” means, and “non-native species,” which were introduced to an area or whose movement was facilitated by humans. However, such a distinction has become reified over time.
The story of non-native species in the Great Lakes is one of accidental and deliberate introductions; of ecosystem perturbation and resilience; of complex and unexpected interactions. The first non-indigenous species to arrive in the Great Lakes and gain widespread notoriety was the dreaded “vampire of the deep.” Sea lamprey are generally thought to have arrived in the Great Lakes sometime after the Erie Canal opened in 1825; the first breeding colony was discovered in 1935. These eel-like blood-sucking fish with green and brown mottled slimy skin and disc-shaped mouth ringed with sharp teeth and piercing tongue would latch on to the bodies of native fish like the lake trout. The lamprey’s appearance and feeding habits fed into every nightmare scenario, the ghoulish stuff of horror movies and vampire lore.
In 1872, an appropriations bill became law allowing the U.S. Fish Commission to fund fish culture and requiring the fish commissioner to introduce shad into the waters of the Gulf states and the Mississippi Valley. Later in the 19th century, the U.S. Fish Commission introduced the common carp to the Green River in an effort to “reengineer the river’s fishery.” The first commissioner, Baird, thought these hardy fish a potential food source for a growing nation. Lacking the cachet of salmon or trout, the carp never caught on. Later, a hundred or so years ago, U.S. streams, rivers, and lakes, well outside the fish’s range, were stocked with rainbow trout in order to encourage sport fishing and “restore the virility of the American male.” The rainbow trout has been highly interbred and engineered in hatcheries and its genetic makeup bears little resembles to the original species which may well be extinct, leading one author to label it “an entirely synthetic fish.” The organization credited with being the first to propagate rainbow trout was The Ornithological and Piscatorial Acclimatizing Society of California, whose mission was to import “all the game birds and fish of the older states and Europe.”
The 1940s ushered to the upper Great Lakes the alewife, a herring native to the Atlantic coast and its tributaries. Around this time, overfishing and sea lamprey nearly eliminated the lake trout, top fish predator of the Great Lakes. Alewives dominated Lakes Michigan and Huron, accounting for 90 percent of the biomass in the lakes. The ensuing massive alewife die-offs “turned vast stretches of Great Lakes beaches into fish graveyards and breeding grounds for flies, maggots, and botulism.” Starting in 1966, the state of Michigan stocked Pacific salmon in Lake Michigan to control alewife and support sports fishery. The commission dispelled doubts about bringing the Pacific salmon (a different species) to the eastern U.S. because “the introduction of new species was, after all, part of the mission of the U.S. Fish Commission.”
The opening of the St. Lawrence Seaway in 1959 brought to the Great Lakes ocean freighters, whose ballast carried hitchhikers like the humpback pea clam, Chinese mitten crab, flatworm, European flounder, Asiatic clam, copepods, spiny water flea, fish-hook water flea, Eurasian ruffe — a perch species. These species raised relatively few eyebrows. It was the mussels that made the next big splash — zebra mussels and quagga mussels. The mussels were followed by the gobies. The bloody-red mysis was the 183rd documented non-native species to reach the Great Lakes.
Ocean freighters have since been compared to Trojan Horses, and the St. Lawrence Seaway was labeled Pandora’s Locks by one author for opening up the Great Lakes to invasion by hordes of foreign species, causing tidal waves of unintended consequences, an ecological domino effect.
Now the threat of the Asian carp looms over us. Asian carp in the U.S. are made up of five carp species. The common carp (Cyprinus carpio), introduced in 1831, is now sometimes considered as a member of native fish communities. Introduced next in 1963 for biological control of submerged aquatic vegetation in aquaculture ponds, was the grass carp (Ctenopharyngodon idell). Some of the fish escaped the ponds and in 1971 the species was documented in the Mississippi River. The three carp that followed — the bighead carp (Hypophthalmichthys nobili), the silver carp (Hypophthalmichthys molitri), and the black carp (Mylopharyngodon piceus) together constitute the “Asian carp,” subject of the current invasive species controversy in the Great Lakes.
By the late 1990s and early 2000s, some native species such as mayflies (which had earlier been nearly eliminated from Lake Erie due to pollution and eutrophication), recovered and even benefitted from the zebra mussel invasion, a demonstration of the resilience of the Great Lakes ecosystem. Zebra mussels decimated native unionids, and played a role in the decline of Diporia and in recent botulism outbreaks, which killed thousands of fish-eating birds in the Great Lakes. But they also improved water quality in the lakes, which in turn increased the population of invertebrates, and increased the catch of the native yellow perch in Lake St. Clair.
Ironically, later arrivals led to the control of previous ones. In Lake Huron, zebra mussels and salmon predation contributed to the decline of alewives leading to the recovery of native walleye, lake trout, and emerald shiners. A threatened native snake species, the Lake Erie water snake, was helped by the round goby invasion. The snake changed its diet to primarily round goby, and the abundance of prey led to an increase in the growth rate, body size, and numbers of offspring. Round gobies, which have been linked with the local extirpation of native benthic fish such as mottled sculpin and john darter, also function as prey for the Lake Erie water snake and sport fish as well as predator of another invader — the zebra mussel. Thus, new arrivals can have seemingly devastating but also complicated and sometimes beneficial effects on the communities and ecosystems in which they become established. Stocking of lakes with predators (trout and salmon) is now carefully balanced such that alewife populations are kept in check yet allowed to persist at sufficient levels to provide forage for the predators. This is the status of the landlocked forms of alewives. The original anadromous alewife, once ranging from Newfoundland to South Carolina is now in serious decline, which in 2006 led the NOAA’s National Marine Fisheries Service to declare it a Species of Concern.
Experts continue to disagree on the threat posed by Asian carp on the Great Lakes ecosystem. Many ecologists and fish experts have argued against the case that the plankton-eating Asian carp pose a serious threat to the Great Lakes. With the exception of warm bays at the mouths of large rivers, the Great Lakes lack adequate food, warm temperatures, or habitat and have an abundance of predators to control carp populations. Ecologists at the University of Michigan labeled the Asian carp controversy “a red herring,” which distracts us from the real threats to the Great Lakes such as toxic chemical sites that remain to be cleaned up, run-off of harmful chemicals from agriculture, and inadequate regulation of ships’ ballast. A recent commentary proposes the hydrologic separation of the Laurentian Great Lakes Basin and the Mississippi River Basin as the only effective solution to prevent the spread of Asian carp based on the analyses that electric barriers have not been fully effective, food and habitat are not limiting factors for Asian carp spread in the smaller, shorter tributaries to the Great Lakes, the carp’s plankton diet would adversely impact an already depleted food base, and hydrologic separation would prevent future invasion by additional species. This point, however, remains highly debatable considering that ten other hydrologic connections have been identified between the Mississippi and Great Lake basins.
Can we rally to restore sanity?
Movement of species is a normal part of the planet’s history and biogeography. Human agency has led to unprecedented rates of species movement. New species have the potential to dramatically alter communities and ecosystems. All of these assertions are true. However, the rhetoric of war does little to provide reasonable or farsighted solutions to the problem of unprecedented rates of species movement. The rhetoric of war often motivates overreaction by the public and policy makers leading to counterproductive, wasteful, or even harmful actions. Certain proposals are backed by an increasing momentum of public support and expedient solutions gain traction, for reasons having to do more with placating inflamed sensibilities or for immediate political gain rather than based on a consideration of their long-term effectiveness.
For the Asian carp, these actions included poisoning lakes and rivers with the pesticide Rotenone, which resulted in huge die-offs of non-target fish species. So far, most of the non-target species affected by rotenone were common carp in the Chicago Sanitary and Shipping canal. However, rotenone used in a river in Michigan would kill off native species and adversely impact the fish community.
A common response for problem plant species, such as garlic mustard, is to harvest and destroy the plants. However, harvesting can backfire and have the opposite effect of a spike in the population by overcompensation arising from the complex population dynamics. Moreover, the more successful garlic mustards are in an area, the less toxic the fungal toxin becomes which they secrete into the soil. This evolutionary process works over time to make older stands of garlic mustard more manageable and less toxic to native plants.
Whether the Asian carp threat is real or not, we can take the long view and change our thinking. Invasion biology is a relatively young sub-discipline. Researchers continue to make progress on determining the impact of non-indigenous species and the evaluation of risk and there is an active and healthy discussion about appropriate approaches and terminology. We can follow Slobodkin’s advice to be vigilant against reification by constantly re-examining accepted concepts and refusing to accept charismatic terms and metaphors unless careful consideration has proved their usefulness in research regardless of the amount of funding available for them. Proposed alternative terms for invasive species have included long-term residents, recently introduced species, or problem species, but these have had little traction in the runaway discourse. We can acknowledge the increased recognition that not all non-native species become invasive and that some environmental changes can change native species into problem species. Certain non-native species can help us achieve conservation goals and can contribute to ecosystem functioning, such as providing habitat or food for rare species and taking over the functional role (niche) of an extinct species within an ecosystem. They are more likely to withstand disturbances from climate and land changes, which may enable them to serve in such capacities for a longer period. We can embrace the idea that the proportion of non-native species that are viewed as benign or even desirable is likely to slowly increase over time.
The change in the direction of the rhetoric and conversation about human immigrants in Michigan has been refreshing and remarkable especially in terms of its contrast with the attitudes in other parts of the country. At a recent conference on Immigration and Michigan’s Economic Future in Detroit, Governor Rick Snyder said that in addition to cultural diversity, immigrants bring jobs to America. He suggested that we should embrace immigration as the key to rebuilding the economy of Detroit and Michigan. Both Governor Snyder and New York Mayor Michael Bloomberg have said that immigrants can help meet Detroit’s needs and revitalize its economy. It sounds a lot like non-native species filling ecosystem niches to restore ecosystem functioning.
It is time to resist the invasion of our psyches by the rhetoric of war and take the long view about the Asian carp and its relative danger in the context of impacts of dreissenids and toxic hot spots, which have serious ongoing adverse effects on faunal and human health in the Great Lakes.