Fishes and Humans

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Fishes and humans

Overview

Fishes have figured prominently in human lives, cultures, and economies since ancient times. Fish themes appear in diverse aspects of human culture, including mythology, religion, literature, and art. In addition, fishes are important to humans as a source of food and income; thus, the quest for fishes played a large role in historical patterns of exploration, settlement, and even war. Fishes are the central focus of recreational activities enjoyed by many as well. Despite their value to humans, fishes are often negatively affected by the direct and indirect consequences of human actions. As a result, many fish species are threatened or endangered, and some have become extinct in recent years.

Fishes in human culture

Mythology and religion

Throughout history, fishes appeared in the legends, myths, and folklore of a variety of cultures. In many societies, fishes were associated with deities, perhaps indicative of the value and mystery of fishes in ancient cultures. In Iran and Babylon, archeological evidence revealed a deity with human legs covered by the full body of a fish. In Syrian culture, the mythical goddess of generation and fertility, Atargatis, was represented as the body of a woman with a tail of a fish—a depiction that gave rise to the image of mermaids. The ancient Egyptian deities Isis and Hat-Mehit were associated with fishes; due to the abundance of fishes available during the spawning season in the Nile Valley, these goddesses symbolized fertility. Many other indigenous cultures recognized deities that were believed to protect fish stocks and those persons that harvested fishes.

In some myths, fishes interact with deities in other ways. For example, two fishes derived from Greek mythology are visible in the sky each night—those of the constellation Pisces. According to this myth, Aphrodite, the goddess of love and beauty, was walking along the Euphrates River with her son, Eros, when they encountered the monster Typhon. One story suggests that Aphrodite and Eros jumped into the river, where they were transformed into fishes and fled. In another version of this myth, two fishes carried the mother and son to safety. Both versions imply that fishes can confer protection to deities.

Fishes continue to serve as important symbols in modern Christianity. The Greek word for fish, ichthys, is derived as the acronym for the biblical phrase Iesous Christos Theou Hyious Soter, which translates to "Jesus Christ, Son of God, Savior." The activity of fishing plays a central role in a variety of encounters between Jesus and his disciples, as he instructs them to be "fishers of men." It is believed that the fish symbol formed by two half-crescents arose as a way for persecuted Christians to identify themselves to one another in ancient Rome; this symbol remains widely used by Christians today and has been adopted in modified forms by those advocating alternative beliefs to certain Biblical teachings.

Literature and art

Many legends in classical and medieval literature convey tales of fishes as monstrous sea creatures that invoke fear into even the bravest humans. In his epic Roman poem The Pharsalia, Lucan suggests that large remoras, or shark suckers, could impede the progress of sailing and naval ships. Other stories tell of menacing sea serpents; some legends, such as that of the Loch Ness Monster, are perpetuated still today. In reality, many of the legendary "sea serpents" turned

out to be nothing more than large eels, cuttlefish, squid, or sharks, and others were dismissed as figments of the imagination created by the interplay of light and water. Initially regarded as a folk legend, reports of "rains of fishes" date back to the third century a.d. Such incidents have been reliably documented in more recent years, and it is believed that violent storms may sweep fishes from water bodies and drop them back to land as air currents dissipate.

Fishes have been depicted in artwork throughout cultural history as well. Hieroglyphics of the ancient Egyptians show precise details of many fishes from the Nile River. Many of these carvings remain preserved on the walls of tombs, as fishes were believed to lead people to and sustain them in the afterlife. Native Americans of the Northwest carve fishes, specifically salmon, on totem poles, thereby conveying myths and spiritual connections of their societies to fishes. Fishes have long served as popular subjects in Asian art, particularly that of the Chinese, through which they are often displayed on pottery, screens, and paintings.

Fishes continue to appear in many forms in literature and media of modern culture. Novels such as Ernest Hemingway's Old Man and the Sea and nonfiction works such as Sebastian Junger's Perfect Storm recount the challenges and rewards of the pursuit of fishes, while childhood stories such as Dr. Seuss's One Fish, Two Fish, Red Fish, Blue Fish are widely recognized and adored. In addition, movies periodically revitalize myths and fears of fishes. In the movie The Little Mermaid, the myths of mermaids, serpents, and sea gods again come to life. In contrast, Jaws preys upon general unfamiliarity with shark behavior to instill viewers with fear of these dominant ocean predators.

Human uses of fish

Historical fisheries

Fishes have been utilized by humans throughout history for food, income, and other purposes. Archeological records indicate that Egyptians exploited fishes in the Nile River from prehistoric times. Carvings record the types of fishes caught, fishing techniques, preparation methods, and the trade of fishes. The Egyptians used spears, hooks, weirs, and nets to capture fishes in the wild, but residents of Mesopotamia constructed ponds in the fertile crescent of the Tigris and Euphrates rivers to maintain regular, accessible supplies of fishes. Pliny the Elder recommended fishes as medicinal remedies for a variety of ailments. Still today, cod-liver oil and castor oil are used to relieve internal and external ailments; and in some parts of the world, otoliths, the small ear bones of fishes, are believed to prevent colic.

The quest for fishes played a large role in early exploration and settlement patterns. Access to herring in the Baltic Sea conferred prosperity upon the Hanseatic League during the twelfth century. Disputes over fishing rights and profits led to conflicts, sometimes escalating to war, that continued among European nations long after the demise of the league. By the fourteenth century, Europeans traversed the sea to fish for cod off of Iceland. They preserved the fish in dried or

salted forms to supply European markets, thereby rendering it a valuable commodity, and disputes over access to cod fishing grounds sparked further wars. Cod constituted a major portion of the diet and trade base of later British colonists that explored and settled on the northeast coast of the United States. By the late 1600s, the international cod trade involved other commodities as diverse as salt, sugar, molasses, cotton, tobacco, and even slaves.

Modern fisheries

Fisheries continue to provide a vital source of food, employment, and income in many countries today. World fisheries catch increased rapidly during the 1950s and 1960s. Following the collapse of the Peruvian anchoveta fishery in the 1970s, total catches appeared to level off, but worldwide catch began growing again in the 1980s. In 2000 marine fisheries captured nearly 95 million tons, and aquaculture production added another 35 million tons of fishes that were consumed by humans in some form—most commonly as food, oil, or fertilizer. Despite the value and varied uses of fishes, relatively few species dominate the catch. In 1997 marine fisheries exploited 186 species, but seven species accounted for 50% of the total biomass harvested.

A variety of gear types are used to catch fishes in modern commercial endeavors. Trawls (nets) may be towed along the ocean bottom to target demersal fish (bottom-dwellers) such

as cod, or suspended in the water column to catch pelagic species such as herring. Purse seines surround migratory schools of fishes such as tuna. And hooks on long lines—baited lines stretched sometimes for miles through the water column—capture large predatory species, including sharks and swordfish. A variety of diverse techniques are utilized by many people throughout the world to harvest fishes for subsistence or local consumption. Much fishing occurs near shore using traps, nets, and spears. However, as fish populations are depleted, particularly in areas with few alternative sources of protein, humans resort to small mesh nets or destructive fishing techniques, including dynamite fishing, to capture as many remaining fishes as possible.

Recreation

Many people throughout the world enjoy recreational activities centered around fishes. Recreational anglers pursue fishes for sport in freshwater, coastal, and deep sea settings. In the United States alone, the number of anglers is estimated at over 50 million. Many of these anglers enjoy the sport for the thrill of hooking and landing a feisty fish; since the catch is of secondary importance, anglers often release their catch to reduce mortality effects on the fish population.

Another recreational pursuit involving fishes is that of maintaining aquariums. The idea of the aquarium was first developed in the mid-1800s, and the first public aquarium opened at the London Zoological Gardens in 1846. Today, the keeping and breeding of ornamental fishes is a popular hobby worldwide. Many individuals maintain smaller, personal aquariums, ranging from a single goldfish in a bowl to elaborate tropical marine tanks. This activity was the third most popular hobby in the United States in 2001. Worldwide, it generates millions of dollars of economic activity.

Conservation of fishes

Despite their value to our society, fishes suffer the direct and indirect consequences of human actions. Habitat alteration including inadequate water supplies and declining water quality, overharvesting, and introduced species all threaten the viability of fish populations. Over time, many humans have recognized the negative impacts of certain actions and initiated efforts to ameliorate the consequences of these activities.

Habitat alteration

Human actions alter fish habitats in a variety of ways, often resulting in the decline of fish populations. Dredging of channels and clearing of debris to maintain navigation in waterways removes substrates and rich food sources that fishes prefer. In addition, the loss of wetlands eliminates spawning and nursery habitats for numerous fish species. In some cases, wetlands are destroyed to create urban living space or agricultural land; in other instances, tapping into groundwater supplies lowers the water table so that wetlands are no longer inundated. While hydroelectric power provides energy to many areas, the construction of dams across rivers substantially alters the nature of flowing-water habitats and limits upstream migrations of fishes. Upstream of the dam, the river essentially becomes a lake, and dam operations control downstream water flows. Further, despite the fact that most large dams are now equipped with fish ladders to facilitate upstream migrations, significant declines in the populations of many fish species are commonly noted following dam construction. Indirect human effects on fish habitat are also important. In many tropical regions, deforestation can destroy a watershed's ability to store seasonal rainfall and release it slowly over an extended period of time. Such alterations to hydrological patterns can induce extreme cycles of flood and drought in streams that result in catastrophic consequences for the local fish fauna.

Humans consume large amounts of water for drinking and irrigation, and much of the water used is obtained from rivers and lakes inhabited by fishes. In many regions, reservoirs of dams offer convenient holding areas from which water can be withdrawn for human uses. In other settings, streams and rivers are diverted to cities for human consumption or to agricultural areas for irrigation. Either scenario results in less water to maintain natural flow patterns in rivers and streams; thus, the flooded habitat area available to fishes shrinks, many species move out of the area or become locally extinct, and

others suffer mortality from crowding and disease. The dramatic collapse of the Aral Sea ecosystem after two major tributaries were tapped for agricultural irrigation in the 1980s demonstrates the potential consequences of water diversion on aquatic systems and their fish faunas. This problem is exacerbated in areas that draw their water from underground aquifers. Water held in aquifers is often extracted at rates that exceed natural replenishment. Mining these aquifers for human use can lower the water table sufficiently to completely eliminate aquatic habitats that are dependent on artesian spring flows, a situation of particular concern in arid regions of the southwestern United States and northern Mexico. As water shortages become more prevalent throughout the world and the human demand for water escalates, the severity of threats to fish populations will likely increase, and decisions concerning the allocation of water will become more complex and contentious.

In addition to concerns about water quantity, declining water quality also has serious implications for fishes. Humans have dumped industrial wastes, agricultural chemicals, and sewage directly into water bodies for much of history, and similar discharges continue in many areas today. Indirect runoff further reduces water quality. For example, deforestation increases siltation in adjacent streams, and nutrient runoff from the watershed may cause algal blooms in the receiving lake. These activities all impair water in ways that may be harmful to fishes. Waste effluents contribute to disease; chemicals may prove toxic or impair reproductive success; and algal blooms and the decay of materials may deplete oxygen to inadequate levels for sustaining fish life.

Overfishing

Overfishing poses another substantial threat to fish populations worldwide. The pattern noted in the history of many fisheries involves discovery, high levels of exploitation until the stock collapses, and then switching to a new stock. Even in classical times, stock collapses due to overfishing were common, and as early as the twelfth century, Edward II banned the use of a specific type of trawl net in the Thames Estuary.

In recent years, we have witnessed the collapse of major fisheries, including those for Peruvian anchoveta, California sardine, and Georges Bank cod. The failure of California sardine and Atlantic cod populations to recover demonstrates that intense fishing may deplete stocks to a point that the surviving population may not be large enough to assure recovery, even if fishing effort is eliminated entirely. In addition to the demise of exploited stocks, overfishing may have consequences at the ecosystem level as well. Fishing activities may destroy habitat if inappropriate fishing gear or techniques are utilized. Further, it has been suggested that as humans deplete stocks at high trophic levels, we move to species lower on the food chain; over time, this pattern of "fishing down the food web" threatens collapse of the whole ecosystem.

Introduced species

Finally, human actions affect fish populations and communities by introducing certain species to areas beyond their native range. In many cases, the introduction to a new environment frees a species from natural controls on its population growth. The introduced species may prey upon native fishes, infringe upon habitats and food supplies used by other species, hybridize with native species and reduce genetic diversity of the stocks, or act as vectors of exotic pathogens and parasites to which native species have no resistance. Some introductions are intentional and others accidental, but both may result in severe consequences to native fish stocks. Intentional introductions often follow collapses of native fish stocks due to overexploitation. As an example, the Nile perch (Lates niloticus) was introduced into Lake Victoria to expand protein production and enhance fisheries after the demise of an endemic tilapia, the ngege (Oreochromis esculentus), due to overfishing. Over three decades, predation by Nile perch resulted in the loss of up to 70% of species in the diverse flock of haplochromine cichlids that evolved in the lake.

Status and future of fishes

The human actions described above may result in fish population declines; in some cases, extinction of the species follows.

As of 2002, 115 distinct species and subspecies of fishes were protected by the U. S. Endangered Species Act, and many other species are threatened or endangered in countries throughout the world. Despite the protection afforded to these species, over 40 species have already been lost to extinction in North America alone since the early 1900s. Estimates suggest that approximately 20% of all freshwater fish species are in serious decline or already extinct. Relatively few marine species are considered at risk of extinction, despite high levels of utilization of these stocks in fisheries. The much higher threat to freshwater fishes likely reflects their utilization of restricted habitats that are intertwined with land-based human populations. It is likely that even higher numbers of species are threatened in many tropical countries due to the rich species diversity and small geographical ranges of many species.

Despite the diversity and immensity of the threats identified above, many people now recognize the negative consequences of environmental decisions and actions. Thus, efforts have been initiated to mitigate impacts to fish species and populations. Local activities often include the rearing of fishes in hatcheries to supplement wild stocks and restoration of habitat areas that have been degraded by human activities. Other efforts involve a broader group of people and often require government mandates. Such endeavors include setting aside reserves to preserve highly diverse areas, protecting critical habitats of threatened species, and developing regulations to reduce overfishing and pollution. Internationally, countries have adopted several treaties that advance conservation of fishes and their habitats, including the Convention on Biological Diversity, the Ramsar Convention on Wetlands, and the Convention on International Trade in Endangered Species (CITES). Locally and globally, it seems that we are beginning to recognize that the futures of fishes and of humans may be closely linked.

Resources

Books

Committee on Ecosystem Management for Sustainable Marine Fisheries, Ocean Studies Board, Commission on Geosciences, Environment, and Resources, National Research Council. Sustaining Marine Fisheries. Washington, DC: National Academy Press, 1999.

Committee on Protection and Management of Pacific Northwest Anadromous Salmonids, Board on Environmental Studies and Toxicology, Commission on Life Sciences. Upstream: Salmon and Society in the Pacific Northwest. Washington, DC: National Academy Press, 1996.

Dobson, Mike, and Chris Frid. Ecology of Aquatic Systems. Essex, England: Addison Wesley Longman, 1998.

Helfman, Gene S., Bruce B. Collette, and Douglas E. Facey. The Diversity of Fishes. Malden, MA: Blackwell Science, 1997.

Kurlansky, Mark. Cod: A Biography of the Fish that Changed the World. New York: Walker and Company, 1997.

McGinn, Nature A., ed. Fisheries in a Changing Climate: Proceedings of the Sea Grant Symposium Held at Phoenix, Arizona, USA, 20–21 August 2001. Bethesda, MD: American Fisheries Society, 2002.

Periodicals

Pauly, Daniel, Villy Christensen, Johanne Dalsgaard, Rainer Froese, and Francisco Torres Jr. "Fishing Down Marine Food Webs" Science 279 (1998): 860–863.

Organizations

American Fisheries Society. 5410 Grosvenor Lane, Bethesda, MD 20814 USA. Phone: (301) 897-8616. Fax: (301) 897-8096. E-mail: [email protected] Web site: <http://www.fisheries.org>

American Sportfishing Association. 225 Reinekers Lane, Suite 420, Alexandria, VA 22314 USA. Phone: (703) 519-9691. Fax: (703) 519-1872. E-mail: [email protected] Web site: <http://www.asafishing.org>