The idiom of a “red herring” supposedly originated in a technique to train scent hounds. One version of the story has a smelly smoked herring being dragged around until a puppy learned to follow the scent. Another etymology points to escaping convicts using the pungent fish to throw off pursuing hounds.
In reality, the term probably originates in an article published 14 February 1807 by radical journalist William Cobbett in his polemical Political Register. In a critique of the English press, which had mistakenly reported Napoleon’s defeat by the Russians at the Battle of Eylau, Cobbett recounted that he had once used a red herring to deflect hounds in pursuit of a hare, pointing to the “transitory effect of the political red-herring” whose scent quickly “became as cold as a stone”.
There is a fishy tale attached today’s ubiquitous tilapia. Lake Nicaragua is the largest body of water in Central America, only slightly smaller than Lake Titicaca. Despite being a freshwater lake, it contains sawfish, tarpon, and sharks – a species of Bull shark known to enter freshwater. It had been presumed that the sharks were trapped in the lake, but in the late 1960s this was found to be incorrect when it was discovered that like salmon they were able to jump the rapids of the San Juan River (which connects Lake Nicaragua and the Caribbean Sea).
Numerous other kinds of fish live in the lake, including at least 16 species of endemic cichlids, of which at least 1,650 species worldwide have been scientifically described. A non-native cichlid, tilapia is widely used in aquaculture in Lake Nicaragua. They are a serious threat to the lake’s ecosystem owing to the large amount of waste they produce and the risk of introducing diseases to which the native fish species have no resistance.
Nicaraguans call the lake Mar Dulce or Sweet Sea (in Spanish, freshwater is agua dulce). Lake Nicaragua has sizeable waves driven by the easterly winds blowing west to the Pacific Ocean. It has two volcanic islands, Ometepe and Zapatera, and has a reputation for periodically powerful, unnavigable storms. In recent decades considerable concern has been expressed about the ecological condition of Lake Nicaragua. In 1981 the Nicaraguan Institute of Natural Resources and the Environment (IRENA) conducted an environmental assessment that discovered that half of the water sources sampled were seriously polluted by sewage. It was found that 32 tons (70,000 pounds) of raw sewage were being released into Lake Nicaragua daily by industry located along the shore. In 2009 a new wastewater treatment plant was opened, but according to some estimates it will be 50 years before the water can be used for consumption.
Nevertheless, the lake is still used to farm tilapia (“St Peter’s fish”), the fifth most important fish in fish-farming, with production worldwide reaching 1,505,804 metric tons in 2000. In 2011 Americans ate 475 million pounds of tilapia, making this once obscure African native the most popular farmed fish in the United States. Most of the tilapia is “harvested” from pens or cages in Latin America and Asia.
Known in the food business as “aquatic chicken” because it breeds easily and tastes bland, tilapia is the perfect factory fish. But compared with other fish, farmed tilapia contains relatively small amounts of beneficial omega-3 fatty acids, the fish oils that are the main reasons doctors recommend eating fish. Salmon has more than 10 times the amount of tilapia. Also, farmed tilapia contains a less healthful mix of fatty acids because the fish are fed corn and soy instead of lake plants and algae, the diet of wild tilapia.
It looks like the tilapia is being foisted on consumers because its prolific breeding makes it cheap to produce. Its questionable health benefits are, of course, a red herring.