A Fish Called Opah Trivia Quiz

Answer: Lampris guttatus

It always been believed that all fish are cold-blooded animals. Enter the opah. In May 2015 scientists rocked our idea of what it means to be warm-blooded when they announced that this amazing fish is the world's first warm-blooded fish. According to NOAA, because opah are not a major seafood species and they live in the deep ocean, scientists know little about their biology and ecology and had assumed them to be similar to other Pacific Ocean pelagic fish. Now nearly everything we know about the opah is up for reinvestigation.

The scientific name for the opah is Lampris guttatus. Holacanthus bermudensis is commonly known as the blue angelfish. Carcharodon carcharias is the great white shark and Carssius auratus is a goldfish. The pelagic zone, also called the open-ocean zone, is from the Greek (pélagos) meaning "open sea".

Answer: They swim in large schools close to shore.

Until the opah became a more mainstream menu item, fishermen would give their opah away as a gesture of goodwill in the hopes of garnering good luck. This has rarely been done since the 1980s when opah flesh became a commercially viable commodity.

Answer: regional endothermy

A fish exhibiting regional endothermy is not a true warm-blooded fish because they cannot maintain a temperature above that of their environment. They must surface to warm their blood which at depth, gives them an advantage in speed, eyesight and agility that sluggish cold water fish cannot attain.

In zoology, a warm-blooded animal is said to be endothermic. The opah is the first documented endothermic fish and does not need to surface to maintain a warm body temperature. Warm-bloodness gives them an edge over cold blooded fish, even fish exhibiting regional endothermy. The word endothermic is also used to denote a chemical change accompanied by an absorption of heat as opposed to the word exothermic which is a chemical change that is accompanied by a liberation of heat.

Answer: birds and mammals

Mammals and birds are warm-blooded. This trait gives them the ability to tolerate external temperature changes better than cold-blooded animals. While lions and tigers are warm blooded animals, a bean is a legume.

Answer: about 5 degrees C above surrounding water

A body temperature just 5 degrees C above the surrounding water gives the opah a decided advantage over competing predators at depths of 150 - 1000 feet. They don't have to surface regularly in order to warm up. The higher body temperature is thought to increase muscle capacity, improve eyesight and brain function, and to resist the effects of cold water at those depths. Their large, specialized pectoral fins combined with the advantage of being warm-blooded allow the opah to move with a swift agility and migrate long distances in an environment where other predators and their prey are slowed by extremely cold water temperatures.

37 degrees C is the normal human body temperature and 78 degrees C is the boiling point of ethanol.

Answer: gills

Unusual tissue in the opah's gills carry warm blood back through its body after cold blood in other vessels in the gills absorb oxygen from cold water. This design is known as "counter current heat exchange". The location of this tissue in its gills allows the opah to maintain an elevated temperature throughout nearly all of its body as it swims rapidly through the water propelled by large pectoral fins. Fatty tissue surrounds the gills and internal organs, insulating the body of the opah from frigid temperatures in its environment and imparting the unique taste that makes it a desirable dinner entrée for humans.

The average opah is caught as a single fish by commercial fishermen and weighs about 100 pounds.

Answer: moonfish

In Hawaii and other places the opah is sometimes called moonfish. Some lesser-used alternate names for the opah are Jerusalem haddock, sunfish, kingfish, and redfin ocean pan fish. It shares some of these names with other species of freshwater and saltwater fish.

Jewelfish and suckfish are fish, but the starfish is an echinoderm.

Answer: a cross between tuna and swordfish

The opah usually swims alone rather than in schools and is harvested in the Pacific for commercial purposes in the USA where it is becoming increasingly popular. It has a rich, creamy taste and a firm, fatty texture making it an attractive option for many types of fish based dishes.

The year-round availability of opah makes it a good commercial fish and it can be found in a wide range of recipies for grilling, broiling and sashimi. Its flesh comes in four different colors depending upon what part of the fish it comes from, and cooks up white except the red breastplate meat which turns brown when heated.

Answer: Gulf of Alaska

Fishermen and fishery biologists have noticed an unusual number of opah catches in the Gulf of Alaska, and at first attributed this phenomenon to ocean warming. With the discovery that the opah is a warm-blooded fish and from data collected from tagged fish, scientists now know that the opah migrates rapidly across long distances and they are having to revist the habits and ecology of the opah because it is obviously a different animal than comparable cold-blooded pelagic fish.

As of May 2015, while the mechanism of that allows the opah to be warm-blooded is understood to working much like the radiator of an automobile, the implications of being a warm-blooded fish which is increasingly showing up in catches in cold waters cannot, with certainty, be attributed to ocean warming. The range of the opah may not be as dependent upon water temperature as the ranges of cold-bloodied fish. Much is unknown of the implications of warm-bloodedness upon an animal in an environment thought to consist entirely of cold-blooded creatures. More study of many aspects of the opah is needed to determine why it is showing up in unexpected places around the world from the Gulf of Alaska to the Southern Ocean.

Answer: Oligocene

The Oligocene is the latest epoch of the Paleogene period lasting 3.339 to 23 million years before the present time. The Eocene (56 to 33.9 million years before present) and Paleocene (66 to 56 million years before present) are earlier epochs of the Paleogene. The Pliocene (5.44 to 2.58 million years before present) is in the Neogene period of the geologic record.