An array of fish share the common name “rockfish.” This illustrates a widespread problem with common names, that it can be difficult to know which animals someone is referring to, especially since many of the rockfish are unrelated and do not share physical traits. Some are commercially valuable, others are threatened or endangered, and some are relatively obscure fish species.
Fish in the family Sebastidae are sometimes referred to as rockfish. These fish physically camouflage with rocks, and their bodies are decorated with distinctive sets of stripes. They are venomous and spiny and can be found in many of the world's oceans. One notable species in this family is Sebastes borealis or the Alaskan rockfish. It is found along the coastline of the eastern Pacific and is sometimes sold labeled as red or Pacific snapper, something for consumers to be cautious of. High levels of mercury have been observed in rockfish and they can be dangerous to consume in large amounts.
In Europe, several species of fish used for "fish and chips" are known as rock salmon or rock fish. The tendency to use the same common name for several different edible fish species is commonly the result of marketing on the part of the fishing industry. As a fish becomes popular and well known, other fish species may be sold under the same name as consumers will feel more confident about buying a fish they are familiar with.
In the west Atlantic, Morone Saxatilis, or the striped bass, is another example of a fish known as a rockfish. These silvery fish have distinctive black stripes and they are a popular sport fish. Concerns about bass populations in some regions have led to restrictions on how many people are allowed to catch the fish, with the goal of allowing fisheries to recover.
The Indo-Pacific region hosts fish in the genus Synanceia that are sometimes known as stonefish or rockfish because their bodies blend in with stones. These fish are toxic and very spiny. Finally, a fish exclusive to New Zealand, the Acanthoclinus littoreus, is known as the New Zealand rockfish or stone fish.
The fish under discussion is sometimes clear from the context; if someone is talking about edible fishes, for example, stonefish are probably not the topic of conversation. However, the tendency to use “rockfish” to refer to a number of different edible fish can lead to confusion. If people want to know more about a specific fish, they should ask for the scientific name.