Попугаевые рыбы: биология, поведение и роль в коралловых рифах.

Family of fishes

Parrotfish are a group of fish species traditionally regarded as a family (Scaridae), but now often treated as a subfamily (Scarinae) or tribe (Scarini) of the wrasses (Labridae). which is distinct from other fish, including other labrids. Their numerous teeth are arranged in a tightly packed mosaic on the external surface of their jaw bones, forming a parrot like beak with which they rasp algae from coral and other rocky substrates The smallest species is the bluelip parrotfish (Cryptotomus roseus), which has a maximum size of .

Some parrotfish species, including the queen parrotfish (Scarus vetula), secrete a mucus cocoon, particularly at night. Prior to going to sleep, some species extrude mucus from their mouths, forming a protective cocoon that envelops the fish, presumably hiding its scent from potential predators. A wide range of other small organisms are sometimes eaten, including invertebrates (sessile and benthic species, as well as zooplankton), bacteria and detritus. A few mostly larger species such as the green humphead parrotfish (Bolbometopon muricatum) feed extensively on living coral (polyps). After they digest the edible portions from the rock, they excrete it as sand, helping create small islands and the sandy beaches. The humphead parrotfish can produce of sand each year. On Caribbean coral reefs, parrotfish are important consumers of sponges. An indirect effect of parrotfish grazing on sponges is the protection of reef building corals that would otherwise be overgrown by fast growing sponge species. Analysis of parrotfish feeding biology describes three functional groups: excavators, scrapers and browsers. leaving visible scars on the surface. Microscopy and molecular barcoding of coral reef substrate bitten by scraping and excavating parrotfish suggest that coral reef cyanobacteria from the order Nostocales are important in the feeding of these parrotfish. Additional microscopy and molecular barcoding research indicates that some parrotfish may ingest microscopic biota associated with endolithic sponges.

The development of parrotfishes is complex and accompanied by a series of changes in sex and colour (polychromatism). Most species are sequential hermaphrodites, starting as females (known as the initial phase) and then changing to males (the terminal phase). In many species, for example the stoplight parrotfish (Sparisoma viride), a number of individuals develop directly to males (i. e., they do not start as females). These directly developing males usually most resemble the initial phase, and often display a different mating strategy than the terminal phase males of the same species. A few species such as the Mediterranean parrotfish (S. cretense) are secondary gonochorists. This means that some females do not change sex (they remain females throughout their lives), the ones that do change from female to male do it while still immature (reproductively functioning females do not change to males) and there are no males with female like colors (the initial phase males in other parrotfish). The marbled parrotfish (Leptoscarus vaigiensis) is the only species of parrotfish known not to change sex. In most species, juveniles have a different color pattern from adults. Juveniles of some tropical species can alter their color temporarily to mimic other species. Where the sexes and ages differ, the remarkably different phases often were first described as separate species. Protecting parrotfishes is proposed as a way of saving Caribbean coral reefs from being overgrown with seaweed and sponges.