Parrotfish

TAXONOMY AND NAMING

Class: Actinopterygii
Order: Labriformes
Family: Scaridae
Common names:
English: Parrotfish
Spanish: Pez loro
French: Poisson perroquet

Parrotfish (Rhincodon typus)©Robert Patzner

DESCRIPTION OF THE SCARIDAE FAMILY

Parrotfishes are a large part of the guild of herbivores that control algal populations on coral reefs via grazing. In terms of richness, four families (Scaridae, Kyphosidae, Pomacentridae, and Acanthuridae) with 41 species in ten genera have been recorded in the Western Atlantic. Of these families, members of Scaridae, with 16 identified species, are the most diverse, ubiquitous and abundant in the tropical and subtropical shallow waters of the Wider Caribbean.

IMPORTANCE OF PARROTFISH FOR CORAL REEF ECOSYSTEMS

Coral cover has suffered a drastic reduction in the last 20 years. Climate change is a growing threat to coral reefs and associated ecosystems. Among the main risks involved are rising temperatures, sea levels, and acidification of the oceans. According to experts, the reduced presence of herbivorous fish in coral reef systems affects their resilience, reducing their ability to recover from natural phenomena like hurricanes.
Indeed, herbivorous fish help maintain healthy coral reefs by controlling the abundance of macroalgae, transfering energy to intermediate carnivorous fish, and supporting coral recruitment. They are natural bioeroders, producing sediments - while grazing on rocks, calcareous algae and living corals (less than 10% of their food) - like the white sand we see on beaches, and through this process they help recycle nutrients and contribute to the reef carbonate budget.

Caribbean parrotfish species, as a guild, provide critical ecosystem services in the form of herbivory and bioerosion. However, the specific functional role of each species is largely distinct, because of diet specialization and habitat preference. Hence, the functional role of herbivory across coral reef habitats and algal taxa is most complete when both the diversity and abundance of parrotfishes is high.

SOCIO-ECONOMIC IMPORTANCE OF THE TAXONOMIC GROUP

Parrotfishes play a critical role in the economies and ecosystem function of Caribbean nations. Caribbean fisheries yield around US $400 million in annual benefit. Parrotfishes support these fisheries benefits via direct harvest in many locations, but also as prey resources and via habitat maintenance for other species. Parrotfishes are a staple food source in many Caribbean countries, particularly in areas where larger commercially important fish (e.g., snappers and groupers) have been overharvested. Besides, the functional role of herbivory, which benefits coral recruitment and maintenance of coral cover, also benefits the tourism industry that relies on healthy Caribbean coral reefs.

BEHAVIOUR AND LIFE HISTORY

Parrotfishes have a complex life history, where some species rely on the existence of several marine habitats (mangroves and coral reefs) to complete their life cycle. They are protogynous (or sequential) hermaphrodites. Females can change sex to become male (known as the ‘terminal phase’) based on social cues of the population often driven by the reduction of the largest individuals.

THREATS

Coral reef fish have been heavily harvested in the Caribbean since the middle of the 20th century. The main threat to parrotfishes is overfishing, mainly via indiscriminate catch with fish traps or selective spearfishing. It is exacerbated by depletion of other target fish stocks such as groupers.

Parrotfishes are a group of species that suffer from a lack of adequate monitoring of capture and bycatch, and illegal fishing. In addition, deforestation of mangroves, along with the dredging of seagrasses, has greatly affected the life cycle of various species of parrotfishes.

ABUNDANCE AND CONSERVATION STATUS

Continued declines in parrotfish abundance have been documented in several locations, especially on unprotected reefs, and large-bodied parrotfish have disappeared from many reefs. Most parrotfishes throughout the Caribbean are small in size, often smaller than sufficient reproductive size or effective algal grazing sizes.

PROTECTION STATUS

At the 34th ICRI General Meeting in Australia on December 2019, in response to the decline of herbivorous fish populations, ICRI developed a new recommendation on addressing the decline of herbivorous fish populations for improved coral reef community health throughout the Tropical Eastern Pacific, the Eastern and Western Atlantic, and the Greater Caribbean Region. This recommendation encourages governments in the Latin American region to coordinate strategies, priorities, and programs leading to ecosystem-based management and sustainable management of fisheries and coastal areas to support the recovery of herbivorous fish.

In the countries of Mexico, Belize, Honduras, and Guatemala, the organizations Healthy Reefs for Healthy People Initiative and AIDA Americas were instrumental in promoting the concept of restricting parrotfish harvesting which led to enacting harvesting bans that eventually became congruent among these Mesoamerican countries.

In 2018, the non-profit organization The Nature Conservancy in the Caribbean led a social media campaign called “Pass on Parrotfish” which developed targeted messaging on social media platforms.

Bibliography
Proposal for the listing of all parrotfish in Annex III of the SPAW Protocol