Bolbometopon muricatum (Bumphead Parrotfish)

IUCN

Scientific Name：Bolbometopon muricatum

Bolbometopon muricatum (Bumphead Parrotfish)

Basic Information

Scientific classification

name：Bolbometopon muricatum (Bumphead Parrotfish)
Scientific Name：Bolbometopon muricatum
Outline：Medium Fish
Family：Scaridae Bolbometopon

Vital signs

length：Typically 80–120 cm; max ~130 cm+
Weight：Up to tens of kilograms in large adults
lifetime：Multiple decades; slow‑growing, late‑maturing

Feature

Largest parrotfish; cephalic hump; scrapes/bites coral; key bioeroder and sand producer; schooling, spawning aggregations.

Distribution and Habitat

Indo‑Pacific outer reef slopes/crests; shallow to mid‑shallow waters from the Red Sea to Micronesia and the GBR.

Appearance

Massive hump‑headed profile; robust beak; grey‑green to bluish‑grey; truncate to slightly emarginate tail; coarse scales.

Details

Bolbometopon muricatum—the bumphead parrotfish—is the world’s largest parrotfish (family Scaridae). Adults have a distinctive forehead “bump” and feed by scraping and biting coral substratesto access algal films and endolithic organisms, acting as key bioeroders and sand producers on coral reefs.

Ecology & Biology

Diet: algal turf and organisms within/among coral frameworks; feeding often involves biting coral skeletons.
Behaviour: commonly schooling by day (dozens to hundreds) on outer reef slopes/crests; communal resting at night.
Reproduction: forms seasonal spawning aggregations with pelagic broadcast spawning; juveniles use more sheltered reef/seagrass habitats.
Life history: slow‑growing, late‑maturing and long‑lived; predictable habitats and aggregations increase fishing vulnerability.

Identification

Very large body with a massive cephalic hump; hump is used in head‑butting displays within schools.
Robust beak‑like jaws (parrotfish rostrum); overall grey‑green to bluish‑grey; juveniles show pale spots/bands.
Caudal fin truncate to slightly emarginate; coarse scales; modest sexual dichromatism.

Size & Longevity

Length: typically 80–120 cm, up to about ~130 cm or more.
Weight: can reach tens of kilograms in large adults.
Life: on the order of multiple decades (region‑dependent).

Range & Habitat

Indo‑Pacific tropical reefs from the Red Sea eastward to Micronesia/Papua New Guinea/the Great Barrier Reef, favouringouter reef slopes, crests and fore‑reefs in shallow to mid‑shallow water.

Conservation & Threats

Threats: night spearfishing, targeting of spawning aggregations, overfishing and habitat degradation.
Measures: aggregation closures, size/bag limits, marine protected areas and community‑based monitoring/management.

IUCN: widely cited as Vulnerable (VU) (check latest assessment for updates).

FAQ

Q1. Why is it called a “sand producer”? By biting and eroding coral skeletons, it excretes fine sand that contributes to reef/sand‑bank formation over time.

Q2. Is it aggressive? Generally non‑aggressive to people; head‑butting occurs in intraspecific social displays.

Q3. Why so vulnerable to fishing? Slow growth, late maturity, long life and predictable schooling/resting make it easy to target, especially with night spearfishing.

Q4. What are effective protections? Seasonal closures around aggregations, MPAs, and minimum sizes reduce pressure and aid recovery.