Stay connected with us
around the nation »

Island Grouper (Mycteroperca fusca)


ESA Threatened - throughout its range

Species Description

up to 17 pounds (7.7 kg)
up to 34 inches  (86 cm)
oblong and compressed body with depth less than head length; lower jaw extends well in front of upper jaw; adults are typically brownish or dark grey, with irregular pale blotches and spots
30-40 years
crustaceans, cephalopods, and fish
protogynous hermaphroditism (sexual transition from female to male); spawning aggregations have been reported in some parts of the species’ range



The island grouper is a shallow water species that occurs near the bottom, predominantly in rocky areas with high structural complexity and upright seaweed cover.


The island grouper is a subtropical species (40° N - 10° N) that is endemic to volcanic archipelagos of Macaronesia: Canary (Spain), Madeira and Azores (Portugal), and Cape Verde.

Population Trends

The island grouper is rare throughout much of its limited range and very rare in areas subjected to heavy fishing pressure. Although there are no population abundance estimates available for island grouper, several studies have shown a negative correlation between island grouper abundance and level of fishing pressure.  These results suggest that fisheries overexploitation has substantially reduced island grouper abundance, and some heavily fished areas in the Canary Islands have likely experienced a sharp decline. 


The island grouper’s intrinsic vulnerability to fishing is very high.  Demographic viability risk factors related to the island grouper’s growth rate, productivity, spatial structure, and range size all contribute to this species’ vulnerability to fishing overexploitation. Certain behavioral traits (i.e., territoriality, site specificity, and spawning aggregations), which are common among groupers, may also add to the fishing vulnerability of this species. Current fishing regulations designed to limit catch and effort are inadequate for addressing the direct threat to island grouper from fishing overutilization.  In general, there are few restrictions placed on demersal fisheries throughout the island grouper’s range. In areas where regulations (e.g., size limits and gear restrictions) do exist, their effectiveness is likely reduced by lack of enforcement and relatively high levels of non-compliance.

Conservation Efforts

There are several conservation initiatives (identified in the Status Review of the species) that are either underway but not yet fully implemented or are still in the planning phase that could potentially provide conservation benefits to the marine ecosystems within the island grouper range. However, given large uncertainties associated with implementation, enforcement, and effectiveness, the conservation efforts identified cannot be considered reasonably likely to significantly reduce the current island grouper extinction risk.

Regulatory Overview

On July 15, 2013, we received a petition from WildEarth Guardians to list the island grouper, along with 80 other marine species or subpopulations, as threatened or endangered under the Endangered Species Act (ESA).  On February 24, 2014, we published a notice that listing may be warranted for the island grouper and nine other fish species (79 FR 10104). We published the proposed rule to list the island grouper as threatened under the ESA on September 23, 2015 (80 FR 57314). The final rule to list the island grouper as threatened under the ESA published on October 20, 2016 (81 FR 72545).


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Epinephelidae
Genus: Mycteroperca 
Species: fusca

Key Documents

(All documents are in PDF format.)

Title Federal Register Date
Final Rule to List as Threatened under the ESA 81 FR 72545 10/20/2016
Proposed Rule to List as Threatened under the ESA 80 FR 57314 09/23/2015
 Status Review of Island Grouper   07/2015
90-day finding on multi-species petition for bony fishes 79 FR 10104 02/24/2014
Petition to List 81 Marine Species under the ESA   07/15/2013

Updated: October 20, 2016