Cubera snapper  (Lutjanus cyanopterus)

Classified as Vulnerable (VU) on the IUCN Red List (1).

The largest of all snapper species (3), the Cubera snapper has an elongated, slender, steely grey to dark brown body with a reddish tinge (4) (5). Most young individuals, and some adults, have irregular pale bands along the upper body (5). This fish has fairly long pectoral fins (6), and dark red eyes (5). Prominent, thick lips cover strong canines that enable it to eat a range of prey, even tough crustaceans (4).  

The Cubera snapper is found in tropical waters of the West Atlantic, as far north as Massachusetts, USA, and as far south as northern Brazil, although it is uncommon north of Florida and in the Gulf of Mexico (4) (6).

Adult Cubera snappers are typically found offshore, over rocky sea floors, reefs and ledges (4) (5). Young Cubera snappers may be found in mangrove areas and grassbeds, even sometimes entering freshwaters (4) (5) (7). It is known to occur at depths of up to 70 metres (8). 

The Cubera snapper is an aggressive carnivore with strong canines that allow it to have a varied diet of fish, shrimps and crabs (4) (6).  However, it is not a top predator and adults are prey to sharks, barracuda, groupers, moray eels and even other snapper species (6).

The Cubera snapper travels great distances between March and August to off-shore reefs, where large numbers aggregate to spawn. The location and timing of these aggregations, which can contain between 4,000 and 10,000 individuals, appears to be consistent every year and are supposedly cued by a range of environmental factors, including the lunar cycle and water temperature (2).

Within 24 hours of spawning, the eggs hatch into larvae which are then dispersed via water currents; little else is known about the larval stage (6). There is also limited information on young juveniles (7), probably as a result of the difficulty in distinguishing young Cubera snappers from the similar, related grey snapper (Lutjanus griseus) (3).

As an aggregation spawner, the Cubera snapper is at risk from overfishing, as fishermen can predict when and where large population of adults will occur, so as to secure enormous landings (9). Although a lack of long-term fishing data makes it difficult to fully understand trends in population sizes, data from Cuba indicate this species has declined over the past 40 years due to over-fishing, with habitat degradation (such as from pollution) over the last 20 years also playing a role (3).

Climate change poses an additional threat to this species. Sea temperature appears to be an important environmental cue for spawning so alterations in this, (in particular changes in the El Niño-Southern Oscillation (ENSO) climatic patterns), could have negative impacts on reproduction and survivorship of larvae (2). Increased sea temperatures and increased algal growth due to ENSO events are also linked with coral bleaching, destroying important habitat for the Cubera snapper and numerous other species (3).

It is essential, for the survival of this over-exploited species, to control the amount of fishing by setting quotas, regulating the minimum size at which fish can be caught, and limiting the times at which boats can fish for this species. Management strategies in Cuba have been implemented by the Ministry of Fisheries and have shown some short-term positive effects on the Cubera snapper population and other vulnerable aggregating spawners in the area. The proposed elimination of bottom trawling (3) (one of the most destructive methods of catching fish (10)) on the Cuban shelf will also help Cubera snapper populations.

The protection of spawning sites and other critical areas of habitat is also vital. Gladden Spit in Belize, an important spawning site, is largely protected from illegal fishing (2) (9), and there are indications that this protection is helping to rebuild the Cubera snapper population (11). The Grammanik Bank in the U.S. Virgin Islands, another site where Cubera snapper aggregate, is currently subject to seasonal closures but may be permanently closed in the future (12). 

View information on this species at the UNEP World Conservation Monitoring Centre.

To learn more about the conservation of fish that form large spawning aggregations see:

• Society for the Conservation of Reef Fish Aggregations:
  http://www.scrfa.org

To see more videos on the Cubera snapper, and other marine life, see:

• Marine and Coastal Geography, Texas A&M University:
  http://www.youtube.com/user/MarineCostalGeogTAMU