Nassau Grouper

The Nassau Grouper (Epinephelus striatus) is a large fish that inhabits our reefs and is especially common in the waters of Saba. As is typical of groupers, it has a robust, elongated body, rounded fins and big lips. Its overall color is pale tan for fish found in shallow areas and pinkish red for fish found in deeper waters. This color can darken or lighten depending on the grouper’s mood and surrounding. The Nassau grouper can be identified by three distinct features: 1) its body is covered in five olive-brown vertical bars, and a diagonal bar goes from its snout, across its eye and to the start of its dorsal fin; 2) the top of its head has a tuning-fork shaped marking; and 3) the base of its tail has a large black saddle spot.

The fact that the Dutch Caribbean has a healthy population of Nassau Grouper is an attestation to the health of our reefs and the success of our marine parks. Nassau Groupers were once plentiful and an important source of food within the Caribbean region, but populations of the grouper are estimated to have declined by approximately 60% in the past 30 years. The Nassau Grouper has been classified as Vulnerable by the IUCN Red List since 1996. One of the biggest threats to this fish species is habitat loss; Nassau groupers inhabit shallow to mid-range coral reefs (typically between 6 and 30 meters) and rocky areas where they can hide in crevices; juveniles are commonly found in seagrass beds. Both coral reefs and seagrass beds have suffered much degradation in parts of the Caribbean within the past few decades.

Overfishing is also threatening the long-term survival of the Nassau Grouper. The fact that they return to the same spawning sites year after year makes them especially vulnerable to exploitation. Spawning aggregations of hundreds to thousands of individuals take place once a year between December and January. At this time, males and females release their eggs and sperm into the water column. Each female releases thousands of eggs. The eggs hatch after 48 hours, and the larval period lasts from 35 to 40 days. A very interesting fact about Nassau Groupers is that while most grouper species change sex throughout their lifetime, Nassau Groupers typically mature as either male or female and remain that gender; however, some female to male sex change may still occur.

Sources:

IUCN Red List of Threatened Species
Arkive
Animal Diversity Web
Oceana
NOAA Fisheries
Fishbase
Ichthyology
Smithsonian Marine Station

Photo Credit: istockphoto.com
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