While everything you’ll see at Flower Garden Banks National Marine Sanctuary is pretty amazing, there are some natural events that truly stand out.
Whale Shark Encounters (Rhincodon typus)
We wouldn’t go so far as to say that whale shark sightings are ever “common” at the sanctuary, but they are definitely not out of the question, especially during July, August and September. Whale sharks seem to prefer the calmer surface conditions typical of that time of year as they cruise along gulping great quantities of plankton. Scientists are hoping to tag whale sharks in the sanctuary in an effort to learn more about their ranges and activities.
At least one whale shark that was tagged off the Yucatan Peninsula in Mexico has visited Bright Bank (about 14 miles from East Flower Garden Bank). This confirms some level of biological connectivity between the northern and southern parts of the Gulf.
As we continue to learn about these animals, we appreciate information on any whale shark sightings. Please report your observations to the sanctuary office.
Manta Ray Sightings (Mobula birostris)
While there is no special time to expect manta rays in Flower Garden Banks National Marine Sanctuary, it is still an awesome experience to see one or more. These large rays glide over the reef, often swooping and turning, to capture plankton in their large open mouths. Distinctive flaps on either side of the mouth let you know that they are in fact mantas, and not stingrays.
Each manta can be identified by the unique markings on its underside. Photographs and videos of these markings are most helpful for making identifications and are the basis of our manta catalog. Over 100 distinct animals have been identified so far. Please report your observations of manta rays to the sanctuary office, especially if you have photos to share.
Through the use of acoustic tags, researchers know that mantas travel between various banks in the sanctuary, but there is still much to learn about their ranges and activities. In 2018, the area around East and West Flower Garden Banks was confirmed as nursery habitat for oceanic manta rays. Many of the manta rays seen there are juveniles.
Schooling Hammerhead Sharks (Sphyrna lewini)
In the early part of the year (roughly January through March) schools of scalloped hammerhead sharks can be found in the sanctuary. Scientists don’t truly know the reason for this seasonal schooling but it’s a regular occurrence in this part of the Gulf.
But these aren’t the sanctuary's only sharky visitors. Various other shark species can be found in the sanctuary year-round, including the occasional hammerhead.
Coral Spawning
Every year, about 7 to 10 days after the full moon in August, generally between 9 p.m. and midnight, several coral species in the sanctuary participate in a mass spawning event. At this time, corals release their gametes into the water column where they can mix and fertilize. Once fertilized, the larvae settle to the bottom and start new coral colonies.
Sanctuary researchers have become quite accurate at predicting which coral species will spawn at what time. Even so, we still have a lot to learn! If you see corals or any other animals spawning in the sanctuary, please make note of the place and time and report your observations to the sanctuary office. Photographs of the spawning are also appreciated.
Squid Aggregations (Loligo roperi)
In August and September, if you look closely, you may see large groups of small squid hidden among the coral spawn, up in the water column. These are the elusive Roper’s inshore squid.
Though the exact reason for the gathering is unclear, there are several possibilities. Squid might be feeding on coral spawn, or they could be using the spawn as ‘cover’ to hide from predators while conducting their own spawning or mating activities. However, both juveniles and adults make up these aggregations, so not all of them are participating in reproductive behavior.
We are still learning about these squid and their behaviors. If you happen to see any, please report your observations to the sanctuary office.
Sea Hare Aggregations (Aplysia morio)
We'll be the first to admit that most people have never even heard of sea hares, let alone knew they did anything special. But, we can't deny that they are unusual looking and what they do in groups is, well, a bit peculiar.
In June 2006, sanctuary researchers noted large numbers of sea hares at Stetson Bank. Sometimes these large, shell-less snails would swim around, using their mantle skin flaps like wings. At other times, groups of sea hares would lie on the bottom and form unique "chains" of animals (header photo), which is apparently a mating behavior.
This is the only time such an event has been observed in the sanctuary, but that doesn't mean it won't happen again. If you happen to see this type of activity, please report your observations to the sanctuary office.