BlogGarmin Fish Finder
As an offshore fisherman, you’ve probably spent a good bit
of time on the water staring at your bottom machine in search of new fishing
grounds. When the screen lights up with ripples or spikes you know the spot could
be holding some awesome fish. And, if you’re anything like me, you wonder
“what’s actually down there?”
As a diver, you might have the opportunity to see for
yourself, or you can drop a camera overboard to get a better look. Chances
are you’ll find some kind of reef. It might be artificial, it might be rocky,
or it might be a coral reef. No matter what, you probably already associate reef
structure with fish.
Photo: Sea Grant

Coral reefs are a crucial foundation for many of the marine
species living in the Gulf of Mexico. They provide food, shelter, and nursery
grounds to a seemingly endless list of fish, shellfish, marine mammals, and
other inhabitants of all shapes and sizes. Many of the fish we target as
commercial or recreational fishermen spend some part of their life on a reef
feeding, growing, or seeking shelter – that’s why these habitats are so

Unfortunately, coral reefs, their health, and abundance, are
threatened by many things including; oil spills, ocean acidification, climate
change, and rising ocean temperatures.  Advances in technology such as satellite
imagery and remote sensors that monitory the ever-changing ocean environment
have allowed scientists to better understand the factors threatening coral
reefs. Knowing the location of known coral communities allows for better
management against the array of threats posed on corals.
The coral web
mapper created by the Gulf Council allows users to explore the different corals
across the Gulf of Mexico. This database will allow scientists, managers, and
the public, to interact with coral reef locations to make protecting them and
understanding their risk much easier so potentially harmful factors can be
managed before coral communities are endangered.
The five categories of corals/organisms that
are depicted on the map tool are:

Photo: NOAA
  • Black Coral (or Antipatharians) – a group of branching corals are often associated with deep reef habits. Although their exterior flesh is usually red, white, or orange, their internal skeleton is black. Black corals can live to for thousands of years. In fact, one from the Gulf of Mexico was aged to be more than 2000 years old. These corals are a valuable tool for scientists because their skeletons contain rings, like trees. The rings have chemical signatures that allow scientists to learn about past oceanic environments. Black corals have also been harvested for jewelry, a practice which is not sustainable.
  • Hydrozoan Coral – colonies of individual animals that form a very rigid soft coral. Fire coral and lace coral are some of the best known colonies of hydrozoan. Hydrozoans have very interesting lives with two different life stages and two different strategies for reproduction. Hydrozoan coral colonies are made up of animals in the polyp stage of life when the animal is attached to a hard surface. Hydrozoan polyps reproduce by releasing buds that become free-swimming organisms. The free swimming hydrozoans are in the medusa state of life. They look very different from their stationary parents and reproduce sexually to form new polyps and begin the cycle again.
Photo: Sea Grant
  • Octocoral (or Anthozoans) – non reef-building soft corals. Octocorals can take on many different shapes, sizes, and colors but are easily identified in any form because they all have eight-fold symmetry. These corals are very hardy and can be some of the easiest corals to grow in aquariums.
  • Stony coral (or Scleractinians) –hard corals that are the primary reef building corals of the world. These corals have skeletons made of calcium carbonate (Aragonite), covered with polyps. All stony corals have a symbiotic relationship with algae that lives inside the polyps. The algae, called zooxanthellae, produce oxygen and other nutrients that are used by the polyps; the polyps produce carbon dioxide that is used by the algae. Brain corals and elkhorn corals are some of the more well known stony corals.
  • Sea Anemones –predatory animals are attached to the seafloor. They feed using tentacles that inject prey with paralyzing neurotoxins and then guide animals into their mouth for digestion. Like stony corals, some anemones have symbiotic relationships with algae that provide sugar and oxygen in exchange for shelter and exposure to the sun. Other anemones have mutualistic relationships with fish that live in their tentacles to escape predation from other fish.

Check out the map tool to explore this comprehensive inventory of known coral locations in the Gulf of Mexico.  Click on each spot for more information on the depth and coral type so you can get more familiar with the types of coral habitats that are common near your fishing grounds.