Controlling the lionfish

The Central Caribbean Marine Institute welcomed two new interns to their Little Cayman station earlier this year.

University of Florida master’s students Morgan Edwards and Savanna Barry will be working with CCMI for the next six months collecting data for their individual research projects.

Both are majoring in Fishery Science.

Edwards is looking at the growth rates of lionfish, while Barry is studying productivity of seagrass.

Here they give their accounts of what they do and why their work is important for marine research.

It Began with a few

The only successful invasion by a non-native, marine fish in the Western North Atlantic and Caribbean started with a few isolated sightings.

In 1985, the first lionfish was captured off the coast of south Florida. In 1992, six fish reportedly survived after being released into Florida’s waters when a hurricane damaged a seaside aquarium.

Things went quiet until 2000, and then lionfish were found north of Miami and eventually up to Cape Hatteras, North Carolina.

Records of lionfish beyond the Atlantic coast also began in 2000, with one lionfish found in a tide pool in Bermuda. From 2004 to 2006, reports came in from the Bahamas, Cuba and Turks and Caicos.

In 2008, lionfish were found off Little Cayman Island, as well as in Jamaica, the Dominican Republic and Puerto Rico. In 2009, these invaders made the leap to Mexico, Honduras and Costa Rica.

At this time, lionfish reproduce successfully in many locations and reach densities of 250 fish in an area equivalent to a soccer pitch.

What makes them so successful?

Research suggests that lionfish have the ability to reproduce ever four days. They are also quick to mature, have a high physical tolerance to a broad range of temperatures, and they are not picky eaters.

What are we going to do about it?

Scientists are working on models that will help predict their prey consumption rates and population growth rates for certain areas.

However, there is some information missing from these models that will help to make them more accurate.

Growth rates for lionfish need to be determined for the areas they have invaded.

This is where I come in.

All fish have a pair of bones inside their heads called sagittal otoliths.

As the fish moves, gravity causes the otoliths to shift and stimulate nerves.

These signals allow the fish to maintain its position in the water column.

Each year a new ring composed of calcium carbonate is added to the otoliths.

By removing these bones and sectioning them, one can determine how old the fish is by counting the rings.

This information is plotted on a graph along with the fish’s length.

Just connect the dots and the resulting image is your growth curve.

The hope is that this information will increase the accuracy of our models and therefore help us to make better management decisions.

While I believe the complete eradication of these fish may be an impossible mission, I have faith that with a better understanding of them we will be able to implement management practices capable of reducing their numbers and hopefully minimize the impacts to our coral reefs.

There is also the possibility that nature (native predators such as grouper and snapper) will figure out what to do with them.

After all, I had lionfish for dinner the other night and it was delicious!

Dancing sea grass

Little Cayman is known for its spectacular reefs and unsurpassed SCUBA diving opportunities, few will argue that point.

No one will give you funny looks if you excitedly describe the tranquil beauty of a sea turtle swimming past or the exhilaration that stems from clearing the edge of Bloody Bay wall.

However, you will, as I routinely do, get odd reactions (or merely glazed looks) if you begin to describe the dancing motion of seagrass with every passing wave or speak about the grazing marks of the bucktooth parrotfish as if they are treasured sightings.

Valuable habitat

Seagrass areas rank among the top three most valuable habitats in terms of the ecosystem services they provide for humans and the environment.

The shelter of their canopy is home to juvenile fish, their blades provide food for sea turtles and manatees, and their extensive root structure stabilizes sediments.

Seagrasses buffer wave energy, sequester CO2 into their tissues through photosynthesis, and provide food to many other areas including reefs and the open ocean.

I could go on…

Despite the obvious benefits of seagrass meadows, they are one of the most understudied systems in the world.

This is where I come in

My research at CCMI focuses on productivity of seagrass beds and calcifying algae.

Calcifying algae share habitat with seagrasses and are able to build calcium carbonate skeletons much like corals.

Much of the sand in the Caribbean originated as algal tissue, and thus calcifying algae are regarded as a very important part of the carbon cycle.

While in Little Cayman I will be measuring the growth and calcification rates of marine plants in shallow lagoons and describing the local community structure of these valuable plants.

In addition, I will perform manipulations of plant density and seawater chemistry to assess how marine plants respond to alterations in their environment.

This information can be used to predict how seagrasses and algae in shallow lagoons will react to the global changes predicted for our oceans.

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