ISLAMORADA -- Keeping track of local fish populations is a way of life for Carlos and Allison Estapé.
If the winds are calm, chances are you won't find this husband and wife at their Lower Matecumbe Key home. Averaging about 250 scuba dives a year, the ocean is their home.
Still, their Islamorada property serves as something of a bureau for the Key Largo-based Reef Environmental Education Foundation, a nonproft reef conservation organization that has recently declared war on the invasive lionfish.
Lionsfish have multiplied in Florida Keys waters and devour native species. They have no fear of humans and have no known predators. REEF supporters use pole spears to kill the fish, which has venomous spines.
Carlos has built his own tools to capture the fish, including a storage system built from used PVC pipe.
"We take out as many we can," he said.
The couple have participated in every lionfish derby since REEF started battling the Indo-Pacific invader.
REEF recently named them as Volunteers of the Year for 2013 for their service and contribution to the nonprofit organization.
In addition to helping eradicate lionfish, the Estapés entertain the REEF interns with dives and parties. The duo host a twice-monthly pizza party culminating in a quiz on fish identification, which is their specialty.
In fact, their passion for identifying and recording marine life fits perfectly with REEF's mission of encouraging citizen scientists.
"Anything we can do to help them is what we do," Carlos said.
The divers encourage REEF staff and volunteers to maximize their underwater experience by counting as many fish as possible, something they call the "100 Species Challenge." The Estapés regularly record more than 100 fish species during a single tank dive at Alligator Reef.
"It's something we want to train the interns on and hopefully get them in the club," Carlos said.
REEF considers the couple to be experts at identifying fish. Whenever the nonprofit is hired to analyze fish populations in the region, it calls on the Estapés to help.
Even when the two are recreational diving, they carry a fish ID slate to record their sightings.
Their interest in recording a variety of species fits nicely with Carlos' work as an underwater photographer. His photography has been used in multiple online publications, including an iPhone application created by a South American scientist.
Elizabeth Underwood, REEF's lionfish program coordinator, said the Estapés are deserving of their recent volunteer honor.
"I've just been blown away by their generosity," she said.
To learn more about volunteering with REEF, call 852-0030. To view the Estapés' photography, visit carlosestape.photoshelter.com.