Lionfish in Biscayne National Park

Two fish with orange stripes and long spines swim at a coral reef.

Lionfish swimming on a coral reef. NPS Photo

Background

Indo-Pacific Lionfish (Pterois volitans and P. miles) the first exotic marine fish to be considered “invasive” in the Atlantic Ocean.

They are native to the Indian and Pacific Oceans and the Red Sea and were likely introduced to the Atlantic via the ornamental fish trade/aquarium releases and/or ballast water exchange.

Three rows of several dead lionfish are arranged on a wooden table, seen from a bird's eye view.

A table of lionfish removed from park waters. NPS Photo

Threats

Lionfish are voracious, opportunistic predators that feed upon marine fish and invertebrates. Gut content analyses indicate that smaller lionfish feed on invertebrates (primarily shrimp) while larger lionfish eat mostly fish.

Lionfish have become successful invaders due to their broad diet, high physical tolerances, lack of natural predators, rapid growth rates, large native range, long life span, early sexual maturity, high fecundity and ability to reproduce year-round.

DNA barcoding of lionfish gut contents revealed the occurrence of six species of fish not previously known to occur in the park!

In conjunction with habitat degradation and over-fishing of native species, lionfish are negatively affecting native reef fish populations, reef ecosystems, and reef structure.

Lionfish possess venomous spines, making them a potential danger to people. A puncture from a venomous spine can cause intense pain, burning, swelling, redness, bleeding, joint pain, anxiety, headache, disorientation, dizziness, nausea, paralysis, and convulsions; however, no fatalities have been reported.

A bar graph displaying annual number of dives in the y axis by each year from 2011-2022 in the x axis.

Lionfish Removal Effort NPS Graph

Management Efforts at Biscayne

Since the first documented sighting in 2009, park biologists have conducted lionfish removals via SCUBA using pole spears and hand nets.

Each year, Park divers spend an average of 235 hours underwater over the course of more than 200 dives removing lionfish

Park scientists have collaborated with federal and state agencies as well as universities to complete studies to better understand and manage the lionfish invasion and it impacts to park resources.

A bar graph of average lionfish removed per dive over time. The y axis shows number of lionfish in increments of 0 to 9 and the x axis shows years from 2011 to 2022.

Average Lionfish Removed Per Dive Over Time NPS Graph

Outcomes

To date, park staff have removed more than 12,000 lionfish from park and immediately adjacent waters.

While lionfish have been observed across all marine habitats and depths, they are most abundant on deeper reefs and artificial habitats.

Removed lionfish average ~25 cm (9.8 inches) in length. The smallest removed lionfish was 3.2cm (1.3 inches) and the largest was 44.4cm (17.5 inches.

Lionfish harvest rates (number of fish per dive) grew steadily for several years and peaked in 2017.

After the passing Hurricane Irma (September of 2017), park divers observed a dramatic reduction in lionfish numbers and a slight increase in the average size of lionfish.

There are an estimated 250,000 lionfish in the park.

A bar graph showing a size-frequency histogram for all lionfish removed from 2010 to present. The y axis shows number of lionfish from 0 to 3000 and the x axis shows total length in centimeters from 0-5cm to 40.1-45cm

Size-Frequency Histogram for all Lionfish Removed from Biscayne, 2010-Present NPS Graph

Visitor and Community Outreach

Presentations and dissection events are offered at local schools, to visiting groups, and at special events.

Biscayne National Park staff guide school /students through lionfish dissections to demonstrate lionfish anatomy. Lionfish stomachs are emptied to determine what lionfish in Biscayne are eating.

Staff encourages spearfishers in the park to remove lionfish using safe removal and handling procedures.

Get involved/ What you can do to protect and preserve Biscayne National Park from lionfish

Report observations of lionfish “hotspots” to Park staff.

If you spearfish, remove lionfish when you see them.

Spread the word to others about the importance of reporting and removing lionfish.

Part of a series of articles titled
Resource Management Efforts in Biscayne.

Next:
Marine Debris in Biscayne National Park

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