The Three Seahorses of Biscayne National Park, Part 1

By Emilie Stump

(Part one of a three part series: in this first part Ecologist and marine life artist Emilie Stump commemorates a national treasure with her latest multimedia piece, “The Three Seahorses of Biscayne National Park”)

Vulnerable coastal habitats such as seagrasses, coral reefs, and mangroves are important for many animals, including species listed as threatened at the state, national, or international level. Among these species of conservation concern are three seahorses, which I feature in this multimedia illustration. “The three seahorses of Biscayne National Park” showcases south Florida’s seahorses and their habitats. With this artwork, I hope to bring awareness to the importance of protected areas like Biscayne National Park in preserving habitat for vulnerable species, while highlighting the challenges of managing a protected area under pressure.

 The three seahorses of Biscayne National Park: The Long-snouted seahorse ( H. reidi,  front left) clutches a submerged mangrove using camouflage to blend into the sponges and other organisms that colonize the roots. The Dwarf seahorse ( H. zosterae , middle right) in a bed of turtle grass, using drift algae as a holdfast. The Lined seahorse ( H. erectus,  back center), holding mermaid’s fan, a type of macroalgae. Coral reefs, which also serve as important habitat for seahorses and their relatives, appear in the background. Artwork by Emilie Stump. This artwork was created referencing the photography of George Grall and Tami Weiss.

The three seahorses of Biscayne National Park: The Long-snouted seahorse (H. reidi, front left) clutches a submerged mangrove using camouflage to blend into the sponges and other organisms that colonize the roots. The Dwarf seahorse (H. zosterae, middle right) in a bed of turtle grass, using drift algae as a holdfast. The Lined seahorse (H. erectus, back center), holding mermaid’s fan, a type of macroalgae. Coral reefs, which also serve as important habitat for seahorses and their relatives, appear in the background. Artwork by Emilie Stump. This artwork was created referencing the photography of George Grall and Tami Weiss.

On the left of the panel, the Long-snouted seahorse (Hippocampus reidi), recognized by its long snout and relatively low coronet, is using the submerged prop root of a red mangrove as a holdfast. Long-snouted seahorses are found in coastal waters of the western Atlantic from North Carolina south along the coast of the U.S., throughout the Gulf of Mexico and Caribbean Sea, and along South America to southern Brazil. This species is found in a variety of habitats including sponges, tunicates, gorgonians, seagrasses, macroalgae, estuaries, and is often found in mangroves. Like all seahorses, the Long-snouted seahorse uses camouflage to better hunt for prey, and to hide from predators. Submerged mangrove roots are often colonized by invertebrates such as brightly colored sponges and tunicates, and, like a chameleon, this seahorse has changed its coloration to match its surroundings. This species of seahorse is highly sought after in the aquarium trade due to its often-bright coloration. The Long-snouted seahorse reaches a maximum height of 17.5 cm and is listed as Near Threatened on the IUCN Red List.

In the lower right of the panel, the tiny Dwarf seahorse (Hippocampus zosterae) clutches drift algae and a blade of grass in a bed of turtle grass (Thalassia testudinum). Florida is the center of the global distribution of this tiny species, representing 46% of its global range. These tiny seahorses reach a maximum height of only 2.5 cm and may rely on rafts of floating algae and vegetation to drift to new areas. The Dwarf seahorse has been described as a generalist in the seagrass landscape. The Dwarf seahorse was recently assessed as Least Concern on the IUCN Red List, largely in response to increases in regulation of the Marine Life Trade, which supplies seahorses and other marine organisms for public and private aquariums. These regulations include reducing the daily commercial limit from 400 to 200 seahorses, establishing an allowable harvest area, and establishing an annual commercial quota. These regulations partially resulted from the 2012 proposed listing of the Dwarf seahorse on the US Endangered Species Act.

Finally, the Lined seahorse (Hippocampus erectus), recognized by the lined pattern on the side of its face, is largest of the three species (19 cm maximum height). This is the most widely distributed of south Florida’s seahorses, being found in the western Atlantic from Nova Scotia south to Brazil, including the Gulf of Mexico and Caribbean Sea, to depths of at least 100 m. This species is also found in a wide variety of habitats including mangroves, seagrasses, macroalgae, floating vegetation, oyster reefs, rocky reefs, and coral reefs. The Lined seahorse is listed as Vulnerable on the IUCN Red List. Research has shown that Lined seahorses are frequently taken as bycatch in commercial trawl fisheries targeting shrimp in Mexico, Florida, and throughout the Gulf of Mexico.

The primary global threats to seahorses around the world include being caught as bycatch in trawl fisheries, loss of habitat, and collection for the aquarium, curio, and medicinal trades. Marine protected areas such as Biscayne National Park (BNP) are one of many tools that can be used for the conservation of seahorses and other endangered animals.

 Map of Biscayne National Park in southeast Florida.

Map of Biscayne National Park in southeast Florida.

Biscayne National Park is a living, breathing emerald and aquamarine jewel in the U.S. National Park System. Located in southeastern Florida, just south of “Magic City” (Miami, Florida), the park protects a 728km2 gradient of vulnerable coastal habitats. The park’s western park boundary protects the longest remaining stretch of continuous red mangrove forest left on the east coast of Florida. To the east, Biscayne Bay is a shallow, clear water lagoon with hardbottom habitat, home to sponges, gorgonians and corals, or seagrass meadows releasing pearls of oxygen into the water. Across the Bay lie the northern-most extent of the Florida Keys barrier island system, colorful and complex patch reefs, and the crest of this portion of the Florida reef tract, followed by a sudden drop to the depths of the Atlantic. The 65 ft (approximately 20 m) depth contour forms the eastern boundary.

 Totten Key, one of the uninhabited northern-most Florida Keys found in Biscayne National Park. Mangrove coastlines and seagrass beds seen in this aerial photograph provide potential habitat for seahorses and pipefishes. Photograph ©US National Parks Service

Totten Key, one of the uninhabited northern-most Florida Keys found in Biscayne National Park. Mangrove coastlines and seagrass beds seen in this aerial photograph provide potential habitat for seahorses and pipefishes. Photograph ©US National Parks Service

In addition to providing valuable seahorse habitat seagrasses, mangroves, and coral reefs are vital to south Florida’s growing economy. Coral reefs protect the shoreline and inshore areas by reducing wave and storm energy. Mangroves provide protection from erosion and are an important source of food and shelter for commercially and recreationally important fishes. Both mangroves and seagrasses absorb nutrients in the water and trap organic material and sediment, helping to maintain pristine, crystal clear waters. Mangroves, seagrasses and coral reefs also provide important habitat for commercially and recreationally important fishes and invertebrates. Residents and visitors to south Florida are spending increasing amounts of time enjoying the outdoors with activities such as recreational fishing, snorkeling, paddle boarding, and scuba diving.

The first in this three-part series introduced the reader to three magical creatures: The Long-snouted seahorse, the Dwarf seahorse, and the Lined seahorse. These animals rely on important coastal habitats such as mangroves, seagrasses, and coral reefs, all of which can be found in Biscayne National Park’s undersea landscape. Part 2 will explore Biscayne National Park as a vulnerable park, subject to an onslaught of internal and external pressures, and showing signs stress.