Big-belly seahorse

Natural history

The Hippocampus abdominalis, a.k.a the big-belly seahorse, was first documented in New Zealand, according to the International Union for Conservation of Nature and Natural Resources. Their specific scientific name abdominalis refers to their enlarged and prominent abdomens. Their coloration is highly variable, from almost white to gray, mottled yellow, orange, reddish, brown, or black, with irregular darker spots and blotches, and a broadly banded tail.

Conservation

The big-belly seahorse faces local threats from coastal development and destructive fishing methods.

Bottom trawling—when commercial fishing boats drag heavy, cone-like fishing nets along the ocean floor to catch fish—destroys the ecosystems of big-belly seahorses. This fishing gear does not discriminate, and usually involves demolishing all animals in its path.

Aside from the threats of bottom trawling, big-belly seahorses are also harvested for unproven Asian and Chinese medicines.

In Australia, all seahorses are protected under:

• The Commonwealth Wildlife Protection (Regulation of Exports and Imports) Act 1982 since 1 January 1998
• s248 of the Environment Protection and Biodiversity Conservation Act (EPBC) Act 1999

In New Zealand, seahorses cannot be targeted by commercial fisheries, but can be sold to Licensed Fish Receivers as regulated quantities of bycatch.

Reproduction

Perhaps one of the most surprises details about big-belly seahorses is the special role males play in the reproduction cycle. Females get a break when it comes to baby making in this genus. Instead, male seahorses do the work of becoming pregnant and delivering baby big-belly seahorses.

The number of baby seahorses a male can birth ranges between 200-1000 at a time. These babies are called "fry" and are completely independent as soon as they leave the male's pouch! 

Cool facts

• The big-belly seahorse is the largest known seahorse species. They have more dorsal fin rays and tail rings than any other seahorse.
• Females deposit eggs in the male’s brood pouch. The eggs are fertilized in the pouch and when they hatch, the baby seahorses look like miniature adults.
• Big-belly seahorses use their long tails to anchor themselves to seagrasses, sponges, macroalgae such as kelp holdfasts, rocky outcrops, and man-made structures.
• Coloration allows them to blend in with their habitat and be more effective ambush predators. They can also change colors to communicate!
• Flathead, Australian salmon, various bird species, and little penguins eat big-belly seahorses.