Northern lined seahorse Hippocampus erectus  in the Peconic Estuary


Male seahorse in Peconic Bay

Pair of seahorses on a Peconic Bay eelgrass meadow.

Seahorse on our eelgrass plantings in Long Island Sound

seahorse fry close-up

seahorse fry close-up

Seahorse in the Peconic Estuary

Peconic Estuary seahorse

mating pair

mating pair-male courting female




Many people are surprised and excited to find that the northern lined seahorse, Hippocampus erectus, is native to the waters of Long Island. Though dubbed by the Greek as “horse” (hippo) and “sea monster” (campus), the seahorse is a docile, slow-moving, non-aggressive and genuinely unique creature. It is unfortunate that because of these traits the seahorse is more susceptible to changes (human made or natural) to its environment. It is because of their sedimentary “home-body” and monogamous lifestyle, a structured habitat suites the seahorse best. Past research has deemed the complex habitat structure of seagrass to be the favorite home to the seahorse and serves their complex feeding and social structure well (James and Heck 1994). The depletion of eelgrass, Zostera marina, has not helped the seahorse plight. In fact, the species is listed as “vulnerable” on the World Conservation Union’s red list of endangered species. Our hope is that with the restoration of eelgrass, seahorses will once again thrive in Long Island waters.

Seahorses are actually true fish, though they have characteristics that make them different than most fish. Hippocampus species have a horse-like curved down head, skin (no scales), a snout that sucks in food, and eyes that can move independent of each other (Foster and Vincent 2004). Hippocampus erectus, in particular, can be identified by white lines down the neck and white dots on the tail. They show considerable site fidelity in that they do not travel far off their home range of approximately 1-2 m².

By far, one of the most interesting facts about the seahorse is that male seahorses become pregnant! In Hippocampus species, the male becomes impregnated by the female (he carries the fertilized eggs), goes into labor and expels live baby seahorses (Lourie and Foster 2004). Once a male finds a female to breed with, both the male and his female mate stay faithful to each other during breeding season and, in many instances, throughout their life. The male and the female do a “dance” once a day. The monogamous seahorse pair meets up, exchange colors and “promenade” and/or interlock their tails and “dance” together for a few minutes before going their separate ways; the next day they will repeat this ritual. Once the pair mate, they will continue to mate together for the season and, in many cases, for years to come. If a mate finds itself to be widowed, only then will he/she search for a new mate in the following season. While mating, the male receives the female’s eggs and caries them until birth. Gestation lasts approximately 21 days (Foster andVincent 2004). At this point the male goes into “labor”. The male pushes and thrusts for a couple of hours and expels developed juvenile seahorses.

Another intriguing fact about the seahorse is its ability to camouflage. They are capable of changing colors ranging from ash grey, orange, brown, yellow, red, and black to blend into their environment (Lourie & Foster, 2004). It is an important adaptation because it allows seahorses to hide easily from predators as well as aids in predation success on prey organisms like amphipods, copepods, and other small crustaceans. Complex habitat structures, like eelgrass beds, are advantageous to a predator like H. erectus, permitting it to hone in on its natural ability of careful movement and visual orientation.

Seagrass is important to seahorses, and has long been considered their preferred habitat. A seahorse will use a blade of seagrass as a “holdfast”. The seahorse will wrap its tail around the blade to stay in place without expending much energy when rough waters might otherwise whisk the seahorse away.  It is also interesting to note that density and height of seagrasses is not important (James & Heck, 1994). What is important, however, is the presence of seagrass.  

Up until now, our interest in the seahorses has mainly been about their dependent relationship on eelgrass habitat. Here at CCE, we have been working to protect and restore our native species of seagrass known as eelgrass Zostera marina for over 30 years. This is the most important thing that can be done in terms of seahorse conservation in our region. Think “If you build it, they will come!” The presence of seahorses indicates a healthy ecosystem (aka indicator species). This is why we are so excited when we find them at our eelgrass restoration sites and why they are the perfect ambassador for the work that we do! They are capable of utilizing other habitats such as seaweeds and artificial structures such as oyster cages, fish traps and other gear deployed underwater. Being that these are not permanent forms of habitat, they would not suffice for a mating/bonded pair to remain and return to. Remember, they possess site fidelity!

This is where our new Seahorse Conservation Initiative comes in!

Problem: There is little to no published information on natural seahorse populations and habitat usage in our region. We desperately need to understand more about their populations.
Solution: We need to establish regular monitoring surveys. This is where we can use your help! We are in the process of establishing seahorse monitoring sites in Shinnecock Bay and eventually other estuaries on Long Island, which will include both seining locations as well as SCUBA diving monitoring transects. We also plan to involve the fishing community, and want to make it easy for fisherman/baymen/aquaculturists to report sightings to us. All of this information will be reported to an international database and will help managers be able to protect areas utilized by seahorses and scientists understand more about their home ranges, migrations, etc.

Problem: Seahorses often utilize artificial habitat where natural habitat can’t be found. Unfortunately, this habitat is often temporary and therefore of limited usage for pair-bonded seahorses.
Solution: Working with our fisheries team, we want to establish “Seahorse Motels” out of derelict fishing gear (old lobster pots, ghost fishing pots, etc) that will be modified to no longer catch anything but rather serve as permanent artificial habitat for seahorses and other sea life. These will also be monitored for usage by divers or snorkelers, and possibly live-cam!

Problem: Seahorses have been observed around the world to exhibit site fidelity. Unfortunately, this is hard to prove especially in our temperate region. We want to know if they truly remain at their “home” of 1-2m² during a season and if they actually come back to the same place year after year.
Solution: Kim Manzo was recently trained to tag seahorses using VIFE, a harmless elastomer (rigorously tested and approved for many fish species including seahorses) that is injected just under the skin in a particular pattern to give them a unique tag that can be identified by the naked eye or by blacklight in dark conditions. Let’s prove once and for all that they do or do not have these tiny home ranges and if so, help us to protect them by protecting their habitat, possibly by working to create “Marine Protected Areas”.

These and many other ideas are in the works! Please check back for more details and future endeavors!


View Seahorse Video in the Video Gallery Section

Next: Eelgrass Epiphytes



Foster, S.J. and A.C.J. Vincent, 2004. Life history and ecology of seahorses: implications for conservation and management. Journal of Fish Biology. 65: 1-61.

James, P.L. and K.L. Heck, Jr., 1994. The effects of habitat complexity and light intensity on ambush predation within a simulated seagrass habitat. Journal of Experimental Marine Biology And Ecology. 176: 187-200.

Lourie, S. A., Sarah J. Foster, Ernest W. T. Cooper, and Amanda C. J. Vincent, 2004. A Guide to the Identification of Seahorses. Project Seahorse and TRAFFIC North America. Washington D.C.: University of British Columbia and World Wildlife Fund. 1-120.


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