Entelurus aequoreus

E. aequoreus inhabits inshore coastal waters, vegetated by seaweed and seagrass beds. But it can also occur in superficial ocean waters. Specimens from the two habitats can be distinguished by morphological differences. The oceanic ones are thinner, smaller and with a paler body colour, compared to the coastal ones. Also, the breeding season occurs at different months according to the habitat. On the ocean, it occurs between March and April, and on the coast between June and July. These differences made researchers suggest different nominations for the two specimens: Entelurus aequoreus for the oceanic and Entelurus anguineus for the coastal individuals. The split was never recognised, due to the lack of genetic differences between the two, being commonly considered different morphological forms of the same species 

The snake pipefish is classified as “Least Concern” by the IUCN Red List due to the constant population size after the early 2000’s fluctuations. Between 2002 and 2007 E. aequoreus experienced a high increase of the population size, but since 2008 the population has decreased and stabilized. The causes for the increment aren’t clear, but researchers suggest that was a consequence of the water temperature increase occurred during those years. The high population number led to consequences on the surrounding environment, where seabirds started to feed on this pipefish. However, the snake pipefish is a bad prey choice, nutritiously poor and with a hard body, difficult to swallow. No further research was performed to evaluate the environmental dynamics, after E. aequeoreus population decreased and stabilized.

image: Rebecca Nason (licensed under http://creativecommons.org/licenses/by/4.0/)