Habitat and Geography

Many studies have stated that Aplysia dactylomela exists in a vast array of aquatic environments world-wide ranging from tropical to temperate oceans, even in the Great Barrier Reef (Cummins et al. 2010) however, it has been observed that true A. dactylomela originates from the Atlantic Ocean and has been rapidly colonizing the Mediterranean Sea (Valdes et al. 2013). Angel Valdes and co-researchers studies on the origins of A. dactylomela within the Mediterranean have led to the discovery that the spotted sea hare is actually composed of two distinctly different Aplysia species, A. dactylomela and A. argus; the distinction can only be made after DNA sequencing (Valdes et al. 2013) Contrarily, cousin to Aplysia dactylomela, Aplysia argus has origins in the Indo-Pacific oceans (Valdes et al. 2013). Prior to Valdes’ research on the Origin and Dispersal Pathway of A. dactylomela in the Mediterranean Sea, A. dactylomela and A. argus were often confused as they look very similar (see picture of A. argus to left). This confusion between the two species, which are only identifiable from each other through DNA examination, may be responsible for inaccurate research results related to the habitat and geography of A. dactylomela during which A. argus could have easily been mistaken for A. dactylomela Therefore one must be mindful while reading articles about the spotted sea hare in the Indo-Pacific oceans, as one should infer the species is A. argus as opposed to the Atlantic species of spotted sea hare, A. dactylomela.

As for the typical habitat for the spotted sea hare, Aplysia dactylomela can be found in high subtidal/intertidal zones (Sterrer 1986)  and shallow waters at about one to two meters depth (Carefoot 1970). At this depth, it is common for vacationers to come across the bizarre looking spotted sea hare while wading in tidal pools. If wading, keep your eyes peeled for the portuguese man of war as it may have been directed to the shallow waters by ocean currents! As A. dactylomela is nocturnal, it makes sense that it prefers the nooks and crannies in somewhat rocky areas to escape from the sunlight during the day (Carefoot 1989) and when feeding, can be found near sea grasses in which it lays its eggs that look like a mass of spaghetti! (Emore 2002).  Because the spotted sea hare is so widely distributed, it is natural that it comes into contact with other organisms such as the sea cucumber. One major component of why the sea hare lives in shallow waters is that it is in close proximity to organisms it feeds on within the clade Archaeplastida, specifically organisms from the kingdoms Green algae and Red algae like Mastocarpus papillatus. Other organisms that live within similar habitats include smaller organisms such as sponges, sea stars like Asterias rubens, bioluminescent ostracods like Photeros annecohenae, clownfish and other small fish, sea horses such as Hippocampus kelloggi, crabs, horse shoe crabs, crustaceans, and even bacteria like Salinispora tropica (University of California Museum of Paleontology 2014). For more information on organisms that interact with A. dactylomela, click here.

Up next: learn more about the sea hare's adaptations to its environment.

References

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