In a new blog series, our Conservation Trainee Abi David explores some of the amazing creatures that call seagrass meadows their home. Sea hares are odd looking creatures. They are mostly soft bodied but have a small internal shell, which separates them from their close relatives – sea slugs. The
In a new blog series, our Conservation Trainee Abi David explores some of the amazing creatures that call seagrass meadows their home. Sea hares are odd looking creatures. They are mostly soft bodied but have a small internal shell, which separates them from their close relatives – sea slugs. The sea hare gets it name from the two rhinophores sticking out from the top of the head as they look like the ears of hares. However, these appendages aren’t used for hearing, but for taste and smell. A sea hare’s favourite snack is seaweed, but they also eat seagrass. Interestingly, the colour of the seaweed species most prominent in their diet influences the colour of the sea hare individual, for example: diets made from mostly sea lettuce will lead to a green body colour and reddish-maroon sea hares will be eating mostly red seaweeds. Sea Hare on seagrass. Photo Credit Lewis M Jefferies A Sea Hare within an Orcadian seagrass meadow. Photo Credit Lewis M Jefferies When threatened, they can produce a cloud of ink which the sea hare can hide in to confuse predators. Scientists have found that this ink has antibacterial properties, thought to be useful in healing wounds and combating harmful bacteria. Additionally, they can produce a slime on their skin which makes the sea hare less tasty and puts predators off from eating it. Sea hare species can range from 2 to 70cm, but the ones found around the UK – Aplysia punctata or dotted sea hare – are on the smaller size of 7 – 8cm and can be found throughout the year in rock pools and shallow waters. They lay their eggs in long string-like structures attached to seagrass, with the seagrass meadow acting as a nursery environment when the eggs hatch. They are hermaphrodites, meaning individuals have both male and female mating organs. Despite this, they still reproduce with others, usually in a line with multiple individuals. Sea Hares in seagrass As well as seaweeds, sea hares will consume seagrasses too. As with many marine species, seagrass meadows provide an important nursery habitat. By attaching developing eggs to seagrass leaves, the eggs are protected from strong currents and predators, as well as providing a food source for newly hatched sea hares. Some species, such as the Phyllaplysia taylori or eelgrass hare, live solely on seagrass. Evidence has shown presence of sea hares increases seagrass productivity as a result of grazing on epiphytes on the leaves. A build-up of too many epiphytes will block the leaves ability to photosynthesize, so these little creatures can be very handy for us seagrass scientists! Sea Hare (with egg strings) on a blade of seagrass. Photo credit Lewis M Jefferies But do sea hares benefit society? Yes! They form an important part of diets around the world. For example, in Hawaii, people wrap the sea hare in to leaves and cook it in an underground oven, called an imu. In the Philippines, egg strands, known as lokot, are eaten raw with vinegar and spices. Samoa, Kiribati and Fuji also have sea hares as part of the traditional diet. Often it is women that will go out and collect the sea hares at low tide on mudflats and seagrass meadows and then sell them at markets, so sea hares have an important economic benefit to these societies too. For further information about how grazers such as the sea hare are beneficial to seagrass, look at this article.
