Micronesian Names by Islands or Island Groups: Char or Gar (Palau – a general name for all seagrasses in Palau), Leem? (Yap), Lo’u (Guam), Ónóót, Anóót, ´Ol´ot or Achékken (Chuuk), Oaloahdilap, Ohu od’lap, Oaloahd or Ohlot (Pohnpei)

Description: There is a common misinterpretation of the taxonomic relationship of seagrasses and species in the grass family (Poaceae). Seagrasses actually have no relation to grasses; this is supported by systematic and phylogenetic evidence. Nevertheless, the term “seagrass” suitably defines a group of flowering plants that are specially adapted to grow in estuaries and marine ecosystems. Seagrasses are thus a group of marine plants that includes 13 genera and approximately 72 species that belong to the following families: Zosteraceae, Potamogetonaceae, Posidoniaceae, Cymodoceaceae, Ruppiaceae and Hydrocharitaceae; and it the family Hydrocharitaceae in which Enhalus acoroides belongs (Short and Waycott 2010). Enhalus acoroides is relatively large "seagrass" or saltwater flowering herb that is the only species in the genus Enhalus, which is therefore a monotypic genus. E. acoroides is also a dioecious species, having individuals that produce only male flowers and others that produce only female flowers. The leaves can be remarkable long, and the female plants of this seagrass species have longer leaves than the male plants. The average leaf blade is about 1-2cm (~0.5-1in) wide and may be up to about 1.5m (~5 ft) long, with in-rolled leaf margins that emerge from a solid creeping rhizome (root-like plant stem) which has tough black bristles. In some tropical saltwater regions, E. acoroides seagrass meadows may stretch for kilometers (i.e., a mile or more). Male flowers are tiny (1 cm or 0.4 in) and when these float on the water surface, they resemble small pieces of styrofoam. These male flowers are produced from a cup-shaped inflorescence formed at the base of the plant. The female flowers are relatively large and attached on a long stalk; they have three large-ribbed white petals about 2-3 cm (1 in) long which usually drop off relatively soon after blooming. The fruit of E. acoroides is round to tear-drop shaped and large about 4-6 cm (~2 in) in diameter with an outer surface or skin that is dark, ribbed, and hairy. As the fruit ripens, it opens and releases 6-7 white seeds. These seeds float for approximately five hours and then they begin sinking which ensures that they are not dispersed far from the mother plants. Roots of the newly germinated seeds develop quickly. However, similar to other seagrass species, E. acoroides spreads mostly by vegetative reproduction. E. acoroides is the only seagrass species that releases pollen to the surface of the water when reproducing sexually. Flowers are water pollinated (hydrophilous). Enhalus seagrass is therefore pollinated by male flowers that detach from the plant to float on the surface until they reach a female flower where pollination can occur. This feature restricts its distribution to intertidal and shallow sub-tidal areas. It is a slow-growing, persistent species with a poor resistance to disturbance, suggesting that areas where E. acoroides is found are quite stable over time. The bristles at the base of the plant are the fibrous remains of old leaves. Indeed, a distinctive characteristic of Enhalus seagrass “are the tough vascular bundles which stiffen leaf margins and remain after leaves are broken or gone” (Falanruw 1992).

Distribution: Seagrasses generally are important primary producers in tropical Indo-Pacific shallow saltwater communities. The attenuation (decreasing number) of seagrass species distribution in Micronesia from west (Palau) to east (Marshalls) was reported several decades ago by Tsuda et al. (1977); for example, their studies indicated that Palau, with 10 described species, has the greatest number of seagrasses in Micronesia, and going eastward, Yap has 7, Chuuk has 5 (see Kock and Tsuda, 1978), Pohnpei 2 and the Marshall Islands only 1. Eel or Tape Grass, Enhalus acoroides, is very widespread in the Indo-Pacific. In the Pacific, “it is found from southern Japan to Taiwan to the Philippines, Indonesia, and Malaysia extending throughout the Gulf of Thailand and the coast of Vietnam to Hainan, China [and] occurs across insular Southeast Asia to New Caledonia, northern Australia and across Micronesia to the Northern Mariana Islands” (Short and Waycott 2010). Dispersal studies indicate that the fruits of E. acoroides can float in seawater for as much 10.2 days, and within that amount of time they could spread out as much as 63.5 km (about 40 miles; see Lacap et al 2002); however, E. acoroides might occasionally be able to disperse much longer distances (>1,000 km) when influenced by strong currents (see Nakajima et al. 2014). Within the many areas of its native range, E. acoroides is common and extensive, especially in embayments. However, its population trend is declining in a number of locations within its range due to local threats, and is most likely declining overall in its areal extent. Threats for E. acoroides include coastal development, dredging and marine construction, minor damage from boating and shipping activities, and coastal runoff (for example, impacts in the Eastern Caroline islands of Pohnpei and Kosrae). E. acoroides is especially threatened by the creation of fish pens for farming. The species is also susceptible to shallow-net trawling and eutrophication. As this species is primarily found in estuaries, shallow lagoons, muddy bays and inside marine basins, it is often disturbed by vessels and anchorage. Furthermore, E. acoroides is found in a narrow depth range. Therefore, this species is especially sensitive to a variety of disturbances, including global climate change, such as sea-level rise.

“In the western Pacific islands, it is recognized in the need for sanctuaries and protected areas and the concept of traditional or community management of these areas. There are NGOs focused on its conservation and environmental protection integrated with traditional leadership and government agencies, suggesting that conservation measures and the acceptance of enforcement will continue to improve” (Short and Waycott 2010, also see Green and Short 2003).

Uses by Island and Island Groups: The literature documenting the traditional knowledge of seagrasses is relatively limited, but there are some important sources of information that describe the unique value and varied uses of seagrasses, including Enhalus acoroides within coastal indigenous societies. In fact, there are several traditional uses of the E. acoroides seagrass among tropical cultures, including some of those in Micronesia, where this species has been a resource for a number of purposes, including as an extractable source of a durable fiber. For example, the black fiber strands extracted from the leaf margins of E. acoroides persist after the leaves decay and are used for making fishing nets (the Moluccas, New Guinea and Micronesia, e.g., see below under uses inYap). These seagrass fibers have also been used for mats, ropes and in making paper. Communities that value seagrass are often suitably located in coastal areas of abundant seagrass meadows which serve as rich and accessible habitat for fishing; and it is from such coastal areas that seagrass can be easily gathered also for use as garden fertilizers, and as a source of food. In India, indigenous people living near coastal environments believe that their ancestors have utilized seagrasses for a variety of uses from food to medicine for thousands of years (e.g., see Short and Waycott 2010). Indeed, the raw, boiled or roasted seeds of E. acoroides are reportedly consumed by traditional people living on the coasts of Australia, India, Indonesia (Java, the Moluccas), and the Philippines, and “are said to taste like water chestnuts.” (e.g., see Kalsom 2016; also see Pradheeba et al. 2011).Further research by Ismail et al. (2012) indicated that there are antimicrobial and anticancer properties in E. acoroides seagrasses. Beyond its direct human uses, this species protects some beaches by dampening wave damage. Furthermore, a study by Qi et al. (2008), indicated that E. acoroides “produces potent antifeedant [protection from insects and other animals], antibacterial, and antilarval secondary metabolites [and that] flavonoids, as one of the characteristic chemical constituents of this species, may play an important chemical defensive role against predators, competitors, and potential pathogens (also see Guiry and Guiry 2018). Furthermore, it should be noted here that E. acoroides is a favored food of the dugong (Dugong dugon), which are large slow-moving mammalian herbivores found mostly in areas of shallow waters along warm coastlines; dugongs are the only living relatives of the three large manatees, the other “sea cows,” and are a threatened tropical marine species.

Uses in Palau: According to the Manual for monitoring seagrasses in Palau, the Republic of Palau “has a total of 10 seagrass species (bedengel el char) but within a given seagrass bed, on average of 5-7 species can be found.” Among the many seagrass species in the tropical inshore waters of Palau, one of the two most abundant and dominant of these marine plants is Enhalus acroides which is widely distributed throughout the main archipelago. E. acoroides plants, with their thick rhizomes that produce long black bristles and cord-like roots, occur in Palau in shallow or intertidal sandy areas or on mudbanks, frequently next to mangrove forests. E. acoroides seagrass serves as the main food source for herbivorous fishes, sea turtles, and dugongs, and their unique flowering events can be quite remarkable: “On May 10 [1910] the lagoon north of Goréor [in Palau] was rendered completely white by the petals of the seaweed Enhalus acoroides Steud.; it was a rare spectacle of nature” (Krämer 2017:200). Reportedly, simaliar to the use of this seagrass in parts of India, local people in Palau, at least on Peleliu Island, collect E. acoroides seagrass from the beaches during low tides then dry them out before using them as a fertilizer in their farming areas (Teri Brugh, Personal Communication, 2002).

Uses in Yap: Enhalus acoroides seagrass has been a resource for a number of traditional purposes in Yap, including as an extractable source of a durable fiber used in the production of fishing nets. Before the introduction of motorized boats, monofilament gillnets and flashlights, the variety of fishing methods used was much greater than at present. The erosion of traditional authority over marine resources has been attributed by many fishermen to these new methods and gears (Lambeth 2001a). Falanruw (1992:1-12; also see Falanruw 1994c) provided a review of the use of the persistent bundles of vascular fibers characterizing the Eel or Tape Seagrass, E. acoroides, in the construction of “nets which last for generations.” These seagrass nets were utilized on Yap until the Second World War, but by the end of the 20th century there were only a few elderly people who could still “make these fine nets.” Among several aspects of E. acoroides seagrass nets in Yap that are described and discussed by Falanruw (1992:1-12), we focus here on the collection of seagrass leaves, extraction of the fibers from these relatively long, strap-like leaves, the production of twine from the extracted seagrass fibers, and the kinds of nets that Yapese people wove using the twine made from the seagrass fibers:

Collection of the seagrass leaves:

“The nets were made in only a few villages located near bays where appropriate seagrass occurred. In the bay of Rumu' village, special marine meadows were protected so that Enhalus acoroides would grow long and unbroken. The fibers were then collected at low tide. Today's elders remember that when they were boys, the area would be filled with older men collecting seagrass fibers at appropriate tides. It is said that suitable seagrass grew in only a few places on Yap. Today E. acoroides is common in many areas of the Yap lagoon however the special beds in Rumu' are being buried in silt as a result of soil erosion from road construction…. When collected, leaves were harvested from, but one side of the plant. One informant said that this helps to conserve the resource, while another suggested that the fibers are stronger on the convex side of the plant” (Falanruw 1992:1).

Dried seagrass fiber extraction and preparation:

“Extraction of the entire length of the thin pale fibers, which are only about 0.3 mm in diameter, is a delicate operation requiring practice. The double strands are held firmly in one hand and then the connecting leaf blade is grasped firmly between thumb and pointer finger, and stripped off. This exposes the light colored fibers. These fibers are then held firmly and the leaf tissue surrounding the fibers like a sheath, is stripped off. This involves an initial jerk followed by a long smooth pull to slide the ensheathing tissue off. The operation is similar to pulling the drawstring out of a narrow hem, but requires a delicate touch similar to that of pulling one thread from a piece of cloth without breaking the thread. The thumbnail is used in making the initial separation but not after this, lest the fiber be broken. Should the sheath tissue get too dry, it can be wet again, and dried to the appropriate condition to be stripped off. In the old days young boys would take the left over tissue stripped from the fibers, and chew it for its salty flavor (similar to the taste of kelp of Japanese cuisine). Once extracted, the pale buff fibers are stable, and are stored until enough have been collected to prepare twine.” (Falanruw 1992:4).

Twine preparation:

“Twine is prepared by twisting seagrass fibers together. The bundle of fibers is held under one arm, and about 4-5 fibers are pulled out, the number depending on the desired thickness of the twine. Initially these fibers are twisted together with the fingers. Once firmly twisted, they are rolled on the thigh. A second strand is prepared the same way. Then the two strands are placed side by side and rolled together, first forward, then briefly back to make the twine tight. Occasionally, when the strands are not tight, or when additional fibers are added, the 2 bunches of fibers may be separately rolled before being rolled together” (Falanruw 1992:4).

Net types:

“The fine mesh nets were used in a variety of ways. These included hand nets called "k’ef, larger nets set to catch seasonal migrations of small fish, and in a special fishing method in which a large net is pulled between two sailing canoes. The last large seagrass net was purchased by a Japanese visitor to Yap, so measurements are not available. The average size of a small k’ef net is about 55cm in height, and about 148 cm in length” (Falanruw 1992:7).

Finally, in her conclusionary comments about seagrass net making and its former place in traditional Yapese culture, Falanruw (1992:12) provides insight into the cultural history and legacy of making seagrass nets:

“The strength of the thin individual fibers is limited and skill and time was required to make them into fine, durable nets. The development and practice of such a skill requires a freedom from other activities-provided by a tradition of specialization. Though seagrass nets were desired by many, making them was the specialty of a limited group, and provided a valuable medium of cultural exchange and prestige for this group. The making and use of seagrass nets also provided for a mutual exchange of talents between generations. Older men, having lost strength and gained patience, made the nets. In gathering the fibers, they shared companionship and mutual endeavor with other elders. The art of making seagrass nets is satisfying. The product is lasting and valued. Even the discarded semi-dried leaf sheaths provided a special taste treat for the children prohibited from frolicking amid the special seagrass - a taste remembered from his youth by our teacher, and now, even by us, his students. The nets were used by fishermen, who would bring their catches to the mens’ house to share with the older men, who would in turn, mend any torn nets and relate their own fishing experience - thus helping to develop the next generation of fishermen, and, eventually, net makers.”

Uses in the Mariana Islands: Seagrass beds are commonly found on the reef flats of Guam. Government researchers believe that seagrass resources have declined over time due to modifications of these reef flat environments including dredging and sedimentation. The Guam seagrass beds include three species: Enhalus acoroides, Halodule uninervis, and Halophila minor; all three are reportedly known in Chamorro as Lo’u which simply may mean “seagrass”? Traditional uses of E. acoroides are not well documented in the Mariana Islands. Seagrasses are critical to productive coastal ecosystems but are endangered and poorly studied, especially in the tropical Indo-Pacific. A key local threat is the increasing anthropogenic input of nitrogen. A recent study provides a useful reference for evaluating mitigation efforts and for tracking the effect of increasing anthropogenic eutrophication on Guam, in this case Nitrogen pollution impact on E. acoroides (see Pinkerton et al. 2015).

Uses in Chuuk: The strong leaves and black base fibers of the seagrasses Enhalus acoroides are or were traditionally used in Chuuk to make fine fishing nets for catching reef fish (e.g., see Manner 2013:237). This seagrass has also been used as protective medicine for women who are going into the ocean.

Uses in Pohnpei: Seagrass meadows occur widely along the coast of Pohnpei, but until only recently the ecological role of these seagrasses, including Enhalus acoroides (known in Pohnpei as Oaloahdilap), has remained relatively undocumented and unfortunately unappreciated. However, a growing concern in Micronesia has developed “for the conservation of sea turtles, for the management of coastal fish populations, and for the protection of coral reefs,” and there is an evident and pressing need for increased “understanding of the role played by seagrasses in grazing and detritus food webs, nutrient recycling, sediment retention, and shoreline stabilization” (McDermid and Edward 1999).
Major environmental threats face several Micronesian Island estuaries, including Pohnpei Island and its seagrass beds as described briefly by Raynor (2006:109):

“The sources of degradation of estuaries are varied and numerous, the most serious being sedimentation and pollution from land-based activities. Dredging and construction of causeways with insufficient openings for current and tidal flow have also further degraded a number of estuaries in the FSM. Sea grass beds are threatened by sedimentation and pollution, but have been spared some of the ravages of estuaries especially where healthy mangrove forests still line the coast and can absorb land-based impacts. To a lesser extent, boat traffic (propeller damage) has had local negative impacts on sea grass beds, especially along regular transportation routes in lagoons. Storms and wave action particularly those resulting from typhoons occasionally impact sea grass beds, as does increased freshwater….”

Today on Pohnpei as well as other Micronesian Islands, monofilament nets are used now instead of nets made from traditional materials. In the past, fibers extracted from the leaves and base fibers of Oaloahdilap (E. acorides) were used traditionally to make nets to catch reef fish on Pohnpei; Oaloahdilap is said to produce the strongest natural fibers in the island. In the past, women on Pohnpei made their own nets and fishing was a community activity. Now people fish more individually. Previously, community fish herding was also a common activity practiced by men, women and children. Monofilament nets are now used, by men and women, to surround a school of fish (Lambeth 2001:18). In addition to the traditional use of Oaloahdilap fibers to make Pohnpeian fish nets, the leaves and lower parts of Oaloahdilap are used for medicine, and the large edible seeds of are a traditional delicacy. According to Balick et al. (2009:282) Oaloahdilaphas had a number of traditional uses on Pohnpei:

“To use as food like a green onion, the base of seagrass is chopped together with sea cucumber…To use for weaving grass skirts and fishnets, the outer stem is scraped off and the inner plastic like fiber is then processed into grass skirts and fishnets…To use to treat soumwahu en eni (ghost sickness) …To dispel enihn nansed (an evil ocean spirit) that has possessed a woman….”

Uses in Kosrae: Enhalus acoroides, along with Thalassia hemprichii and Cymodocea rotundata are the three species of seagrass that reportedly occur in Kosrae, covering an estimated total area of seagrass meadows around Kosrae of about 3.5 km2; however, it should be noted that modern airport runway and coastal road construction of Kosrae as well as other islands in the Federated States of Micronesia have contributed to the loss of seagrass habitat (Coles et al. 2003:164-166).