Value of Seagrass

Functional

Throughout its distribution, seagrass performs numerous important functions:

1. High Production and growth – extremely rapid growth and high net productivity (leaves typically grow 5 mm/day) allows seagrass to exert a major influence on the marine seascape.
2. Food – living seagrass material may be directly consumed or organisms may consume the detritus from decaying seagrass.
3. Shelter – seagrass can serve as a spawning habitat for birds (e.g. Pacific herring - lays its eggs on the blades of seagrass). Also provides critical nursery area for juvenile fish of commercial and recreational importance, which seek protection within the beds from predators.
4. Habitat stabilization – Seagrass stabilizes sediment in two ways: 1) leaves reduce current flow and subsequently water velocity, allowing sedimentation of particles, and inhibiting resuspension of organic and inorganic material. 2) Rhizomes and roots form a complex matrix, binding the sediment and reducing erosion.
5. Nutrients – the production of detritus and sedimentation provides organic matter for the sediments and maintains an active environment for nutrient recycling (Romero et al, 2006).

Economic

Seagrass, as an ecosystem, is economically valuable (Constanza, 1997; Carlisle, 2004). Seagrass habitats provide nursery and foraging areas for many commercial and recreational fish and shellfish species, and thus support the production of numerous living marine resources.

Cultural

The value of seagrasses, as perceived by humans, has changed historically through time and place (Kenworthy et al., 2006). In the past, seagrasses have been valued because the plants yielded material for various practical purposes. The direct use of seagrass has a long history for a variety of needs. In the seventeenth and eighteenth century, Z. marina seeds were a major food source of the Seri Indians living along the Gulf of California. The Seri harvested the carbohydrate-rich seeds to obtain flour for use in a variety of dishes (Felger et al, 1980). Z. marina seeds, roots and leaf bases have and continue to be a food source in the north-west Pacific, and in South-East Asia.

Globally, the net fibres in Z. marina have been used to create cordage and nets. Z. marina has also been used for basket weaving, bedding, clothing, insulation, mulch and high-grade paper (Kenworthy et al., 2006).

© Jessica Smith 2008

Carlisle. E. (2004) Seagrass research and management in Washington state. Univerity of Washington – School of Marine Affairs.

Constanza. R, d'Arge. R, de Groot. R, Farber. S, Grasso, M, Hannon. B, Limburg. K, Naeem S (1997) The value of the world's ecosystem services and natural capital. Nature 387: 253-260.

Felger. R, M. Moser, E.Moser. (1980). Seagrasses in Seri Indian culture. Handbook of Seagrass Biology:  an ecosystem perspective. Garland STPM Press. New York.

Kenworthy. W, Wyllie-Echeverria. S, R. Coles, G. Pergent, C. Pergent-Martini (2006) In: Larkum.A, R.Orth, C.Duarte. (2006). Seagrasses: Biology, Ecology and Conservation. Springer.

Romero. J, Kun-Seop. L, Perez. M, Mateo. M, T. Alcoverro (2006) In: Larkum.A, R.Orth, C.Duarte. (2006). Seagrasses: Biology, Ecology and Conservation. Springer.