Atlantic Eelgrass Monitoring Consortium:

SeagrassNet Training July 2015

Seagrasses are underwater plants, as opposed to algae (seaweed), that provide shelter, food and nurseries to many commercially and ecologically important marine animals. Seagrasses also protect, filter and provide stability in coastal zones. Many seabirds depend on seagrass beds for food stops during their long migrations.

Dr. Fred Short, director of the New Hampshire-based SeagrassNet was invited to visit Port Mouton July 16-18, 2015 to direct a three day workshop, aimed to set up a permanent eelgrass-monitoring site that will provide information on the status of eelgrass, an ecologically important species for coastal communities.

During the workshop, Dr. Short provided information on seagrasses and demonstrated the monitoring site setup and protocols to workshop participants, who included members of local community group, Friends of Port Mouton Bay.

The workshop also consisted of locating an eelgrass site and how to collect and analyze data produced from the eelgrass site. The new eelgrass monitoring site is located in Jones Cove at Port Mouton. SeagrassNet sites are located internationally, in places like Australia, Belize, Coatia, India, and Madagascar and are monitored synchronously four times a year. SeagrassNet provides free, online sampling protocol manuals for the different bioregions around the world, along with informative brochures on seagrasses.

Site Set-Up

The seagrass bed site should be easily accessible by shore. It should also be characteristic of the conditions in the area. During the workshop, Fred Short demonstrated how to properly sample seagrass. The full, detailed procedure for seagrass site set up and monitoring is found in the Manual for scientific Monitoring of Seagrass Habitat by SeagrassNet

SeagrassNet monitoring sites include transects parallel to the shoreline placed: in the shallow area (Transect A), at deep region of the seagrass bed (Transect C) and at an intermediate zone (Transect B). Each transect is 50 meters long.  At 0, 25 and 50 meters on each transect, a permanent station marker is placed.

  • Distribution is measured by mapping the position of seagrass relative to permanent transect. 
  • Species composition is measured by collecting seagrass along the permanent transect. A herbarium sheet of each seagrass species should be prepared and sent to SeagrassNet at the University of New Hampshire. 
  • Abundance is measured by taking measurements of cover, canopy height, density, biomass and by taking photographs.  
  • Sexual reproduction is measured by counting the number of flowers, fruits and seeds or flowering stems in a core for all seagrass species and calculating flower/fruit/seed per area. 
  • Environmental variables such as water temperature and surface light are continuously measured by permanent sensors.   
  • Biomass is collected by collecting a core 10 cm deep outside each quadrat. 

The health of seagrass beds mirrors the health of the coastal ecosystem that they inhabit; once the seagrasses are diseased it is probable that the marine ecosystem they inhabit is declining as well. Globally, Eelgrass and other seagrasses have found to be in decline in coastal zones due to threats such as: increased nutrients and sediments entering the ocean from land based sources, human activity that causes direct physical damage, and climate change.


The sampling quadrats are placed along the transect at specific distances which are standard to the monitoring protocol and provided in the SeagrassNet data sheet. Each of the measurement methods described below is sampled for each quadrat. There are 12 quadrats for each of the three (A, B and C) transects.


Go to top