Tuesday, January 7, 2020
DURHAM, NH. (AP) - Peering over the side of his skiff anchored in the middle of New Hampshire's Great Bay, Fred Short liked what he saw.
Read the whole article here:
Scientists Struggle to Save Eelgrass from Coastal Pollution, December 23, 2019 AP news.com
Friday, August 30, 2019
Kathryn Ford, Steve Voss and I are happy to announce our recent publication in Estuaries and Coasts
"Reproducibility,Precision, and Accuracy of a Hydroacoustic Method to Estimate Seagrass Canopy Height and Percent Cover in Massachusetts"
published online yesterday in Estuaries and Coasts.
The full-text view-only version is here.
Here's the abstract:
Measured decreases in the spatial extent of seagrasses in Massachusetts are attributed to declining water quality, disease, or direct and indirect impact from dredging or construction. Routine aerial monitoring of seagrasses along the 2400-km coastline is costly and therefore limited both temporally and spatially. Diver surveys are used at two sites for in situ assessments of seagrass meadow structure. In order to examine spatial and temporal trends in seagrass extent and structure, a survey methodology that is less expensive and better at capturing structural characteristics than aerial photography and more efficient than divers is needed. Hydroacoustic methods are relatively inexpensive and rapidly deployed and can measure characteristics including canopy height and percent cover of eelgrass meadows. We tested the capabilities and limitations of a BioSonics DT-X echosounder using the EcoSAV algorithm to measure presence/absence, canopy height, and percent cover of eelgrass. Measurements were found to be reproducible on duplicate transects but had low precision: 36 cm for canopy height and 34% for percent cover. To assess accuracy, we compared EcoSAV estimates of canopy height and percent cover with diver measurements. The EcoSAV estimates of canopy height and percent cover were significantly higher than diver measurements by 60 cm and 46%. We conclude that the BioSonics with EcoSAV processing is an efficient tool to map eelgrass meadows and assess relative change over time, but because of differences in the way the echosounder measurements are made compared with diver measurements, echosounder data should not be used to directly compare with diver data or for surveys that require high accuracy and precision.
Wednesday, June 12, 2019
Tuesday, August 28, 2018
|Kristen with the camera frame used to take pictures of a 1/4 m2 area at set locations throughout the bay|
|Tay measuring an eelgrass sample from NW Duxbury|
|Measuring an eelgrass sample from NW Duxbury|
|Another eelgrass sample from NW Duxbury|
|Eelgrass leaf with low wasting disease and low epiphytes|
|Patchy eelgrass in PKD|
Monday, August 20, 2018
|Eelgrass monitoring stations in Duxbury Kingston and Plymouth Bays (The DKP)|
Tuesday, March 6, 2018
Happy World Seagrass Month!
Seagrass is an underwater, flowering plant that can be found in relatively protected and healthy bays, with 60 species worldwide. Seagrass meadows are a critical habitat for young finfish and crustaceans, help protect our coastlines from storms and rising tides, and also soak up nutrients and bacteria, helping to keep our seawater clean. Two species of seagrass are found in Massachusetts: eelgrass and widgeon grass.
But seagrasses around the world are being lost at a rate of about two football fields every hour. Many things can damage seagrass, from polluted water to boats dragging their anchors. To track changes in eelgrass, Mass DMF conducts diver-based and remote-sensing eelgrass surveys in bays throughout our coast and participates in SeagrassNet, an international seagrass monitoring network.
In addition to successfully restoring tens of acres of eelgrass in Boston Harbor and Salem Sound, the team collaborates with partners on interesting projects like genetic diversity, citizen science monitoring, wasting disease, invasive species, and conservation moorings. DMF provides expertise and leadership in issues pertaining to seagrass and other sensitive habitats through the Technical Review process.
Keep tuning in to the blog to learn more about the exciting seagrass projects DMF has planned in 2018, and HAPPY SEAGRASS MONTH!