The following is a preliminary report of the 2019-2020 MarineGEO Global Seagrass Survey. You can read more about the survey’s goals and methods here: https://marinegeo.github.io/projects/seagrass-food-webs/.

The data are currently stored in an invite-only Dropbox for all participants. Please contact MarineGEO if you have not yet received an invitation to the Dropbox!

As more data are being uploaded all the time to our MarineGEO Data Portal, this script may produce different results, depending on whether new data have been added since the last run.

Metadata Summary

First, let’s see the locations of places where participants have been working, and have already submitted data:

As of 27 July 2020, 20 sites on six continents have contributed data to the database–fantastic!

Now, let’s see which variables were measured at which sites:

Site
Seagrass
Fish
Environment
Process
Density Shoots Biomass Macroalgae Epifauna Seines Visual census Water quality Organic matter Squidpops
AUS-PRB X X X X X X
BEL-CBC X X
CAN-BCC X X X X X X X
FIN-GOF X X X X X
KOR-DDB X X X X X X X
MDG-RGN X X X
MDV-OIL X X X X X X
MEX-ENS X X X X X X X X
MEX-PUM X X X X X
NOR-ROV X X X X X X X
PAN-BDT X X X X X
PHL-PBT X X X
POR-MAD X X X
USA-AKA X X X X X X
USA-IRL X X X X X X X X
USA-MDA X X X X X X
USA-TXS X X X X X
USA-VAS X X X X
USA-WAR X X X X X X
VEN-LCO X X X X X X

Data Summary

Seagrass Characteristics

The median cover bin was 2, suggesting reasonably low cover at the plot-level in most locations, but ranged from 0-5, suggesting no to complete cover in some plots.

The median shoot density was 16.58 shoots m-2, although ranged as high a 513 shoots m-2 in Texas, USA.

Participants found between 0-15 species in each plot, ranging from bare sediment, to at least 9 sepecies of seagrasses, to various macroalgae, to corals, sponges, and tunicates.

Epifaunal characteristics

A median of 4.6 epifaunal individuals per plot were obtained, and were predominantly small amphipods and isopods, shrimps, crabs, and gastropods, with a few polychaete and sipunculid worms.

The individuals were predominantly small, falling into the 0.5-1.4 mm size classes.

Median epifaunal richness was 11 species, and ranged from 0 to a maximum of 50 in the Indian River Lagoon, Florida, USA.

Epifaunal abundance and epifaunal richness were weakly negatively correlated (r = -0.23) but not significantly so (P = 0.28).

Fish characteristics

We conducted two kinds of fish surveys: seines and visual census.

We obtained a median of 7 individuals per seine, and 42 individuals per visual census, with a maximum of 66 fish in a seine and 232 in the visual census.

Median fish size was 5.8 cm in the seines, and 81 cm in the visual census.

Median fish richness was 7 for the seine and 5 for the visual census, with a maximum of 15 species in the seines in Texas, USA and 22 species in the visual survey in Madagascar.

Fish abundance and fish richness were positively but non-significantly correlated for seines (r = 0.47, P = 0.08), and highly significantly correlated for the visual census (r = 0.84, P < 0.001).