2016 Great Scallop Survey

Situation

Bay scallop (Argopecten irradians) were once common along the entire Gulf coast of Florida and portions of the Atlantic coast along southeast Florida.  A combination of habitat loss, poor water quality, and over harvesting reduced their populations to where the commercial harvest had to be banned and recreational harvest restricted to a specific season and to specific areas where populations remain healthy enough to support it.  There has been research and discussion as to why scallop populations declined, and whether they can be restored in Florida waters.

 

The Florida Fish and Wildlife Conservation Commission is interested in scallop restoration. Portions of Pensacola Bay historically supported scallops and is a possible target for a restoration project.  Conversation with residents who remember, and personal experience, indicates that populations existed in both Santa Rosa Sound and Big Lagoon.

 

Area of Survey

Santa Rosa Sound is approximately 32 nautical miles long running east-west and about 1.5 nautical miles wide (north-south). It is bordered to the north by a portion of the Gulf Islands National Seashore known as Naval Live Oaks, residential communities of Santa Rosa County, the town of Navarre and Ft. Walton Beach in Okaloosa County.  To the south is a large area of the Gulf Islands National Seashore, Pensacola Beach, Navarre Beach, Eglin Air Force Base, and a portion of the Ft. Walton Beach community on what is called Okaloosa Island.

In the Pensacola Bay system, Santa Rosa Sound begins about 6 nautical miles east of the Pensacola Pass (entrance to the Gulf of Mexico) with the community of Gulf Breeze to the north, Gulf Islands National Seashore and Pensacola Beach to the south. It is relatively shallow (0-25 feet) with submerged meadows of shoal grass (Halodule wrightii) and turtle grass (Thalassia testudinum).

 

Big Lagoon begins just west of Pensacola Pass and extends 6.2 nautical miles (east-west) to the Theo Baars Bridge. It is about 0.9 nautical miles wide (north-south).  It is bordered to the north by the community of Grand Lagoon, Big Lagoon State Park, and a portion of NAS Pensacola.  It is bordered to the south by the Perdido Key portion of the Gulf Islands National Seashore.  Depths within Big Lagoon are between 0-22 feet and support submerged meadows of both Halodule and Thalassia beds; as well as small populations of manatee grass (Syringodium filiforme).

 

Method of Survey

The method used for this survey is the same that Florida Sea Grant Agents are using in Lee and Charlotte counties in southwest Florida. 1-nautical mile square grids are mapped out in each body of water with the assistance of the Florida Fish and Wildlife Conservation Commission (FWC).  Citizen volunteers are trained by Sea Grant Agents on the methods of setting up, swimming, and counting scallop along a 50 meter transect line.  Teams of 3-5 trained volunteers are assigned one grid and are asked to conduct four 50-m transects within that grid.  The number scallop, scallop shells, bottom type, amount of epiphytic macro-algae, and clams are logged on a data sheet.  For the Pensacola Bay survey, we included manatee grass (not as common locally), horseshoe crab and lionfish.  Volunteers returned data sheets to Sea Grant Agents at assigned boat ramps.

The Santa Rosa Sound survey was conducted on Saturday July 30, 2016.

The Big Lagoon survey was conducted on Saturday August 6, 2016.

 

Results

 

  SRS BL Total Other
# of volunteers

 

63 33 96  
# of grids surveyed 20 11 31 The number of grids did not significantly differ between 2015 and 2016
# of transects surveyed 68 43 111 There were more transects conducted in Big Lagoon in 2016
# of scallop found 0

 

1 1 The first live scallop was found in Big Lagoon
# of grids with scallop shell 4

20%

4

36%

8

26%

The number of scallops shells reported declined in both bodies of water in 2016
# of grids with epiphytic algae  

73%

 

28%

 

57%

There was very little macro-algae in Big Lagoon in 2016
# of grids with horseshoe crab 0 0 0 Live horseshoe crabs were reported in Santa Rosa Sound BEFORE the surveys were conducted in 2016
# of grids with lionfish 0 0 0 No lionfish found
# of grids with manatee grass 0 0 0 No manatee grass reported in 2016

 

 

There was a slight drop in the number of volunteers in 2016 but the number of grids and transects surveyed did not – so the effort was the same.

The first live scallop was reported in 2016.  It was found in Big Lagoon.

NOTE: The morning of July 31 – when heading out for the Santa Rosa Sound survey – a pile of cleaned scallop shells were found in the parking lot.

N = 67 (assuming 34 scallops)

Shell length range = 45.2 – 63.0 mm; Mean length = 51.8mm ± 3.1 (73% of the shells were between 50-59mm)

There were fewer scallop shells found in both bodies of water in 2016.

The amount of macro-algae found in Santa Rosa Sound was not significantly different between 2015 and 2016 but there was a significant reduction of macro-algae reported in Big Lagoon.

 

Discussion

There appears to be evidence of live scallops living in our waters. One live scallop was found in Big Lagoon and 67 cleaned shells were found in a parking lot on Santa Rosa Sound (not sure where they came from).  This is encouraging but more education is needed to make sure residents and visitors are aware that harvesting scallops in Escambia and Santa Rosa counties is illegal.  There was an interesting reduction of macro-algae in Big Lagoon; not sure why.  Dr. Steve Geiger (FWC) indicated if the mean salinity of these bodies of water are above 20‰ that this area could be a candidate for a restoration project.  We will begin to monitor salinity in both bodies of water in 2017.  We are also going to include seagrass and blue crab abundance to this survey.  Both of these are of importance and interest to the local area.

Submitted

 

Rick O’Connor                                                                                   Chris Verlinde

Florida Sea Grant                                                                             Florida Sea Grant

University of Florida / IFAS                                                           University of Florida / IFAS

Escambia County Extension                                                         Santa Rosa County Extension

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