Survey Report #1

(*Please Note: This initial report was written based on available data immediately following the 1999 Pensacola Great American Fish Count. As no other members had yet turned in their survey forms, the report was based soley on the data collected by Field Station founders Greg Bunch and Danielle Dowdy. In addition, the GAFC dives were focused on one site at the request of Mr. Goodman. Therefore, in-depth details were recalled in this report that are not part of the REEF fish identification program. Subsequent reports will differ in format as the availability of information changes.)


The Cover Letter

Dear Trey:

Enclosed is our survey report for Blackwater Bridge Rubble Site 15-G along with printouts of some photos of the life on it. The report was compiled from data collected during our dives on July 11 and 15. Also included are copies of the REEF optical scan sheets which contain the raw fish census data. We have requested for you a copy of the REEF survey methods book, which provides details about the collection, statistical analysis, and application of REEF data. We'll have that to you as soon as we receive it from REEF headquarters.

Keep in mind that the report is based only on our initial five dives on site 15-G. However, even these few dives provided us with a good overview of the site and the life it harbors. We are excited about continuing and expanding our monitoring efforts on this and other sites.

If you have any further questions, please feel free to call or email.

Thank you very much.

Most sincerely yours,

Danielle Dowdy and Greg Bunch

The Report


Survey Report for Escambia County Artificial Reef Site
Blackwater Bridge Rubble Site 15-G
Latitude 30 11.800' N
Longitude 87 14.170' W

Dates of survey: July 11, 1999 and July 15, 1999
Surveyed by: Greg Bunch and Danielle Dowdy
Method: 5 open water SCUBA dives were done on the site. Bottom times were as follows:

Date_____Start time____Max depth (feet)____Bottom time (minutes)___ Diver_
7/11/99..........10:45......................78......................................45.....................G. Bunch
7/11/99..........10:45......................78......................................45.....................D. Dowdy
7/11/99..........12:27......................77......................................38.....................G. Bunch
7/15/99..........10:28......................78......................................38.....................D. Dowdy
7/15/99..........12:46......................77......................................36.....................D. Dowdy

Visual fish surveys were performed using the Roving Diver Technique (RDT) employed by the Reef Environmental Education Foundation (REEF) to record species and abundance. Also, general environmental conditions of the artificial reef were observed and noted.

I. Fish census data

As per the REEF survey method, all positively identifiable species were recorded, and a relative abundance code was assigned to each. The abundance codes were assigned as follows:

(S)ingle.........................1 individual, (M)any..................................11-100 individuals
(F)ew................2-10 individuals, (A)bundant....................more than 100 individuals

Common name____________Proper name______________Abundance code
Seaweed blenny..............Parablennius marmoreus...................................A
Tomtate.............................Haemulon aurolineatum.....................................A
Cubbyu.............................Equetus umbrosus.............................................M
Blue angelfish...................Holacanthus bermudensis.................................F
Whitespotted soapfish.....Rypticus maculatus............................................M
Gray snapper...................Lutjanus griseus.................................................F
Slippery dick.....................Halichoeres bivittatus.........................................M
Belted sandfish................Serranus subligarius..........................................M
Spotfin butterflyfish .........Chaetodon ocellatus...........................................F
Cocoa damselfish............Stegastes variabilis............................................M
Great barracuda..............Sphyraena barracuda.........................................S
Purple reeffish.................Chromis scotti.....................................................M
Leopard toadfish.............Opsanus pardus..................................................F
Yellowmouth grouper......Mycteroperca interstitialis....................................F
Greater amberjack...........Seriola dumerili....................................................M
Spanish mackerel............Scomberomorus maculatus.................................M
Yellowtail reeffish...........Chromis enchrysurus..........................................S
Barbfish...........................Scorpaena brasiliensis........................................S
Sheepshead....................Archosargus probatocephalus............................S
Twospot cardinalfish.......Apogon pseudomaculatus..................................M
Bank seabass..................Centropristis ocyurus..........................................F
Planehead filefish.............Monacanthus hispidus........................................F
Atlantic spadefish............Chaetodipterus faber..........................................M

TOTAL POSITIVELY IDENTIFIED SPECIES: 23

Also observed were 6-10 small grouper in the 12-16" overall length range. These could not be positively identified, but are most likely Scamp (Mycteroperca phenax.) 3-4 other grouper were observed which, although these also could not be positively identified, appeared to be Gag (Mycteroperca microlepis.) These included one large individual, which was 2.5 - 3' in overall length.

II. Observations of fauna

On many levels, the fishes identified showed a great diversity. Benthic species, such as Seaweed blennies (Parablennius marmoreus) were extremely prevalent, as were coral reef species such as Tomtate (Haemulon aurolineatum.) Other reef species included the Cocoa damselfish (Stegastes variabilis), all of which were extremely small (less than 1") juveniles, as were the Purple reeffish (Chromis scotti) and Yellowtail reeffish (Chromis enchrysurus). The site seems to harbor a significant population of young juveniles. Constantly present slightly shallower in the water column above the site were Spanish mackerel (Scomberomorus maculatus.) Also present were extremely large schools of unidentified baitfish, which hovered in close proximity to the structure. A school of 20-25 young Greater amberjack (Seriola dumerili) was fairly constant on the 7/11 dives. The individuals within this school were mainly young animals, about 18" in overall length. On the second dive of 7/11, three larger individuals were observed in the school, about 30" overall length.

Various other animals were also apparently taking refuge at the site. Sand dollars were numerous on the bottom around the structure. Shells and shell fragments were evident, indicating the probable presence of gastropods and bivalves, although sightings of live mollusk specimens were limited to only one large octopus observed by other divers. Additionally noteworthy is the fact that the site did contain several clusters of gastropod eggs. Also on 7/11, three elasmobranch eggs were found, which appear to be from a clearnose skate (Raja eglanteria.) As described in the 'environmental observations,' a variety of species from the phylum Cnidaria were present as well.

III. Environmental observations

July 11, 1999: Visibility at depth was estimated to be 40'. Little to no current was present at depth. From the surface to approximately 30', there was a moderate (less than 1 knot) current, and visibility was greatly reduced due to heavy planktonic concentrations. Considerable numbers of small stinging jellyfish as well as comb jellyfish were present, in addition to smaller cnidarians. Wave heights were 2-3'. Water temperature on the surface was 84F, at depth 81F.

There was no evidence of human refuse (cans, bottles, etc.) observed. One grouper, most likely a Gag (Mycteroperca microlepsis) was observed trailing a section of fishing leader from its mouth. One lead fishing weight was seen on the site.

July 15, 1999: These dives were conducted on the same site, but slightly east of those from 7/11. Visibility on this day was reduced to 20', with increased planktonic biomass and weak to no current. Wave heights were 1.5-2'. The number of stinging jellies was lower than on 7/11. Water temperature was approximately 80-81F at the surface and 76-78F at depth. On the second dive, we observed a section of the site which had a pile of bridge rubble with relief up to about 65' and an area of sunken culverts in one spot. Here a single beer can was found.

IV. General site observations

We estimate that the structure exhibits 85% coverage of heavy, healthy barnacle growth, with light algae over most of the barnacles. Approximately 15% coverage is encrusting sponge. Purple sea whips and a yellow sea whip, all of which seem to be healthy, are present in those parts of the reef not directly exposed to currents. The barnacle/algal substrate supports a thriving community of benthic fishes, providing shelter for many very small juveniles. In addition, the site harbors a noticeably large grouper population, the vast majority of which are also juveniles.

V. Conclusions

Preliminary observations are that the site serves as a healthy, thriving reef community. In spite of only having been down 2 years, it exhibits many of the characteristics of sites (such as Three Barges) which were sunk decades ago. It supports a significant benthic community, large numbers of juveniles, a constant baitfish population, and attracts transient pelagic predatory fishes like Spanish mackerel (Scomberomorus maculatus) and Greater amberjack (Seriola dumerili.) While it lacks the dense growth of sea whips and other invertebrates, they are present in numbers consistent with the young age of this site. The area seems to be very receptive to the use of the bridge rubble in assisting the establishment of a diverse marine environment.

VI. Future study

We would like to continue to monitor this and other sites on a regular periodic basis. Further goals are to conduct video transect and possibly repetitive still photographic records. Mapping the reefs surveyed is a desired strategy and would be beneficial to further studies. Also, quadrat counts could be utilized to establish baselines for benthic coverage density and species diversity.




Please email all questions to info@reefngom.org.