Bryozoans.nl - bryozoa I found around Dahab - Gulf of Aquaba

Last update 13-5-2010


Below the bryozoa I found in a 5 day - 15 dives search for bryozoa around and south of Dahab Egypt on the shore of the Gulf of Aqaba. There were three places I found bryozoa:

I failed to find bryozoa underneath table corals (suggested by [Vine 1986]), on or underneath coral rubble (and in many other places).

The 'Caves' divesite consists of two caverns (undeep caves) that are several meters (5 to 10) high, around 10 meters deep and 20 to 30 meters wide. The ceiling of the caverns are two - three meters below the surface. Exact location: 28"24'59.55 N 34"27'21.53" O.
As bryozoa like low sedimentation areas that do not have direct sunlight I expected Caves to be a good area to search for bryozoa, which came true. Both caverns are also rich in sponges and gorgonians, which hang from the ceiling. I also found hydrozoa.
Given limited time (40 - 50 minutes per cavern) I limited myself to searching the bottom and lower walls. The higher wall parts and the ceiling remain for a next visit.

Besides in the Caves i also searched below (dead) table corals up to 20 m depth without succes. Maybe deeper is better. This was around divesite 'Moray Garden', mostly to the left towards 'Golden Blocks'. Exact location: 28"26'15.51" N 34"27'31.68" O.

Divesite Lighthouse has a small wall with an overhang and small holes in it, but I failed to find bryozoa there. The only bryozoan I found was on a rock that stuck out of the rough-sand slope directly in front of the place of entry at around 5 meters. The bryozoa lived on the downward facing side of the rock. I examined many other rocks and other objects, such as ropes, metal objects, old car tires, amphoras and alike in the area without success. However i found something that may well be a bryzoan in divesite Garbage Dump, which is the same location, but to the right rather than to the left (which is Lighthouse reef). Exact location: 28"29'56.09" N 34"31'10.62" O.

Any garbage encountered while diving is removed. On plastic that had been longer in the water and had a slippery biofilm feel to it bryozoa were likely to be found - more than 50% of the plastic garbage of this kind had bryozoa on them, sometimes also hydrozoa. Newer plastic closer to the surface did not have bryozoa, nor did I find any bryozoa on plastic objects (bottles) that got stuck in the reef, but there where few of them.

Given Egypts strict laws of preservation of the marine environment I did not take any samples. Even the bryozoa colonies found on free floating plastic where returned to the sea, after making photographs in a small container and after removing excess plastic.

Canda pecten

Canda pecten

I found this species only in the rightmost cave on the right back end (as seen from the entrance swimming in) and only in two places. One was a lonely colony on a stone, as shown above, the other where multiple colonies on the lower part of the wall with some other species growing over them (shown below).
Species identification was kindly provided by marine biologist Christian Alter of the Dahab RSEC field station. It is also listed as such in [Lieske 2004] page 279.

Canda pecten

Unknown bryozoan 1

Unknown byrozoan 1

I found this species in both caves in significant numbers and size, mostly on the side and back wall, well into the caverns.
The photo above provides a detail, below a photo with an overview of a larger colony and another photo with more detail. The zooids and their lophophores can be easily seen.

Unknown byrozoan 1 Unknown byrozoan 1

Unknown bryozoan 2

Unknown byrozoan 2

The following species had formed a significant sized colony growing from the branches of a branching coral colony growing from the ceiling. At first i thought it was a hydrozoan, but after studying the photo details (as shown below) I now believe this is a bryozoan. It seems unlikely to me that the polyp shape is that of a hydrozoan. The colony had a significant size, about the size of a small football.

Unknown byrozoan 2

Unknown bryozoan 3

Unknown byrozoan 3

This species I have found on several free floating pieces of plastic, like plastic bags. The plastic had a slippery feel to it, probably due to a biofilm. Generally plastic floating at around 1 meter depth was too new in the water to develop a biofilm and secundary species like bryozoa or hydrozoa.
I took the plastic garbage out of the water with me, saved the ones with bryozoa colonies on them in a salvaged bottle with water and made photos on shore (in a clean ashtray as that was the only available bowl like object). The bryozoa colonies were returned to the sea afterwards after gently removing the excess plastic. The photo below shows the setup. Below that the full colony. This is the same photo the one above was cut out from.
On the same piece of plastic a hydrozoan was living, see last photo.
This particular colony was found on a piece of plastic floating around in dive location 'Islands'.

Unknown byrozoan 3 Unknown byrozoan 3 Unknown hydrozoan

Unknown bryozoan 4

Unknown byrozoan 4

This species I have found on the downward facing side of a small rock sticking out of a sandy slope in dive location 'Lighthouse', almost straigt down (slightly left) from the entrance at around 5 meters depth. Possibly there are even two species of bryozoa. Below a cutout with relevant details and another cutout with the possible second species.
The photo above shows there are several colonies, one large and about 10 smaller, of the first species. The possible second species has only one colony. I have not seen both species anywhere else.
The circumstances for underwater macro photography were difficult, given an object close to the bottom, a downward slope and a downward current, so these are the best photos I have. Due to the very small distance between colony and photo camera required for this level of detail many zooids have retracted their polyps.

Unknown byrozoan 4

Unknown bryozoan 5

Unknown byrozoan 5

This species grew on the same rock as the species above.

Unknown bryozoan 6

Unknown byrozoan 6

This species I have found on one of the coral blocks as can be found in divesite 'Moray Garden' if one swims to the left (towards 'Golden blocks') at somewhere between 12 and 8 meters of depth.
The problem with the photos I have is that none of them show a lophophore, so i am unsure if this is really a bryozoan.

Unknown bryozoan 7

Unknown byrozoan 7

Again this species could be a bryozoan or maybe not. There is not enough detail and too much confusing material to be sure.
This photo was made in the same divesite as the one above, but deeper, probably around 12 meters. It is blue as I did not use a flash.

Unknown bryozoan 8

Unknown byrozoan 8

This is most likely to be a bryozoan (species unknown) that required very carefull scruntiny of the photos to identify it as such. It looks like some form of algae, but if one looks most closely, there are lophophores extending from the top of each 'candlebra arm'.
I found this species during a nightdive in dive location 'Garbage Dump', which is in the middle part of the bay of Dahab.
Surrounding the bryozoan there are true algae (the tubes) and fair sized grains of sand. This bryozoan is tiny.

Unknown bryozoan 9

Unknown byrozoan 9

This is also most likely to be a bryozoan (species unknown) that required very carefull scruntiny of the photos to identify it as such. It looks like a dead stick, but carefull study show it has a fairly extensive 'root' or 'attachment' system (fine white lines on the stone). I failed to take a photo with lophophores extended (if this really is a bryozoan).
I found this species during a dive in dive location 'Caves' somewhere in the back of the left cave.
Just above the bryozoan there is a tiny white sponge and underneath it an empty shell.