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Sea urchin
Sea urchin Surface winds are predominantly from the south, south-east and east with currents setting predominantly north except in December, January, and February when they are usually variable or from the north. Probably more important in defining the shells distribution are water temperature and salinity. Mean sea surface temperatures are about the same in each area for any given time of the year and range from the upper-seventies to high-eighties. Salinity in the three comparative areas is fairly constant at 37 to 40 parts per thousands. (See chart on page 5. [Chart omitted.])
This probably limits the range of the species to some extent as, for example, in the far northern part of the Red Sea near the Suez Canal, water temperature ranges from the low sixties to about 80 maximum. Salinity remains high at about 41 parts per thousand.
Still other interesting aspects of the three localities are: all localities are comparatively far removed and protected from the abyssal zones of the seas (depths to as much as 16,000 feet) that surround the Arabian Peninsula including very deep water in the Red Sea; the land masses surrounding the three localities are an desert regions with little if any rainfall or run-off of fresh water into the sea.
Specifically, the Port Sudan area (1) is characterized by a fringing reef immediately along the coast line, the barrier reef about one mile offshore, and isolated coral atolls outside the barrier reef. Tides in this area are hardly perceptible with a range of only 0.1 feet and a seasonal change of water level of about 3 feet due to barometric pressure. The collecting locality of Al Masirah (3) was probably in the channel between the island and the Arabian Peninsula. This is a very remote area but frequented occasionally by fishermen while the seaward side of the island, open to the vast expanse of the Arabian Sea, is subjected to heavy swells even in calm weather and is almost never visited, a wreck on the rocky shore attesting to the potential hazards of the place. The channel between Al Masirah and the mainland is shallow and filled with coral reefs, islets, and submerged rocky areas. The Hormuz Straight area (2) is also characterized by offshore coral reefs and atolls with considerable shallow water and protected from the open sea and deep water environment by both barrier and fringing reefs.
Rejected localities have opposite characteristics. The coast of Aden, (4) including the Port of Aden, are predominately rocky, steep-to [?] with sandy bottom and little if any coral except, in a few places, narrow coral fringing reefs. Aden is primarily a transshipment port through which a great many commodities flow. Mocha, (5) from which nine specimens of C. teulerei have been reported, is a small sea port just north of the entrance to the Red Sea. It is a trading port and the shells might easily have been brought to the port from other areas by fishermen or traders. However, the off-shore characteristics are such that C. teulerei might possibly be collected there since many coral reefs and shoals are found out to about 3 miles from shore.
Sea urchin The original purpose of any artificial reef is to provide additional habitat for the marine life in an area. A study of the succession of life onto the artificial reef has shown a tenfold increase in the fish and a corresponding increase in invertebrate life. As mentioned before a few mollusks have found niches that would otherwise be unavailable to them in a natural reef situation.
Mollusks, like any other animals, can contribute to the food chain of the sea in two ways: they are important as prey and as predators. Their diets are so varied that it is impossible to enumerate them here. However, those that attach directly to the pipes, i.e., the oyster, vermetids and limpets are primarily herbivores feeding on unicellular algae and other algal bits.
At least 24 families of fish found on the reef have diets which are composed wholly or in part of mollusks. This is certainly a significant part of the fish population.
Interesting shells collected from the area include: Cypraea tessellata, C. talpa, C. gaskoini, C. schilderorum, C. tigris, Murex pele, M. torrefactus insularum, Mitra mitra, M. newcombii, M. stictica, M. papalis, Conus marmoreus, C. leopardus, C. bullatus, C. obscurus, C. textile, Cassis cornuta, Tritonalis
Dr. Schilder writes, "Today, I send you one more manuscript for your periodical. It is quite a different kind than my usual descriptions of single interesting shells: I think most conchologists have no idea of the quantity of names published for 'new species and varieties', and about the difference in the number of living and fossil species. Therefore, I think the present paper The number of sea shells and semi-sea shells will interest many readers. To illustrate the figures, I have added a simple diagram understandable for everybody. This time, my wife, who has done the major part of the 510-pages catalogue mentioned in the paper, will sign as co-author."
fossil living
Triviidae: Eratoinae 91 29
Triviinae 94 82
Pediculariidae: Pediculariinae 4 10
Cypraediinae 39 -
Cypraeidae: Bernayinae 188 14
Cypraeinae 52 55
Erroneinae 120 134
Erosariinae 68 60
Ovulidae: Eocypraeinae 144 2
Ovulinae 26 88
Total 826 474
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