78
The Suez Canal
Sirbonic Lagoon (Bardawil), or the Qishon estuary near Haifa. He considers
among the unfavorable conditions for the plankton life in the Canal, besides the
high salinity and turbidity, "the shallowness of the Canal which alm ost excludes
the passage, or even the temporary habitation of pelagic organisms committed to
a certain degree of vertical migration". In my opinion vertical movements of the
planktonic organisms are further hindered by the saline stratification of the waters in the Canallakes.
It is interesting in tbis connection that the snail Murex anguliferus, which
hatches already in the "swimming-crawling" stage and has probably a very short
pelagic life, is widespread in the Canal. Another Red Sea species, Murex ramosus
has a veliger with three days of pelagic life: this species has not penetrated into the
Canal [letter by Thorson, Israel J. Zool. 21 (1972), p.375]. Probably also the wide
array of crab species which live in the littoral of the Red Sea often at fairly high
salinities did not settle in the Canal because of their planktonic larval life: only
one species of each Majidae, Grapsidae and Ocypodidae are widespread (Holthuis, 1956). After having listed 12 species of Echinodermata from the Canal (the
crinoid Lamprometra palmata has been found only at Km 146), Mortensen (1926)
discusses the fact that the widest-spread species in the Canal is the brittle star
Amphipholis squamata which has no pelagic larvae. He writes: "pelagic larvae are
not a necessary condition for rapid spreading (in the Canal)".
The combination of high salinity and turbidity is to blame for the peculiar
composition ofthe fish-fauna and of the benthic fauna in the Suez Canal.
The fishes are first of all characterized by the euryhaline-estuarine species.
These are still the numerically dominant group in the Canal. Despite the fear
expressed in the Mediterranean world that the opening of the Suez Canal would
result in an invasion by the man-eating Red Sea sharks, nothing similar happened. The Selachia are among the less-well represented animal groups in the
Canal. There is in fact only one species of bottom sharks, Himantura uarnak
which lives in the Canal. Gruvel (1936) speaks of occasional captures of hammersharks in the Bitter Lakes, but the report is not scientifically documented.
Understandably also high-sea pelagic fishes-such as Scombridae-are
poorly represented in the Canal fauna. Exceptions among the pelagic fishes are
Sardinella aurita, which penetrates from the Mediterranean, the euryhaline anchovy Engraulis enchrassicolus, Pomatomus saltatrix and the migrant Dussumieria
acuta. The second and fourth of these species were reported in the Canal waters
already by Tillier (1902).
Several families of fishes such as Labridae, Scaridae, Chaetodontidae, and
Scorpaenidae, are not represented in the Canal fauna. One is inclined to think
that the reason is first of all the lack of rocky bottoms and the associations of
animals it carries, and especially the scleractinian reefs.
There are no coral reefs in the Suez Canal. From all the wealth of skeletonforming Hydrozoa and Anthozoa, only the small gorgonarian Acabaria erythraea is found. This is an inhabitant of infralittoral boulders in the Red Sea,
exposed to fluctuating environmental condifions. Dean (1929) reports that Acabaria was found growing on a sunken dredger which had been brought to Port
Said, and eventually survived there for two months.
The Suez Canal
Sirbonic Lagoon (Bardawil), or the Qishon estuary near Haifa. He considers
among the unfavorable conditions for the plankton life in the Canal, besides the
high salinity and turbidity, "the shallowness of the Canal which alm ost excludes
the passage, or even the temporary habitation of pelagic organisms committed to
a certain degree of vertical migration". In my opinion vertical movements of the
planktonic organisms are further hindered by the saline stratification of the waters in the Canallakes.
It is interesting in tbis connection that the snail Murex anguliferus, which
hatches already in the "swimming-crawling" stage and has probably a very short
pelagic life, is widespread in the Canal. Another Red Sea species, Murex ramosus
has a veliger with three days of pelagic life: this species has not penetrated into the
Canal [letter by Thorson, Israel J. Zool. 21 (1972), p.375]. Probably also the wide
array of crab species which live in the littoral of the Red Sea often at fairly high
salinities did not settle in the Canal because of their planktonic larval life: only
one species of each Majidae, Grapsidae and Ocypodidae are widespread (Holthuis, 1956). After having listed 12 species of Echinodermata from the Canal (the
crinoid Lamprometra palmata has been found only at Km 146), Mortensen (1926)
discusses the fact that the widest-spread species in the Canal is the brittle star
Amphipholis squamata which has no pelagic larvae. He writes: "pelagic larvae are
not a necessary condition for rapid spreading (in the Canal)".
The combination of high salinity and turbidity is to blame for the peculiar
composition ofthe fish-fauna and of the benthic fauna in the Suez Canal.
The fishes are first of all characterized by the euryhaline-estuarine species.
These are still the numerically dominant group in the Canal. Despite the fear
expressed in the Mediterranean world that the opening of the Suez Canal would
result in an invasion by the man-eating Red Sea sharks, nothing similar happened. The Selachia are among the less-well represented animal groups in the
Canal. There is in fact only one species of bottom sharks, Himantura uarnak
which lives in the Canal. Gruvel (1936) speaks of occasional captures of hammersharks in the Bitter Lakes, but the report is not scientifically documented.
Understandably also high-sea pelagic fishes-such as Scombridae-are
poorly represented in the Canal fauna. Exceptions among the pelagic fishes are
Sardinella aurita, which penetrates from the Mediterranean, the euryhaline anchovy Engraulis enchrassicolus, Pomatomus saltatrix and the migrant Dussumieria
acuta. The second and fourth of these species were reported in the Canal waters
already by Tillier (1902).
Several families of fishes such as Labridae, Scaridae, Chaetodontidae, and
Scorpaenidae, are not represented in the Canal fauna. One is inclined to think
that the reason is first of all the lack of rocky bottoms and the associations of
animals it carries, and especially the scleractinian reefs.
There are no coral reefs in the Suez Canal. From all the wealth of skeletonforming Hydrozoa and Anthozoa, only the small gorgonarian Acabaria erythraea is found. This is an inhabitant of infralittoral boulders in the Red Sea,
exposed to fluctuating environmental condifions. Dean (1929) reports that Acabaria was found growing on a sunken dredger which had been brought to Port
Said, and eventually survived there for two months.