142
The Migrant Biota
eommunities, some of them even oeeupied dominant positions ... There is
evidenee that there is no regress in the building up of populations of the new
immigrants".
Some data exist from three ecologieal eategories of migrants, namely: demersal fish; infralittoral level-bottom maerofauna; and intertidal roek-dwelling
fauna.
The role played by the fish among the Lessepsian migrants has been shown to
be very important. According to Ben-Tuvia (1972), 11.6 % of the fish species along
the Israel eoast are immigrants from the Red Sea. No less than 21 of the 27 species
of High Probability Lessepsian migrants appear regularly in eommereial eatehes.
According to George and Athanassiou (1966), 5 of the 26 eommercially important
fishes of the beaeh seine eatehes of the Gulf of St. George in Lebanon are immigrants.
The analysis of the eateh statistics of the Israel fisheries gives very interesting
information eoneeming a few migrant species sueh as Upeneus moluccensis, Upeneus asymmetricus, Saurida undosquamis, Leiognathus klunzingeri, Sphyraena
chrysotaenia, Atule djeddaba, Dussumieria acuta, Pranesus pinguis, and H emiramphus far. While the pelagie fishery landings are mostly eomposed of the autoehthonous species Sardinella aurita (Ben-Tuvia, 1973), the pelagie Lessepsian migrants play ehiefly a role offood basis for the big open sea predators. Ben-Tuvia
(1973) quotes the work done by Bograd-Zismann between 1963-1970 on the food
ehain ofthe little tuna Euthynnus alleteratus. Several Lessepsian species oeeurred
in the stomaeh eontents of this species, especially in younger age groups. H emiramphus far made up 3% of the food of older specimens of Euthynnus. Another
species, Pranesus pinguis. was an important food item in the month of January.
Among the trawl eatehes of demersal fish there are several species of migrants
of the highest economieal value (here the statistics enabled some analytical eonclusions). Especially important are the indications eoncerning direct or indirect
eompetition between species.
The first pair of species whieh has been investigated are from the Mullidae
(goat fishes): the loeal Mullus barbatus (the red mullet), and the immigrant Upeneus moluccensis (the yellow-striped goat fish). Wirszubski (1953) eonsidered that
10-15% ofthe eateh ofMullidae in the years 1946-47 and 1949-1950 was made
up ofthe immigrant species. According to Oren (1957), following an exeeptionally
warm winter the eateh of Upeneus moluccensis was 83% of the mullet eatehes of
1956. Sinee 1954 the Lessepsian migrant species has maintained a more or less
permanent pereentage of 30% (Ben-Tuvia, 1973). There are indieations that temperature plays an important role in the quantitative relationship between Mullus
and Upeneus.1t is interesting also to note (Ben-Tuvia, 1973) that Mullus remained
eonsistently dominant on bottoms deeper than 70 m.
A similar relationship was studied by Ben-Yami and Glaser (1974) and is the
first attempt to reaeh eonclusions about the niehe eompetition between a Ioeal
species and an invader: The invader Saurida undosquamis was first reported in the
Mediterranean in 1952; in 1953 it appeared in trawl eatehes in the EI Arish-Gaza
area (Ben-Tuvia, personal eommunication).
In thewinter of 1954-55 the amount oflizard fishes inereased dramatically and
since then it has eonstituted 20% of the trawl eatehes and 11 % of the total
landings ofthe Israel sea fisheries (Ben-Yami and Glaser, 1974). Saurida does not
The Migrant Biota
eommunities, some of them even oeeupied dominant positions ... There is
evidenee that there is no regress in the building up of populations of the new
immigrants".
Some data exist from three ecologieal eategories of migrants, namely: demersal fish; infralittoral level-bottom maerofauna; and intertidal roek-dwelling
fauna.
The role played by the fish among the Lessepsian migrants has been shown to
be very important. According to Ben-Tuvia (1972), 11.6 % of the fish species along
the Israel eoast are immigrants from the Red Sea. No less than 21 of the 27 species
of High Probability Lessepsian migrants appear regularly in eommereial eatehes.
According to George and Athanassiou (1966), 5 of the 26 eommercially important
fishes of the beaeh seine eatehes of the Gulf of St. George in Lebanon are immigrants.
The analysis of the eateh statistics of the Israel fisheries gives very interesting
information eoneeming a few migrant species sueh as Upeneus moluccensis, Upeneus asymmetricus, Saurida undosquamis, Leiognathus klunzingeri, Sphyraena
chrysotaenia, Atule djeddaba, Dussumieria acuta, Pranesus pinguis, and H emiramphus far. While the pelagie fishery landings are mostly eomposed of the autoehthonous species Sardinella aurita (Ben-Tuvia, 1973), the pelagie Lessepsian migrants play ehiefly a role offood basis for the big open sea predators. Ben-Tuvia
(1973) quotes the work done by Bograd-Zismann between 1963-1970 on the food
ehain ofthe little tuna Euthynnus alleteratus. Several Lessepsian species oeeurred
in the stomaeh eontents of this species, especially in younger age groups. H emiramphus far made up 3% of the food of older specimens of Euthynnus. Another
species, Pranesus pinguis. was an important food item in the month of January.
Among the trawl eatehes of demersal fish there are several species of migrants
of the highest economieal value (here the statistics enabled some analytical eonclusions). Especially important are the indications eoncerning direct or indirect
eompetition between species.
The first pair of species whieh has been investigated are from the Mullidae
(goat fishes): the loeal Mullus barbatus (the red mullet), and the immigrant Upeneus moluccensis (the yellow-striped goat fish). Wirszubski (1953) eonsidered that
10-15% ofthe eateh ofMullidae in the years 1946-47 and 1949-1950 was made
up ofthe immigrant species. According to Oren (1957), following an exeeptionally
warm winter the eateh of Upeneus moluccensis was 83% of the mullet eatehes of
1956. Sinee 1954 the Lessepsian migrant species has maintained a more or less
permanent pereentage of 30% (Ben-Tuvia, 1973). There are indieations that temperature plays an important role in the quantitative relationship between Mullus
and Upeneus.1t is interesting also to note (Ben-Tuvia, 1973) that Mullus remained
eonsistently dominant on bottoms deeper than 70 m.
A similar relationship was studied by Ben-Yami and Glaser (1974) and is the
first attempt to reaeh eonclusions about the niehe eompetition between a Ioeal
species and an invader: The invader Saurida undosquamis was first reported in the
Mediterranean in 1952; in 1953 it appeared in trawl eatehes in the EI Arish-Gaza
area (Ben-Tuvia, personal eommunication).
In thewinter of 1954-55 the amount oflizard fishes inereased dramatically and
since then it has eonstituted 20% of the trawl eatehes and 11 % of the total
landings ofthe Israel sea fisheries (Ben-Yami and Glaser, 1974). Saurida does not