The calamari Uroteuthis duvauceli is a commercially of import piscary species in many coastal parts of the Red Sea. This species was the first recorded Lessepsian immigrant calamari species in the Suez Canal and has successfully established in its new environment. In this survey, the systematic position of this species in the Gulf of Suez, North of the Red Sea, and Suez Canal was elucidated by morphological and familial analyses. Fourteen morphometric indices were used to separate the two populations. ANCOVA revealed that there was a important separation in morphometric indices between locations ( R=0.1, P & lt ; 0.001 ) . Indexs fin length, five breadth, arm lengths, tentacle and tentacle nine length to mantle length, every bit good as five breadth index to fin length indicated the most difference between the two populations. The morphometric difference between the two populations is most likely due to differences in environmental conditions and resource handiness. Familial analysis based on the mitochondrial cytochrome B ( cyt B ) cistron revealed that the two populations are one species and have note diverged ; the intraspecies distance was really low, runing from 0 to 0.003 in U. duvauceli from the Suez Canal and Gulf of Suez.
Keywords: morphological surveies, familial analyses, Lessepsian Migration, Uroteuthis duvauceil
Over the past two decennaries, cephalopods, and calamaris in peculiar, have increased in importance as alternate resources to the traditional finfish piscary in different countries in the universe ( Boyle & A ; Pierce, 1994 ; Boyle & A ; Rodhouse, 2005 ) . Among the most of import calamari species in the commercial piscaries are the venose calamari Loligo forbesi ( Streenstrup, 1856 ) , European calamari L. vulgaris ( Lamarck, 1798 ) ( Moreno et al. , 1994 ) and Uroteuthis duvauceli ( Orbigny, 1848 ) ( Sukramongkol et al. , 2007 ) . U. duvauceli is a demersal cephalopod and its scope extends from Indian Ocean fringe, including the Red Sea and the Arabian Sea, widening due easts from Mozambique to the South China Sea and Philippines Sea, northerly to Taiwan ( Roper et al. , 1984 ) . It is abundant both in the Egyptian Red Sea seashore and Gulf of Suez. Along these seashores, the commercial gimmick of U. duvauceli is chiefly landed as bycatch of multispecies demersal trawling piscaries. Nevertheless, directed artisanal fishing takes topographic point on a broad graduated table.
U. duvauceli appeared foremost in the Suez Canal in 1998 ( Personal observation ) . The commercial piscary was really limited with gimmicks of less than 10 Kg/day in 2006. Then gimmicks increased quickly to a reported gimmick of 40 Kg/day Kg. in 2008 ( Personal observation ) . There is no dependable set downing informations on commercial gimmicks of U. duvauceli in Suez Canal as its landings are incorporated with those of cuttlefish, but there is now an established commercial market. The rapid addition in gimmicks has given rise to serious concerns about the Lessepsian migration. The gap of the Suez Canal in 1869 allowed the migration, termed Lessepsian, of 100s of Red Sea species that have become established ( Por, 1978 ) . Although, squid are extremely nomadic ( Boyle, 1990 ) , small is known about Lessepsian migration of these species. Since the work of Por ( 1978 ) , no work has been carried out to depict the in-migration and constitution of any cephalopod species in Suez Canal. Therefore we set out to document the happening and depict how successful the constitution of U. duvauceli was along the Suez Canal.
The purpose of the present survey was to clarify the morphometric relationships of U. duvauceli from Suez Canal and Gulf of Suez North of the Red Sea and see if altering of home grounds changed morphometry ; sex ratio and adulthood phases of the two populations were besides examined. Mitochondrial Deoxyribonucleic acid was used in this survey to find whether they are two species or one species.
MATERIALS AND METHODS
U. duvauceli were collected in February 2008 from two populations along the seashores of Suez on the Gulf of Suez and the seashores of Ismailia on the Suez Canal ( Figure 1 ) . The samples were caught by local fishermen utilizing industrial trawling cyberspaces in Gulf of Suez and artisanal beach Seine and gill cyberspace in Suez Canal. In entire, 374 persons were analyzed, 191 collected from Gulf of Suez and 183 from Suez Canal. All the specimens were stored at? 20 & gt ; C instantly after aggregation.
Fig. 1. Map of Egypt demoing the two trying locations in the Gulf of Suez and in the Suez Canal.
Sexual activity was established by analyzing the generative variety meats. A three-stage system based chiefly on the development of generative variety meats and place of spermatophores or eggs ( Boyle & A ; Ngoile, 1993 ) was used to measure single adulthood: I- immature, II- maturing, III- mature. Tissues from the mantle of five representative specimens were preserved in 95 % ethyl alcohol until DNA extraction.
The morphometric and meristic characters analyzed were selected and modified from those recommended by Roper and Voss ( 1983 ) and those used in old surveies ( Clarke, 1962, 1986 ; Augustyn & A ; Grant, 1988 ; Boyle & A ; Ngoile, 1993 ) . Fourteen morphometric characters were recorded ( Table 1 ) . Measurements were made on the frozen samples with a swayer or a calliper to the nearest 1 millimeter. To avoid the consequence of size difference, most characters were analyzed in proportion to the dorsal mantle length ( DML ) . A sum of 15 indices were calculated and used for analysis ( see Table 1 for abbreviations ) : MC/DML, FL/DML, FW/DML, FW/FL, HL/DML, HW/DML, HW/HL, ALI/DML, ALII/DML, ALIII/DML, ALIV/DML, TL/DML, TCL/DML, FcL/DML, GW/DML. Most of these indices have been used routinely in old morphometric surveies of calamaris ( Haefner, 1964 ; Bar? N & A ; R & gt ; , 2002b ) . Two meristic characters were besides measured ; the figure of denticles on the largest chump pealing on Arm R3 ( NDA3 ) and on the tentacle nine ( NDTC ) .
Table 1. Morphologic characters recorded on Uroteuthis duvauceli.
The relationship between dorsal mantle length ( DML ) and weight were analyzed by the power arrested development method, W=aDMLb. Analysis of covariance ( ANCOVA ) was used to prove the effects of sex and location on the length & gt ; weight relationship.
Datas were analyzed utilizing an ANCOVA to look into the presence of important differences in morphometric indices between the two locations. The same trial was used to look into the important difference of morphometric indices between the adulthood stages for both sexes. All statistical analysis was performed utilizing the bundle SYSTAT ( 2001 ) .
Deoxyribonucleic acid EXTRACTION, PCR AMPLIFICATION AND SEQUENCING
Entire Genomic Deoxyribonucleic acid of U. duvauceli samples from the Suez Canal and Gulf of Suez was extracted from a piece of 30 milligram of mantle tissue harmonizing to the standard CTAB phenol-chloroform protocol described by Roger & A ; Bendic ( 1988 ) with little alterations. The extracted DNA was visualized on agarose gels ( Sigma, M & gt ; nchen, Germany ) at 1 % in TBE buffer with 5? g/mL of ethidium bromide ( Sigma, M & gt ; nchen, Germany ) under UV visible radiation utilizing a Molecular Imager Gel Doc XR System transiluminator and the package Quantity One V 4.5.2 ( Bio-Rad, M & gt ; nchen, Germany ) . The 100-1500 bp DNA ladder ( Dominion, MBL, C? rdoba, Spain ) was used as molecular weight marker.
The pureness and measure of the Deoxyribonucleic acid obtained was measured at 260 nanometer with a NanoDrop & gt ; 1000 spectrophotometer ( Thermo Scientific, Bonn, Germany ) . The pureness of DNA was determined by ciphering the ratio of optical density at 260 nm versus 280 nanometer.
The primers used were CEF H and CEF as designed by Santaclara et Al. ( 2007 ) . The elaborations were carried out in a concluding volume of 50? L incorporating 100 nanogram of DNA templet, 5? L of 10X buffer, 2 millimeter MgCl2, 0.4? L of 100 millimeter dNTP, 4? L of a 10? M solution of each primer, and 1 unit of Taq-polymerase ( Bioline, Luckenwalde, Germany ) . PCR was performed in a Bio-Rad & gt ; MyCyclerTM thermocycler. The rhythms plan was the undermentioned: a preheating measure of 3 min at 95? C, so 35 rhythms of 30 s at 95 & gt ; C, 1 min at 50 & gt ; C, 1 min and 30 s at 72 & gt ; C, and a concluding extension measure of 7 min at 72 & gt ; C. To guarantee the proper working of PCR elaboration, PCR merchandises were loaded in agarose gels ( Sigma, M & gt ; nchen, Germany ) at 2 % in TBE buffer and 5? g/mL of ethidium bromide to let band sensing. The size of the amplified fragments was estimated from a 100 – 1500 bp molecular marker ( Dominion-MBL, C? rdoba, Spain ) .
PCR merchandises were cleaned before the sequencing reaction utilizing the NucleoSpin Extract II ( Macherey & gt ; Nagel, D & gt ; ren, Germany ) kit harmonizing to the protocol of the maker. PCR merchandises were sequenced on both waies utilizing CEQ 8800 Genetic Analysis System ( Beckman Coulter, M & gt ; nchen, Germany ) , with the primers described antecedently ( CEF H and CEF L ) and utilizing the CEQ Dye Terminator rhythm sequencing Quick Start kit ( Beckman Coulter, M & gt ; nchen, Germany ) , harmonizing to the recommendations of the maker. Nucleotide sequences obtained were corrected with Chromas 1.45 ( Mc Carthy, 1996 ) .
Sequences obtained were aligned with Clustal W ( Thompson et al. 1997 ) available in the BioEdit 7.0 plan ( Hall 1999 ) and manually checked. The sequences of U. duvauceli from the Suez Canal and Gulf of Suez were compared. The phyletic analysis was carried out with Mega 4.0 ( Tamura et al. 2007 ) utilizing the Tamura-Nei theoretical account ( Tamura and Nei 1993 ) to cipher the familial distances between sequences. Neighbor-Joining algorithm was used as theoretical account of development ; bootstrapping analysis was used to formalize the duplicability of the ramification form of the tree ( Saitou and Nei 1987 ) . Sequences obtained by Santaclara et Al ( 2007 ) from the same part of other species belonging to Uroteuthis, Loligo, Loliolus, Lolliguncula, and Alloteuthis genera were included in the analysis ( EF423052-69 ; EF4223074-77 ; EF423104-09 ; EF423116-23 ; EF423011-14 ; EF423128-35 ; EF423148-51 ; EF423158-61 ; EF423110-15 ) .
There was considerable fluctuation in organic structure size in samples between the two locations. The dorsal mantle length ( DML ) of calamari collected from the Gulf of Suez ranged between 11.0 and 22.7 centimeter ( 14.7 & gt ; 2.6, n = 114 ) in males and between 11.3 and 17.1 centimeter ( 13.2 & gt ; 1.4, n = 77 ) in female animate beings. The mantle length scope of the Suez Canal calamari samples was 8.4 & gt ; 26.5 centimeter ( 14.4 & gt ; 4.2, n = 87 ) in males and 7.5 & gt ; 19.4 centimeter ( 12.2 & gt ; 3.2, n = 96 ) in females. In the Gulf of Suez sample, males outnumbered females ; out of a entire 191 gathered animate beings, 114 were males ( 59.7 % ) and 77 were females ( 40.3 % ) . While in the Suez Canal sample, females outnumbered males out of a entire 183 gathered animate beings ; 87 were males ( 47.5 % ) and 96 were females ( 52.5 % ) .
ANCOVA indicated extremely important difference ( P & lt ; 0.001 ) between the sample collected from the Gulf of Suez and the sample collected from Suez Canal for all variables except for the indices of MC, HL, FCL and GW to dorsal mantle length ( DML ) and the index of HW to HL of each sex. All the indices for Gulf of Suez population are significantly higher ( P & lt ; 0.001 ) than those of Suez Canal population ( Table 2 ) . It should be noted that the samples included persons at different adulthood phases ( Table 3 ) . In the Gulf of Suez, 89.1 % of sampled males were at phase III while 64.9 % of sampled females were at phase II. In the Suez Canal sample, 80.5 % of sampled males were at phase III and 61.4 % of sampled females were at phase II. In
Table 2. Ranges, agencies and standard divergences of morphometric measuring ratios in Uroteuthis duvauceli, collected from Gulf of Suez and Suez Canal. ( See Table 1 for abbreviations ) .
Table 3 The per centum of Uroteuthis duvauceli samples for different adulthood phases in the two vicinities
position of these differences, the consequence was besides analyzed harmonizing to adulthood phases, but for females merely as more than 80 % of the male sample was at phase III. The analysis was performed merely for the females in adulthood phases II & A ; III, as persons at phase I were excessively little to be included in the analysis ( n= 4 & A ; 2 for Gulf of Suez and Suez Canal, severally ) . Between the two locations, there was no important difference in all indices ( P & gt ; 0.001 ) between phases II and III except for MC index ( P & lt ; 0.001 ) . MC was significantly higher in phase II ( 59.0 % & gt ; 2.0 & A ; 58.6 % & gt ; 4.9 for Gulf of Suez and Suez Canal samples, severally ) than in phase III ( 55.5 % & gt ; 2.1 & A ; 49.2 % & gt ; 2.3 for Gulf of Suez and Suez Canal samples, severally ) .
There was no significantly different ( P & gt ; 0.001 ) for the two measured meristic characters between the calamaris collected from the Gulf of Suez and those collected from Suez Canal for each sex. The average denticle figure on 3rd arm chump rings was 8.56 & gt ; 0.85 ( scope: 8-12 ) for males collected from Gulf of Suez and 8.56 & gt ; 2.1 ( scope: 6-12 ) for males collected from Suez Canal, while the mean was 8.46 & gt ; 0.52 ( scope: 8-10 ) for females collected from Gulf of Suez and 8.90 & gt ; 1.2 ( scope: 6-11 ) for females collected from Suez Canal. The average denticle figure on tentacle nine chump rings was 18.88 & gt ; 2.1 ( scope: 11-24 ) for males collected from Gulf of Suez and 18.0 & gt ; 3.2 ( scope: 11-28 ) for males collected from Suez Canal, while the mean was 20.0 & gt ; 3.1 ( scope: 13-28 ) for females collected from Gulf of Suez and 19.0 & gt ; 3.2 ( scope: 10-24 ) for females collected from Suez Canal.
The length & gt ; weight relationship of U. duvauceli was described by the undermentioned equations:
W = 0.120 DML 2.32 r2 = 0.96 for Gulf of Suez males
W = 0.67 DML 2.59 r2 = 0.88 for Gulf of Suez females
W = 0.120 DML 2.23 r2 = 0.98 for Suez Canal males
W = 0.084 DML 2.46 r2 = 0.96 for Suez Canal females
All length-weight relationships were extremely important ( P & lt ; 0.05 ) with R values greater than 0.80. The arrested development coefficient ( B ) of each sex in the two vicinities is significantly different from 3. ANCOVA revealed that the arrested development inclines did non differ significantly for both sexes between the two vicinities ( P & gt ; 0.05 ) . While the inclines for males and females in the two locations were significantly different ( P & lt ; 0.05 ) .
The sequences obtained in the present work were deposited in the NCBI database with accession Numberss FJ899694 to FJ899704, consecutively ( 11 sequences ) . Lolignidae sequences reported by Santaclara et Al. ( 2007 ) were included in the distance matrix for the building of the phyletic tree and Todarodes sagittatus sequence was added as an out group.
All sequences belonging to the same species were grouped in the same bunch. The tree obtained had a good supported genus-level topology as all the species from the genera Loligo, Lolliguncula, Loliolus, Uroteuthis and Alloteuthis appeared good grouped in bunchs. Furthermore, the tree topology was in harmony with the phyletic and biogeographic surveies reported by Anderson ( 2000a & A ; B ) for species belonging to the Loliginidae household utilizing 16S rRNA and COI mitochondrial molecular markers. In the present work, the species were besides grouped on footing of their geographic distribution and the undermentioned three major clades could be discerned: West Atlantic and East Pacific species ( L. gahi, L. opalescens, L. pealei, L. diomedeae, L. panamensis and L. bleekeri ) , East Atlantic species ( L. reynaudi, L. vulgaris, L. forbesi, and A. subulata ) and Indo-West Pacific species ( L. japonica, U. duvaucelli, U. chinensis ) ( Figure 2 ) . The bootstrap values of subdivisions at degree species were 99-100 % , reflecting the hardiness of the phyletic tree.
The familial distances between the obtained cytochrome B cistron sequences reveal that the intraspecies distance mean was 0.002 & gt ; 0.000, whereas the interspecies distance was two orders of magnitude higher holding a value of 0.134 & gt ; 0.009. The average interspecies distance between species of the same genus was 0.056 & gt ; 0.004. These estimations show that the intraspecies distances are really low, runing from 0 to 0.003 in U. duvauceli from the Suez Canal and Gulf of Suez. Distance matrix tonss for the Uroteuthis genus vary between 0.134 and 0.136, as shown in Table 4. When species from different genera are compared with U. duvauceli, these distance tonss are higher, for illustration in the instance of Loligo, Loliolus, Lolliguncula, Alloteuthis and Uroteuthis chinensis species where the tonss range from 0.134 to 0.197.
Fig. 2. Phylogenetic tree of household Loliginidae demoing the relationships among of the species, carried from the alliance of cytochrome B cistron.
In the present survey, two populations of the calamari U. duvauceli were compared morphologically and genetically. Although the two populations were found to be genetically really similar ; there was important separation in most of their morphometric indices. The multivariate analysis of morphological differences shows clear separation between the two population ( ANCOVA, R=0.1, P & gt ; 0.001 ) . Nine morphometric indices from a entire 14 could be used to efficaciously separate the two populations. ANCOVA indicated that five length, five breadth, arm lengths, tentacle, and tentacle nine length to mantle length indices, every bit good as five breadth index to fin length were the indices that contributed most to the difference between two populations. These indices are significantly higher in Gulf of Suez population than in those at Suez Canal. While it is common for the morphometric characters of cephalopods to change harmonizing to geographical location ( Boyle & A ; Ngoile, 1993 ; Carvalho & A ; Nigmatullin, 1998 ) , it has besides been found that this variableness could be undistinguished among distant populations of some loliginid species ( Cohen, 1976 ) . In this survey, it is improbable that the difference in morphometric characters of U. duvauceli between two the different vicinities can be accounted for the differences in adulthood phase composing as most samples contained persons of similar adulthood provinces. Most male persons from two vicinities were at phase III, while most female persons from two vicinities were at phase II. This illation is farther supported by the observation that most of the morphometric indices for the females were non significantly different between phases II and III. Therefore, the ascertained difference in morphometric characters of two U. duvauceli populations is most likely due to the difference in environmental conditions and resources handiness. The present survey besides indicated the presence of considerable fluctuations in the organic structure construction between the two locations. Population size in Suez Canal was comparatively larger than in Gulf of Suez ( maximal size 26.5 centimeter in mantle length for Suez Canal population while 22.7 centimeter for Gulf of Suez population ) . Geographic fluctuations in population construction have been reported in other cephalopod species and were normally attributed to the consequence of temperature on growing rate ( Pierce et al. , 1994 ; Jackson et al. , 1997 ; Forsyth, 2004 ; Pecl, 2004 ) . In the present survey, it is improbable that size differences can be accounted for the consequence of H2O temperatures on growing rate ; there is no big difference in surface saltwater temperature between Gulf of Suez and Suez Canal. Summer sea-surface temperatures in the Gulf of Suez reach 30 & gt ; C ( Mahmoud, 2003 ) compared to 29 & gt ; C for Suez Canal ( Madkour et al. , 2007 ) . The possible factor to account for this difference could be fluctuation in nutrient copiousness. On the other manus, the Gulf of Suez population was observed to hold longer tentacles and weaponries and longer tentacular nines compared to those from the Suez Canal. Tentacles and weaponries are specialized for prey gaining control. It has been suggested that, since tentacles and tentacular nines are the variety meats which cephalopods use to capture their quarry, persons with relatively longer nines might capture larger quarry, hence leting them to turn relatively faster ( Mangold-Wirz, 1963 ; Bello & A ; Motolese, 1983 B ) . Besides, long tentacles and weaponries may ease prey gaining control if the onslaught distance is longer ( Bello, 1991 ) . Longer tentacles and weaponries in the Gulf of Suez samples compared to those in Suez Canal are believed to be an advantage in capturing more nutrient for growing. Longer nines in the Gulf of Suez besides might capture larger quarry, hence leting them to turn relatively faster. Prey handiness has been reported to impact the size construction of some squid species as it influences growing ( O’Dor et al. , 1980 ; Brodziak & A ; Macy, 1996 ) . Consequently, it could be hypothesized that the fluctuations in population construction and morphometric characters of the two populations observed in this survey might be related to differences in environmental conditions between Gulf of Suez and Suez Canal. The first is really nutrient-limited, it has been called an oligotrophic sea ( Baars et al. , 1998 ; Mahmoud, 2003 ) while the Suez Canal has been called an eutrophic sea ( Madkour et al. , 2007 ) .
It is possible that the difference in sex ratio between two vicinities could be due to type of cogwheel instead than to population construction and the little sample sizes need to be taken into consideration. In Suez Canal U. duvauceli were sampled chiefly as a bycatch of artisanal beach Seine and gill cyberspace, whereas in the Gulf of Suez, calamari were sampled by industrial trawling techniques.
The computation of the length-weight relationship showed that the length advocate for weight was less than the expected cubic ( b=3 ) relationship in the two vicinities, bespeaking that weight additions more easy than a corresponding addition in unit length. Meanwhile, the inclines from the arrested development equations did non differ significantly between the two populations ( ANCOVA ; P & gt ; 0.05 ) , bespeaking that Gulf of Suez population have the same weight of Suez Canal population at a given length.
Meanwhile, the inclines from the arrested development equations between the two sexes in the two locations differ significantly ( ANCOVA ; P & lt ; 0.05 ) , bespeaking that females are heavier ( b= 2.59 & A ; 2.46 in Gulf of Suez and Suez Canal populations, severally ) than males ( b= 2.32 & A ; 2.23 in Gulf of Suez and Suez Canal populations, severally ) of the same mantle length. This agrees with similar differences observed in other loliginids ( Rao, 1988 ; Coelho et al. , 1994 ; Hendrickson, 2004 ) . The larger weight of female may be related to the fact that the mass of the sex gland and accessary generative variety meats constitute a greater proportion of the organic structure mass in females than males at larger sizes, therefore for a given length, a female will be heavier than male.
The figure of dentitions on the arm chump ring and tentacle nine was antecedently used to separate calamari species ( Gray, 1849 ; Hoyle, 1885 ) . The figure of dentitions ( 6-12 ) on 3rd arm chumps in the two populations is within the reported scopes ( Roper et al. , 1984 ; Riad, 2008 ) . While, the figure of 11-28 on tentacle nine exceeds the reported scopes which ranges from 14-17 ( Roper et al. , 1984 ) and 14-17 ( Riad, 2008 ) for the same species. Meristic characters are extremely sensitive to environmental fluctuations during their formation ( Barlow, 1961 ) and teeth figure is non a good character for species designation. In the present survey the dentitions figure was a good diagnostic character for U. duvauceli, since there was no important difference between the two agencies of dentitions figure on 3rd arm and tentacle nine chump and their scopes overlap between the two populations.
The mitochondrial cytochrome B ( cyt B ) cistron has been widely used as a molecular marker for familial designation of a great figure of species belonging to different taxa, such as anchovies ( Santaclara et al. , 2006a ) , pilchards ( Jerome et al. , 2003 ) , pelecypods ( Santaclara et al. , 2006b ; Espi? Eira et al. , 2009 ) , hakes ( Perez & A ; Garcia-Vazquez, 2004 ) , goosefishs ( Espi? Eira et al. , 2008a ) , gadoid ( Calo-mata et al. , 2003 ) and flatfishes ( Espi? Eira et al. , 2008b ) . This cistron has besides been applied for the designation of cephalopod species ( Anderson 2000a, 2000b ; Santaclara et al. , 2007 ) .
Mitochondrial DNA has assorted advantages in comparing to atomic: maternal heritage ; 100s to 1000s of transcripts per cell ; absence of recombination ; high and changeless rate of evolutionary alteration ( Mackie et al. , 1999 ) . All these features allow the familial designation of closely related species, for case, species belonging to a concrete genus.
The set of primers CEF H and CEF L used in the current survey was described by Santaclara et Al. ( 2007 ) . The Neighbor-Joining distance-based phyletic tree building with Tamura-Nei nucleotide permutation theoretical account was applied.
The familial grounds indicates that U. duvauceli from the Suez Canal and Gulf of Suez are one species. Deoxyribonucleic acid sequence divergency in the cyt B cistron was compared for U. duvauceli from these two geographic countries. In the mitochondrial sequences insufficient accumulated permutations were found and for this ground low degrees of interspecies polymorphism existed which did non allow the assignment of the samples to two different species. Therefore, our phyletic analysis informations revealed that these stocks can non be distinguished.
In decision, U. duvauceli was non merely the first recorded Lessepsian immigrants squid species in Suez Canal but besides it has successfully established itself in the environment. The studied morphometric indices provide utile information for separating the two U. duvauceli populations but did non corroborate that these two populations are the same species. The difference in growing form between the two populations could be of adaptative significance for the end point alterations in environmental conditions. Genetic survey of the mitochondrial cistrons of U. duvauceli in the two vicinities clearly reveals that they are the same species.
I am highly grateful to Dr. John Scarpa for his valuable unfavorable judgment on bill of exchanges of this paper. The writers would wish to besides thank Dr. Rafik Riad ( National Institute of Oceanography and Fisheries, Alexandria, Egypt ) for aid with roll uping squid samples from Gulf of Suez.