Tag Archives: Mediterranean Sea

Some traits of zooplankton in the wave-breaking region of rocky and sandy shores of the eastern Libyan Mediterranean Sea (Published)

Zooplankton in seawater samples collected from two wave-breaking regions at the rocky shores of Al-Satah and Al-Warsh, and the shore of a brackish lagoon (Um-Hufayan) devoid of strong waves, during summer, fall, winter, and spring 2019/2020, and filtered through 600µ. 300µ. 75µ, and 40µ sieves stacked on top of each other, were investigated qualitatively and quantitatively. The repeated bombardment of waves on rocky shores of Al-Satah, Al-Warsh, that normally continue for days, had no deleterious effect on plankton. Altogether, 45 zooplankton species or lower-taxa were encountered during the study, the overall concentration of zooplankton was 23199 to 23764 individuals per m3. Zooplankton diversity indices by major-group or major-taxon, species or lower-taxa, site, season, and sieve mesh were established and discussed in terms of salinity, runoff regime, type of bottom substratum and hydrographic conditions of waves and winds. In general, the descending order of zooplankton richness by the number of species per major-groups or major-taxa was Arthropoda, Protozoa, Chordata, Coelenterata (Cnidaria and Ctenophora), Mollusca, Annelida, Gelatinous species, Rotifera, Nematoda, Chaetognatha, and Echinodermata. Abundance by the number of individuals per major-groups or major-taxa was of the order Arthropoda, Protozoa, Mollusca, Annelida, Chordata, Platyhelminthes, Coelenterata, Nematoda, Rotifera, Chaetognatha, Echinodermata, and Gelatinous species.

Citation: Nesreen Ahmed Atea, Sayed Mohamed Ali, Ramadan A. S. Ali(2022) Some traits of zooplankton in the wave-breaking region of rocky and sandy shores of the eastern Libyan Mediterranean Sea, International Research Journal of Natural Sciences, Vol.10, No.1, pp.1-21

Keywords: Mediterranean Sea, Phytoplankton, SURF, Zooplankton, micro-plastics, wave-breaking

Morphology of Phorcus turbinatus (Gastropoda) in the Eastern Libyan Mediterranean Sea (Published)

Three hundred and five Phorcus turbinatus collected from the rocky littorals of Al-Haneah and Susah, eastern Libya’s Mediterranean Sea, were used to establish 15 measured shell-parameters and 18 calculated shell-shape indicators, which were then compared between sites, and related to shell height (HBA) and length of shell base (LB) by regression equations to find out how they vary as the animal grows. Al-Haneah P. turbinatus was larger than Susah’s (HBA = 13.729 and 12.818mm consecutively, corresponding to total weights (TW) of 3.766 and 3.179gm). As a result, the majority of Al-Haneah’s P. turbinatus measured parameters were of greater magnitude. The exponents “b” of the TW-HBA power regressions indicated negative allometric growth, while that of TW-LB indicated positive allometry. The values of the shell shape indicators of P. turbinatus in both sites were close, the shell apex was tilted to the front and to the left, the shell base was almost circular, the opening was slightly oval, and the operculum was circular. All the measured parameters, and most of the shell-shape indicators, increased with growth.

Citation: Adam Ali Faidallah, Ramadan A. S. Ali, Sayed Mohamed Ali, (2021) Morphology of Phorcus turbinatus (Gastropoda) in the Eastern Libyan Mediterranean Sea, International Research Journal of Natural Sciences, Vol.9, No.1, pp.12-18

 

Keywords: Mediterranean Sea, Monodonta turbinata, Phorcus turbinatus, morphometry, shell shape

Some Aspects of the Reproductive Biology of the Long Fin Gurnard Aspitrigla Obscura (Linnaeus, 1764) In Dernah Coast, Eastern Libya (Published)

The reproductive biology of 389 specimens of Aspitrigla obscura (Family: Triglidae) obtained from catches collected by gill and trammel nets from Dernah coast, eastern Libya, Mediterranean Sea, was established during a one year study period (April, 2013 to January 2014). There were monthly variations in sex ratio between males (193 fish = 49.6%) and females (196 fish = 50.4%). The overall sex ratio was 1: 1.02 in favor of females. The breeding season extended from December to May. Oocyte diameters increased gradually and progressively during October (87 ± 4.27 μm) to December (250 ± 40.38 μm), then recorded highest values of 367 ± 41.39 in January to 567 ± 21.14 in May. The average absolute fecundity ranged from 535±33.9 in October to 8891±1231.4 in May for fish of total length ranging from 19.1 to 33.9 cm.. Overall absolute fecundity was 5875±503.1, whereas overall relative fecundity was 176±23.3cm-1.

Keywords: Aspitrigla Obscura, Mediterranean Sea, Reproductive Biology, Triglidae, eastern Libya, the Long Fin Gurnard

Historical records of the Lessepsian migrants, the dusky spinefoot fish Siganus luridus (Ruppell, 1829) and the marbled spinefoot S. rivulatus (Forsskal, 1775), in the eastern coast of Libya Mediterranean Sea (Published)

A brief comprehensive account on Lessepsian migration is given in the present study. Earlier publications reported that the dusky spinefoot fish Siganus luridus (Ruppell, 1829) and the marbled spinefoot S. rivulatus (Forsskal,1775) were recorded in Libya Mediterranean coastal waters for the first time in 1968 and 1970 in order. The present study however, shows that they were in Libya since the 1950ties: in Tobrok in 1950, in Darna in 1954 and in Benghazi in 1960. These findings were based on questionnaires filled by middle age and elderly fishers (located in Tobrok, Ein Ghazala, At Timimi, Ras Ettin, Darna, Khalij Bumba, Susah, Benghazi fishing sites on eastern Libya), on reports and documents of  “Darna Fishers Trade Union”, “Tobrok Fishers Trade Union” and “Office of Marine Resources in Darna” and on consultations with members of these institutions. Estimates of monthly catch from the two Siganids per fisher per fishing site shortly after they established themselves in the eastern coast ranged between 2 to 60 kg (average = 17.25 kg) with S. luridus been more abundant than S. rivulatus. Both fishes are residents of shallow coastal water, 1 – 8 meters deep (average = 4.25 meters).  Average total length of the initial population the two Siganids was 23.44 cm. Questionnairing fishers, in particularly elderly ones, is a powerful technique for establishing records of first entry and scientists are encouraged to use it. However, this technique is limited by the scarcity in elderly fishermen who are inventory of information of the old times but are unfortunately eliminated through time.

Keywords: Lessepsian migrants, Mediterranean Sea, Siganus luridus, Siganus rivulatus, dusky spinefoot fish, eastern Libya, marbled spinefoot

Historical records of the Lessepsian migrants, the dusky spinefoot fish Siganus luridus (Ruppell, 1829) and the marbled spinefoot S. rivulatus (Forsskal, 1775), in the eastern coast of Libya Mediterranean Sea (Published)

A brief comprehensive account on Lessepsian migration is given in the present study. Earlier publications reported that the dusky spinefoot fish Siganus luridus (Ruppell, 1829) and the marbled spinefoot S. rivulatus (Forsskal,1775) were recorded in Libya Mediterranean coastal waters for the first time in 1968 and 1970 in order. The present study however, shows that they were in Libya since the 1950ties: in Tobrok in 1950, in Darna in 1954 and in Benghazi in 1960. These findings were based on questionnaires filled by middle age and elderly fishers (located in Tobrok, Ein Ghazala, At Timimi, Ras Ettin, Darna, Khalij Bumba, Susah, Benghazi fishing sites on eastern Libya), on reports and documents of  “Darna Fishers Trade Union”, “Tobrok Fishers Trade Union” and “Office of Marine Resources in Darna” and on consultations with members of these institutions. Estimates of monthly catch from the two Siganids per fisher per fishing site shortly after they established themselves in the eastern coast ranged between 2 to 60 kg (average = 17.25 kg) with S. luridus been more abundant than S. rivulatus. Both fishes are residents of shallow coastal water, 1 – 8 meters deep (average = 4.25 meters).  Average total length of the initial population the two Siganids was 23.44 cm. Questionnairing fishers, in particularly elderly ones, is a powerful new technique for establishing more accurate records of first entry than that given by scientist. However, this technique is limited by the scarcity in elderly fishermen who are inventory of information of the old times but are unfortunately eliminated through time. Yet the approach may not be too late for many Lessepsian fishes and scientists are encouraged to use it.

Keywords: Lessepsian migrants, Mediterranean Sea, Siganus luridus, Siganus rivulatus, dusky spinefoot fish, eastern Libya, marbled spinefoot

Length-Weight Relationship and Growth of the Striped Seabream Lithognathus Mormyrus (Linnaeus, 1758) From Al Haneah Fish Landing Site, Mediterranean Sea, Eastern Libya (Published)

Length-weight relationship and growth characteristics of the striped Seabream Lithognathus mormyrus (Linnaeus, 1758) was established using 164 fish collected from Al-Haneah (eastern Libya, Mediterranean Sea) artisanal catch during March  to October 2015. The power relationship between total weight (W in gm) and total length (L in cm) for L.  mormyrus was highly isometric: W = 0.0132L^3.0008   (R2 = 0.8291). The length based von Bertalanffy equation of the order: Lt = L∞ (1 – exp (-K (t –t0 ))) was Lt = 30.465 (1 – exp (-0.159 (t + 2.5435))). The weight based equation was Wt =  374.2523  (1 – exp (- 0.159 (t  + 2.5435))) 3.0008. The growth index was low: ɸ = 2.169.

Keywords: Length-Weight Relationship, Libya., Lithognathus Mormyrus, Mediterranean Sea, Sand Steenbras, Striped Seabream, Von Bertalanffy Growth Equation