Length-weight relationship and condition factor of three endemic fish species, Ponticola bathybius, Neogobius caspius and N. pallasi (Perciformes: Gobiidae) from the Southern Caspian Sea basin, Iran

In this study, the length-weight relationships (LWRs) and condition factors were estimated for 445 specimens belonging to three gobiid species viz. Ponticola bathybius (Kessler, 1877), Neogobius caspius (Eichwald, 1831) and Neogobius pallasi (Berg, 1916) from the Southern Caspian Sea basin. Total length and total weight of the examined specimens ranged 4.9-28.3 cm and 0.64-263.4 g, respectively. The length-weight parameter b of the studied species found between 2.47 (N. caspius) and 3.45 (N. pallasi) with r2 ranging 0.831 to 0.988. LWR and K parameters are reported first time for N. pallasi from the Caspian Sea basin. The condition factor estimated was calculated from 0.94 (N. pallasi) to 0.98 (N. caspius) and 1.00 (P. bathybius). The basic biological information on the LWRs of these three gobies will be useful as baseline information for further biological research in the region.

Increased haplotype diversity of Emys orbicularis (Linnaeus, 1758) (Reptilia: Emydidae) in northern Iran

Emys orbicularis is an Old World terrapin that has a wide distribution range from Russia to Iran, Europe, and Northwestern Africa. In this study, we compare the Southern Caspian Sea lineage (in northern Iran) of E. orbicularis with other lineages of this species in Europe using the Cyt b gene fragment. Based on our results, the Caspian Sea lineage shows a high value of PhiPT (> 0.87) in comparison with other lineages that means the lineage isolated more from other lineages. Molecular phylogenetic analyses indicate that Iranian and Caucasus lineages are distinct from other lineages. The Mantel test confirmed the pattern of isolation by distance for the lineages from Western Europe to Asia. These results indicate that the Iranian population has a long history in the Caucasian and Southern Caspian Sea region (> 6 MYA). There are many reasons to conserve this species in Iran, as high inbreeding rates, low genetic variability, accidental events on the roads, and pet trade must be considered in future conservation action plans.

Currents Generated by the Sea Breeze in the Southern Caspian Sea

The sea breeze system is the dominant atmospheric forcing at high frequency in the southern Caspian Sea. Here, we describe and interpret current meter observations on the continental margins of the southern Caspian from 2013 to 2014 to identify and characterize the water column's response to the sea breeze system. Time series analysis provides evidence for diurnal baroclinic current signals of O (0.02 m s−1) and surface height changes of O (0.03 m). A two-layer model, including interfacial and bottom friction is developed to further investigate the sea breeze response. This model is able to reproduce the structure, amplitudes, and phases of observed diurnal current fluctuations, explaining half of the variance in observational current response at frequencies at 1 cpd and higher. The sea breeze response thus results in a “tide-like” daily cycle which is actually linked to the local forcing all along the southern Caspian coast.