Reproduction biology of CASPIAN SAND GOBY, Neogobius fluviatilis pallasi, was studied during July 2004 to June 2005. Thirty fish were caught each month and their total length (TL), standard length (SL) and total weight were measured. Fish were then dissected and their liver and gonads were weighed. The average TL, SL and total weight were 102.85 6.7 mm, 86 5.1 mm and 12.23 3.05 g. For mature specimens, the average total length and weight in males (126.2 and 26.26) were more than females (106.3 and 12.65). Length – weight relationship showed isometric growth in this species. The estimated sex ratio of 1♀: 1.04♂ wasn’t significantly different from 1:1 (P<0.05), but at the start of reproduction in April, male ratio increased and in May, female ratio was more than male. Gonadosomatic index (GSI) changed when considerable changes in salinity, pH, temperature, and turbidity of water during March to April increased to maximum degree in April observed and decreased until July. Hepato-somatic index (HSI) decreased during this time, too. It seems that females mature in lower age. Results show that this subspecies breeds once a year and has relatively long reproductive season.

CASPIAN Sea SAND GOBY, Neogobius fluviatilis pallasi (Berg, 1916), due to lack of commercial exploitation and richness of their population, have an important role in food chain of CASPIAN Sea. This study carried out during July 2004 to June 2005 and documents their diet in shallow coastal waters of Noor at southern part of CASPIAN Sea. In this regard, diet regime of 240 specimens was analyzed. According to results of present study, the relative length of gut was 0.576±0.099, Vacuity Index for all of specimens was 39.58, so this subspecies classified in relatively gluttonous group. While matured males show increased value of this index during reproduction season, so they can be categorised as medium feeders group. In April, May and June Gastrosomatic Indices were higher than other months. Also study on composition of digestive system, shows that CASPIAN SAND GOBY was fed on nine different kind of food with Preferences following food: 1- Amphipods from order Amphipoda, 2 - fish larvae, 3- Barnacels from family Balanidae, 4 - Shrimps from family Plaemonidae, 5 - Bivalves from family Mytilidae, 6 - Round crabs from family Xanthidae, 7 - Bivalves from family Cardidae, 8 - Fish eggs, 9- Wormes from order Oligochaeta. In the basis of food preference indices, non of mentioned organism were considered as main food item during the study period. It seems that CASPIAN SAND GOBY diet has been changed during different seasons, according to adaptation with environmental changes.

CASPIAN SAND GOBY, Neogobius jluviatilis pallasi belongs to Gobiidae family. Because of their abundance in CASPIAN Sea, they have important role in the sea food chain in this area. This study was conducted from October 2005 to September 2006 in southwest coasts of the CASPIAN Sea in Guilan province. Samples were collected monthly from four stations (Astara, Anzali, Chamkhaleh and Chaboksar coasts) from coastal areas to waters 15meters deep using bottom trawl. Result of differential function analyses on corrected morphometric statistic showed three functions 51.3%, 28.4% and 20.3%, respectively, and sum of differentiative function percentage was 80% which proved difference among groups. The functions showed that samples in Astara station were completely different from other regions while they were similar to Anzali station only in some sampling points. Chamkhaleh and Astara stations were the same but Chaboksar station was a separated group. Analysis of differential functions for studied characteristics included on average 86.3% of the population with most of it belonging to Astara station (93.3%) and Anzali (90%). The minimum amount belonged to Chamkhaleh with 79.3%. The results showed that Neogobiusjluviatilis pallasi probably has three different populations in Astara, Anzali, Chamkhaleh and Chaboksar populations.

This study carried out on distribution of SAND GOBY in the south west coast of the CASPIAN Sea (from Astara to Chaboksar) from October 2005 to September 2006 during 1 year. Samples were collected from 3 stations (Astara, Anzali, and Chaboksar coasts) from 0 to 15 meters of depth. They have been captured monthly by bottom trawl. It has been determined CASPIAN SAND GOBY density per trawling and its relative and absolute abundance in station. The minimum abundance (7.70% of total catch) took place in the study in January 2006 and the maximum abundance (32.85% of total catch) in December 2005. The minimum and maximum catch for SAND gobies made up 9.98% and 41.64%, of the total catch respectively for CASPIAN Sea gobies area was recorded. A significant decrease in density of SAND gobies specimens was observed with an increase in depth. Among studied coast, Abundance ofN. fluviatiliswas the most amount in Astara Coast. An interacting effect among the different factors was also seen (non-parametric Spearsman, s test) indicating that among depth, sampling station and depth-sampling station only depth influences on absolute density of the fish. Correlation coefficient betweenN. fluviatilis pallasi abundance and biotic factors and abiotic factors were tested using Spearman non-parametric test. Significant correlation was observed between abundance of SAND GOBY and factors of total catch (0.703), abundance of gobies (0.672), temperature (0.683) and dissolved oxygen (0.419) at 99% confidence level, however negative correlations existed between abundance of SAND GOBY and zooplankton (-0.300) and phytoplanktons (-0.388)). No correlations were observed between abundance of SAND GOBY, N. fluviatilis pallasi and other studied parameters. The closest linked factor (PCA) to absolute abundance and biomass of SAND gobies (biomass) were gobies, total catch, temperature and dissolved oxygen in order of their reference.

‏‏The SAND GOBY Neogobius pallasi (Berg, 1916) belongs to the family Gobiidae which has a wide distribution in the south of the CASPIAN Sea basin and its tributaries. The purpose of this study was to determine some of the morphological parameters of SAND GOBY and the appropriate characteristics for the separation of populations in Kaboodval, Zaringol and Shirabad Streams. Both males and females consisted of five age groups (0+-4+). Seven meristic and 31 distance-based morphometric characters from 104, 30 and 62 specimens were investigated in three streams during the summer in 2008. The comparison of the morphological characteristics among the samples of SAND GOBY showed the significant differences in three Streams (p<0.05), but principal components analysis (PCA) showed that the low characteristics play a role in the population separation. Only the mouth width, lower jaw and upper jaw coefficients were greater than 0.75. It seems that there is more overlap between the samples of Kaboodwal and Zaringol compared to those of Shirabad. This finding is also consistent with their geographic distances.

The CASPIAN bighead GOBY (Ponticola gorlap), a member of the family Gobiidae, is found on the southern CASPIAN Sea basin. Since little information is available about the skeletal structure of this species, therefore, this study was conducted to describe its detailed skeletal structure in the southern CASPIAN Sea. For this purpose, a total of 17 specimens were collected from Sefid River by electrofishing device. After anesthesia, they were fixed into 10% buffered formalin, and for osteological examination, they were cleared and stained and, their bony characteristics were described in detail. The results showed that Iranian populations of this species can be identified by having traits, including sharp point of the lateral ethomoid, lack of the nasal, separation of the horizontal part from the vertical part of the premaxilary, presence of an ascending process in the dentary and separation of the symplectis and metapterygoid.

Karyological characteristics of bighead GOBY (Neogobius kessleri) in the CASPIAN Sea were studied by examining 30 metaphase chromosome spreads from the kidney tissue of 10 specimens. The chromosome number of this species was found 2n=46 and the arm number as NF=46. The prepared karyotype of this species consisted of 23 pairs acro-telocentric (a-t) chromosomes. The chromosomal formula can be stated as 2n=46 (a-t). Karyological parameters showed that relative length was between 2.34-7.04 and length variation range of chromosomes was between 1.67-5.01 and total length was 71.16 mm. It was found that the best chromosomal spread quality were obtained from intraperitonial injection of 40 mg/gcolchicine for 5 hours, hypotonization of samples in %1 sodium tri-citrate solution in 4°C and preparation , of spreads on cooled slide with flame technique.

This project has been conducted in Gorgan bay in 1994. this fish was the little population of gobiidae in Gorgan bay. the frequency much was in january with % 60.5 and the frequency little was in march with %7. The distribution of fish was only in 3th station. The total length and total weight average of all population was 35+5.1 (mm) and 0.34+0.12 (g) respectively. The correlation positive between the total length and weight has been observed more in females than the males. The fish have positive alometric growth rate. The sex ration of male to female was 1:1.1. In addition the average fecundity rate was 395.5 (290-550) eggs depending on the fish.

Age structure, growth, reproduction and feeding habits of SAND GOBY Neogobius fluviatilis pallasi, were studied in the Zarrin-Gol River (Eastern Alborz Mountain) between October 2005 and September 2006. Both sexes included five age groups (0+-4+). The Maximum lengths were 121mm (TL) in males and 108mm (TL) in females, both were 4+ years old. The most frequent ages were 3+ and 2+ in males and females respectively. There were no siginficant differences in sex ratio from unity (P<0.05). Growth model was negetive allometrice for both sexes (b<3). The highest values of condition factor were observed in early September. After 1+ year age, the males showed higher value of growth rate than females. Average absolute and relative fecundities were 508.47 and 61.27 respectively. Considering GSI, reproductive season of SAND GOBY in Zarrin-Gol River is March-April. The most frequent food items in gut contents were Trichoptera, Mollusca, Chironomidae and Gammaridae, and according to Ivlev index, the first three items showed positive values.    

Considering its Gobiidea and feeding fish sturgeon CASPIAN Sea highest main and the need to fecundity this fish, this study was done in Babolroud and Tajan rivers in Mazandaran. In order to conduct the study, 197 SAND GOBY we were caught using an Electros choker machine (V300-200) in the spring of 1390, which was the spawning season, at the Tajan River (Sari) and Babolrood (Babol).103 fish which had not spawned were analyzed. According to the results of the study, the highest average standard length of fish 96.99 ± 1.43, body weight 25.01±9.83 g, gonad weight 1.39 ± 1.03 g and absolute fecundity 952.19 ± 8.49 number of egg fish belonged to SAND GOBY in Tjan and the least average of standard length 74.12 ± 1.38 mm, weight 11.03 ± 7.23 g, gonad weight 0.61 ± 0.27 g and 684.53 ± 2.24 numbers of egg were reported for SAND GOBY on the babolrod river. The maximum and minimum averages of relative fecundity were respectively 76.96 ± 3.65 and 39.39 ± 2.65 SAND GOBY in Babolroud and Tajan Rivers. The highest mean of egg diameter 1.11 ± 0.28 mm gonad somatic index 7.44 ± 5.05% belonged to SAND GOBY in Babolroud river and the lowest, percentages were respectively 1.06 ± 0.28 mm and 5.66 ± 3.10 for the SAND GOBY in BabolroUd. According to the measured biometrics and fecundity factors of the rivers, there is no significant difference between the two (p>0.05).