Investigating and determination exploitation pattern of jinga shrimp (M.affinis) in the Khouzestan Province waters

Study of shrimp stock was carried out from September 2007 to November 2009 in west of Khuzestan coastal waters. In this period, twelve cruises in Life- Buseif (western coastal area) were carried using shrimp trawl net. In Life- Buseif fishing area, the CPUE of total shrimp was the highest (44.2 kg/h) in 21st October 2008. In this area, the highest biomass of total shrimps was in same time (982.4 t). This value was 808.5 t for M. affinis. Maximum mean length of males and females of M.affinis were observed in 4th November 2009 (12.1 & 11.3 cm respectively). Maximum and minimum sex ratio (f:m) of this species was 1.8:1 in 15th November 2008 and 0.6:1 in 3rd November 2008. Relative frequency of shrimp in total catch was observed in November (22.2%). According to the results of this study, shrimp catch season was opened in Life- Buseif from 4th Nov until 24th Dec 2007, from 24th Oct until 14th Dec 2008 and from 27th Oct until 17th Dec 2009

Study of some biological characteristics (Tiger tooth croacher, Silver pomfert, Yellow fin seabream, Hilsa shad, Indo-pacific king mackerel, Narrow-bared Spanish mackerel) in the coastal waters of the Persian Gulf

The present study was carried out in the fishing landing center in khozestan using the commercial catch data. The data of total cutch of fishes and effort were prepared from the deputy of statistic office. Based on the pre data, the effort of gill-net fishery was being decreased from 1996 to 2000 and then had a trend to increase from 2001. The maximum and minimum of trap fishery of dhows ware observed 2005 and 1996 respectively. The maximum and minimum of total catch were observed in 2005 in Hilsha shad and Spanish mackerel with 4174.95 tones and 73.33 tons respectively. In this year the total catch of silvery pomfret and tiger tooth croaher species were recorded 323.6 tones and 1700.44 tons respectively. The growth parameters of Hilsha shad were estimated from 10071 specimens in Abadan and 4032 specimens of length frequencies from Hendijan, statistic program of t-test was used for the mean total length and the results showed the significantly different (p < 0.05) in the two areas during 12 months. The Von Bertalanffy growth parameters were estimated from the FISAT II and ELEFAN.The asymptotic length (L) was estimated using the Powell – Vetheral method in Abadan and Hendijan, 42.74 cm and 37.02 cm respectively. Growth coefficient or K for both areas were 0.77 and 0.71 per year respectively. The instantaneous rotes of total mortalities (Z) were estimated from length-converted catch curves and the values were at 2.55 year^-1 for Abadan and 2.81 year^-1 for Hendijan. The instantaneous rate of natural mortalities (M) and fishing mortalities (F) for both areas, Abadan and Hendijan were 0.75 year^-1, 0.732 year^-1 and 1.8 year^-1, 2.078 year^-1 respectively. The exploitation rates (E) for both populations were 0.7 year^-1 in Abadan and 0.73 year^-1 in Hendijan. However the optimum level of E should be 0.5 and the estimated valves of E is more than 0.5 and shows the pressure of fishing effort and overexploited on the population of this stock. The instantaneous rate of total mortalities of Tiger tooth croacker was 1.95 year^-1 the instantaneous rate of natural mortality using Pauly empirical formula was estimated 0.7 year^-1 and fishing mortality were 1.52 year^-1. The exploitation rate for this species was calculated 0.62 year^-1. The values of M and F for silvery pumfret were obtained 0.91 year^-1 and 1.47 year^-1 respectively. The exploitation rate was estimated 0.61 year^-1

A study on fishing status and some reproductive characteristics of Klunzinger’s mullet (Lize klunzingeri) in coastal waters of Khuzestan province

Biological characteristics of Liza klunzingeri were studied in two coastal areas, Sajaphi and Bahrekan, of eastern Khuzestan during March to February 2007. Among total 1880 measured fish specimens, 947 specimens were analyzed. The mean value of Gonado-somatic Index (GSI) for the male and female fish were calculated as 0.96± 1.39 and 3.25 ± 3.26 respectively. The GSI value was highest in November and lowest in July. The mean value of condition factor (K) was 1.25± 0.14 in male and 1.21± 0.15 for female. The highest K value were observed in June and the lowest value in February. The lenght at first maturity regardless of sexuality, was found to be 14.5 cm and the time of spawning based on reproduction pattern were determined in Nov- Dec. The length-weight relationship were calculated as Y=0.024L^2.76 (n=226R2=0.72) for males, Y=0.011L^3.00 (n=444R2= 0.78) for females and Y=0.0208L^2.82 (n=670R2 =0.82) for total fishes and also it’s found significant in level length weight relationship in (P<0.05). According to biological characteristics and referring to American fisheries society (AFS) indices and Fuzzy logic expert system, Lize klunzingeri is classified as low vulnerable species

Reproduction and feeding biology of madagascar meager (Argyrosomus hololepidotus) from Khuzestan coastal waters

Biological attributes of Madagascar Meager (Argyrosomus hololepidotus) was studied from October 2008 to September 2009 in coastal waters of Khuzestan province. Average maximum length was 128.4±7.50 in October and average minimum length was 104.86±12.47 in May. The maximum weight was 27500g, the minimum weight was 5700g and mean weight for males and females were 15.222±4.40 and 16.942±5.09, respectively. Reproductive studies showed that peak maturity season occurred in July. The length­ weight relationship were calculated as W=0.042L 2 70 for males and W=0.06L2 61for females. The male-female sex ratio was calculated as 1:1.07 and chi-square analysis showed no significant difference (P>0.05) between the two sexes. The average absolute and relative fecundity were estimated to be 4054045±37265 and 179.19±50.41, respectively Madagascar Meager is carnivore and we found the diet of the species consisted of fish (75%), crustaceans (20%) and mollusks (5%). Analysis of monthly variation in the condition factor (CF) indicated a fluctuation throughout the year, with a high level during May. Vacuity index indicated a higher feeding rate in males compared to females. We also found that the species continues feeding in the spawning season

Stock assessment of zobaidy, Pampus argenteus, in the north of Persian Gulf

The project “Stock Assessment of Zobaidy, Pampus argenteus, in the North of Persian Gulf” started in April 2003 and completed by the end of April 2006 as a cooperative research project to assess the valuable stock of zobaidy shared between Kuwait and Iran in the North of Persian Gulf. The main objectives were to investigate and determine the basic biological parameters, the standing biomass, seasonal abundance, and the impact of regional fishery activities. These studies are necessary to recommend practical management policies and measures for long-term sustainability of the zobaidy stock. The sampling of fisheries data (catch, effort, fish length distributions, and biological data) was started in May 2003 and ended December 2006. Monthly length frequencies data were collected from both the drift gill net and shrimp trawl fisheries. Age determination was based on otolith sectioning, polishing, etching, and staining method. The age groups ranged from 0 to 10 yrs but the dominant age groups were 1-3 years and the estimated parameters for both sexes were L_∞ = 32.0-36.0 cm FL and K = 0.26-0.30 yr^-1, females grow faster than males. Sea survey on board of two dhow boats was carried out using swept area method. Higher abundance was always obtained in Kuwait Bay rather than the other areas surveyed in Kuwait and Khuzestan waters. The total estimated stock biomass in the surveyed areas varied from 42 t in January 2004 to 2,633 t in November 2004, while the Iranian biomass varied from as low as 19 t in October 2005 to 295 t in November 2003. The data indicated that Ras Al-Gaid, Bubiyan Island is the main nursery area in Kuwait waters, while Lifah, Busaif, and Bahrakan are important nursery areas in the Khuzestan waters. Kuwait Bay and Khor Musa are considered important spawning grounds and should be protected. Yield per recruit analysis showed that higher yield could be gained with increasing fish effort, which is not recommended under the present status of high exploitation rate. In contrast, virtual population analysis indicated that future catches will reduce if the fishery continues with present level fishing effort. A reduction of 50% would be required to maintain the present level of catches as well as to enhance the stock biomass. Formulation of a joint advisory management committee would be advisable approach to manage and monitor the zobaidy stock in the region. This will need commitment from the three countries in the region for data collection on regular basis on length frequency, statistics, and biological data. Copepods with high occurence of 64% - 88% is considered as the main item in the Pomfret fish, while jelly fish and other decapods crustaceans are considered as minor items. Observation of pre- flexion stage larvae of pampus genus among the specimens collected from Khuzestan coast water could be considered as an evidence for the spawning of this fish in this region. The occurrence of pampus larvae in Khuzestan coast during the months of June to October has been reported for several times. Examination of 101 specimens (38 from Kuwait, 63 from Iran) for molecular survey does not show any significant differences between Kuwait and Iran water stocks for this fish, so it is possible to hypothesize a unit population for zobidy stock in Persian Gulf and Oman Sea as whole

Biology of southern meager (Argyrosomus hololepidotus) in Khouzestan province coastal waters

In order to study feeding and reproductive biology of Southern meager (A.hololepidotus) in North West of Persian Gulf. 143 (74 males and 69 females) species were collected between October of 2008 to October of 2009 in coast of Khouzestan. Maximum and minimum length of fish were 143 cm and 81 cm respectively Maximum mean length (128.4±7.5) and Minimum mean length (104.86±12.47) were detected in October and May respectively. Maximum weight (27.5Kg) and Minimum weight (5.7Kg) and also mean weight to males (15222±1371) and Min mean weight of females (16942/02±2095) were detected. Absolute fecundity (4111847.66) and relative fecundity (268.33) were analyzed. GSI Analysis showed that these species (A.hololepidotus) spawn during June to September with highest spawning rate in September. Results showed that Southern meager is a batch spawner species relationship between length and weight of male Y=0.042L^2.70 (n=74,R2 =0.86) and female species Y=0.061L^2.61(n=69, R2=0.85) and also total species Y=0.059L^2.62 (n=143, R2=0.86) were measured. Due to not finding Immature species during sampling LM50 wasn’t analyzed. Analysis HSI and K index showed highest value in April and May and lowest value in August and September respectively. Prey occurrence index showed that fish is main food item and Crustacean specially Shrimp and Mollusca are secondary food item of this species. Analysis of vacuity index showed that females of Southern meager are more gluttonous than males and this species feed during spawning season. In general we can classify Southern meager as a moderate feeding rate species

Biomass estimation of demersal resources in the Persian Gulf and Oman Sea by Swept Area Method

Regarding to monitor of demersal resources in the Persian Gulf and Oman Sea, and also biomass and CPUA estimation of them, a series of research cruises (5 cruises per year) were carried out by R/V Ferdows-1covering the area from 49 00 E in the west (Khoozestan provice) to 61 25 E in the east (Gwater) in a 5 years program form 2004 up to 2008 (no cruise in 2006). The study area was stratified into 17 strata (A to Q) of which 10 starta (A to J) were in the Persian Gulf and 7 strata (K to Q) were in the Oman Sea, covering the depths of 10-50m in the Persian Gulf and 10-100m in the Oman Sea. A total of 316 stations were randomly selected. The biomass and CPUA were estimated by Swept Area method. The comparison between two regions indicated that the percentage of density of demersal fishes in the Persian Gulf during years 2004, 2005, 2007 and 2008 were 3.3, 3.9, 2.3 and 2.4 times more than the Oman Sea and totally 70-80% of total biomass was calculated for the Persian Gulf. Also a comparison among 17 starta, the highest biomass was found for starta C & D in the Bushehr province waters. The amount of CPUA for both regions of the Persian Gulf and Oman Sea was compared and it was concluded that in years 2004 and 2005, the mean CPUA in the Persian Gulf was partially higher than the Oman Sea with 1.06 & 1.20 times more; and on the contrary for the next two years this value was higher in the Oman Sea with 1.3 times more. The highest CPUA of demersal resources for the Oman Sea belonged to the strata K & O for years 2004, 2007 and 2008 and for year 2005 was for L and strata. It can be concluded that the north-west of Oman Sea has the best condition of biomass of commercial and non-commercial species and the O stratum will be in the second ranking. With review the mean CPUA in different depth-layers for years 2004, 2005, 2007 and 2008, it was concluded that with increasing the depth, the mean CPUA is decreased in which the CPUA values in depth-layer 10-20m for these years were 8.3, 3.0, 2.1 & 1.6 times more than depth-layer 50-100m. The comparison of mean CPUA for 10 strata of the Persian Gulf showed that in years 2004 and 2005, the mean CPUA of demersal fishes in the Hormuzgan province waters was higher than in Bushehr province waters (1.2 times more). In total, the highest maen CPUA belonged to F (Naiband to Mogham) and G (Mogham to Farour) in Hormuzgan waters. On the contrary, in years 2007 and 2008 this value in Bushehr waters was 1.3 times higher than western part of Hormuzgan waters with the highest value in D stratum(Boordekhoon to Dayyer). Also the comparison of mean CPUA for different depth-layers, it was found that the mean CPUA has ascending trend with increasing the depth, with the highest value in depth-laer of 30-50m in which contains the 55-68% of total biomass. The lowest biomass is found in depth-layers of 10-30m. Totally, the minimum CPUA and biomass for both commercial and non-commercial species belonged to a stratum located in Khouzestan province waters and it was shown the over-exploitation of resources in this area. The comparison between commercial and non-commercial groups in both ecosystems , it was concluded that the density of commercial species was higher than non-commercial ones , and in all years the Persian Gulf indicated higher values than the Oman Sea