IBN AL- HAITHAM J. FOR PURE & APPL. S CI VOL.23 (1) 2010 Observations o n the Age and Growth of Shank (Acanthopagrus latus (Houttuyn, 1782)) from Al-Razzazah Lake H.A.M. Dauod, R. A. Al-Aamery, A. I. Ali*,*F. M. Chabuk * and *K. M. Abbas* Departme nt of Biology, College of Education Ibn Al-Haitham,Unive rsty of Baghdad *General Board for Fish Resources Development, Al-Wazeria Abstract From February 2007 to January 2008, monthly samples of shank (Acanthopagrus latus) were taken from three st ations at Al-Razz azah lake,by using a range of gill nets and seine nets. A t otal of 318 fish were taken from all st ations. The age data determined from the scales showed that there were eight age classes p resent in st ation 1 and 2 and seven age classes in st ation 3. The increment in length of A. latus at t he area of st udy showed a tendency to decrease with the increase in age after the fourth y ear of life. The length- weight relationship s of both sexes sp ecimens are exp ressed by the following equations: Log  = -1.93 + 2.67 Log  ….. for st ation (1) fish Log = -2.08 + 2.74 Log  …. For station (2) fish Log = -2.02 + 2.39 Log  …. For station (3) fish It seems from the above equations that the growt h of A. latus in the area of st udy is allometric. Introduction Decreased catches of different fish sp ecies from Al-Razz azah lake have caused anxiety among the General Board for Fish Resources Development (GBFRD) during the y ear 1996. The (GBFRD) suggested to introduce some fish sp ecies from Shatt Al-Arab, sout h of Iraq, in an attemp t to cultivate Mugil sp ., in the lake, since then A. latus which was introduced randomly with Mugil sp . became the most abundant fish sp ecies available in the lake [1]. A. latus is one of marine fish belonging to the family Sp aridae, which is represented by more than 120 sp ecies. It is an economic fish in west Indian ocean countries. It is represented in Arabian Gulf by several sp ecies including the sp ecies under invest igation [1,2]. The p resent p aper reports p art of an extensive st udy which was carried out in an att emp t to st udy the biological asp ects of the sp ecies under invest igation. One of the major drawbacks with t he current invest igation is almost the lack of the scientific data about t he age and growt h of this fish in Al-Razz azah lake with the excep tion of the p reliminary data reported by M ansour[1] who used the length frequency distribution to determine the age. It is hop ed that the information obtained would be of interest to ichthy ologists who are looking to cultivate suitable sp ecies of fish in Al-Razzazah lake as it is subjected to sever water level fluctuation which affects the hy drological condition in the lake and community st ructures of t he contained macro invertebrates. Area of Study Al-Razz azah lake is one of the largest water body in Iraq. It is situated in Nort h west of Karbala city at 4354 & 4322' E, and 3213 & 339' N. The maximum length of the lake IBN AL- HAITHAM J. FOR PURE & APPL. S CI VOL.23 (1) 2010 is about 76Km from the beginning of Al-M ajarah channel to the white valley near Karbala city , while the maximum width is about 40Km[3]. The area of the lake is in between (1050-1700)Km 2 , and the cap acity of the lake is (4.85-250.25)Km 3 . The maximum dep th is 17.0m, and the mean depth is (4.6-11.9)m [3]. The geology of the area is the sandstone underlying clay[4]. Several fish sp ecies occur in the lake, Barbus xanthopterus, B. grypus, B. esocinus, B. luteus, B. sharpeyi, Aspius vorax and Liza abu [3]. Al-Razz azah lake is subjected to water level fluctuation which leads to sever changes in the hy drological condition of the lake and the community st ructures of the contained macroinvertabrates. It is not p ossible to say how much damage has been caused to the flora and fauna by the fluctuating water levels nor is it p ossible to surmise neither or not community st ructures have altered. Materials and Methods Acanthopagrus latus fish was obt ained from three st ations at Al-Razz azah lake within Karbala province area Fig.( 1) M onthly samples were taken during the p eriod from February 2007 to January 2008, by using gill & sein netting. The sp ecimens were measured by using total length (TL) and wet weight of each fish were recorded to the nearest 1mm and 0.1g resp ectively. The numbers measured and aged fishes are list ed in table (1). Scales of each fish were removed, cleaned, dried and fixed between two glass slides, and then the age read from them. Re sults and Discussion Age Distribution: The age st ructure of the p op ulation revealed that there were eight age classes at the area of st udy . These results agree with the data reported by M ansour [1] who used length- frequency distribution to determine the age. The results of the p resent st udy showed that the pop ulation of A. latus in the area of st udy was dominated by four and five y ears. The dominance of four and five y ears through the p eriod of invest igation, is difficult to exp lain but is though related to the fact that nets missed some of the small fishes which were able to escape by swimming under stones at some sites, or p erhap s due to the gear selectivity [5, 6, 7]. Length and Growth: Treasurer [8] has indicated that the length measurements are more reliable indicator of growt h than weight data since they are less suscep tible fluctuation. The number of fish examined, the mean length p er age class and their ranges at the sites of st udy are shown in tables (2,3 and 4). The average growt h of fishes in the area of st udy is illustrated in figures (2,3 and 4). It seems from the above tables and figures that the highest increment in length app ear during the 2 nd , 3 rd and 4 th y ears and then showed a tendency to decrease with the increase in age after the 4 th y ear of life. It is imp ortant to note that there is no scientific data about the age and growt h (increment of length) of A. latus in Al-Razz azah lake to discuss and comp are the p resent results. The growt h of A. latus in the area of study seems t o be poor. This is not unexp ected as the lake is oligotrop hic (4). Several workers including [6, 9,10,11] agree that the best fish growt h is achived in alkalin water. It is also generally accep ted that where fishes are p lentiful, as well as fast growing invertebrates are p resent in abundance[6,9,10]. The poor ionic content of water and the p aucity of the invertebrate fauna are militate against Al-Razz azah fishes. One further complication in Al-Razz azah lake is t he fluctuation IBN AL- HAITHAM J. FOR PURE & APPL. S CI VOL.23 (1) 2010 of water levels which lead to marked changes in the p roductivity of the water body [6, 11,12, 13]. In the p resent st udy , results obtained for the age and growt h of A. latus showed low growt h rate in comp arison with the data reported from other water bodies [14,15,16]. This low growt h rate may be related to the different environmental factor such as the temp erature, availability of food and/ or the ionic content of water [6, 9,10]. The relationship s between the length and weight of A. latus at the different st ations, derived by fitt ing st raight lines to the logarithms of the two variables, were exp ressed by the following equations: Log = -1.93 + 2.67 Log  ….. for st ation (1) (Al-Shuaib) fish  = 0.99 Log w= -2.08 + 2.74 Log  …. For station (2) (Al-Rahalia) fish  = 0.78 Log w= -2.02 + 2.39 Log  …. For station (3) (Ain Temer) fish  = 0.93 It seems from the above equations that the growt h of A. latus at Al-Razz azh lake is allometric as the regression coefficient (b) values are less than 3 [17]. The results of t he present study differ numerically from that reported by M ansour [1]. Review of the literature showed that there are several factors affected the length- weight relationship such as age, maturity of gonads, sex and the time of catch [18,19]. It seems that the above factors may be militated agains the relationship in the p resent study in comp arison with the data rep orted by M ansour[1]. In conclusion, it app ears that A. latus fish have managed to maintain themselves naturally in Al-Razz azah lake, which means that they introduced to a suitable environment. Nevertheless it would p rovide bett er returns and should at least be given a trial as it is the only course of action which will imp rove the current situation until the fluctuating water levels are corrected. Re ferences 1.M ansour, R.H. (2004). Some biological characterist ics of silver sheim (Shank) Acanthopagrus latus (Hout tuy n, 1782) in Razzaza lake. M . Sc. Thesis, T echnical College of Al-M ussayib. (In Arabic). 2.Al- Daham, N.K. (1979). Fishes of Iraq and Arabian gulf. Vol. 2. Al- Basrah University Press, 406 p p (In Arabic). 3.Anon (1985). State and p rosp ective of fisheries in Razz azah lake. Polservice consulting engineers. A rep ort of st ates fisheries organization. 4.Al- Saadi, H. A.; Al-Tamimi, A.A. and Al- Ghafily , A.A. (1995). Basrah J. Sci. 13(1): 41- 48. 5.Samuel, M .; Bawazer, A.S. and M atheus, C.P. (1984). Ann. Res. Kuwait Inst . Sci. Research. 1: 52-61. 6.Dauod, H.A.M . (1986). Studies on some asp ects of t he biology of brown t rout (Salmo trutta L.), minnow (Phoxinus phoxinus (L.) and the three- sp ined st ickleback (Gasterosteus aculeatus L.) from an up land reserovoir sy st em, Co. Wiklow. Ph.D. Thesis, National University of Ireland. 7.Dauod, H.A.M .; Al-Rubai, R.K.S. and Al-Douri, T.Y. (1999). The Veternarian, 9(3): 64-79. 8.Treasurer, J.W. (1976). J. Fish Biol. 8: 241-253. 9.Kennedy, M . and Fitz maurice, P. (1971).Proc. R. Ir. Acad. 71 B: 269-352. 10.O'Grady, M .F. (1981). A st udy of brown t rout (Salmo trutta L.) p op ulations in selected Irish lakes. Ph.D. Thesis, National University of Ireland. 11.Dauod, H.A.M . and Al-Rubai, R.K.S. (1996). J. Ibn Al-Haitham Pur. Ap p l. Sci. 7(2): 1-21. 12.Grimas, U. (1961).Rep. Inst . Freshwat. Res. Drottingham, 42: 183-237. IBN AL- HAITHAM J. FOR PURE & APPL. S CI VOL.23 (1) 2010 13.Hy nes, H. B. N. (1961).Verh. Internat. Verein. Limnol. 14: 652-656. 14.Jasim, F.K. (2002). A st udy on gonads histology and fecundity of Acanthopagrus latus (Hout tuy n, 1782) in Iraqi sea water. M .Sc. Thesis, College of Agricultur, Basrah University (In Arabic). 15.Al-Aareky, M .K. (2001). Biology of Acanthopagrus latus (Hout tuy n, 1782) in Iraqi sea water- M . Sc. Thesis, College of Agricultur, Basrah University . ( In Arabic). 16.Samuel, M . and M athews.C.P. (1987).Bull. M ar. Sci. 9: 159-171. 17.Bagenal, T.B. and Tesch, F.W. (1978). Age and growt h. In "M ethods for assessment of fish p roduction in freshwater". (Ed. T.B. Bagnal). I.B.P. No. 3: 101-136. 18.Le Cren, E.D. (1951). J. Anim. Ecol. 20: 201-219. 19.Bagenal, T.B. (1978). M ethods for assessment of fish p roduction in freshwaters. 3 rd ed. Blackwell Scientific p ublication Oxford, London. I.B.P. Hand book No. 3: 365. Table (1): Numbers of fish caught and ae d on each sampling data at each site Month S tation (1) (Al- Shuaib) Number aged S tation (2) (Al- Rahal ia) Number aged S tation (3) (Ain Tamr) Number aged February 2007 10 11 9 M arch 10 12 10 Ap ril 12 11 10 M ay 13 11 12 June - - - July 12 13 13 August - - - September - - - October 7 12 9 November 14 15 12 December 13 12 14 January 2008 14 14 13 Total 105 111 102 IBN AL- HAITHAM J. FOR PURE & APPL. S CI VOL.23 (1) 2010 Tab le (2): Mean(…) and range of length of A. Latus at the end of each growth period (Station 1- Al- Sh uaib). Age Number of fish Length at age 1 2 3 4 5 6 7 8 8 2 (5.25) 4.4-6.0 (8.75) 5.5-12 (14.0) 11.0- 15.0 (19.0) 14.5- 23.5 (23.0) 20.5- 25.5 (26.5) 24.0- 29.0 (29.5) 28.0- 31.0 (32.0) 30.5- 33.5 7 5 (5.5) 4.5-7.0 (9.2) 7.5-12.5 (13.5) 12.0- 17.5 (18.5) 17.0- 24.0 (23.2) 22.0- 25.0 (26.2) 23.5- 28.0 (29.7) 27.0- 31.5 - 6 9 (5.5) 4.5-8.5 (10.22) 8.0-13.0 (14.5) 11.5- 17.0 (19.5) 16.0- 22.5 (23.5) 21.0- 25.0 (26.3) 23.5- 28.5 - 5 25 (6.0) 4.0-9.0 (10.0) 7.5-12.0 (16.5) 12.5- 19.5 (21.5) 18.0- 24.0 (24.0) 22.0- 26.5 - 4 34 (6.25) 4.5-8.0 (10.5) 7.0-12.0 (17.5) 11.5- 19.5 (22.5) 17.5- 24.0 - 3 22 (5.5) 5.0-8.0 (10.5) 7.0-12.5 (16.25) 12.0- 17.5 - 2 8 (5.25) 5.0-7.5 (10.0) 7.0-13.0 - 1 - - - - - - - - - Over all 105 (5.8) 4.0-9.0 (9.9) 5.5-13.0 (15.4) 11.0- 19.5 (20.2) 14.5- 24.0 (24.3) 21.0- 26.5 (26.3) 23.5- 29.0 (29.6) 27.0- 31.5 (32.0) 30.5- 33.5 Increment of mean Length (cm) 5.8 4.1 5.5 4.8 4.1 3.0 3.3 2.4 Table (3): Mean(…) and range of length of A.Latus at the end of each growth period (S tation 2- Al-Rahalia) Age Number of fish Length at age 1 2 3 4 5 6 7 8 8 1 (4.0) 4.0-4.0 (7.5) 7.5-7.5 (10.5) 10.5- 10.5 (16.2) 16.2- 16.2 (21.5) 21.5- 21.5 (24.5) 24.5- 24.5 (26.5) 26.5- 26.5 (29.0) 29.0- 29.0 7 3 (6.0) 5.5-6.5 (10.0) 6.0-12.0 (14.5) 9.5-18.0 (19.7) 17.5- 24.0 (23.36) 23.0- 27.0 (26.3) 25.5- 28.0 (29.0) 27.0- 30.0 - 6 7 (5.78) 5.0-6.5 (10.36) 6.0-14.5 (15.36) 13.0- 18.0 (20.36) 18.0- 27.5 (24.17) 24.5- 30.0 (27.8) 26.0- 32.0 - 5 29 (5.97) 4.5-8.0 (11.0) 7.0-15.0 (15.5) 14.5- 16.0 (20.0) 14.5- 26.5 (24.0) 23.0- 29.5 - 4 33 (6.5) 5.0-8.5 (11.5) 8.0-14.5 (14.5) 13.0- 15.5 (19.5) 14.5- 27.0 - 3 25 (5.5) 4.5-8.0 (11.5) 7.5-15.0 (15.5) 14.0- 21.0 - 2 12 (5.4) 4.5-10.0 (10.3) 9.5-14.0 - 1 - - - - - - - - - Over all 111 (5.6) 4.0-10.0 (10.3) 6.0-15.0 (14.3) 9.5-18.0 (19.2) 14.5- 27.5 (23.3) 21.5- 30.0 (26.2) 24.5- 32.0 (27.7) 26.5- 30.0 (29.0) 29.0- 29.0 Increment of mean Length (cm) 5.6 4.7 4.0 4.9 4.1 2.9 1.5 1.25 Table (4): Mean(…) and range of length of A.Latus at the end of each growth period (S tation 3- Ain-Tamr) Age Number of fish Length at age 1 2 3 4 5 6 7 8 8 - - - - - - - - - 7 2 (6.5) 5.0-8.0 (9.5) 7.5-12.0 (14.5) 11.0- 18.0 (20.25) 16.5- 24.0 (24.0) 23.0- 25.0 (26.5) 25.0- 28.0 (28.75) 27.5-30.5 - 6 11 (5.8) 4.5-8.5 (8.5) 7.0-11.5 (14.12) 10.0- 17.5 (20.27) 16.0- 23.0 (24.12) 21.0- 26.0 (27.89) 24.0- 29.0 - 5 24 (5.97) 4.5-8.0 (9.48) 7.5-13.0 (15.21) 12.5- 19.0 (20.48) 18.0- 23.0 (24.2) 22.0- 26.0 - 4 36 (5.79) 4.5-9.0 (10.28) 9.5-13.0 (15.38) 12.5- 19.0 (20.73) 17.0- 25.5 - 3 15 (5.93) 5.0-8.0 (10.2) 6.5-13.5 (15.47) 11.0- 19.5 - 2 14 (5.87) 5.0-9.0 (10.5) 9.5-12.5 - 1 - - - - - - - - - Over all 102 (5.9) 4.5-10.0 (10.6) 6.5-13.5 (14.9) 10.0- 19.5 (20.1) 16.5- 25.5 (24.2) 21.0- 26.0 (27.2) 24.0- 29.0 (28.75) 27.0-30.5 - Increment of mean Length (cm) 5.9 4.7 4.3 5.2 4.1 3.0 1.5 Fig. (1): Location of study area. * sampling station Fig.(2) : Mean length and increment of mean length in A. latus at station (1). (Al-shuaib) 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 Mean length Increment of mean length T .L . (c m ) IBN AL- HAITHAM J. FOR PURE & APPL. S CI VOL.23 (1) 2010 at stati on (2). A. latus(3) : Mean length and increment of mean length in Fig. (Al-Rahal ia) Fig. (4) : Mean length and increment of mean length in A. latus at station (3).(Ain Tamr). 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 Mean length Increment of mean length 2 3 4 5 6 7 M ean len gth Increment of mean length T .L . (c m ) T .L . (c m ) T .L . (c m ) 2010) 1( 23مجلة ابن الھیثم للعلوم الصرفة والتطبیقیة المجلد مالحظات عن العمر والنمو في سمكة الشانك Acanthopagrus latus (Houttuyn, 1782) في بحیرة الرزازة وكامل محمد *د جابك، فراس مجی*عیسى علي حسین عبد المنعم داود، رنا عالء العامري، علي *عباس - ، جامعة بغداد، كلیة التربیة ابن الهیثم قسم علوم الحیاة الهیئة العامة لتنمیة الثروة السمكیةالوزیریة* الخالصة ألســماك ) سـمكة 318(جمــع عینـات شـهریة 2008الـى كـانون الثـاني 2007ة الممتـدة مــن شـباط یـتم خـالل المـد مـن ثــالث محطـات علــى بحیـرة الـرزازة، واســتخدمت فـي عملیـة الصــید شـباك خیشــومیة Acanthopagrus latusك الشـان القشــور لحســاب العمــر إن هنــاك ثمـــان لاج الدراســة الحالیـــة ومــن خــالل اســتعمأظهــرت نتــائ. مختلفــة الســعة وشــباك كرفــة ).عین تمر(مجامیع في المحطة الثالثة ، وسبع)الشعیب والرحالیة(لثانیة مجامیع عمریة في المحطتین االولى وا تـم التعبیــر . أظهـرت معـدالت الزیـادة فـي الطـول إشـارة إلـى النقصـان مـع زیـادة العمـر بعـد السـنة الرابعـة مـن العمـر -:یةعالقة الطول بالوزن بالمعادالت اآلتعن Log  = -1.93 + 2.67 Log  أسماك المحطة األولى ..… Log = -2.08 + 2.74 Log  أسماك المحطة الثانیة .… Log = -2.02 + 2.39 Log  أسماك المحطة الثالثة .… ـــي ــــ ــــ ـــــــر قیاســــ ــــ ـــــوًا غیــــ ــــ ــــ ـــــر نمـــ ــــ ــــ ــا یؤشــ ــــ ــــ ــــ ـــــو مـ ــــ ــــ ـــــــل ال(Allometric) لوهــ ــــ ــــ ـــــاط اقـ ــــ ــــ ــــــل االرتبــ ــــ ــــ ن معامـ ).3(من