Int. J. Life. Sci. Scienti. Res., 4(2): 1639-1643, March 2018

Studies on Population Characteristics of Frigate tuna, Auxis thazard (Lacepede, 1800) Occurring in the North West Coast of India

Vinod Kumar Mudumala^*, Mahesh Kumar Farejiya , Kiran S. Mali, Rama Rao Karri,  D.E. Uikey, Pradnya A. Sawant, A. Siva

^*Asst. Professr, Department of Zoology, Govt. PG & Degree college, Jammikunta, Satavahana Univerity, Karimnagar, Telangana State, India

^*Address for Correspondence: Mr. Ashwini G. Darokar, Assistant Professor, Department of Physiology, IGGMC, Nagpur, India

ABSTRACT- This study is an attempt to understand the population characteristics such as Length-weight relationships, age, growth, mortality, length at age and exploitation rate of Frigate tuna, Auxis thazard occurring in the North west coast of India. The data collected from various fish landing centers from 2008 to 2012 were considered for this study. The mean fork length and weight 32.35 cm and 1.040 kg was observed respectively. The length-weight relationship W=2.4321x10-1 FL 2.27658, and r2 0.9576 was obtained. The value of ‘b’ found to be less than 3 and hence this species is showing negative allometric growth. The growth parameters on von Bertalanffy for L∞ estimated as 47.03, K was 1.30 and to was -0.23. The Phi-prime value (⏀) of 3.33 was derived. The length at age observed at the end of 1 to 4 years was 27.0, 42.0, 50.0 and 55.0 cm year-1 respectively. The natural mortality (M) 1.00 year-1, total mortality (Z) of 4.43 year-1 and fishing mortality (F) 3.43 year-1 were derived with the mean temperature of 27°C. The exploitation ratio (E) and exploitation rate (U) was 0.77. The results derived in the present study with regard to population characteristics of frigate tuna in the coastal waters of North west coast of India indicate catching of this species in the area to be minimized.

Keywords: Length-weight relationships, Mortality, Length at age, Exploitation ratio, Exploitation rate

INTRODUCTION: Among the neritic tunas occurring in the Indian waters, under the genus Auxis, two species viz.,  Auxis thazard and Auxis rochei are contributing to the marine fish landings to the tune of 13,418 tonnes during 2016 ^[1].  An increase of 64% of these species landings has been observed when compared to 2015 (8,176 t). Determinations of population characteristics are vital for understanding changing trends in the marine fish production and also to evaluate the level of exploitation. The effective fisheries management depends on the fish catch data, biological information and population characteristics etc. As per the literature, the developed countries in the world observed to conduct regular stock assessments for the major commercial fisheries, thereby, the resources are better managed. Commendable works on this species have been attempted by various researchers from the Philippines waters, Indonesia, Taiwan, Sri Lanka and Thailand. The works of Ingles and Pauly ^[2] on the growth, mortality and recruitment of Philippines fishes, Yesaki ^[3-4] on biological & environmental observations from the West Coast of Thailand and age and growth of Kawa kawa, longtail tuna and frigate tuna from the gulf of Thailand, Dwinpongo et al. ^[5] on the growth, mortality and recruitment of commercially important fishes in Indonesian waters, Lu et al. ^[6] on the growth and mortality of Auxis thazard in the Taiwan Strait and its adjacent seas, Yesaki and Arce ^[7] on review on the Auxis fisheries in Philippines and some aspects of biology of frigate and bullet tuna in the Indo-Pacific region, Tao et al. ^[8] on the age and growth changes and population dynamics of black pomfret and frigate tuna from the Taiwan strait, Geehan and Pierre ^[9] reviewed the statistical data of neritic tunas, Hartaty & Setyadji ^[10] on the population parameter of frigate tuna in the Sibolga and adjacent waters worth to be mentioned. From the Indian waters, these studies are very limited and the works carried out are pertaining to either entire coast of India or limited to a coast of the coastal district of maritime states of India and recent investigations are meagre rather scanty. Mentioned may be made of the works carried out from Indian waters by Pillai and Ganga ^[11] on the fishery and biology of tunas in the Indian seas, Silas et al. ^[12] on the population dynamics of tunas and stock assessment, Siraimeetan ^[13] on the fishery and bionomics of tunas from Tuticorin coast, Joseph et al. ^[14] on the fishery, age & growth of kawa kawa and frigate tuna, Kasim ^[15] on fishery growth, mortality rate and stock assessment of Auxis thazard along Tuticorin coast of Gulf of Mannar, Jude et al. ^[16] on the gillnet selectivity studies for fishing frigate tuna in Tuticorin waters of south east coast of India, Kasim and Abdussamad ^[17] stock assessment of coastal tunas along the east coast of India, Abdussamad et al. ^[18] on Fishery and population characteristics of coastal tunas at Tuticorin, Ghosh et al. ^[19] on the fishery, population characteristics and yield estimates of  coastal tunas from Veraval coast, Ghosh and Shivadas ^[20] on the fishery, population dynamics and stock structure of frigate tunas exploited from Indian waters, Abdussamad et al. ^[21] on the neritic tuna fishery along the Indian coast, biology and population characteristics of longtail and frigate tuna. Monitoring of changes in the population characteristics is very much essential as the present scenario of the harvested fishery is showing fluctuating trends. Therefore, regular studies are required to be carried out and hence this study is an attempt to derive the population parameters of Auxis thazard so as to understand whether this fishery is overexploited or at the risk of overfishing.

MATERIAL AND METHODS- The fish samples of Auxis thazard were collected from the commercial fish landings at Porbandar in the state of Gujarat, Sassoon Dock and New Ferry Wharf, Mumbai in the state of Maharashtra, India during 2008-12 (Fig. 1). A total of 924 specimens with the size ranging between 16 to 50 cm and weight between 0.200-1.880 kg were considered for this study. The equation W=aL^b was applied to calculate the statistical relationship between length and weight. In order to understand the degree of association of two variables, the correlation coefficient was derived from length and weight data.  The popular technique of computer analysis of monthly length frequency distributions, FiSAT-II programme developed by Gayanilo et al., ^[22] was used for estimation of growth parameters.

Fig. 1: Study area: North west coast of India

 

The total mortality (Z) was derived using Beverton and Holt model ^[23]. The natural mortality (M) was calculated using regression analysis developed by Pauly ^[24] with the average sea surface temperature 27°C. On estimating the mortality parameters, the exploitation ratio (E=F/Z) and exploitation rate (U=F/Z*(1-e^-z) were calculated. After deriving the growth parameters, in order to understand the reliability index, these parameters are evaluated using Phi Prime Test (⏀) developed by Munro & Pauly^[25]  and Pauly & Munro^[26] using the equation lnK + 2*lnL∞.

 

RESULTS

Length weight relationship- Length weight relationship calculated for Auxis thazard was W=2.4321x10^-1 FL^2.27658 wherein, the value of ‘b’ is less than 3 indicating negative allometric growth. The reason for less ‘b’ value might be due to an absence of juveniles. The coefficient of determination ‘r²’ value was 0.96 indicating a high degree of correlation and better fit of length weight relationship (Fig. 2).

 

Fig. 2: Length-weight relationship for Auxis thazard

Growth parameters- The values of growth parameters derived are 47.38 cm, 1.35 and -0.23 for L∞, K, and t_o respectively. The length at an age at the end of 1-4 years was 26.5, 41.7, 50, and 55Cm per year respectively (Fig. 3). The growth performance index based on Phi prime test (⏀) was observed as 3.48. The value of Phi prime is not showing any significant difference.

Fig. 3: Length at age for Auxis thazard

 

Mortality, exploitation rate and exploitation ratio- The total mortality (Z) calculated as 4.43 year^-1 while the natural mortality was 1.00 year^-1. The fishing mortality (F) obtained was 3.43. The exploitation ratio (E) and exploitation rate (U) were estimated at 0.77 year^-1 which is relatively high, indicating the sign of overexploitation. This species assessment status indicated that, the fishing mortality obtained in the study was 3.43 y^-1 which is far higher than the targeted optimum fishing mortality (F_opt) of 0.42 y^-1 and limit of fishing mortality (F_limit=0.58 y^-1) in terms of the biological reference point, thereby, overexploitation of this species in this region is indicated.

The estimates of growth and mortality parameters derived in the present study are showing variations in L∞ and K values with earlier estimates. The range of L∞ is between 47.38 (present study) to 58.00 (Pillai and Ganga, 1985) and the range of K value is from 0.51 (Lu et al., 1991) to 1.35 (present study). These variations in population parameters might be the difference in selection of samples and method of sampling application of different methodologies/ techniques. A comparative estimate of growth parameters, mortality rates and the exploitation ratio of frigate tuna from earlier studies are presented in Table 1.

Table 1: Comparative estimates of growth parameters, mortality rates and exploitation ratio of Frigate tunas (Auxis thazard)

 

DISCUSSION- In the length weight relationship, the ‘b’ value obtained in the present study is less than 3 indicating negative allometric growth. This might be due to the absence of younger/ juvenile specimens. The K value obtained was 1.35 year^-1 and this value is nearer to the value of 1.20 year^-1 found by Ghosh et al. ^[20]. The length at age value at the end of 1-4 years derived as 27.0, 42.0, 50.0, and 55.0 cm year^-1 respectively were comparable to the values calculated by Abdussamad et al., ^[18]. Growth performance index (⏀) derived using the parameters of L∞ and K value was 3.48, which is in confirmation with the value (3.31) obtained by Ghosh et al., ^[19]. The natural mortality (M) was 1.00 year^-1, total mortality (Z) was 4.43    year^-1 and fishing mortality (F) was 3.43 year^-1 derived which are near to the values obtained by Lu et al., ^[16] and Pillai and Ganga ^[11].                   

From the past five years, the catch trends of Auxis sp. in the Indian waters have been showing fluctuations. Auxis thazard fishery was found to be the underexploited resource ^[18] during 2005, whereas, in 2010, it showed signs of over-exploitation, where the exploitation ratio obtained were 0.75 year^-1.  In the present study the exploitation ratio of 0.77 year^-1 was derived, thus showing signs of overexploitation which is in agreement with the studies of Ghosh et al., ^[19].  Therefore, this study is an attempt to monitor the population parameters in order to understand the status of exploitation of Auxis thazard in North-West coast of India.

CONCLUSIONS- Management of fisheries is a major concern for sustainable exploitation with due to consideration of ecosystem and conservation of biodiversity. In order to meet the management strategies, assessment of fish stocks and population parameters are crucial. Auxis thazard showed negative allometric growth and the exploitation ratio indicated signs of overexploitation. The fishing mortality (F) appears to be high therefore, this fishery needs proper management advisories. The result of this study provides information on the changes in the population parameters thereby, useful in sustainable exploitation of this resource duly considering conservation and management issues in the North west coast of India.

ACKNOWLEDGEMENTS- All authors are hightly thankful to the Fishery Survey of India and the Dept. of Animal Husbandry, Dairying and Fisheries, Min. of Agriculture and Farmers’ Welfare for extending constant support for accomplishing this work.

REFERENCES

1.         CMFRI. Central Marine Fisheries Research Institute, Cochin, Annual Report, 2016- 17. 2017; 289.

2.         Ingles J, and Pauly, D. An atlas of the growth, mortality and recruitment of Philippines fishes. ICLARM Technical Report 1985; (13):127.

3.       Yesaki M. Thailand. Biological and Environmental Observations. A report prepared for the Pole-and-Line Tuna Fishing in Southern Thailand Project. FAO. FI: DP/THA/77/008: 1982; Field doc. 3, p. 46.

4.         Yesaki M. Estimates of age and growth of kawakawa (Euthynnus affinis), longtail tuna (Thunnus tonggol) and frigate tuna (Auxis thazard) from the Gulf of Thailand based on length data. IPTP-89-GEN-17- AUG_1, Indo-Pacif, p. Development Management Programme. 1989.

5.         Dwiponggo A, Hariati T, Banon S, PalJmares ML, and Pauly D. Growth, mortality and recruitment of commercially important fishes and Penaeid shrimps in Indonesian waters. ICLARM Technical Reports 17, p. 91. Research Institute for Marine Fisheries, Jakarta, Indonesia and International Centre for Living Aquatic Resources Management, Manila, Philippines. 1986.

6.         Lu Z, Quanshui D, and Youming Y. Growth and mortality of Auxis thazard in the Taiwan Strait and its adjacent sea. J. Fish. China, 1991; 15(3): 228-235.

7.         Yesaki M and Arce F. A review of the Auxis fisheries of the Philippines and some aspects of the biology of Frigate (A. thazard) and bullet (A. rochei) tunas in the Indo-Pacific region. In: Shomura, R.S., Majkowski, J. & Langi, S. (Eds.) Proceedings of the First FAO Expert Consultation on Interactions of Pacific Tuna Fisheries, 3-11 December 1991, Noumea, New Caledonia, FAO Fisheries Technical Paper 336/2, 1994.

8.         Tao Yu, Chen Mingru, Du Jianguo, Lu Zhenbin and Yang Shengyun. Age and growth changes and population dynamics of the black pomfret (Parastromateus niger) and the frigate tuna (Auxis thazard) in the Taiwan Strait. Department of Oceanography, Xiamen University, Xiamen, China Lat. Am. J. Aquat. Res., 2012; 40(3): 649-656.

9.         Geehan J, and Pierre L. Review of the statistical data available for neritic tuna species. IOTC-2015- WPNT-07 Rev 1, 2015; 39.

10.     Hartaty H and Setyadji DB. Population parameter of frigate tuna (Auxis thazard) in the Sibolga and Adjacent waters. BAWAL. 2016; 8(3) December 2016: 183-190.

11.     Pillai NGK, and. Ganga U. Fishery and Biology of Tunas in the Indian Seas. CMFRI, Cochin: 1985; 35.

12.     Silas EG, Pillai PP, Srinath M, Jayaprakash AA, Muthiah C, Balan V, Yohannan T M, Siraimeetan P, et al. Population dynamics of tunas: stock assessment. In: Silas, E.G. (Ed.), Tuna fisheries of the exclusive economic zone of India: biology and stock assessments. CMFRI Bulletin 1985; (36): 20-216.

13.     Siraimeetan P. Fishery and bionomics of tunas at Tuticorin. In: Silas, E.G. (Ed.), Tuna fisheries of the Exclusive Economic Zone of India: biology and stock assessments. CMFRI Bulletin  1985; (36): 86-216.

14.     Joseph L, Maldeniya R, and Van der Knaap M. Fishery and age and growth of kawakawa (E. affinis) and frigate tuna (A. thazard). In: Collective Volume of Working Documents presented at the Expert Consultation on Stock Assessment of Tunas in the Indian Ocean, Colombo, Sri Lanka, 4-8 December 1986. Indo-Pacific Tuna Development Management Programme, 1986; (l 2): 113-23.

15.     Kasim HM. Fishery, growth, mortality rates and stock assessment of Auxis thazard (Lacepede) along Tuticorin coast, Gulf of Mannar. The Fifth Indian Fisheries Forum Proceedings, 2002; 17-20 January 2000, Orissa, India.

16.     Jude D, Neethiselvan N, Gopalakrishnan P, and Sugumar G. Gill net selectivity studies for fishing frigate tuna, Auxis thazard Lacepede (Perciformes: Scombridae) in Thoothukkudi waters, southeast coast of India. Indian J. Mar. Sci., 2002; 31(4): 329-333.

17.     Kasim HM, and Abdussamad EM. Stock assessment of coastal tunas along the east coast of India. In: Somvanshi, V.S., Varghese, S., & Bhargava, A.K. (Eds.), Proceedings of Tuna Meet-2003, Kochi, 2003; 42–53.

18.     Abdussamad EM, Pillai PP, Kasim HM, and Balasubramanian TS. Fishery and population characteristics of coastal tunas at Tuticorin. J. Mar. Biol. Ass. India, 2005; 47(1): 50-56.

19.     Ghosh S, Pillai NGK, Dhokia HK. Fishery, population characteristics and yield estimates of coastal tunas at Veraval. Indian J. Fish, 2010; 57(2):7-13.

20.     Ghosh Shubhadeep, Sivadas M, Abdussamad EM, Rohit Prathibha, Koya KP. Said, Joshi KK, Anulekshmi C, et al. Fishery, population dynamics and stock structure of frigate tuna Auxis thazard (Lacepede, 1800) exploited from Indian waters. Indian J. Fish., 2012; 59 (2): 95-100.

21.     Abussamad EM, Koya KP, Rohith P, and Kuriakaose S. Neritic tuna fishery along the Indian coast and biology and population characteristics of longtail and frigate tuna. IOTC–2013–WPNT03–18, 2013; 2: 8.

22.     Gayanilo FC. Jr, Sparre P, and Pauly D. The FAOICLARM Stock Assessment Tools (FiSAT) User’s Guide. FAO computerized information series (Fisheries). No. 8. Rome, FAO, 1996; 26.

23.     Beverton RHJ and Holt SJ. A review of methods for estimating mortality rates in exploited rates in exploited fish populations with special reference to source of bias in catch sampling. Rapp. P.V. Reun. CIEM, 1956; (140): 67-83.

24.     Pauly D. On the interrelationships between natural mortality, growth parameters and mean environmental temperature in 175 fish stocks. J. Cons. Int. Explor. Mer., 1980; 39: 175-192.

25.     Munro JL and Pauly D. A Simple Method for Comparing Growth of Fishes and Invertebrates. ICLARM Fishbyte, 1983; 1:5-6.

26.     Pauly D and Munro JL. Once More on the Comparison of Growth in Fish and Invertebrates. ICLARM Fishbyte, 1984; 2: 21.