Studies Regarding the Biological Parameters of Azov Shad (Alosa tanaica, Grimm, 1901) from the Romanian Black Sea Coast George TIGANOV 1,2*), Lucian OPREA2), Valodia MAXIMOV1) 1) National Institute for Marine Research and Development “Grigore Antipa“ Constanta, Mamaia Bvd, 300, Constanta, Romania 2) Faculty of Food Science and Engineering, “Lower Danube” University of Galati, Domnească Str, 111, Galati, Romania *Corresponding authors, e-mail: gtiganov@alpha.rmri.ro Bulletin UASVM Animal Science and Biotechnologies 73(1)/ 2016 Print ISSN 1843-5262; Electronic ISSN 1843-536X DOI:10.15835/buasvmcn-asb: 11947 Abstract Azov shad (Alosa tanaica, Grimm 1901) is a marine anadromous species, which migrates for spawning from sea into fresh water lakes and rivers. It winters in the sea and appears close to shore in spring when the water temperature reaches the value of approximately 6 degrees Celsius. The paper presents the biological parameters such as length and weight class structure, age, sex ratio and degree of maturation of the commercial fish Azov shad belonging to the family Clupeidae. The investigations were performed during 2014 on fish caught along the entire Romanian coast from Sulina to Vama Veche. The study of the behaviour of Azov shad (reproduction, migration, feeding) is important to understand the impact on populations and to find sustainable solutions to manage these aspects. The preference for certain areas of distribution, for feeding and breeding was determined by analysing samples collected by passive fishing (shad gillnets set in all fishing points across the Romanian Coast). The main aim of this research is to identify the current state of Azov shad population along the Black Sea Coast considering that its biology and conservation are less known. Keywords: Black Sea, Azov shad, catches, length, weight, age INTRODUCTION Three shad species of the genus Alosa are known in the north–western basin of the Black Sea, including the Sea of Azov: Danube shad (Alosa immaculata–Bennett, 1835), Caspian shad (Alosa tanaica – Grimm, 1901) and Black Sea shad (Alosa maeotica– Grimm, 1901). The concept of sustainable use, addressing the impact of fishing on the stock dynamics, is recently introduced for the inland waters of Romania, with applications to freshwater fish stocks in the Danube Delta (Staras et al., 1993; Navodaru and Staras, 1996). Studies on the dynamics of shad stocks in relation to operation have been previously conducted by the Bulgarian researcher Ivanov, in collaboration with Beverton (1985). The current level of knowledge of the biology of shad originates from the research of Romanian and Russian specialists in the 1960’s and 1970’s, but in the last 30 years many changes have occurred in the environmental and exploitation conditions of Alosa species. The biology, ecology and status of Alosa in Romanian waters have been studied by many authors since the beginning of the 19th century: Antipa (1905; 1909); Kovachev (1922); Drensky (1923); Leonte (1943); Cristea A. and Cristea E., TIGANOV et al 2 (1958); Banarescu (1964); Kolarov (1991 a, b and c); Navodaru (1996; 1997); Navodaru et al.,(1997, 1998, 2003, 2008); Maximov (2006, 2007) and Maximov et al.,(2011 a, 2011b). The research performed has led to the knowledge of the current state of Alosa immaculata populations characterised by constantly decreasing numbers under anthropogenic pressure. Investigations were conducted along the entire Romanian Black Sea Coast, in almost all fishing points, by organising both expeditions along the coast (gillnet fishing) and sea surveys (pelagic trawl fishing). Azov shad (Alosa tanaica, Grimm, 1901) is the smallest representative of the three shad species present in the north – western part of the Black Sea, a commercial fish species that has modest economic value in this area of distribution. The main goal of this research is to identify the current state of Azov shad population along the Black Sea Coast. The paper presents the biological parameters, such as length and weight class structure, age, sex ratio and degree of maturation of the commercial fish Azov shad, belonging to the family Clupeidae. MATERIAL AND METHODS The data and information regarding the geographic distribution of Alosa species were collected within the monitoring plan developed during 2014, for research expeditions carried out at sea, on board the research vessel “Steaua de mare”, equipped with pelagic trawl (Photo 1) and pneumatic boat in order to carry out specialised fishing with gillnets (Photo 2). Photo 1 Pelagic trawl fishing Bulletin UASVM Animal Science and Biotechnologies 73(1) / 2016 A total of 4 complex scientific expeditions have been conducted, in which 41 pelagic hauls have been performed, a fishing effort of 41 hours of trawling and over 1,200 hours effort of gillnet fishing (four strings, of four nets, with a length of 400 m/each, and the mesh size varying between 28÷ 36 mm). The perimeters were selected to be representative for each habitat type and species of interest (Fig.1). The qualitative and quantitative composition of Azov shad catches was achieved by centralising, over periods of time, the data obtained during the research surveys and interviews with fishermen in the area. In order to study the biological parameters of the Azov shad species, from the specimens collected samples were taken for each species, which were analysed in the laboratory, focusing in particular on: length class structure, weight and age, sex, degree of gonad maturity, elements required to estimate the growth parameters. Biometric measurements were made for total length (Lt), while for centralisation the errors were lower than 1 centimetre. The weight was determined in grams, with an accuracy of ±1 g. For the determination of the total length (Lt) - weight (W) ratio, the following relation was used (Carlander, 1977): W = a · Ltb where: W = fish body weight; Lt = total length of the fish; a and b = regression constants. The values of a and b were determined using the least squares method (Snedecor, 1968), Photo 2 Gillnet fishing Studies Regarding the Biological Parameters of Azov Shad (Alosa tanaica, Grimm, 1901) from the Black Sea Coast included in the FISHPARM programme (Prager, Saila and Recksiek, 1987, 1989, 1994). RESULTS AND DISCUSSIONS Azov shad (Alosa tanaica, Grimm 1901) is a marine anadromous species, which migrates for spawning from sea into freshwater littoral lakes and rivers. It winters in the sea and appears close to the shore in spring, when the water temperature Fig. 1 Areas where shad survey fishing was performed 3 reaches the value of approximately 6 degrees Celsius. During the analysed period, Azov shad was present throughout the survey fishing perimeter. The largest number of specimens was caught in the perimeters Sulina, Sf. Gheorghe, Sakhalin and Zatoane, and the fewest in the perimeters Vadu, Chituc and Periboina. → in spring season (April, 2014) was highly productive for the scientific fishing of Azov shad, approx. 36.50% of the total catches of 2014 being caught now (123 individuals). The geographical distribution was broad, being reported in all perimeters of ROSCI 0066 Danube Delta - marine zone site. Thus, in mid-water trawl fishing, of the ten hauls, the Azov shad was caught only in the sectors Sakhalin and Perisor, at depths of 10.6 - 17.1 m (2 individuals each, yield 0.1 - 1.00 kg/ hour), while in gillnet fishing set at 3.0 - 10.0 m depths, Azov shad was reported in all sectors: Periboina (13 individuals), yields 0.1 – 1.00 kg/ hour, Sakhalin (48 individuals) and Zatoane (36 individuals), yields 0.1 – 1.00 kg/hour, Chituc (6 individuals) and Perisor (18 individuals), yields 0.1 – 1.00 kg/hour, were the sectors with the highest distribution; → in summer season (July 2014) was the most productive for Azov shad research fishing, approx. 49.1 % of the total number of individuals (165 individuals) being caught now, yet its distribution was more scarce, occurring in catches only in the perimeters Sulina (79 individuals), Sf. Gheorghe (65 individuals) and Sakhalin (21 individuals). In mid-water trawl fishing, in the ten hauls performed, Fig. 2 - Spatial distribution of Azov shad caught off the Romanian coast Bulletin UASVM Animal Science and Biotechnologies 73(1) / 2016 TIGANOV et al 4 % Alosa tanaica 336 individuals Lm - 165.5 mm Gm - 42.1 g 60 50 40 30 20 10 0 Class size (mm) Female Male Total Fig. 3 - Length class structure in Azov shad Fig. 4 - Age class structure in Azov shad (%) Fig. 5 - Sex ratio in Azov shad Fig. 6 - Length / weight relationship for Azov shad (Alosa tanaica) Bulletin UASVM Animal Science and Biotechnologies 73(1) / 2016 Studies Regarding the Biological Parameters of Azov Shad (Alosa tanaica, Grimm, 1901) from the Black Sea Coast Azov shad did not occur. In gillnet fishing set at 3.0 – 7.9 m (Sulina), the fishing effort ranged between 0.1 – 1.00 kg/hour, at 5.9 - 6.4 m depth (Sf. Gheorghe), yield 0.1 - 2.0 kg/hour, and at 4.3 – 7.9 m depth (Sakhalin), yield 0.1 – 1.00 kg/hour;→ in autumn (September, 2014), the Azov shad was reported only in gillnet fishing, in the perimeters Perisor, Zaton and Sahalin. Thus, the gillnets were set at 4.3 - 6.7 m depths, 48 individuals being caught (yields ranging between 0.1- 1.00 kg/ hour), namely in Perisor (18 individuals), at 5.3 - 6.8 m depths, the yields ranged between 1.0 2.99 kg/hour and 3.0 - 4.99 kg/hour, while in the sector Zaton (16 individuals) and Sakhalin (14 individuals), the yields ranged between 0.5 - 1.0 kg/hour and 1.0 - 2.99 kg/hour. Length / weight relationship The coefficients of the length / weight relationship determined for the period 2014 for the Azov shad : CONCLUSION The shad species are present throughout the year, the abundance of distribution increases from south-west to north-east and from open sea, at the 20 m isobath, towards the shore, with a maximum reached at the Danube mouths; The population structure comprises 2-5 year old generations, in both the Danube and the Black Sea, therefore they are part of the same migratory spawner populations. The maturity degree of shads in the Black Sea suggests the fact that shads are here in spring - for feeding and the breeding migration towards the Danube mouths - and in summer and autumn for feeding before the breeding of the subsequent spring or after breeding the ongoing year. The management measures for the conservation of Alosa involve actions both in the Black Sea and in the Danube, consisting of: - protection of migrants breeding in time and space (prohibition/closed areas and seasons); - protection of populations of Alosa by regulating the methods and fishing tools both in the sea and in the Danube; - regulatory measures on the fishing effort and catch extracted for sustainable fishing. It is necessary to restore the connectivity of the Black Sea to the lagoon coastal lakes, which 5 are essential habitats for the reproduction and feeding of Alosa juveniles. Only two shad species occurred in survey fishing, namely Alosa immaculata and Alosa tanaica; During the past 50 years, Alosa maeotica has not been reported as occurring in Romania, thus considering the official fishery records of the past years erroneous. REFERENCES 1. Antipa Gr. (1905). Die Clupeinen des Westlichen Teiles des Schwatzen Meeres der Donaumündungen. Denkschr. Akad. Wiss. Wien, Marh.-Naturw. Kl., 28:1-56, 3 pl. 2. Antipa Gr. (1909). Fauna ichtiologica a Romaniei, Bucuresti, Acad. Rom., Publ. Fond. Adamachi, 294:31 3. Banarescu P. (1964). Fauna R.P.R.. Pisces-Osteichthyes. Ed. Acad. R.P.R., Bucuresti, vol. XIII, 959 p. 4. Cristea A, Cristea E. (1958). Unele rezultate obtinute in urma cercetarii prolificitatii scrumbiei de Dunare (Alosa pontica Eichwald), Bul. ICP, 17 (3): 25-32. 5. Drenski P.(1923). Contribution to the study of fishes in the Black Sea collected near the Bulgarian Coast. 6. BAS, Sofia, 59–112 p. 7. Kolarov P (1991a). Alosa pontica pontica (Eichwald, 1938). Pages: 338–387 In H. Hoestland, Editor. The freshwater fishes of Europe. Clupeidae, Anguilidae. Aula-Verlag, Wiesbaden, Germany. 8. KolarovP. (1991b). Alosa caspia nordmani (Eichwald, 1938); Pages 154–209; In: H. Hoestland, Editor. The freshwater fishes of Europe. Clupeidae, Anguilidae. Aula-Verlag, Wiesbaden, Germany. 9. Kolarov, P. (1991c). Alosa maeotica maeotica (Grimm, 1001). In H. Hoestland Editor: p. 309–322. The freshwater fishes of Europe. Clupeidae, Anguilidae. Aula-Verlag, Wiesbaden, Germany. 10. Kovachev, V. (1922). Freshwater ichthyofauna of Bulgaria. Arhkivi na Ministerstvoto na Zemedelieto [Archives of the Ministry of Agriculture of Bulgaria], 3:1–142. (In Bulgarian.) 11. Leonte V. (1943). Cateva observatiuni asupra biologiei speciei Alosa nordmanni Antipa. Analele Institutului de Cercetari Piscicole Romane 2:273–280. 12. Maximov V. - (2006) - Studii de evaluare a stocurilor de resurse acvatice vii în vederea stabilirii capturii totale admisibile (TAC), pe specii si zone (Marea Neagră, Delta Dunării, fluviul Dunărea, lacurile de acumulare) - zona Marea Neagra, contract ANPA 2006: 56p 13. Maximov V. (2007). Studii de evaluare a stocurilor de resurse acvatice vii in vederea stabilirii capturii totale admisibile (TAC), pe specii si zone (Marea Neagră, Delta Dunării, fluviul Dunărea si râul Prut, lacurile de acumulare) - zona Marea Neagra, contract ANPA 2007, 69 p 14. Maximov V, Radu G, Anton E, Zaharia T. (2010).The Analysis of the Evolution of Fishing and the Biological Characteristics of the Main Species from the Romanian Pontic Basin, between 2000 and 2008 - J. Environ Prot Ecol. 12 (3):999–1007 http://www.jepe.gr Bulletin UASVM Animal Science and Biotechnologies 73(1) / 2016 6 15. Maximov V, Patras E, Oprea L, Zaharia T, Radu Gh. (2011a). Contributions to the Knowledge of the Biological Characteristics of Main Marketable Fish Species from the Black Sea Romanian Area, between 2005-2009. J. Environ. Prot. Ecol., 12 (3): 990 999; 16. Maximov V, Patras E, Oprea L, Zaharia T, Radu Gh. (2011b). The Analysis of the Evolution of Fishing and the Biological Characteristics of the Main Species from the Romanian Pontic Basin, between 2000 and 2008. Marine Res, 39: 211238 17. Michael H, Prager S, Saila B, Recksiek CW - Fishparm: A Microcomputer Program for Parameter Estimation of Nonlinear Models in Fishery Science, Old Dominion University Oceanography Technical Report: 87–10, Issued November, 1987, Sec Ed: December, 1989, Reprinted November, 1994 18. Navodaru I, Buijse AD, Staras M. (2003). Fish community structure in lakes of the Danube Delta. International Review Of Hydrobiology, 87 (2-3), pp. 329-348, RIZA Inst In: Inland Water Management & Waste Water T, NL-8200 AA Lelystad, Netherlands. 19. Navodaru I. (1997). Evolutia efectivelor scrumbiei de Dunare in noile conditii ecologice ale fluviului si masuri de mentinere a lor. PhD Thesis. ”Lower Danube” University of Galaţi”. 198 p. Bulletin UASVM Animal Science and Biotechnologies 73(1) / 2016 TIGANOV et al 20. Navodaru I. (2008). Estimarea stocurilor de pesti si a pescariilor. Ed. Dobrogea, Constanta, Romania: 295 p. 21. Navodaru I. (1996) Exploitation of Alosa pontica in the Danube Delta, Romania. In: I.G. Cowx (Ed.) Stock Assessment in Inland Fisheries. Oxford: Fishing News Books. Blackwell Science, pp. 448–453. 22. Navodaru I.(1998). Pontic Shad: a short review of the species and its fishery. Shad Journal, 3(4): 3–5 23. Navodaru I.,Waldman JR (2003). Shads of Eastern Europe from the Black Sea: Review of Species and Fisheries. American Fisheries Society Symposium 35: 69-76. In: K. E. Limburg and J. R. Waldman, Ed., Biodiversity and Conservation of Shads Worldwide. 24. Staraş M, Cernişencu I, Năvodaru I. (1993). Contribuţii la cunoaşterea stării şi exploatării stocului de şalău (Sitzostedion lucioperca L) din lacul Razim. In: Analele Ştiinţifice ale Institutului Delta Dunării, Tulcea. pp. 255258. 25. Staras M, Corhan Gh, Daneş M, Cernisencu I, Navodaru I, Grigoraş I. (1996). Pachet de programe pe calculator pentru estimarea stocurilor de peşti. Analele Ştiinţifice ale Institutului Delta Dunării, Tulcea, 2:339-343.