STATE OF THE FISHERIES, STOCK ASSESSMENT AND MANAGEMENT OF THE BLACK SEA TOURBOT (PSETTA MAXIMA MAEOTICA P.) IN ROMANIA

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1 STATE OF THE FISHERIES, STOCK ASSESSMENT AND MANAGEMENT OF THE BLACK SEA TOURBOT (PSETTA MAXIMA MAEOTICA P.) IN ROMANIA V. MAXIMOV, T. ZAHARIA, S. NICOLAEV National Institute for Marine Research and Developmen Grigore Antipa Constanta / Abstract: The Black Sea ichthyofauna suffered major changes in the last 50 years, concerning both the qualitative and quantitative structure, and the different species behavior. These changes are the consequences of the human activities, both directly by the fishing pressure and indirectly by deteriorating the environmental conditions, especially in the Western part of the sea. The turbot (Psetta maxima maeotica Pallas, 1811), a demersal species that populates the continental shelf found under the Romanian jurisdiction at the Black Sea, represents an important segment of the fishing potential under the aspect of the commercial interest, the demand on the internal and international market. From among the demersal species, the turbot presents a big interest because it is suitable for practicing an industrial, specialized fishing, and by an appropriate management of the exploitation and a good valorisation of the catches to ensure the economical relaunching of the national marine fisheries, determined by the offer on the market of some valuable fishing products, which demand on the market is poorly satisfied. The paper presents the present state of turbot fishing, at the Romanian Black Sea shore, based on the obtained results in the researches made during The investigations on the turbot populations in the Romanian sector focused on: captures evolution, fishing effort and c.p.u.e., population structure, biological parameters and fishable agglomerations biomasses. At the same time, the main biological characteristics of the turbot are presented, referring to the length class structure, mass and age. Also, the paper refers to the present tendencies in the evolution of the exploitable turbot stocks. At the end, the legislative frame in which the fishing activity takes place is presented, focusing on territorial waters and economical exclusive zone, the main reglementations being quoted. Keywords: Black Sea, catches, c.p.u.e., turbot, growth parameters, reproducers biomass, stock, management. INTRODUCTION Over the last 50 years, the Black Sea ichthyofauna has undergone major changes concerning either its qualitative and quantitative structure and the behaviour of various species. These changes are consequences of human activities, directly through the fishing pressure and indirectly through the deterioration of the environmental conditions, especially in the Western part of the Black Sea. Demersal marine fish species in Romania enjoys a long tradition, its practice was recorded as an occupation of the fishing settlements in Dobrogea eighteenth and nineteenth centuries and marine 1

2 fisheries Romanian century period. The bottom fish species inhabiting the Romanian Black Sea shelf represent the most important part of the regional fishery potential considering the commercial interest, the demand in the home and foreign market 1, 3. MATERIAL AND METHOD Methodology and techniques used for collecting, checking, processing and data analyzing, as well as for assessment of fish stocks are generally those accepted in the whole Black Sea basin and in compliance with the international one. The qualitative and quantitative composition of fish catches was obtained from the fishing statistic achieved through the centralization, on times, of data obtained from the commercial companies in the field, through interviews with the fishermen and scientific cruises especially organized every year. RESULTS AND COMMENTS Turbot marine demersal species, belonging to soft bottoms. The juveniles stay close to the shore, on sandy bottoms and as they grow up they retire to bigger depths. The adults are located in winter at depths of m. In spring (March April) they come close to the shore, to a depth of m (the inferior limit of the Corbulomya facies), but not everywhere, only in specific places, where they form big reproduction crowds. The specie reproduces along the whole Black Sea shore (8 12ºC temperature, 16,29 19,3 salinity), from the end of March to July, close to the shore, at depths of 50 meters. After they reproduce, they dissipate on the whole surface of the Romanian continental platform and than retire again at depths of over m (Fig.1) 1, 3. Fig. 1 Migrating routes and feeding sectors of the turbot, on the Black Sea continental platform Current status of marine fisheries The marine demersal fishing along the Romanian Black Sea shore is made in two ways: 2

3 fishing with coast trawler vessels, B-410, Baltica and T.C.M.N. types, equipped with pelagic trawl and gill nets, which activate offing, at depths bigger than 20 meters; fishing along the shore, practiced in the 28 fishing points, between Sulina Vama Veche, in shallow waters (3,0 11,0 m), using fix tools (trap nets, gill nets, longlines and beach seines) and at depths of m, using gill nets and longlines 5, 6, 7. Capture, fishing effort and c.p.u.e In the 80 s, by buying the first two fishing vessels type B-410 and the reorganization of the coastal fishing fleet by buying new trawlers (Baltica and TCMN), the Romanian catches grew progressively, year by year, from t/1981 to t /1986. Although the annual catches doubled, the demersal species percentage, especially turbot, reduced, varying from 2 and 10 tones per year ( ), and turbot fishing was declared almost abandoned 3, 4. After 2001, the economic operators that activates in the Romanian marine sector changed their options, by doting their vessels with equipments and fishing tools specialized in turbot fishing. The catches easily grew, year by year, to 12,527 kg/2001 and almost kg/year during (48,064 tons/2007 and 47,112 kg/2008 (Fig. 2) 2, 4, 5, 6. Kg Psetta maxima maeotica turbot Total catchs 266,175 Kg Turbot Fig. 2 Turbot catches years In the coastal area of the Romanian shallow marine sector, fishing with fix tools is characterized by concentrating the activity in the first three/four months of the season (April July), when usually the turbot comes close to the shore for reproduction and feeding. The fishing is practiced along the shore, from Sulina to Vama Veche, in the 28 fishing points. For practicing an industrial demersal fishing (turbot), 120 boats were licensed (71 having motors), and over 150 persons who use 30 trap nets, gill nets, 10 beach seine and having about a 515 fishermen personal. The catches and fishing productivity differed from year to year, alter the fishing effort (trap nets number, gill nets number and fishing efectives), the hydroclimatic conditions evolve and the state of the turbot stock. The best periods for fishing are in the intervals from March to July and from November to December. Those intervals coincide with the formation of turbot agglomerations near the coast for breeding and feeding. For the rest periods, the species are spreading across the entire continental platform of the Romanian Black Sea (Fig. 3) 2, 4, 5, 6. 3

4 kg I II III IV V VI VII VIII IX X XI XII Fig. 3 Capture of turbot, between 2006 and 2008 The average productivity obtained in was of kg/nets, kg/day, kg/hour, in about fishing days with 3,794-4,450 turbot gillnets and 4,560-4,925 hours of fishing (the interval in which the fishing gear was in the water)(table 1) 4, 5, 6, 7. Table 1 Evolution of catches, fishing effort and c.p.u.e. in turbot fishing, between 2006 and 2008 Years Catch (kg) e f f o r t c. p. u. e. no. gill nets no. day no. hours kg / gill nets kg/day kg/hours , , , , , , Determination of biological parameters Determination of biological parameters of fish species with economic interest is an important structure in determining the demographic parameters of growth and other parameters needed to study recruitment, mortality, number and biomass by age class. a. Structure classes lengths, mass and age The study of the turbot s biological parameters, between , was made by biometrical and gravimetrical measurements, and age determinations, from April to November, at a number of 1,951 individs. The analises of the turbot catches lenght class and mass structure, evinced the presence of mature individuals and a high homogenenity of the crowds. The turbot individuals lenghts varied between cm /247 7,392 g, the dominant classes being cm/1,227 3,457 g (Fig. 3) 2, 4, 5, 6. The average body lenght was 48,16 cm and the average mass 2,127 g. The age componence of the turbot catches, from all the analised period, evinces the presence of the 1 to 7 years old individuals, the basis of the captures being made by the 5years old individuals (30.6% of all the analised) and 4 years (28.3%), closely followed by the 3 years old (18.5%) and 6 years (9.20%)(Fig. 4) 2, 4, 6. The sex ratio was roughly 1/1, with a small female dominance (57.2%). b. Determination of vital parameters * relationship length/mass - the coefficients of the relationship between length/mass 4

5 % Turbot (Psetta maxima maeotica) no. total - 1,354 exp. L. med. - 50,5177 cm W. med ,57 g classes length (cm) Fig. 3 The lenght frequency (%) of the turbot capture % Turbot (Psetta maxima maeotica) no. total - 1,331 exp. L. med. - 50,159 cm W. med ,5 g year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 years ,6 26,7 27,6 19,4 6 6,5 1, ,4 9,3 20,2 29,3 29,3 7,3 2,2 0,9 0, ,2 23,2 43,6 18,8 5,6 1, ,1 19,7 21,7 33,4 14,8 5,2 2, ,4 20,5 28,7 22,5 12,3 7,5 3,1 2 Fig. 4 Age class structure (%) of the turbot catches have been determined annually in the period from 2006 to It establishes the following equation for the turbot species (Table 2 and Fig. 5) 4, 6, 7 : W t = x L t, r = ; Table 2 Coefficients relationship length / weight to skate species established Parameters Length Year a b r interval (cm) , ,1459 0, , ,2104 0, , ,2162 0, * growth parameters - during , these parameters indicated a fast rate of growth for the first years of life, with values of the coefficient of catabolism (k) between Based on the growth parameters, it was established the following Von Bertalanffy equations for turbot (Table 3 and Fig. 6) 4, 6, 7 : L t = [1- e (t+3.81)] ; W t = [1 -e 0149 (t ) ] 3 5

6 * estimation of mortality rates - using Pauly's relationship and other formulas were determined values of M, for year 2008, Z and M , 6, 7. Fig. 5 The relationship curve between length/weight Table 3 Parameters of growth of turbot in Romanian seaside Year L (cm) W (g) k t 0 Length interval (cm) method Gulland and Holt , , , method Walford ,14 0, ,90 0, ,30 0, method Von Bertalanffy ,15 0, ,40 0, ,50 8,374 0, Ages composition ,30 0,215-1, Fig. 6 The growth curve of turbot The research fishing was in three ways (Fig. 7): * stationary fishing using traps net and gill nets - practiced in three locations, along the Romanian seashore, in 2 Mai Vama Veche, Constanţa and Cap Midia Vadu sectors; * fishing using beach seine practiced from April to July, in two sectors, 2 Mai Vama Veche and Constanţa Cap Midia; * fishing using the bottom trawl practiced from April to November, by organizing four expeditions on sea, on the whole continental bottom, until 80 meters depths, practiced between Sulina and Vama Veche. 6

7 fishing using the bottom trawl stationary fishing using traps net and gill nets fishing using beach seine Fig. 7 The research fishing Experimental fishing made with the bottom trawl Between , research expeditions were organized over 200 trawlings made, at different depths (10, 20, 30, 40, 50, 60 and 70 meters). The activity sector extended on the whole Romanian continental platform, between Sulina and Mangalia. For estimating the fishable turbot crowds biomass, the holistic method of experimental trawling was used (the research surface method / Fig. 7), and for sampling the demersal trawl was used. The analize of the obtained results when the four expeditions were made, which covered a big part of the Romanian sector between Mangalia and Sulina, evinced the following aspects 6, 7 : * during the survey from spring season (April-May), the method of sweeping area was done on a surface of 2,702 Mm 2. The researched area is situated between 20 and 66 m isobaths, more exactly between Sulina and Mangalia. 28 trawlers survey with demersal trawl. The agglomerations reached an average of t/mm 2. This value it s much higher compared to the values obtained in the previous years when the maximum value was about t/mm 2, in addition, it is much closer to the value from 2006 when the value reached was about t/mm 2. The average values of the turbot catches, were contained in the limits between 0,001 kg/mm 2 and t/mm 2. Significant catches were recorded between 35 and 55 m isobates, in the Cap Midia - Tuzla (the change of abundance t/mm 2 ) Eforie Sud-Vama Veche ( t/mm 2 ) and Corbu - St. Gheorghe ( t/mm 2 )(Table 4, Fig.8). 7

8 Nr. square Evaluation of agglomerations of turbot in 2008 Researched area (Mm 2 ) Limites of variation of abundancy (t/mm 2 ) Media (t/mm 2 ) Total (t) Spring seson , Total 2, ,712 Autumn seson Total 2, Table 7 Total shelph (t) 2,661 t 3,581 t * the scientific research organized in autumn season (October-November), revealed that turbot had a flat distribution in large area between Mangalia and Sulina, with a greater density in Vama Veche-Constanta and Vadu-Sf. Gheorghe, agglomerations reaching an average of t/mm 2, respectively t/mm 2 (Table 7). During 32 sweeping area procedures conducted on an area of Mm 2, the distribution of turbot agglomerations was different. The average values of turbot catches, were situated in the limits between and t/mm 2. Some significant catches have been recorded between 30 and 45 m isobaths in Corbu-Sulina (limits of variation of the abundance of t/mm 2 ) and between 45 and 65 m isobates in the area that lies between Constanta-Vama Veche ( t/mm 2 )(Table 7 and Fig. 8). Maximum sustainable production (MSY), according to the method of Gulland (1970), was calculated for the two periods significant to turbot, respectively spring season and autumn season, added the biomass of standard and sub-standard individuals. The results obtained are 4, 6, 7 : spring seson - MSY = 0.5*0.27*1,712 = t, standard and sub-standard; autum seson - MSY = 0.5*0.27*2,356 = t, standard and sub-standard. Maximum sustainable production (MSY), calculated for the two periods according to the method Cadima, are the following (7): spring sesonl - MSY = 0.5 * (y + MB) = 254 tones; autum seson - MSY = 0.5 * (y + MB) = 341 tones. For the Romanian Black Sea sector, the maximum sustainable production (MSY) must not exceed tones. 8

9 spring seson autumn seson Fig. 8 Distribution and abundance of turbot agglomerations in 2008 Measures and recommendations concerning sustainable management of resources According to the present state of the fisheries the improvement and financial support for the reorganisation of the activities also ensuring a sustainable fishing are required, taking into account the environment protection, social development and economical welfare aspects. Romania is interested in protection of the turbot resources and in preservation of the customs of the fishermen communities and in their social and economical development for stabilisation of the turbot population from the coastal zone. 1. Creating the necessary premises for development of specialized turbot fishing, along the Romanian coast, is necessary 3, 5, 6, 7, 9 : a. renewal and vessel modernization for improving navigation safety and to ensure preservation of fishery products design; b. introduction of vessels for specific marine activities; c. equipping the fishermen with boats smaller than 12 m, designed, constructed and adapted to the marine environment; d. redesigning and improvement of fishing gears; e. establishment the clothes and gears manufactures; f. infrastructure development in order to ensure a long term profitable and competitive fishing industry; g. modernization of fish ports and landing points; 9

10 h. development of professional training for fishermen for acquiring knowledge on minimum necessary living marine resources and their place in the ecosystem; i. development of downloading shelter for coastal fisheries in order to improve working conditions, discards and their conditioning before market capitalization; j. establisment of first-sale centers; k. implementing the European quality standards; l. assuring the financial support to fishermen and producers; m. improving the image of the fishery sector; n. development the socio-economic measures to help fishermen: providing premium to young fishermen (under 40 years) which are starting for the first time a business in the fishing sector by purchasing a fishing boat / vessel; developing programs for professional reconversion of fishermen in areas outside fisheries (tourism and ecotourism); activity diversification in order to promote several occupations for fishermen. 2. Encouraging measures for reduction of fishing effort with the aim of protecting the resource 1, 3, 6, 7, 8 : Turbot fishing in the Black Sea is based on a special turbot fishing permits issued by NAFA, according with the Romanian legislation. A boat may obtain special authorization for turbot fishing under following conditions: a. to be included in the index of ships and fishing boats; b. to hold valid fishing license; c. to pay taxes in force; d. to be equipped with turbot gillnets, with a side mesh size of at least 400 mm and marked in accordance with legal provisions; e. to have global positioning equipment (GPS) to mark the place where they are located and where turbot fishing gear are used; f. to assure the vessels greater than 15 meters to hold Black Sea fishing diary and ships / boats less than 15 meters to hold coastal fishing logbook; g. to have VHF communications equipment or GSM, as appropriate; h. have service contract with a center point of landing and first sale of the subordinated; i. was not involved in illegal fishing; j. to meet the work program of the center point of landing and first sale. The obligations that vessels should have for special turbot fishing permits are: a. to comply the allocated area; b. to unload the caugh fish on the given landing point center and to transport it obligatory to the center of first sale subordinated c. to use tools (gill nets) side mesh 2a = 400 mm; d. to meet the minimum size for turbot, at discharge to be at least 45 cm; e. fishing diary to record the date and time of launching and positioning the turbot gillnets, position (latitude, longitude, depth) of installed tools and length of gillnets installed and the number of people involved in these activities. CONCLUSIONS The present paper draws the turbot management at the Romanian Black Sea littoral in 10

11 order to find the ways to protect this valuable resource and to sustain its exploitation. Modern fisheries management is often referred to as a governmental system of appropriate management rules based on defined objectives and a mix of management means to implement the rules, which are put in place by a system of monitoring control and surveillance. The main objectives of the turbot sustainable management are to: maximize sustainable biomass yield, maximize sustainable economic yield, secure and increase employment in coastal region, secure protein production and food supply, increase income from export, etc. REFERENCES 1. V. MAXIMOV, T. ZAHARIA: Sinteza datelor şi informaţiilor privind situaţia actuală a pescuitului demersal din zona litoralului românesc al Mării Negre; AGRAL Bucureşti, 29 p, 2000; 2. V. MAXIMOV, G. RADU, I. STAICU: Contributii la cunoasterea caracteristicilor biologice ale unor specii de pesti demersali din zona marina romaneasca a Marii Negre INCDM Constanta, Cercetari Marine / Recherches Marines nr. 36, p , ISSN: , 2006; 3. S. NICOLAEV, V. MAXIMOV: Cerinţe tehnice şi legale necesare promovării pescăriilor marine la scară mică în România, Simposionul International Protecţia şi Gestionarea Durabilă a ecosistemului Mării Negre, Imperativ al Mileniului trei, Ediţia a III-a, dedicat Zilei Internaţionale a Mării Negre, I.N.C.D.M. "Grigore Antipa", 29-31octobrie 2007, Constanta; 4. V. MAXIMOV, S. NICOLAEV, G. RADU, I. STAICU: Estimation of Growing Parametees for Main Demersal Fish Species in the Romanian Marine Area. Cercetări marine, INCDM Constanţa,. 37:p , 2008; 5. V. MAXIMOV, I. STAICU: Evolution of Demersal Fish Species catches from the Romanian Marine Area between 2000 and 2007; Cercetări marine, INCDM Constanţa, 37: , ISSN: , 2008; 6. V. MAXIMOV, G. RADU, I. STAICU, E. ANTON: Assessment study of turbot stocks (Psetta maxima maeotica) on Romanian Black Sea coast area; ANPA Bucureşti / JRC/STECF-UE / DG MARE, p 46, 2009; 7. V.S. RAYKOV, V. SHLYAKHOV, V. MAXIMOV, G. RADU, I. STAICU, M. PANAYOTOVA, M. YANKOVA, I. BIKARSKA: Limit and target reference points for rational exploitation of the turbot (Psetta maxima L.) and whiting (Merlangius merlangus euxinus Nordm.) in the western part of the Black Sea; Acta Zoologica Bulgarica 6th Anniversary Conference of Zoology May, Sofia. 8. G. DASKALOV, V. MAXIMOV, M. PANAYOTOVA, G. RADU, V.S. RAYKOV, M. ZENGIN: Review of Stock Assessment and Fisheries Management Advice of Black Sea Stocks in 2009; JRC/STECF-UE, 2008; 9. V. S. RAYKOV: Primary management objectives for sustainable Sprat (Sprattus sprattus L.) stock exploitation at the Bulgarian Black Sea coast - 11

12 preliminary results J. Environmental Protection and Ecology, 8 (2) (2007). 12