TY  - JOUR
AU  - Smederevac-Lalić, Marija
AU  - Kalauzi, Aleksandar
AU  - Regner, Slobodan
AU  - Navodaru, Ion
AU  - Višnjić Jeftić, Željka
AU  - Gačić, Zoran
AU  - Lenhardt, Mirjana
PY  - 2018
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1148
AB  - The relationship between the Lower Danube River level and Romanian annual catches of Pontic shad (Alosa immaculata, Bennett 1835) were analyzed. For analysis of long term data on the Danube River water level and Pontic shad catch, combinations of different methods were applied using statistical programs, SPSS 13.0 and MATLAB 6. Periodograms, containing cyclic patterns, were obtained using Fourier analysis. Significant oscillations were determined with Fisher-Whittle' s tests and residuals were calculated after subtracting these significant oscillations from the original signals. Autoregressive moving average (ARMA) models of residuals were finally applied. Results indicated that river water levels, and especially those in May, greatly explained the fluctuations of Pontic shad catch. Annual landings varied greatly and appeared to be cyclic. Varying river flow was considered to be one of the most important factors that cause fluctuations in the size of populations. Forecast indicates gradual increase of the catch in the next decade, followed by a decrease in other decades. Estimated as a vulnerable species of fish by the IUCN, development of the forecasting model of the future catch oscillations could be very helpful to regulate fishing efforts towards the sustainable use of stocks and species conservation.
PB  - Iranian Fisheries Science Research Inst-Ifsri, Tehran
T2  - Iranian Journal of Fisheries Sciences
T1  - Analysis and forecast of Pontic shad (Alosa immaculata) catch in the Danube River
EP  - 457
IS  - 3
SP  - 443
VL  - 17
DO  - 10.22092/IJFS.2018.116611
ER  - 

@article{
author = "Smederevac-Lalić, Marija and Kalauzi, Aleksandar and Regner, Slobodan and Navodaru, Ion and Višnjić Jeftić, Željka and Gačić, Zoran and Lenhardt, Mirjana",
year = "2018",
abstract = "The relationship between the Lower Danube River level and Romanian annual catches of Pontic shad (Alosa immaculata, Bennett 1835) were analyzed. For analysis of long term data on the Danube River water level and Pontic shad catch, combinations of different methods were applied using statistical programs, SPSS 13.0 and MATLAB 6. Periodograms, containing cyclic patterns, were obtained using Fourier analysis. Significant oscillations were determined with Fisher-Whittle' s tests and residuals were calculated after subtracting these significant oscillations from the original signals. Autoregressive moving average (ARMA) models of residuals were finally applied. Results indicated that river water levels, and especially those in May, greatly explained the fluctuations of Pontic shad catch. Annual landings varied greatly and appeared to be cyclic. Varying river flow was considered to be one of the most important factors that cause fluctuations in the size of populations. Forecast indicates gradual increase of the catch in the next decade, followed by a decrease in other decades. Estimated as a vulnerable species of fish by the IUCN, development of the forecasting model of the future catch oscillations could be very helpful to regulate fishing efforts towards the sustainable use of stocks and species conservation.",
publisher = "Iranian Fisheries Science Research Inst-Ifsri, Tehran",
journal = "Iranian Journal of Fisheries Sciences",
title = "Analysis and forecast of Pontic shad (Alosa immaculata) catch in the Danube River",
pages = "457-443",
number = "3",
volume = "17",
doi = "10.22092/IJFS.2018.116611"
}

Smederevac-Lalić, M., Kalauzi, A., Regner, S., Navodaru, I., Višnjić Jeftić, Ž., Gačić, Z.,& Lenhardt, M.. (2018). Analysis and forecast of Pontic shad (Alosa immaculata) catch in the Danube River. in Iranian Journal of Fisheries Sciences
Iranian Fisheries Science Research Inst-Ifsri, Tehran., 17(3), 443-457.
https://doi.org/10.22092/IJFS.2018.116611

Smederevac-Lalić M, Kalauzi A, Regner S, Navodaru I, Višnjić Jeftić Ž, Gačić Z, Lenhardt M. Analysis and forecast of Pontic shad (Alosa immaculata) catch in the Danube River. in Iranian Journal of Fisheries Sciences. 2018;17(3):443-457.
doi:10.22092/IJFS.2018.116611 .

Smederevac-Lalić, Marija, Kalauzi, Aleksandar, Regner, Slobodan, Navodaru, Ion, Višnjić Jeftić, Željka, Gačić, Zoran, Lenhardt, Mirjana, "Analysis and forecast of Pontic shad (Alosa immaculata) catch in the Danube River" in Iranian Journal of Fisheries Sciences, 17, no. 3 (2018):443-457,
https://doi.org/10.22092/IJFS.2018.116611 . .

TY  - JOUR
AU  - Lenhardt, Mirjana
AU  - Navodaru, Ion
AU  - Vassilev, M.
AU  - Kalauzi, Aleksandar
AU  - Regner, Slobodan
AU  - Višnjić Jeftić, Željka
AU  - Tošić, K.
AU  - Smederevac-Lalić, Marija
PY  - 2016
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/961
AB  - Data on the catch of Pontic shad in the Lower Danube River Region for the period 1920-2008 were used to make one-component and two-component models. The catch model for Pontic shad showed natural cyclic fluctuations with no sign of population decrease. The oscillation periods were 11.17 years and 9.56 years, which corresponded to solar activity cycles. In addition, as anchovy represents the main food source of Pontic shad in the Black Sea, the catch of anchovy in the Black Sea for the period 1950-2006 was modelled. Pearson's coefficient (cc=0.6785) indicated that 67.86% of the Pontic shad catch was dependent on the anchovy catch during the analysed time period. Besides the necessity for better gathering of data in the Lower Danube River Region on the catch of Pontic shad, there is also a need for more profound studies on this species. It is evident that this valuable fish species requires more attention from fish managers in all countries of the Lower Danube River Region.
PB  - Bulgarian Academy of Sciences
T2  - Acta Zoologica Bulgarica
T1  - Model of the Pontic Shad Alosa immaculata (Bennet, 1835) and Anchovy Engraulis encrasicolus (Linnaeus, 1758) Catch in the Danube River and Black Sea for the Period 1920-2008
EP  - 561
IS  - 4
SP  - 557
VL  - 68
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_961
ER  - 

@article{
author = "Lenhardt, Mirjana and Navodaru, Ion and Vassilev, M. and Kalauzi, Aleksandar and Regner, Slobodan and Višnjić Jeftić, Željka and Tošić, K. and Smederevac-Lalić, Marija",
year = "2016",
abstract = "Data on the catch of Pontic shad in the Lower Danube River Region for the period 1920-2008 were used to make one-component and two-component models. The catch model for Pontic shad showed natural cyclic fluctuations with no sign of population decrease. The oscillation periods were 11.17 years and 9.56 years, which corresponded to solar activity cycles. In addition, as anchovy represents the main food source of Pontic shad in the Black Sea, the catch of anchovy in the Black Sea for the period 1950-2006 was modelled. Pearson's coefficient (cc=0.6785) indicated that 67.86% of the Pontic shad catch was dependent on the anchovy catch during the analysed time period. Besides the necessity for better gathering of data in the Lower Danube River Region on the catch of Pontic shad, there is also a need for more profound studies on this species. It is evident that this valuable fish species requires more attention from fish managers in all countries of the Lower Danube River Region.",
publisher = "Bulgarian Academy of Sciences",
journal = "Acta Zoologica Bulgarica",
title = "Model of the Pontic Shad Alosa immaculata (Bennet, 1835) and Anchovy Engraulis encrasicolus (Linnaeus, 1758) Catch in the Danube River and Black Sea for the Period 1920-2008",
pages = "561-557",
number = "4",
volume = "68",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_961"
}

Lenhardt, M., Navodaru, I., Vassilev, M., Kalauzi, A., Regner, S., Višnjić Jeftić, Ž., Tošić, K.,& Smederevac-Lalić, M.. (2016). Model of the Pontic Shad Alosa immaculata (Bennet, 1835) and Anchovy Engraulis encrasicolus (Linnaeus, 1758) Catch in the Danube River and Black Sea for the Period 1920-2008. in Acta Zoologica Bulgarica
Bulgarian Academy of Sciences., 68(4), 557-561.
https://hdl.handle.net/21.15107/rcub_rimsi_961

Lenhardt M, Navodaru I, Vassilev M, Kalauzi A, Regner S, Višnjić Jeftić Ž, Tošić K, Smederevac-Lalić M. Model of the Pontic Shad Alosa immaculata (Bennet, 1835) and Anchovy Engraulis encrasicolus (Linnaeus, 1758) Catch in the Danube River and Black Sea for the Period 1920-2008. in Acta Zoologica Bulgarica. 2016;68(4):557-561.
https://hdl.handle.net/21.15107/rcub_rimsi_961 .

Lenhardt, Mirjana, Navodaru, Ion, Vassilev, M., Kalauzi, Aleksandar, Regner, Slobodan, Višnjić Jeftić, Željka, Tošić, K., Smederevac-Lalić, Marija, "Model of the Pontic Shad Alosa immaculata (Bennet, 1835) and Anchovy Engraulis encrasicolus (Linnaeus, 1758) Catch in the Danube River and Black Sea for the Period 1920-2008" in Acta Zoologica Bulgarica, 68, no. 4 (2016):557-561,
https://hdl.handle.net/21.15107/rcub_rimsi_961 .

TY  - CONF
AU  - Lenhardt, Mirjana
AU  - Višnjić Jeftić, Željka
AU  - Navodaru, Ion
AU  - Jarić, Ivan
AU  - Vassilev, Milen
AU  - Gačić, Zoran
AU  - Nikčević, Miroslav
PY  - 2012
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/515
AB  - The Danube River is 2,857 km long and navigable along the major part of its flow (2,411 km). Human activities have started to influence Danube River flow more significantly since the sixteenth century, through the flood prevention, navigation and hydropower plant construction activities. Two largest dams in the Danube, located at 943 river km ("Iron Gate I", constructed in 1970) and 863 river km ("Iron Gate II", constructed in 1984), have formed a large accumulation lake. These dams represent obstacles for migratory fish species, such as sturgeons and shads. Beside the negative impact of dams and the river flow regulation, common stocks of these species in the Lower Danube Region (LDR) are also impacted by unsustainable and illegal fishery and pollution. Major obstacle to an efficient common management of these fish stocks by LDR countries is a lack of management harmonization and coordination, as well as lack of common management plans that would be based on coordinated monitoring and research efforts in all LDR countries. Guiding principles for a good management plan for sturgeons and shads in the LDR should include efficient public and stakeholder participation, and a long-term vision that would be harmonized with the short-term social, cultural and economic needs. Availability of timely scientific information, provided through the broad and long-term monitoring and research activities, could determine the state of sturgeon and shad stocks and the efficiency of their current management.
PB  - Springer, Dordrecht
C3  - Environmental Security in Watersheds: the Sea of Azov
T1  - Fish Stock Management Cooperation in the Lower Danube Region: A Case Study of Sturgeons and Pontic Shad
EP  - +
SP  - 127
DO  - 10.1007/978-94-007-2460-0_7
ER  - 

@conference{
author = "Lenhardt, Mirjana and Višnjić Jeftić, Željka and Navodaru, Ion and Jarić, Ivan and Vassilev, Milen and Gačić, Zoran and Nikčević, Miroslav",
year = "2012",
abstract = "The Danube River is 2,857 km long and navigable along the major part of its flow (2,411 km). Human activities have started to influence Danube River flow more significantly since the sixteenth century, through the flood prevention, navigation and hydropower plant construction activities. Two largest dams in the Danube, located at 943 river km ("Iron Gate I", constructed in 1970) and 863 river km ("Iron Gate II", constructed in 1984), have formed a large accumulation lake. These dams represent obstacles for migratory fish species, such as sturgeons and shads. Beside the negative impact of dams and the river flow regulation, common stocks of these species in the Lower Danube Region (LDR) are also impacted by unsustainable and illegal fishery and pollution. Major obstacle to an efficient common management of these fish stocks by LDR countries is a lack of management harmonization and coordination, as well as lack of common management plans that would be based on coordinated monitoring and research efforts in all LDR countries. Guiding principles for a good management plan for sturgeons and shads in the LDR should include efficient public and stakeholder participation, and a long-term vision that would be harmonized with the short-term social, cultural and economic needs. Availability of timely scientific information, provided through the broad and long-term monitoring and research activities, could determine the state of sturgeon and shad stocks and the efficiency of their current management.",
publisher = "Springer, Dordrecht",
journal = "Environmental Security in Watersheds: the Sea of Azov",
title = "Fish Stock Management Cooperation in the Lower Danube Region: A Case Study of Sturgeons and Pontic Shad",
pages = "+-127",
doi = "10.1007/978-94-007-2460-0_7"
}

Lenhardt, M., Višnjić Jeftić, Ž., Navodaru, I., Jarić, I., Vassilev, M., Gačić, Z.,& Nikčević, M.. (2012). Fish Stock Management Cooperation in the Lower Danube Region: A Case Study of Sturgeons and Pontic Shad. in Environmental Security in Watersheds: the Sea of Azov
Springer, Dordrecht., 127-+.
https://doi.org/10.1007/978-94-007-2460-0_7

Lenhardt M, Višnjić Jeftić Ž, Navodaru I, Jarić I, Vassilev M, Gačić Z, Nikčević M. Fish Stock Management Cooperation in the Lower Danube Region: A Case Study of Sturgeons and Pontic Shad. in Environmental Security in Watersheds: the Sea of Azov. 2012;:127-+.
doi:10.1007/978-94-007-2460-0_7 .

Lenhardt, Mirjana, Višnjić Jeftić, Željka, Navodaru, Ion, Jarić, Ivan, Vassilev, Milen, Gačić, Zoran, Nikčević, Miroslav, "Fish Stock Management Cooperation in the Lower Danube Region: A Case Study of Sturgeons and Pontic Shad" in Environmental Security in Watersheds: the Sea of Azov (2012):127-+,
https://doi.org/10.1007/978-94-007-2460-0_7 . .

TY  - JOUR
AU  - Višnjić Jeftić, Željka
AU  - Lenhardt, Mirjana
AU  - Navodaru, Ion
AU  - Hegediš, Aleksandar
AU  - Gačić, Zoran
AU  - Nikčević, Miroslav
PY  - 2009
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/311
AB  - Specimens of Pontic shad (Alosa pontica Eichwald, 1838) were collected during April and May of 2006 in the Danube River (rkm 863) just downstream of the Iron Gate (Djerdap) II dam. Twenty-eight scales and 30 vertebrae were prepared and given to five interpreters with fish aging experience of from 3 to 30 years and with shad aging experience of from 0 to 12 years. Interpreters with experience in shad age determination showed lower values for the index of average percent error (IAPE) and an index of coefficient of variation (ICV). In regard to within-interpreter reproducibility, no significant differences were found between scale and vertebrae as structure for age determination. The most experienced reader showed the lowest value for IAPE, while the least experienced reader showed the highest value for IAPE. The results of this work indicate that experience in age determination by particular structure had more impact on age determination precision than specificity of structure, scale or vertebra. More work is needed on adopting standard protocols that must include some sort of common interaction between responsible age readers.
PB  - Srpsko biološko društvo, Beograd, i dr.
T2  - Archives of Biological Sciences
T1  - Reproducibility of age determination by scale and vertebra in pontic shad (alosa pontica eichwald, 1838), from the Danube
EP  - 341
IS  - 2
SP  - 337
VL  - 61
DO  - 10.2298/ABS0902337V
ER  - 

@article{
author = "Višnjić Jeftić, Željka and Lenhardt, Mirjana and Navodaru, Ion and Hegediš, Aleksandar and Gačić, Zoran and Nikčević, Miroslav",
year = "2009",
abstract = "Specimens of Pontic shad (Alosa pontica Eichwald, 1838) were collected during April and May of 2006 in the Danube River (rkm 863) just downstream of the Iron Gate (Djerdap) II dam. Twenty-eight scales and 30 vertebrae were prepared and given to five interpreters with fish aging experience of from 3 to 30 years and with shad aging experience of from 0 to 12 years. Interpreters with experience in shad age determination showed lower values for the index of average percent error (IAPE) and an index of coefficient of variation (ICV). In regard to within-interpreter reproducibility, no significant differences were found between scale and vertebrae as structure for age determination. The most experienced reader showed the lowest value for IAPE, while the least experienced reader showed the highest value for IAPE. The results of this work indicate that experience in age determination by particular structure had more impact on age determination precision than specificity of structure, scale or vertebra. More work is needed on adopting standard protocols that must include some sort of common interaction between responsible age readers.",
publisher = "Srpsko biološko društvo, Beograd, i dr.",
journal = "Archives of Biological Sciences",
title = "Reproducibility of age determination by scale and vertebra in pontic shad (alosa pontica eichwald, 1838), from the Danube",
pages = "341-337",
number = "2",
volume = "61",
doi = "10.2298/ABS0902337V"
}

Višnjić Jeftić, Ž., Lenhardt, M., Navodaru, I., Hegediš, A., Gačić, Z.,& Nikčević, M.. (2009). Reproducibility of age determination by scale and vertebra in pontic shad (alosa pontica eichwald, 1838), from the Danube. in Archives of Biological Sciences
Srpsko biološko društvo, Beograd, i dr.., 61(2), 337-341.
https://doi.org/10.2298/ABS0902337V

Višnjić Jeftić Ž, Lenhardt M, Navodaru I, Hegediš A, Gačić Z, Nikčević M. Reproducibility of age determination by scale and vertebra in pontic shad (alosa pontica eichwald, 1838), from the Danube. in Archives of Biological Sciences. 2009;61(2):337-341.
doi:10.2298/ABS0902337V .

Višnjić Jeftić, Željka, Lenhardt, Mirjana, Navodaru, Ion, Hegediš, Aleksandar, Gačić, Zoran, Nikčević, Miroslav, "Reproducibility of age determination by scale and vertebra in pontic shad (alosa pontica eichwald, 1838), from the Danube" in Archives of Biological Sciences, 61, no. 2 (2009):337-341,
https://doi.org/10.2298/ABS0902337V . .