Bluefish | European Tracking Network

Bluefish

Pomatomus saltatrix

 

Species description and status: The bluefish (Pomatomus saltatrix Linnaeus, 1766) are migratory pelagic predators that are distributed over continental shelves and in estuaries of temperate waters throughout most of the world, with the exception of the northern and mid-Pacific Ocean [1]. Bluefish is distributed throughout the Mediterranean but is more abundant in the southern and eastern coasts. Bluefish are migrating via the Aegean Sea to the Black Sea from the Mediterranean in spring and returning south in early autumn [2]. During this migration, adults of bluefish overwinter in the Sea of the Marmara Sea and the Aegean Sea. They then migrate through the Bosporus towards the Black Sea in spring. Spawning occurs from June to September, primarily on the western and north­ western shelf along the Bulgarian and Ukrainian coasts [3]. They are overfished especially at the western Black Sea and the Marmara Sea during their seasonal migration of nutrition-reproduction [4]. Commercial global capture of bluefish is 13272 tons and, Turkey has 2995 tons of this capture in 2017[5]. The International Union for the Conservation of Nature (IUCN) has assessed the Bluefish as “Vulnerable” indicating also a “decreasing” status for the population trend, due to intense exploitation, especially in the Eastern Mediterranean.

Regions of interest: Bluefish is a migratory species, occur in temperate and warm temperate zones throughout the world and are generally found in continental shelf waters. It is distributed throughout the Mediterranean Sea, the Black Sea, the eastern Atlantic Ocean, from Portugal to Senegal, including the Azores (Fig.1). However, due to reproductive migration in the Aegean Sea and Black Sea coastal countries are more common.

Fig 1. Distribution of Bluefish (Pomatomus saltatrix) taken from FAO.org

 

Knowledge gaps: Migration and movements between the seas of bluefish are not fully understood and also existing literature might be changing in response to rising sea temperatures. Furthermore, the lack of general data on stocks and migration patterns of bluefish also restrains the development of a realistic management and conservation model. The migration of the bluefish between the Black Sea and the Aegean Sea through the straits of Dardanelles and Bosporus and the time spent there should be better defined. Data on wintering sites in the Black Sea and the Aegean Sea are insufficient. In addition, there is not enough information about migration routes, periods and populations of bluefishes in other parts of the Mediterranean. Another important issue is the interaction between sea-cage fish farms and bluefish in the Mediterranean Sea.

Telemetry tools: Acoustic telemetry represents the best available tools for characterizing the movement patterns of bluefish in the marine environment. Receivers to be placed in the straits of Dardanelles and Bosporus can provide important data for the migration and residency of Bluefish. Additionally, these points are among the key sites highlighted by ETN. Besides, active telemetry studies can be conducted in order to monitor the brief behavior of bluefish. In previous years, telemetry studies were conducted to investigate the movements of bluefish in lagoons in South Africa and America. Passive telemetry methods were used in the studies where a total of 44 fish were tagged with acoustic transmitters [6], [7]. Similar to these studies, movement patterns of bluefish around the sea-cages fish farms in Spain were observed. 23 fish were marked with acoustic transmitters and monitored with receivers placed in the mooring systems of fish farms [8]. Unlike passive telemetry studies using this method, short-term movement’s of bluefish in the artificial reef area in Turkey were monitored by active telemetry methods. In the study where 10 fish were tagged with continuous transmitters, daily movements of bluefishes in artificial reef area were examined [9]

Benefits: Using the ETN to further characterize bluefish migration and behaviour between the Aegean Sea and the Black Sea and beyond would greatly enhance our ability to better manage this culturally and economically important species. In addition, ETN would give additional insights into the location of the wintering and spawning grounds as well as the environmental preferences of the species. This is a common territory of few countries so joint research efforts, sharing of infrastructure and international collaborations are required.

Contacts: Aytaç Özgül (aytac.ozgul@ege.edu.tr) and Altan Lök (altan.lok@ege.edu.tr)

Join the team and contact Dr. Aytaç Özgül (aytac.ozgul@ege.edu.tr) from Ege University, Faculty of Fisheries to be involved in this project/species and being involved in future project proposals to pan- European Calls to address these key knowledge gaps in the Blueish.

References:

[1] Briggs, J.C., 1960. Fishes of world-wide (circumtropical) distribution. Copeia, 1960 (3): 171-180.

[2] Ceyhan, T., Akyol, O., Ayaz. A., Juanes, F. 2007. Age, growth, and reproductive season of bluefish (Pomatomus saltatrix) in the Marmara region, Turkey. ICES Journal of Marine Science, 64:531–536.

[3] Juanes, F., Hare, J.A., Miskiewicz, A.G., 1996. Comparing early life history strategies of Pomatomus saltatrix: a global approach. Marine and Freshwater Research, 47: 365-379.

[4] Ceyhan, T., Akyol, O., 2006. Age distribution and relationship between fork length and otolith length of bluefish (Pomatomus saltatrix L.,1766) in the Sea of Marmara. E.U. Journal of Fisheries & Aquatic Sciences, 23 (3):369-372.

[5] FAO, 2019. Fisheries and aquaculture software. FishStat Plus - Universal software for fishery statistical time series. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 14 September 2017. [Cited 10 December 2019]

[6] Hedger, R.D., Næsje, T.F., Cowley, P.D., Thorstad, E.B., Attwood, C., Økland, F., Wilke, C.G., Kerwath, S. 2010. Residency and migratory behaviour by adult Pomatomus saltatrix in a South African coastal embayment. Estuarine, Coastal and Shelf Science, 89:12–20

[7] Grothues, T.M., Able, K.W., 2007. Scaling acoustic telemetry of bluefish in an estuarine observatory: detection and habitat use patterns. Transactions of the American Fisheries Society, 136:1511–1519

[8] Arechavala-Lopez, P., Izquierdo-Gomez, D., Uglem, I., & Sanchez-Jerez, P. 2015. Aggregations of bluefish Pomatomus saltatrix (L.) at Mediterranean coastal fish farms: seasonal presence, daily patterns and influence of farming activity. Environmental biology of fishes, 98, 499-510

[9] Özgül, A., Lök, A., Ulaş, A., Düzbastılar, F.O., Tanrıkul, T.T. 2016. Determining movement patterns of fish around of artificial reefs and use for small scale fisheries. TÜBİTAK-112O383 Research projects. 176 pp.