Contribution and acclimatization of the swarming tropical copepod Dioithona oculata (Farran, 1913) in a Mediterranean coastal ecosystem

Tuba Terbiyik Kurt

doi:10.3906/zoo-1802-42

Abstract

In this study, tropical oithonid copepod Dioithona oculata was recorded for the first time in the Mediterranean Sea. This species is distinguished easily by its large ocular lenses and by the number of setae on the endopod of the maxillule. The study was conducted seasonally in the coastal area of Iskenderun Bay between April 2013 and December 2016. D. oculata was first observed in October 2013 in the study area (Station 4; 3.1 ind. m − 3 " role="presentation"> − 3 − 3 ^{-3} )); after this period, this species became an important contributor to zooplankton assemblages in October with the highest level seen in 2016 (Station 4, 834.5 ind. m − 3 " role="presentation"> − 3 − 3 ^{-3} ). The proportion of this species in the copepod community varied from 0.14% (2014) to 29.4% (2016), and the highest proportions, observed in October 2016, were at Stations 3 and 4 (51.1% and 65.3%, respectively). Females dominated the D. oculata population and the ratio of female to male was 5.6 ± 7 on average. Copepodit stages were also observed in the population. Altogether, these data indicate that the D. oculata population increased year after year. In addition, the presence of copepodits in the population suggests that this species was established and successfully acclimatized to the conditions, becoming an important component of the zooplankton community in the Iskenderun Bay ecosystem.

Highlights

IntroductionThe eastern Mediterranean is sensitive to alien invasions due to its geographic position (i.e., its connection with Atlantic Ocean, Black Sea, and Erythrean regions), crowded maritime traffic, fisheries, and tourism activities in the coastal regions (Galil and Zenotos, 2002)
The eastern Mediterranean is sensitive to alien invasions due to its geographic position, crowded maritime traffic, fisheries, and tourism activities in the coastal regions (Galil and Zenotos, 2002)
Alien species increased after the opening of the Suez Canal in 1869 and construction of the Aswan Dam (Galil, 2000); hundreds of alien species passed through the Suez Canal to the Mediterranean Sea, forming thriving populations along the Levantine coast (Galil and Zenetos, 2002)

Summary

Introduction

The eastern Mediterranean is sensitive to alien invasions due to its geographic position (i.e., its connection with Atlantic Ocean, Black Sea, and Erythrean regions), crowded maritime traffic, fisheries, and tourism activities in the coastal regions (Galil and Zenotos, 2002). Oithonidae species are important contributors to ecosystems of the Mediterranean Sea (Siokou-Frangou et al, 1997; Andersen et al, 2001; Fernandez de Puelles et al, 2003; Gaudy et al, 2003; Mazzocchi et al, 2003; Saiz et al, 2003; Licandro and Icardi, 2009; Siokou et al, 2010; Terbıyık Kurt and Polat, 2013; Mazzocchi et al, 2014) and dominate zooplankton with other cyclopoid families such as Oncaeidae and Corycaeidae, as well as small calanoids including Clausocalanus and Paracalanus in eastern Mediterranean ecosystems (Siokou et al, 2010). Except for Dioithona rigida, all of these species are oithonid copepods

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Results

Conclusion