Tamara A. Shiganova

The ctenophore Mnemiopsis in native and exotic habitats: U.S. estuaries versus the Black Sea basin

The native habitats of the ctenophore, Mnemiopsis, are temperate to subtropical estuaries along the Atlantic coast of North and South America, where it is found in an extremely wide range of environmental conditions (winter low and summer high temperatures of 2 and 32 °C, respectively, and salinities of <2–38). In the early 1980s, it was accidentally introduced to the Black Sea, where it flourished and expanded into the Azov, Marmara, Mediterranean and Caspian Seas. We compile data showing that Mnemiopsis has high potentials of growth, reproduction and feeding that enable this species to be a predominant zooplanktivore in a wide variety of habitats; review the population distributions and dynamics of Mnemiopsis in U.S. waters and in the Black Sea region; and examine the effects of temperature and salinity, zooplankton availability and predator abundance on Mnemiopsis population size in both regions, and the effects of Mnemiopsis on zooplankton, ichthyoplankton and fish populations, focusing on Chesapeake Bay and the Black Sea. In both regions, Mnemiopsis populations are restricted by low winter temperatures (<2 °C). In native habitats, predators of Mnemiopsis often limit their populations, and zooplanktivorous fish are abundant and may compete with the ctenophores for food. By contrast, in the Black Sea region, no obvious predators of Mnemiopsis were present during the decade following introduction when the ctenophore populations flourished. Additionally, zooplanktivorous fish populations had been severely reduced by over fishing prior to the ctenophore outbreak. Thus, small populations of potential predators and competitors for food enabled Mnemiopsis populations to swell in the new habitats. In Chesapeake Bay, Mnemiopsis consumes substantial proportions of zooplankton daily, but may only noticeably reduce zooplankton populations when predators of Mnemiopsis are uncommon. Mnemiopsis also is an important predator of fish eggs in both locations. In the Black Sea, reductions in zooplankton, ichthyoplankton and zooplanktivorous fish populations have been attributed to Mnemiopsis. We conclude that the enormous impact of Mnemiopsis on the Black Sea ecosystem occurred because of the shortage of predators and competitors in the late 1980s and early 1990s. The appearance of the ctenophore, Beroe ovata, may promote the recovery of the Black Sea ecosystem from the effects of the Mnemiopsis invasion.

Invasion of the Caspian Sea by the Comb Jellyfish Mnemiopsis Leidyi (Ctenophora)

Vladimir P. Ivanov1, Andrey M. Kamakin1, Vladimir B. Ushivtzev1, Tamara Shiganova5, Olga Zhukova1, Nikolay Aladin2, Susan I. Wilson3, G. Richard Harbison4 & Henri J. Dumont6,∗ 1CaspNIRH, Astrakhan, Russia; 2Brackish Water Laboratory, Russian Academy of Sciences, St.-Petersburg, Russia; 3School of Biology and Biochemistry, Queens University, Belfast, UK; 4Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA; 5P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia; 6Laboratory of Animal Ecology, Ghent University, Belgium; ∗Author for correspondence (e-mail: Henri.Dumont@rug.ac.be)

Aquatic Invasions in the Black, Caspian, and Mediterranean Seas

Preface H.J. Dumont, T.A. Shiganova, U. Niermann. 1: Mnemiopsis leidyi, Beroe cf ovata, and their interaction. 1. Mnemiopsis leidyi: distribution and effect on the Black Sea ecosystem during the first years of invasion in comparison with other gelatinous blooms U. Niermann. 2. Interactions between the invading Ctenophores Mnemiopsis leidyi (A. Agassiz) and Beroe cf ovata Mayer 1912, and their influence on the Pelagic Ecosystem of the Northeastern Black Sea T.A. Shiganova, et al. 3. Population dynamics of Mnemiopsis leidyi in the Caspian Sea, and effects on the Caspian ecosystem T.A. Shiganova, et al. 4. Distribution and biology of Mnemiopsis leidyi in the northern Aegean Sea, and comparison with the indigenous Bolinopsis vitrea T.A. Shiganova, et al. 5. Effects of Beroe cf ovata on gelatinous and other zooplankton along the Bulgarian Black Sea coast L. Kamburska. 6. Decreased levels of the invasive ctenophore Mnemiopsis in the Marmara Sea in 2001 M. Isinibilir, et al. 7. Preliminary investigation on the molecular systematics of the invasive ctenophore Beroe ovata K.M. Bayha, et al. 8. Support for the position that a deliberate introduction of Beroe cf ovata to the Caspian Sea will control the local population of Mnemiopsis leidyi S.P. Volovik, I.G. Korpakova. 9. Feeding, respiration and growth of the Ctenophore Beroe cf ovata in the conditions of low salinity of the Caspian Sea A.E. Kideys, et al. 10. A brief resume of the status of the Mnemiopsis population in the Turkmen sector ofthe Caspian Sea according to observations during the first half of 2002 F.M. Shakirova. 11. Dynamics of Mnemiopsis distribution in the Azerbaijan sector of the Caspian Sea in 2001 - 2002 Z.M. Kulijev. 12. Investigation on distribution and biomass of Mnemiopsis in the Kazakhstan sector of the Caspian Sea in May 2002 Y.A. Kim, et al. 2: Ponto-Caspian species invading Europe: information networking. 13. Range extensions of Ponto-Caspian aquatic invertebrates in Continental Europe H.A.M. Kentelaars. 14. Living in a sea of exotics - the Baltic case E. Leppakoski. 15. Internet-based information resources of aquatic alien species relevant to the Ponto-Caspian region V.E. Panov. 3: Other Mediterranean Invaders. 16. Invasion of the jellyfish Pelagia noctiluca in the Northern Adriatic: a non-success story A. Malej, A. Malej Jr. 17. Caulerpa taxifolia: 18 years of infestation in the Mediterranean Sea T. Thibaut, A. Meinesz. 4: Conclusions from the Meeting. 18. Henri J. Dumont, Tamara A. Shiganova & Ulrich Niermann. Index.

Changes in appendicularian Oikopleura dioica abundance caused by invasion of alien ctenophores in the Black Sea

Oikopleura dioica is the only recorded appendicularian in the Black Sea. During the last two decades major changes in the O. dioica population size as well as total zooplankton community structures were recorded when invasive ctenophore species appeared in the Black Sea ecosystem. The state of the O. dioica population, before the invasion of ctenophores Mnemiopsis leidyi and Beroe ovata , is reviewed. The effect of the invasion of these ctenophores on the total zooplankton and particularly on the O. dioica standing stock is summarized from our long-term data and published information. The abundance, biomass and species composition of zooplankton greatly decreased after the ctenophore Mnemiopsis leidyi invasion due to predation by M. leidyi . Specifically, the abundance of O. dioica declined at that period. But with increasing numbers of a new invader, the ctenophore Beroe ovata , a predator of M. leidyi , in 1999, the zooplankton community began to recover. The population density of Oikopleura dioica also gradually increased to a level that was within the range of its abundance before the M. leidyi outbreak and even higher due to increasing its prey bacteria, which was provoked by the mucus released by B. ovata.

Invasion Pathway of the Ctenophore Mnemiopsis leidyi in the Mediterranean Sea

Gelatinous zooplankton outbreaks have increased globally owing to a number of human-mediated factors, including food web alterations and species introductions. The invasive ctenophore Mnemiopsis leidyi entered the Black Sea in the early 1980s. The invasion was followed by the Azov, Caspian, Baltic and North Seas, and, most recently, the Mediterranean Sea. Previous studies identified two distinct invasion pathways of M. leidyi from its native range in the western Atlantic Ocean to Eurasia. However, the source of newly established populations in the Mediterranean Sea remains unclear. Here we build upon our previous study and investigate sequence variation in both mitochondrial (Cytochrome c Oxidase subunit I) and nuclear (Internal Transcribed Spacer) markers in M. leidyi, encompassing five native and 11 introduced populations, including four from the Mediterranean Sea. Extant genetic diversity in Mediterranean populations (n = 8, N a = 10) preclude the occurrence of a severe genetic bottleneck or founder effects in the initial colonizing population. Our mitochondrial and nuclear marker surveys revealed two possible pathways of introduction into Mediterranean Sea. In total, 17 haplotypes and 18 alleles were recovered from all surveyed populations. Haplotype and allelic diversity of Mediterranean populations were comparable to populations from which they were likely drawn. The distribution of genetic diversity and pattern of genetic differentiation suggest initial colonization of the Mediterranean from the Black-Azov Seas (pairwise F ST = 0.001–0.028). However, some haplotypes and alleles from the Mediterranean Sea were not detected from the well-sampled Black Sea, although they were found in Gulf of Mexico populations that were also genetically similar to those in the Mediterranean Sea (pairwise F ST = 0.010–0.032), raising the possibility of multiple invasion sources. Multiple introductions from a combination of Black Sea and native region sources could be facilitated by intense local and transcontinental shipping activity, respectively.

A risk assessment of biological invasions in the inland waterways of Europe: the Northern Invasion Corridor case study

INTRODUCTIONInland waterways have provided opportunities for the spread of aquaticnon-indigenous species (NIS) for many centuries (reviewed in Ketelaars 2004,Galil and Minchin 2006, Galil et al. 2007). Canals connecting different riverbasins have allowed for range extensions of many species, either by activemovement and/or by ship transport. Over the past century, the potential forspecies to expand their range has been enhanced due to increasing trade andthe construction of canals. The waterways occur at low altitudes and presentlythe main European corridor routes consist of an interlinked network of 30main canals with more than 100 branches, and more than 350 ports exist inlow-altitude Europe.The European Agreement on Main Inland Waterways of InternationalImportance (AGN) was signed under the framework of the United Nations639

First record of Beroe gracilis Künne, 1939 (Ctenophora: Beroida: Beroidae) from Norway, found in a Mnemiopsis leidyi A. Agassiz, 1865 bloom

In September 2014 an unusual mixture of ctenophores was recorded at Arboretet, south-western Norway and at Flødevigen, near Arendal on the south coast of Norway. In addition to the invasive American lobate ctenophore, Mnemiopsis leidyi, the common northern lobate ctenophore Bolinopsis infundibulum and the cydippid Pleurobrachia pileus, two beroid ctenophores, were noted – Beroe cucumis and Beroe gracilis. The latter species had not been documented before in Norwegian waters.

Feeding, respiration and growth of ctenophore Beroe cf ovata in the low salinity conditions of the Caspian Sea

We conclude that (1) Beroe is able to adjust to and survive in Caspian water, (2) in a Caspian Sea water environment, Beroe is ingesting Mnemiopsis to a degree sufficient to decrease its abundance as sharply as in the Black Sea, (3) reproducing Beroe in Caspian water in limited preliminary laboratory trials was not successful, but should be repeated.