PARENT SESSION
Contributed Oral Session 119: Invasive Species : Aquatic Invaders
Thursday, August 11, 8:00 AM - 11:30 AM, Meeting Room 520 A, Level 5, Palais des congrès de Montréal
Study of possible introduction of Beroe ovata into the Caspian sea as biologic control of invader comb jelly Mnemiopsis Leidyi (Lobata).
Javanshir, Arash*,1, 1 University of Tehran, Karaj, Iran
ABSTRACT- The introduction of the invasive comb jelly Mnemiopsis leidyi into the Caspian Sea caused many economic problems, including the rapid decline of the planktivorous fish industry. This unplanned introduction severely disrupted ecological function, causing large declines in zooplankton populations and large shifts in the species composition of the zooplankton community. Based upon recent experience with Mnemiopsis leidyi in the Black Sea, a series of in situ mesocosm experiments were carried out at the Caspian Sea Ecological Institute, Sari, Iran in order to predict the impact of the predatory Beroe ovata on Mnemiopsis leidyi in Caspian waters and to determine whether Beroe ovata would consume ecologically significant numbers of zooplankton. In the mesocosms, mortality of Mnemiopsis leidyi was more than four times higher in treatments with B. ovata (t = 15.5, p <0.0001). Mnemiopsis leidyi alone significantly decreased zooplankton density, while Beroe ovata alone did not decrease the zooplankton density (zooplankton + Beroe Vs. Mnemiopsis +zooplankton: p < 0.005, t = 2.14; zooplankton + Beroe Vs. Z: p > 0.7, t = 0.37). This same pattern is present for zooplankton nauplii. Mnemiopsis leidyi significantly decreased zooplankton density, while Beroe ovata did not (zooplankton + Beroe Vs. Mnemiopsis + zooplankton: p < 0.05, t = 2.35, zooplankton + Beroe Vs. Z: p > 0.2, t = 1.19). Overall, Beroe ovata significantly decreased Mnemiopsis leidyi population density (p < 0.005, F = 19.41) and significantly increased zooplankton abundance (p < 0.03, F = 8.91). These studies identified no significant negative consequences of the introduction of Beroe ovata into the Caspian Sea. The introduction of Beroe ovata is likely to decrease the impact of Mnemiopsis leidyi and have substantial positive consequences for the ecology of the Caspian Sea and the economy of the region.
Key words: Mnemiopsis leidyi, Beroe ovata, caspian, biological control