Taxonomy and Distribution of the Unarmored Dinoflagellates Cochlodinium polykrikoides and C. fulvescens

Abstract

Red tides of the unarmored dinofl agellate Cochlodinium polykrikoides and related chain-forming Cochlodinium species have been responsible for the mass mortality of fi sh in coastal areas of East Asia, and in Central and North America over the past few decades. Since 2000, C. polykrikoides has been reported for the fi rst time from Southeast Asia, India, the Middle East and the Mediterranean, so its distribution has seemingly expanded. Recent molecular phylogenetic works have detected intraspecifi c populations of C. polykrikoides , which presumably indicates their original distribution area. Reported occurrences of the chain-forming Cochlodinium spp., Cochlodinium fulvescens and C. polykrikoides are summarized with reference to their ribotypes, in order to consider the expansion of their distribution area and recent migration. The ultrastructure of C. polykrikoides was recently analyzed and showed the characteristic features seen in all other dinofl agellates. The apical groove structure of C. fulvescens is also provided in this chapter, for morphological comparison with C. polykrikoides and further characterization of chain-forming Cochlodinium spp. that produce fi sh-killing red tides.

Metagenomic Sequencing Identifies Highly Diverse Assemblages of Dinoflagellate Cysts in Sediments from Ships’ Ballast Tanks

“…Seven other well-known toxic dinoflagellates were detected, including the PSP toxin producer Gymnodinium catenatum [91], the azaspiracids producers Azadinium poporum and A. polongum , the yessotoxin producers Gonyaulax polygramma [86] and G. spinifera [88,89], the aerosol toxin producer Karenia cristata [115], and the polyether brevetoxin-2 (PbTx-2) producer Karenia papilionacea [2]. Some ichthyotoxic species with toxins, as yet unidentified, were also detected, including Apocalathium aciculiferum [58], Margalefidinium fulvescens (= Cochlodinium fulvescens [18]) [120], Karlodinium antarcticum [117,154], and Takayama helix [147]. The reactive oxygen species producer Prorocentrum micans was detected from one sample but with low abundance [121].…”

Resting Cyst Distribution and Molecular Identification of the Harmful Dinoflagellate Margalefidinium polykrikoides (Gymnodiniales, Dinophyceae) in Lampung Bay, Sumatra, Indonesia

“…After microscopic observations, it appeared that the unarmored dinoflagellate Margalefidinium was abundant in the water column [Main Center for Marine Aquaculture of Lampung (BBPBL) monitoring observations]. Based on the position of the sulcus and shape of chloroplasts, the possible causative species was identified as M. polykrikoides and was clearly differentiated from the similar species Cochlodinium fulvescens Iwataki, Kawami and Matsuoka, which had previously been reported in Hurun Bay, a semi-enclosed bay part of Lampung Bay (Iwataki et al, 2007, 2010, 2015). Observed cell concentrations reached up to 110 × 10 6 cells L -1 (BBPBL monitoring unpublished data).…”

“…Kudela and Gobler (2012) compiled a complete inventory of the expansion and ecological strategies of M. polykrikoides . Before 1990, its blooms had mainly been observed in Japan and in Central and North America (Matsuoka et al, 2008; Iwataki et al, 2015). As of the early 1990s, it spread to South Korea, where the fisheries sector experienced annual losses of over USD 100 million (Kim, 1997).…”

Morphological variation and phylogeny ofKarenia selliformis(Gymnodiniales, Dinophyceae) in an intensive cold-water algal bloom in eastern Hokkaido, Japan in September–November 2021

“…mikimotoi was first found in Hakodate Bay, southern Hokkaido in 2015, while the negative impact was not intensive, and cells of harmful raphidophyte Chattonella marina (Subrahmanyan) Hara et Chihara and dinoflagellate Cochlodinium polykrikoides Margalef (= Margalefidinium polykrikoides) were detected during summer (Shimada et al, 2016a(Shimada et al, , 2016bKakumu et al, 2018). Blooms of these harmful microalgae are common in the coasts of western Japan, and even in Southeast Asia (Imai et al, 2006;Yamatogi et al, 2006;Iwataki et al, 2008Iwataki et al, , 2015Imai and Yamaguchi, 2012;Furuya et al, 2018;Thoha et al, 2019;Lum et al, 2021;Sakamoto et al, 2021;Yñiguez et al, 2021). It was assumed that the motile cells of these harmful species recently detected in the coastal Hokkaido might be transported by the Tsushima Warm Current from the Sea of Japan (Shimada et al, 2016a;Sildever et al, 2019).…”