Most previous studies on dinoflagellates in Korean coastal areas were conducted without morphological descriptions and illustrations of the observed dinoflagellates. This indicates that the species and diversity of dinoflagellates may have been respectively misidentified and underestimated in the past, probably due to cell shrinkage, distortion and loss caused by sample fixation. This study provides information on the morphological observations of four dinoflagellate orders (Prorocentrales, Dinophysiales, Gonyaulacales and Gymnodiniales) from Jangmok Harbour in Jinhae Bay, Korea. The unfixed samples were collected weekly from December 2013 to February 2015. A total of 13 genera and 30 species were identified using light and scanning electron microscopy, although some samples were not clarified at the species level. Harmful dinoflagellates, Prorocentrum donghaiense, Tripos furca, Alexandrium affine, A. fundyense, Akashiwo sanguinea and Cochlodinium polykrikoides, were identified based on the morphological observations. The results also reflect the occurrence and identification of dinoflagellates that had not been previously recorded in Jangmok Harbour.

Introduction
 Materials and methods
 Results and Discussion
 References

• Hyeon Ho Shin(Library of Marine Samples, Korea Institute of Ocean Science and Technology, Geoje 53201, Republic of Korea) Corresponding author
• Eun Song Kim(Library of Marine Samples, Korea Institute of Ocean Science and Technology, Geoje 53201, Republic of Korea)
• Zhun Li(Library of Marine Samples, Korea Institute of Ocean Science and Technology, Geoje 53201, Republic of Korea)
• Joo Yeon Youn(Library of Marine Samples, Korea Institute of Ocean Science and Technology, Geoje 53201, Republic of Korea)
• Seul Gi Jeon(Library of Marine Samples, Korea Institute of Ocean Science and Technology, Geoje 53201, Republic of Korea)
• Seok Jin Oh(Pukyung National University, Busan 48513, Republic of Korea)