North Pacific Anadromous Fish Commission

Technical Report 11

Table of Contents

Toxic “bloom” and Pacific Salmon (Catch, Spawning Migrations, Production) in the Far Eastern Seas of Russia—Are There New Risks?

Authors:
Ekaterina Lepskaya, Kseniya Efimova, Sergei Shubkin, and Vladimir Kolomeitsev

Abstract Excerpt:
“Red tide” was again observed in Olyutorsky Gulf in July 2017. This specific phenomenon was successfully studied in detail for the first time due to the concern and consequent interest of commercial fishermen whose trade nets appeared to be in the “bloom” zone. Having carried out species definition of the microalgae on the basis of morphology we stated that the “bloom” was caused by dinoflagellates from Alexandriumtamarense-species-complex. The taxonomic position of Alexandrium was more exactly defined by molecular-genetic analysis,
ascertaining that the sample contained essentially a monoculture of A. fundyense (Balech) (Group I ribotype, previously known as the North American ribotype) from the above-mentioned complex. The number of dinoflagellates in the sample was estimated. On the basis of the satellite data, the “bloom” development dynamics were reconstructed using the chlorophyll-a accumulation. The presence of saxitoxin was revealed in the water sample that contained the suspension of Alexandrium cells. We collected information on unusual behavior of pink salmon which entered the zone of the “bloom,” on peculiarities of the seabirds’ behavior, on the air quality in the near-shore area; on weather conditions prior to and during the “bloom;” and the contents of the biogenic elements in the coastal water at the beginning of the “bloom.” Also, on the basis of the satellite data the dynamics of surface water temperature in the coastal zone of Olyutorsky Gulf were reconstructed. The population rate of spawning areas in main rivers of reproduction of pink salmon and chum salmon in the basin of Olyutorsky Gulf–Pakhachi and Apuka–and terminal neighboring rivers was estimated by air search (Lepskaya et. al. 2017, 2018).

*This is the first paragraph of an extended abstract. Download the full abstract below.

DOI:
https://doi.org/10.23849/npafctr11/80.86

Citation

Lepskaya, E., K. Efimova, S. Shubkin, and V. Kolomeitsev.  2018.  Toxic “bloom” and Pacific salmon (catch, spawning migrations, production) in the Far Eastern seas of Russia—are there new risks?  N. Pac. Anadr. Fish Comm. Tech. Rep. 11: 80–86.  https://doi.org/10.23849/npafctr11/80.86