11:00 〜 11:15
[AOS13-08] Ocean as Core Biome
★Invited Papers
キーワード：温度、安定性、潜水目視調査
Ecosystems in the ocean can be characterized by stability, resilience and high biodiversity. Seasonal temperature change is generally less in the ocean than in land. Nutrition can be transferred through sea water, making various sessile animals to survive. This makes the ocean to host most phyla of organisms, many of which found only in the ocean. Ocean also provides protection against harmful factors from outside such as ultraviolet radiation. Major component organisms in the ocean have relatively short life cycles and high fecundity. Phytoplankton, algae and sea grass are major primary producer in the ocean, having shorter life span than typical producers in land.
The author has conducted underwater visual censuses in three locations in Japan. The results of these monitoring can be interpreted with a view of general aspects of the ocean mentioned above.
Twice-a-month visual censuses have been conducted in Nagahama, Maizuru, northern Kyoto, where fish species and abundance are recorded since January 2002 (Masuda 2008). Bottom water temperature fluctuated within the range of 8.5–29.6 °C. A total of 109 fish species have been recorded so far. Both fish abundance and species richness are high in summer and low in winter. Warm-water fish species are increasing within these 20 years. Empirical model on species interaction in the dominant species revealed that the fish community tends to be more stable when there are more interspecific interactions (Ushio et al. 2018).
Visual censuses have been conducted in Otomi, Takahama, Fukui Prefecture, to elucidate the impact of thermal discharge from Takahama Nuclear Power Plant (TNPP) since January 2004 (Masuda 2020). Water temperature is about 2 °C warmer in Otomi compared to adjacent areas such as Nagahama. Tropical fishes and sea urchins dominate in this area when TNPP was in operation, while they ceased to survive when the operation was suspended.
Recovery of marine animals after tsunami has been monitored in Moune, Kesennuma, northeast Japan since May 2011 by once in two months surveys (Masuda et al. 2016, 2021). Fish abundance saturated withing the first year after the tsunami, while species richness recovered in 3 years after the tsunami. Animals with shorter life span, such as jellyfishes and gobies, recovered earlier than those with longer life span, such as sea cucumber, abalone, and rockfish. Jellyfishes are particularly abundant within the first two years after the tsunami. Increase of warm water species is also detected in recent years due to warming trend in offshore waters.
Fishes and marine invertebrates are thus highly sensitive to temperature. Even if one species has a wide range of physiological temperature tolerance, they may lose against competitors depending on temperature. Unfavorable temperature may also reduce activity and increase the risk of predation.
Each fish species has specific feeding habit. In general, target fishes in marine aquaculture are carnivores as are seen in yellowtail, tuna and red sea bream. Omnivores (ex. black sea bream) and herbivores (ex. rabbitfish) may be the target of future aquaculture including those planned outside this planet.
References
Masuda R (2008). Seasonal and interannual variation of subtidal fish assemblages in Wakasa Bay with reference to the warming trend in the Sea of Japan. Environmental Biology of Fishes 82: 387-399.
Masuda R, Hatakeyama M, Yokoyama K, Tanaka M (2016). Recovery of coastal fauna after the 2011 tsunami in Japan as determined by bimonthly underwater visual censuses conducted over five years. PLOS ONE 11: e0168261.
Masuda R (2020). Tropical fishes vanished after the operation of a nuclear power plant was suspended in the Sea of Japan. PLOS ONE 15: e0232065.
Ogata M, Masuda R, Harino H, Sakata MK, Hatakeyama M, Yokoyama K, Yamashita Y, Minamoto T (2021). Environmental DNA preserved in marine sediment for detecting jellyfish blooms after a tsunami. Scientific Reports 11: 16830.
Ushio M, Hsieh CH, Masuda R, Deyle ER, Ye H, Chang CW, Sugihara G, Kondoh M (2018). Fluctuating interaction network and time-varying stability of a natural fish community. Nature 554: 360-363.
The author has conducted underwater visual censuses in three locations in Japan. The results of these monitoring can be interpreted with a view of general aspects of the ocean mentioned above.
Twice-a-month visual censuses have been conducted in Nagahama, Maizuru, northern Kyoto, where fish species and abundance are recorded since January 2002 (Masuda 2008). Bottom water temperature fluctuated within the range of 8.5–29.6 °C. A total of 109 fish species have been recorded so far. Both fish abundance and species richness are high in summer and low in winter. Warm-water fish species are increasing within these 20 years. Empirical model on species interaction in the dominant species revealed that the fish community tends to be more stable when there are more interspecific interactions (Ushio et al. 2018).
Visual censuses have been conducted in Otomi, Takahama, Fukui Prefecture, to elucidate the impact of thermal discharge from Takahama Nuclear Power Plant (TNPP) since January 2004 (Masuda 2020). Water temperature is about 2 °C warmer in Otomi compared to adjacent areas such as Nagahama. Tropical fishes and sea urchins dominate in this area when TNPP was in operation, while they ceased to survive when the operation was suspended.
Recovery of marine animals after tsunami has been monitored in Moune, Kesennuma, northeast Japan since May 2011 by once in two months surveys (Masuda et al. 2016, 2021). Fish abundance saturated withing the first year after the tsunami, while species richness recovered in 3 years after the tsunami. Animals with shorter life span, such as jellyfishes and gobies, recovered earlier than those with longer life span, such as sea cucumber, abalone, and rockfish. Jellyfishes are particularly abundant within the first two years after the tsunami. Increase of warm water species is also detected in recent years due to warming trend in offshore waters.
Fishes and marine invertebrates are thus highly sensitive to temperature. Even if one species has a wide range of physiological temperature tolerance, they may lose against competitors depending on temperature. Unfavorable temperature may also reduce activity and increase the risk of predation.
Each fish species has specific feeding habit. In general, target fishes in marine aquaculture are carnivores as are seen in yellowtail, tuna and red sea bream. Omnivores (ex. black sea bream) and herbivores (ex. rabbitfish) may be the target of future aquaculture including those planned outside this planet.
References
Masuda R (2008). Seasonal and interannual variation of subtidal fish assemblages in Wakasa Bay with reference to the warming trend in the Sea of Japan. Environmental Biology of Fishes 82: 387-399.
Masuda R, Hatakeyama M, Yokoyama K, Tanaka M (2016). Recovery of coastal fauna after the 2011 tsunami in Japan as determined by bimonthly underwater visual censuses conducted over five years. PLOS ONE 11: e0168261.
Masuda R (2020). Tropical fishes vanished after the operation of a nuclear power plant was suspended in the Sea of Japan. PLOS ONE 15: e0232065.
Ogata M, Masuda R, Harino H, Sakata MK, Hatakeyama M, Yokoyama K, Yamashita Y, Minamoto T (2021). Environmental DNA preserved in marine sediment for detecting jellyfish blooms after a tsunami. Scientific Reports 11: 16830.
Ushio M, Hsieh CH, Masuda R, Deyle ER, Ye H, Chang CW, Sugihara G, Kondoh M (2018). Fluctuating interaction network and time-varying stability of a natural fish community. Nature 554: 360-363.