Satoshi Tomano, PhD
1990 Born in Setouchi City, Okayama Prefecture
Doctor of Agriculture
I was born into a family of oyster farmers and fishermen, and have been familiar with the sea and fish since I was a child. I love the sea and was a member of the sailing club in high school and university. To study the ocean and biology, I enrolled in the Faculty of Bioproduction at Hiroshima University, where I have been conducting research under Associate Professor Tetsuya Unno of the Graduate School of Biosphere Science.
Since November 2017, I have been studying at the Barber Lab, Department of Ecology and Evolutionary Biology, University of California, Los Angeles, under the JSPS Fellowship Program. I have continued my research on the reproductive biology of squids in the Atmosphere and Ocean Research Institute, the University of Tokyo.
I am now working for a private company and conducting research on efficient aquaculture using science and technology.
What can I do to ensure that we continue to enjoy the gifts of the sea in the future? I would like to think about the answer to this question through my research.
Research on the stock structure of the reef squid Sepioteuthis lessoniana
Japan, one of the world's largest squid consuming countries
Marine resources contribute to food security and adequate nutrition for a global human population, providing protein to about 3 billion people with at least 15 percent of their average per capita animal protein intake (FAO 2016). Generally, fish populations can be sustainably harvested if the method of harvest does not destroy the reproductive potential of species (Hilborn & Hilborn 2012). However, global finfish stocks have been declined over the past 40 years, possibly due to the overfishing and environmental change such as rising water temperature (Meyer & Worm 2003).
In such a status, the amount of squid catch increased 4 times over the past 40 years in order to satisfy an increasing global demand for protein (Arkihipkin et al. 2015). In addition, squid abundance has also increased despite to marine environmental changes (Doubleday et al. 2016). Squids have special biological characteristics including rapid growth and short life span, which allow them to adapt to changing environmental conditions more quickly than other marine species.
They are called the king of squid due to its high market value
My target species Sepioteuthis cf. lessoniana is called as "king of squid" because one of the most widely distributed neritic squids occurred in coastal waters throughout the Indo-West Pacific region including Japan to Australia and New Zealand, and from Hawaii to East Africa, north to the Red Sea and south to Madagascar, where one of the most commercially important species with the highest market value. It's captured with a variety of gears including lure-hook called "Egi"-ing, set net, purse seine (Jereb & Roper 2010, Ueta & Umino 2013). Egi is the traditional squid jig that looks like fish and shrimp.
About the three species of reef squids in Japan
Red, White and Small squid
Previous studies have demonstrated this stock actually comprises three reproductively isolated taxa: Sepioteuthis sp. 1 (Red squid), Sepioteuthis sp. 2 (White squid) and Sepioteuthis sp. 3 (Small squid). Accurate identification of these taxa is necessary for appropriate stock management. These three taxa are morphologically very similar and difficult to differentiate morphologically, but they are distinct at the molecular level. The primary objective of our study is to determine the structure of the oval squid stock around Japan using sensitive DNA markers.
Conservation Ecology Research on the Reef squid
To continue to receive the benefits of this squids
Information that is essential for resource conservation, such as the distribution of the three species of reef squid, the proportion of the three species in the catch, and differences in spawning ecology, was limited to the Okinawa Islands, and was unknown in Honshu, Kyushu, and Shikoku, where reef squid catches are large.
Knowledge of the species being fished is the most basic and essential information for establishing effective conservation policies. In actual conservation management, it is necessary to consider the geographic population as a unit with which there is genetic exchange. Therefore, to determine effective conservation units, it is important to examine the genetic heterogeneity (population structure) of populations and to identify the boundaries between populations (Sale et al. 2005).
For example, is there exchange between Pacific and Japan Sea reef squids? To date, several studies have been published, but there has been no unified view among researchers.
Compared to other squids, the reef squid is known to lay fewer eggs during its lifetime. The life span is about one year, and the parent squid dies after spawning. By clarifying the spawning ecology of the three species of reef squids, we can apply this information to more effective breeding support, such as measures to increase the number of spawners and the maintenance of spawning grounds.
It is thought that the spawning season, spawning depth, and spawning location differ among the three species, but the details are still unknown.
I am conducting research with the following four objectives.
1. Establishment of a DNA identification method that can accurately distinguish the three species of the reef squid.
2. To clarify the distribution of the three species along the coast of Japan and the dominant species in each area.
3. To determine whether or not the breeding populations of the three species interact in different geographic regions
4. To clarify the differences in spawning ecology among the three species.
Artificial spawning reefs to support reproduction of the reef squid
Reef squid spawning in a "tree" in the sea
Reef squids lay their eggs on structures in the sea. This property has been exploited to support breeding by artificial spawning reefs. Although squids spawn on seaweed from spring to summer, their spawning grounds are decreasing due to high water temperatures and lack of nutrients. Fishermen are voluntarily providing reproductive support to compensate for the decrease in spawning grounds. Artificial spawning reefs made of wood are called "ika shiba" means squid brushwood .
Awards and honors
【JSPS Grant-in-Aid for Scientific Research （KAKENHI）
Awards and Grants
Not yet translated.
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