The nucleation process for Akoya pearls this year began in early April. I would like to provide an update on the current situation, which is approximately two months after the process started. Currently, we are conducting daily nucleation procedures on the Akoya oysters. However, there has been a slight increase in the probability of either the nuclei being expelled from the oysters or the oysters themselves dying, compared to last year. Nevertheless, this increase is not a significant concern as the mortality rate was very low last year.
Just to give you some numbers, last year the probability of nucleated Akoya oysters dying one month after nucleation was between 5% and 10%. This year, the probability of mortality stands at 15% to 20%. The period immediately following nucleation is when the cultured Akoya oysters are most susceptible to mortality. For Akoya oysters, nucleation is equivalent to a surgical procedure in which a softball-sized nucleus is inserted into their bodies, similar to a human undergoing abdominal surgery. Once the oysters successfully endure this operation, they can recover peacefully.
The next challenging period for the Akoya oysters is the heat of summer. During this time, they face harsh conditions.
The table provided represents the sea water temperature measured daily at the same location (at a depth of 3 meters) in a pearl cultivation farm. It is an excerpt from April 2014 to April 2023. Over the span of these eight years, the sea water temperature has generally followed a similar trend. In 2019, it appears to have recorded the highest temperatures for several months compared to the previous eight years. Additionally, the years 2014 and 2015 experienced slightly lower temperatures compared to other years. However, when examining the semi-monthly sea water temperatures, it seems that the period of increasing temperatures each year is occurring earlier. While it may be easy to assume that this indicates “global warming,” the impact does not appear to be significant based on this table alone. Nonetheless, it is important to note that August is consistently hot, and on average, the sea water temperature is 27.8 degrees Celsius. There are also a few days each year when the temperature exceeds 30 degrees Celsius. Such conditions pose challenges for the Akoya oysters. Please understand that based on this table.
The table above represents the yearly average sea water temperature. When viewed in this manner, it appears that the sea water temperature has been increasing in recent years. However, even before 2013, there were years within this eight-year period where the average sea water temperature exceeded 19.6 degrees Celsius. Thus, the impression can vary significantly depending on the selected time frame. Over the past three years, the issue of “mass mortality of Akoya oysters” has become a serious concern in the Japanese pearl industry. Several local governments and organizations have issued statements attributing the cause to “rising sea water temperatures.” I have personally analyzed sea water temperatures using a similar table for the past 30 years, but I have not found a clear causal relationship. Scholars and pearl industry professionals on land tend to conduct such analyses frequently, and that is an important endeavor. However, those who are directly involved in pearl cultivation show little interest in such analyses. Some even question, “What good does it do?” This is because those engaged in pearl farming, well aware of the vastness of the ocean, understand that manipulating sea water temperatures is impossible. Moreover, even if it were due to a contagious disease, evacuating the millions of Akoya oysters being cultivated to protect them from the disease is not feasible. Simply cleaning all the cultured Akoya oysters would take over a month. It is important to recognize the divide between those who seek to investigate the causes of mass mortality in Akoya oysters and those who are actually involved in pearl cultivation. I experience this disparity on a daily basis. Failure to understand this divide often leads to unproductive conversations. Such situations are not unique to pearl farming. It is like the stress felt by neighbors due to a barking dog every night, the dog owner, and the dog itself, which can’t help but bark. Although it may be a flawed analogy, each party has different perspectives and circumstances. First and foremost, it is crucial for both parties to understand each other’s positions and situations. However, we must also acknowledge that in the broader society, these considerations may simply become empty words.
As for the progress of pearl cultivation, there are currently no significant issues. However, there is another problem concerning the shortage of Akoya oyster babies. Pearls are created by inserting a nucleus into Akoya oysters, and it is common to be used oysters that will be in their second year of life. In pearl cultivation farms, preparations for next year’s oysters that will be nucleus insertion, using parent oysters, begin during this period. For example, this year, we will start collecting parent oysters at the end of 2022 to produce babies for nucleus insertion in the following year. We rely on specialized companies for the production of these babies. The production process often takes place between February and March. We have entrusted several companies to diversify the risks on our pearl cultivation farm. However, since this involves living organisms, it is not uncommon to receive reports stating, “It was challenging to produce babies,” or “Even if we successfully produced them, most of the babies died.” In the past few days, we have received reports from several companies that they are facing difficulties with the production process. For pearl farmers, the shortage of Akoya oyster babies for nucleus insertion in the coming year is a serious problem. We are reaching out to various cultivation companies to ensure that we gather the required number of Akoya oyster babies. By the way, the production activities also take place in May. If the number is insufficient, it may seem reasonable to produce babies in May. However, if production is done in May, there may not be enough time for the babies to grow sufficiently for nucleus insertion in the following year. In such cases, they will be used as Akoya oysters for nucleus insertion in the year after next, and they cannot be included in the count for the following year.
Additionally, the produced Akoya oyster babies are shipped to our pearl farming operation after approximately 45 days. At that point, they are smaller than a grain of rice. We place them in fine-meshed baskets and nurture them. After a few weeks, they gradually grow in size. If left unattended, the baskets will become crowded, so we transfer the small Akoya oysters into several baskets with appropriate mesh sizes to disperse them. They are placed in baskets with mesh sizes that correspond to the size of the Akoya oyster babies. The environment changes gradually, similar to a nursery, kindergarten, or elementary school. In summary, the nucleus insertion process for Akoya oysters is progressing smoothly, but there are some difficulties in producing Akoya oyster babies for the coming years. This discussion has become a bit complex. However, behind the beautiful luster of pearls, there is this kind of work. Beyond the radiant beauty of pearls, there are images of workers running on the sea or silently producing babies for nucleus insertion in a library-like serenity. Similar to the hidden efforts and struggles behind people’s smiles, there may also be hidden struggles, efforts, and even sadness.
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