[Series] Part 1: Reasons for the decline of Japan's fishery resources and four necessary measures - Considering the future management of Japan's fishery resources

In the first episode of a series titled "Considering the future management of Japan's fisheries resources," Kumei Makoto, representative of the UMINEKO Sustainability Institute, will explain the current state of Japan's fisheries resources, the reasons for the decline in Japan's fisheries resources, challenges facing Japan's fisheries resources management policy, and what Japan's fisheries resources management should be like.

Japan's total fish catch (including farmed fish) peaked at 1984 million tons in 1,282, and has since fallen to about one-third of that amount.

In light of this background, the Fisheries Act was revised in 2018 to clearly state that "sustainable use of fishery resources" is required. In addition, in order to secure fishery resources, it was also stated that catch volumes would be regulated based on scientific evidence.

With rising sea temperatures due to climate change, a decline in the number of people working in the fishing industry, and IUU (illegal, unreported and unregulated) fishing adding to the problem, how can Japan manage resources in the future to allow fish to return to the seas?

We will hear the opinions of academics, local fishermen, and NGO members to outline what resource management should look like in the future.

The first article was contributed by Kumei Makoto, representative of the UMINEKO Sustainability Institute (USI).

[Series] Part 1: Reasons for the decline of Japan's fishery resources and four necessary measures

1. Current Status of Japan's Fisheries Resources

Many people are probably already aware that Japan's fisheries production volume has fallen to one-third of its peak in 1984, as this has been widely reported (Figure 3).

The main reasons for the decline in fishery production from its peak are, first, the contraction of deep-sea fishing, and, second, the decrease in the catch of sardines in offshore fishing. Deep-sea fishing was forced to be withdrawn when countries established exclusive economic zones, and it is known that sardine resources are subject to large and periodic natural fluctuations.

Figure 3: Fisheries production has fallen to one-third of its peak [1]

However, as these two impacts subsided and the catch of sardines has increased in recent years, the overall catch has continued to decline. Even looking at the production volume of coastal fisheries alone, it has fallen to less than half of its peak (Figure 2).

Figure 2. Coastal fisheries production has fallen to less than half of its peak[2] 

Furthermore, the combined catch of saury, Japanese flying squid, and salmon, which are commonly eaten, decreased by approximately 2014% between 2022 and 75 (Figure 3).

Figure 3. The total catch of Pacific saury, Japanese flying squid, and salmon has declined by about 2014% since 75.[3]

Although catch volume does not necessarily equal resource volume, as in the case of deep-sea fisheries, the main reason for the decline in catch volume in both offshore and coastal fisheries is the decline in marine resources.

In the resource assessment for fiscal year 5, of the 38 resources for which maximum catch yield (MSY) has been calculated, the resource status of 23 resources is below the MSY level (Figure 4). In addition, of the remaining 50 resources for which MSY has not been calculated, the resource status of 31 resources is considered to be low (Figure 5).

Figure 4. Status of 38 stocks for which MSY is calculated (parent fish biomass ratios of 1 or less are below the MSY level)[4]

Figure 5. Of the 50 stocks for which MSY has not been calculated, 31 are rated low.[5]

Looking at the resource status of major fish species, the resource condition of sardines, which are the fishery's largest catch in Japan, is currently relatively good. However, the recruitment rate of sardines (the amount of fish that have grown to adulthood and are considered a resource) has been decreasing in recent years, and it has been pointed out that there is a possibility of future resource decline.

For mackerel, the second most commonly caught fish species, the latest resource assessment revealed that parent fish mass is significantly below the target (MSY level). For skipjack and tuna, the third most commonly caught fish species, Pacific bluefin tuna stocks are showing signs of recovery, and the parent fish mass of Alaska pollock, the fourth most commonly caught fish species, and anchovy, the fifth most commonly caught fish species, are both above the MSY level, indicating that some stocks are in good condition.

As such, the state of resources differs depending on the individual fish species. However, the resource status of squid, salmon, and trout species is at a critical state, and overall, as can be seen from Figures 4 and 5, the resource volume is considered to be low.

Figure 6. Stock status of top-caught fish species[6]

2. Reasons for the decline of Japan's fishery resources

Factors that affect fishery resources can be broadly divided into 1) environmental factors and 2) overfishing.

First, environmental factors include changes in water temperature and water quality that affect fish growth, the amount of food, changes in ocean currents, and the amount of predators that eat the fish. Resources are also affected by the presence or absence of habitats such as seaweed beds and tidal flats that serve as spawning grounds and places for juvenile fish to grow. In Japan, the deterioration of the coastal environment caused by large-scale land reclamation and development during the period of high economic growth is also thought to have had an impact on fishery resources.

Next is the impact of overfishing. The idea of ​​fishing appropriate amounts of coastal resources, which will disappear if caught in excess, has existed since ancient times, and Japan has many good examples of voluntary resource management of coastal resources. On the other hand, when it comes to fishing for fish that migrate offshore, overfishing was not often an issue in the past, as fishing was not conducted to the extent that it would affect the overall resource.

However, as the capabilities of fishing boats have improved and the accuracy of targeting fish has improved thanks to the development of fish finders, even offshore, fish are caught as much as possible, and resources are being depleted. Furthermore, as not only Japan but also other countries have increased the amount of fish caught, the impact of overfishing on resources is becoming greater, and inadequate resource management is affecting fishery resources.

The factors behind resource decline vary depending on the individual fish species and region, but an analysis conducted by the Umineko Sustainability Institute (USI) in 2022 found that of 20 fishery resources with high catch volumes and declining resource abundance, 11 are affected by environmental factors, 17 are affected by domestic overfishing, and 9 are affected by international factors.

In recent years, the impact of the marine environment on fishery resources has become even greater, as seen in the frequent occurrence of marine heat waves around Japan. Rising seawater temperatures not only shift fish distribution northward, but also affect their growth. For example, when the surface seawater temperature becomes too hot, the vertical circulation of seawater stagnates, preventing nutrients and oxygen from the deep sea from being transported to the upper layers, resulting in a decrease in plankton, which fish feed on. There is concern that rising seawater temperatures are reducing the ocean's environmental carrying capacity (the amount of resources that can be maintained under the current environment).

3. Issues facing Japan’s fisheries resource management policy

As mentioned above, the causes of decline in fishery resources are environmental factors and overfishing. In many cases, it is thought that there is more than one factor at play. Whatever the cause of the decline in resources, proper resource management is essential to recover the declined resources and maintain appropriate resource levels.

Based on this idea, the revised Fisheries Law, which came into force in 2020, stipulates that resource assessment and resource management should be carried out based on the latest scientific knowledge, and sets a goal of managing fish species that account for 8% of the catch by TAC (maximum allowable catch). However, although four years have passed since the revised Fisheries Law came into force, no new fish species have yet been fully subject to TAC, and the first step of TAC has only been started for four fish species (nine stocks).

The reasons why the introduction of TAC is slower than expected include: 1) fishers do not trust the results of scientific resource assessments, which are the premise of TACs, 2) fishers are worried that restrictions on catches will reduce their income and make it impossible for them to continue fishing, and 3) issues with allocating and adjusting fishing quotas, and technical issues such as bycatch in set nets. We need to continue to address issues 2 and 3, but here I would like to focus on issue 1, the issues with the system for scientific resource assessment and management.

To carry out resource assessment and management based on science, it is necessary to develop the necessary personnel and secure the necessary budget. However, the fisheries-related budget, which was about 2,300 billion yen per year, has increased to over 3,000 billion yen since the revised Fisheries Law was enacted, but most of this is used for public fisheries projects such as fishing port development and measures to stabilize the income of fishermen (Figure 7). No matter how good a fishing port is built, it cannot be utilized if the fisheries resources are declining. The author believes that the biggest challenge to promoting fisheries resource management and building a sustainable future for the fisheries industry is the lack of sufficient personnel and budget to carry out resource assessment and management based on science.

Figure 7. Fisheries-related budgets before and after the revision of the Fisheries Law (including the previous year's supplementary budget)[7]

4. How should Japan's fisheries resources be managed?

I would like to highlight four initiatives that are necessary to move Japan's fisheries resource management forward.

(1) Avoid catching small fish

The type of fishing that has the most negative impact on resources is catching small, immature fish. If we continue to catch fish before they have grown and spawned, we will not be able to increase the resources, and the risk of the resource condition rapidly deteriorating increases. Many efforts to prevent the catch of small fish, such as limiting the size of catches, have already been made throughout Japan, but there are still many fisheries where this has not been implemented thoroughly. I think it is important to make an even greater effort to prevent the catch of small fish as a policy for the whole of Japan.

(2) The number of fishing vessels should be in proportion to the size of the resources.

If there are too many fishing boats in relation to the amount of resources, each boat will try to secure a certain amount of catch to make a living, and in some cases may even catch small fish. If there are too many fishing boats, there is a concern that it will have a negative impact on the resources and ultimately put everyone in a difficult financial situation. For this reason, we believe it is necessary to calculate the appropriate number of fishing boats in relation to the amount of resources, and if there are too many fishing boats, we need to take measures such as reducing the number of boats, promoting collaboration, and switching to fishing that targets other fish species.

(3) Expanding the budget for resource assessment and management

There are many things that cannot be done at present due to a lack of budget for resource assessment and management; conversely, there are many things that should be tackled by increasing the budget.

One is the rapid implementation of resource assessments. Currently, resource assessments are conducted by limited personnel, which takes time, hindering appropriate management in line with resource fluctuations. For example, taking catch samples for each fish species and region and analyzing body length composition is essential for resource assessments, but there is a shortage of personnel at prefectural fisheries research centers responsible for these tasks, and this situation needs to be improved.

Furthermore, in order to respond to recent changes in the marine environment, it is also necessary to strengthen monitoring of the marine environment and resource status by promoting ICT. For example, I believe it is necessary to install automatic observation equipment in fixed nets nationwide and to further advance the automatic collection of data from fishing boats.

In order to carry out more accurate resource assessments and management, the promotion of "ecosystem-based resource management" has been raised as a challenge. Current resource assessments do not fully consider the impact that changes in environmental factors (such as water temperature, food supply, and number of predators) have on resources, which is one of the reasons why the reliability of resource assessments and future predictions is not high.

In order to carry out effective resource management, in addition to managing catch volumes and sizes, it is important to further strengthen research into fish life cycles (where spawning occurs, what food they eat, what predators there are, how they migrate, and under what ecosystem conditions resources increase or decrease, etc.) and incorporate this into resource assessments, while also working to conserve the entire ecosystem (for example, conserving the environment of seaweed beds and tidal flats that serve as spawning grounds). This is easier said than done, but such research is already becoming more and more popular overseas, and we believe that Japan also needs to create a system to strengthen this research.

(4) Building trust among researchers, government officials, and fishermen

In order to move Japan's resource management forward, it is necessary to build a relationship of trust among researchers who conduct scientific surveys of the state of resources, administrative authorities who establish management measures based on the survey results, and fishermen who implement the management measures.

However, this is not sufficient at present, and fishermen in the field have doubts about the results of resource assessments conducted by scientists, and are not fully convinced by the management measures that the government is trying to implement, which is a major factor in the lack of progress in resource management.

The West Coast of the United States, which is seen as a precedent for science-based resource management, also faced a similar situation when the initiative first began. However, by spending more time together, the three parties gradually built up a relationship of trust.

One of the specific initiatives is the implementation of resource surveys in collaboration between researchers and fishermen. By doing so, researchers can obtain first-hand information from fishermen who watch the ocean every day, while fishermen can gain a deeper understanding of what data is needed for what purpose, and it is expected that by being involved in the surveys and communicating directly with researchers, they will be more convinced of the survey results.

Another is the opportunity for training (workshops, etc.) in which researchers, government officials, and fishermen participate on an equal footing. This allows fishermen to learn the knowledge and ideas necessary for resource management, while researchers and government officials can spend time with fishermen to understand each other's values ​​and what they place importance on, and build relationships that cannot be built in official meetings. EDF, an environmental organization in the United States, is already conducting such training, and it would be good if it were to be spread to more regions and fish species.

Makoto Kume
UMINEKO Sustainability Institute (USI)Representative
Born in Hokkaido in 1975. Worked at the Ministry of Agriculture, Forestry and Fisheries from 14 to 25. After working as a consultant on agriculture, forestry and fisheries business and environmental policy in the private sector, he established the UMINEKO Sustainability Research Institute in 3. He is responsible for running forums aimed at restoring fishery resources.

Other articles by Kumei are here
-Establishing Marine Protected Areas in the High Seas: How the UN Treaty on the High Seas will affect Japan's fishing industry
-The type of budget necessary for the development of Japan's fisheries industry - Examination of the fisheries budget in light of the WTO Fisheries Subsidies Agreement -

[1] Source: Fisheries Agency, "Fisheries White Paper 5," Figure 2-1
[2] Created based on Figure 5-2 in the Fisheries Agency's "Fisheries White Paper 1"
[3] Source: Fisheries Agency, "Fisheries White Paper 5," Figure 3-24
[4] Source: Fisheries Agency, "Fisheries White Paper 5," Figure 3-2
[5] Source: Fisheries Agency, "Fisheries White Paper 5," Figure 3-3
[6] Created based on the Fisheries Research and Education Agency’s “Fish Species Resource Assessment for 6” and “Current Status of International Resources.”
[7] Source: Fisheries Agency, "Summary of Fisheries Budget and Settlement"