Department of Fisheries Resource Management
Tokyo University of Fisheries
5-7, Konan 4, Minato-ku, Tokyo 108, Japan
ABSTRACT The propagation of masu salmon (Oncorhynchus masou) to increase fishery production in an economically efficient manner faces major challenges. There are three methods of seed production and release. The economic advantages and disadvantages with regard to each method are analyzed and discussed. Costs are higher for propagation of masu salmon than for chum and pink salmon. An important comparison is the combined production and release costs in relation to the smoltification ratio that is strongly influenced by the character of seed.
It should be mentioned, however, that production and release costs are only one part of the overall economic aspect of propagation of masu salmon. Recapture ratios and market prices also play vital roles. Moreover, natural conditions such as fresh water, climate, and water temperature are also important factors. Methods of seed production and release should reflect whatever natural conditions prevail at the propagation and release sites. These factors may point to the conclusion that the propagation of masu salmon has little potential as an economical profitable project in comparison to the propagation of chum salmon.
There are some other problems and challenges of an ecological and social nature with respect to the propagation of masu salmon. Mixture of stocks from different rivers is a big problem. Masu salmon, especially landlocked, is one of the most popular game fishes in Japan. Consideration from this viewpoint should be stressed. The most important challenge from both an ecological and social perspective is preserving natural reproduction. There are few natural stocks remaining in Japan. The propagation of masu salmon should not be undertaken if naturally reproducing stocks are lost.
INTRODUCTION Masu salmon (Oncorhynchus masou) inhabits the Asian side of the northern Pacific Ocean. Population size is not well known. The catch along the Japanese coastal area is about 2,000 or 3,000 metric tons and only 1 or 2% of the total catch of salmonid fish in Japan. Populations are thought to be decreasing to low levels. In contrast, artificial propagation of chum salmon is a strong success in Japan. The catch of chum salmon in the Japanese coastal area has increased in recent years. However, there are some problems. Along the northern coast of the Japan Sea, the rate of return is stilllow. Also, the quality of chum salmon caught in the coastal area is poor. The total supply of all salmonid fish is too large, because of the increase of imported and cultured fish. Price has dropped to a very low level.
The quality and flavor of meat of masu salmon is very good, and its price on the market is much higher than that of chum salmon. Locally, it is sometimes more than 8,000 per kilogram. The geographical distribution of the catch for 1984 is shown in Table 1. Most of the masu salmon is caught along the Japan seacoast rather than the Pacific Ocean coast. The Japan Sea coastal fisheries have strongly requested that masu salmon resources be increased. Masu salmon is an endangered species, but it is also expected to be a fishery resource.
Masu salmon usually spend 1 year in fresh water prior to seaward migration as a smolt. They then stay in the coastal sea for 1 or 2 years until beginning a spawning up its parent river. Recent environmental degradation in these spawning rivers has resulted in serious decreases in masu salmon resources. We cannot expect masu salmon to increase only by natural reproduction in their native rivers. Artificial propagation technology should be established, based on the many studies and investigations that have been done. However, this practice point should be checked from an economic and social viewpoint. This is important in order for the fisheries to be successful.
VALUE OF MASU SALMON
The value of masu salmon is not only to the commercial and sport fisheries; it is of social value to these people who want to preserve the salmon as an important part of the ecology of the river environment and as an important genetic resource. Thus, it is necessary to understand that the future of masu salmon cannot be determined only by its profitability in the fishery.
PROFITABILITY AND COST OF ARTIFICIAL PROPAGATION OF MASU SALMON
In Japan, there are three methods of masu salmon seed production and release: fry-release in the first spring; fingerling-release in the late autumn prior to the overwintering period; and yearling-smolt-release at the time that wild smolts normally migrate to the sea. Each of these methods has its own advantages and disadvantages. Each method is suitable depending on geographic conditions.
Economic advantages and disadvantages and other problems associated with each method were analyzed and discussed for 5 prefectures with different geographic conditions--Iwate, Hokkaido, Aomori, Niigata, and Toyama. Differences in costs were determined among the three methods. The approximate seed production costs expected using each of the three methods are shown in Table 2. These costs are increased by initial or start-up costs. In many cases, however, initial costs are assumed by the government and can then be omitted.
The most important consideration, however, is the combined production and release costs per fish in relation to the smoltificatin ratio (Table 3). Actually, in many cases yearling-smolt release is chosen because of its cost advantage. These costs are much higher than in the case of chum salmon. Production and release cost of chum salmon is about 4 per fish. Production and release costs are only one part of the overall economic aspects of masu salmon artificial propagation. The recapture ratio also plays vital role.
CONDITIONS NECESSARY FOR MASU SALMON FISHERIES SUCCESS
We expect to be able to achieve a high profit rate in this project similar to that for chum salmon. A rough estimate of profit rate for chum salmon is shown in Table 4. The profit rate is more than 90%, which is a very high level.
The average price of masu salmon is about 1,500 per kilogram, higher than that of chum salmon. The average catch weight of fish is about 1.5 kilograms, and thus the price per fish is 2,250. If the expected profit rate is over 90%, the cost per caught fish should be under 225. Then, the rate of return necessary to achieve 90% profit rate can be estimated. Table 5 shows the rate of return necessary to achieve a profit rate similar to that for chum salmon. Yearling-smolt-release is the most profitable.
Yearling-smolt-release is also preferred for other reasons. In the case of fry-release, fry remain for a year in the river where the survival rate is estimated to be vary low and a high rate of return is then not expected. Fingerling-release is not preferred for the same reason. Moreover, hatcheries for these life stages need much water and there are very few places available. An additional reason exists. In the case of yearling-smolt-release, parent fish should be bred in ponds because the eggs must be taken in summer by artificial methods. These parents are selected from stocks that achieve a high smoltification ratio.
The rates of return shown on Table 5 may be achieved only in special cases and not under the technical level of production and release existing today. Normally, the rates of return reported are under 1%. Therefore, masu salmon fisheries cannot achieve an acceptable profit rate as long as the rate of return remains low. These rates on Table 5 thus become the targets for Japanese scientists and technicians to achieve.
ESTIMATION OF OTHER VALUES
It is also important to understand values other than commercial and recreational harvest. The degradation of rivers is occurring everywhere, and the environment suitable for masu salmon reproduction is being destroyed. We should not exterminate the masu salmon species in its natural habitat. Conserving the natural environment in rivers and preserving natural stocks of masu salmon has great ecological value. From the standpoint of preservation of genetic resources, preservation of natural stocks of masu salmon is also of great value. At present, however, there is little societal support in Japan for the preservation of natural stocks of masu salmon.
Outside of the harvest fisheries, only sport fishing can exert social pressure that may influence the future existence of masu salmon. Masu salmon is considered the finest sport fish in the river systems of Japan in size, style, and fighting ability. The fish caught in the sport fishery are wild fish that return to the river for spawning. Because there are so few, many regulations exist for fishing. Since artificial propagation began in many districts, masu salmon fishing in rivers has been prohibited because the spawning fish in the river are used for propagation only. However, there are strong demands by the sport fishing community for masu salmon. Sport fishermen are gaining strong power in the Japanese society in response to the demand for leisure time. The masu salmon sport fishery depends on the existence of natural stocks. This is an important point to note.
PHASES OF EXISTENCE OF MASU SALMON IN JAPAN
There are three phases of masu salmon existence in Japan. Figure 1 shows phase one when the life cycle of masu salmon is still natural and unaltered. Masu salmon can utilize the productivity of both the river and the sea. Figure 2 shows the second phase when development of rivers has begun, and environmental disturbances in the rivers have resulted in decreases in masu salmon resources. Artificial propagation begins in this phase. The natural process is still the most important component of the phase, and artificial propagation is expected only to replace losses. Sport fishing is still allowed. Figure 3 shows the final phase where development of rivers has progressed to the point that natural stocks of masu salmon nearly disappear. In this phase, only artificial propagation can preserve masu salmon resources. Natural processes have been replaced by artificial processes such as the case of chum salmon. Reproduction is controlled artificially, and the cost is shared by the government and beneficiaries similar to the set-net fisheries. All of the spawning fish are caught, and there is no escapement for natural reproduction or the sport fishery.
It is an important question as to what phase our society should support for masu salmon resources. Actually, there is no choice. The development of rivers for flood control or water supply to big industries is continuing. Japan is presently in the second phase in Hokkaido and the final phase in Honshu Island. The ability to propagate artificially has been one of the conditions for which permission has been granted to develop rivers. The development of rivers has been one of the reasons that artificial propagation was needed. It is a vicious circle. Throughout this process, replacement has been continuing. It has become difficult to preserve the natural stocks.
There are many problems in the final phase for masu salmon resources. One of the biggest problems is that the reproduction of masu salmon is influenced by the profitability of fisheries. If the profitability of a project is not sufficient or if there are losses, then the project can no longer continue. The previous discussion on profitability shows this risk. If natural stocks are replaced completely by artificially propagated fish, then masu salmon will disappear. Of course, if the project is operated bythe government, then any losses will be absorbed by them. However, such costs cannot continue if this project is to be on a profit-making basis. Thus, projects should be done with two purposes: 1) to make a profit, and 2) to preserve masu salmon resources.
In the second phase, masu salmon resources are common property based on natural reproduction, and artificial propagation only replaces the losses. We catch and use masu salmon as a natural resource. However, in the final phase, masu salmon is no longer a natural resource. It is a kind of domesticated livestock or fish and may belong to anyone who pays for the cost of propagation. In Japan, because of the social and geographical background, the final phase tends to be prevalent. There are large changes in Japanese rivers. Because much of the population live in the low plains, flood control is necessary. Large manufacturing industries and cities demand a lot of water. To promote industry and to supply water to the people in the cities, the government constructed many dams on numerous rivers where masu salmon migrated for spawning.
However, society needs to consider all facets of these problems, including the value of natural stocks and how to preserve them. Artificial propagation is necessary for the commercial fisheries and for the preservation of masu salmon. It will be a difficult challenge to stay in phase 2.
The sport fishing community is only one component of society that has considerable power to insist on the continued existence of natural stocks of masu salmon. However, there is no resource management system that includes sport fishing. Only commercial fisheries can manage the resource.
In my opinion, we should create a resource management system that will include both commercial fisheries and sport fishing. Then, the sport fishing constituency can help pay for the propagation. This system should be operated on a non-profit basis and supported by the public. Through this arrangement, artificial propagation could be promoted as well as the preservation of natural stocks through negotiation with industries.
TODAYS CHALLENGES IN STUDYING MASU SALMON ARTIFICIAL PROPAGATION
In the United States, resources of salmonid fish are maintained primarily by natural reproduction. Natural environments suitable for their reproduction are scientifically studied and investigated. Research on the fresh water environment and ecological system have been done for a long time. Sport fishing plays a vital role in resource management.
In contrast, in Japan research is focused on the technology of artificial propagation. There has been little study of the environment or the ecology of freshwater systems. Also, minimal attention has focused on developing a resource management system for salmon. In Japan, the condition of the rivers is very different from the United States. Research on the freshwater environment and ecological system should be urged. Based on these studies, a resource management system for masu salmon should be established. This system should include sport fishing, in order to preserve the natural stocks and provide for commercial fishery resources. This is a difficult but important challenge for todays Japanese researchers.
