Formosan Landlocked Salmon

Introduction

Formosan landlocked salmon is a fresh water type of salmonid fish that is endemic to Taiwan (Gwo, Ohta, Okuzawa & Wu, 1998). It is also vital to note that the Formosan landlocked salmon is a sub-species of the West-Pacific cherry salmon that is quite widespread (Gwo, Ohta, Okuzawa & Wu, 1998). The Formosan landlocked salmon is a highly endangered, sensitive and threatened species because of the existing biodiversity crisis in Taiwan. It is currently at the risk of extinction. It is normally protected within its native habitat. The Formosan land-locked salmon remains to be among the types of fish that are quite rare to find in the world. This type of fish was at one point the staple of the Taiwanese aborigine food. This salmon species is known for always inhabiting the fresh water streams (Carruth, Dores, Maldonado, Norris, Ruth & Jones, 2000). Despite the fact that it moves away over a long distance while migrating, the species usually returns to the home habitat, but amid very strong obstacles to it on the way. It must be understood that the survival of this species has become an issue of concern given the high number of deaths being experienced as a result of pollution of the stream waters. The whole issue of biodiversity crisis is at the center of the imminent extinction of this species. Some of the issues of concern include the destruction of the natural habitat for this species, overfishing and the introduction hatchery fish in the fresh water streams (Healey, Kline & Chu-Fa, 2001). Moreover, the issue of global warming is bringing about high thermo-temperatures in the fresh water streams making it difficult for this species to survive. Really, the Formosan land-locked salmon is a species that is currently facing possible extinction because of the existing biodiversity crisis making it endangered.

The main body

The Formosan landlocked salmon species was declared a critically endangered species and included in the IUCN Red List of Threatened Species. This rare of type of fish is at the risk of extinction because of its high rate of decline. This decline has become a real cause for worry because it may lead to the total extinction of this species. The population of the Formosan land-locked salmon has been extirpated from close to 40% of its historical habitat in Taiwain. Half of the remaining population is at the high risk of extinction (Chen, Wen, Meng, Cherh & Shao, 2015). More importantly, the unique thing about the decline in the number of salmon is that it affects all people who live in Taiwan both directly and indirectly. This type of fish has stood out as the main symbol and pillar of life within this country. It is important to note that the salmon fish species is the one that provided the basis for the development of the ancient cultures of the local people. Moreover, salmon fish was the pillar of the economy of this part of the world. It even indirectly shaped the earliest religion of the people. As noted earlier, the Formosan land-locked salmon has been the staple of the Taiwanese aborigine diet. However, its population currently stands at barely over 400. This figure implies that the people of Taiwan are missing their staple food. 

It must be noted that, in the past, fishing activities generated up to 1 billion dollars in terms of revenue. This was just the collective personal income in every year. Over 60,000 people would get jobs within the fishing industry. However, the situation has changed today, since many people in Taiwan now compete with the salmon fish for the fresh water in the rivers, where this species spawns to produce new generations (Lin, Tsao, Lee & Shaw, 2004). Some of the human activities that continue to affect the survival of salmon species negatively include the construction of dams, irrigation and sewerage disposal into the rivers. These are human activities that are greatly destroying the salmon fish species habitat.

Fishing 

Over-fishing has brought more harm on the number of Formosan landlocked salmon fishes in Taiwan. An example is in most fresh water streams of Taiwan, where there is a significant variation in the rate of harvests for the Formosan landlocked salmon fish populations between now and in the 1980s. Overfishing activities in the fresh water rivers have added to the problem of possible extinction of the salmon fish population. There are fishing mechanisms that do not focus on size selection hence catch even the very young and small salmon fish (Hsu, Tzeng, Yeh, Kuan, Kuo & Lin, 2010). This kind of fishing is harmful to the continued survival of the salmon populations. Moreover, some fishers use harmful chemicals to kill and catch fish. When such chemicals are put into the fresh water rivers, the salmon habitat for spawning is destroyed hence most of them end up dying.

Loss of habitat 

The major biodiversity crisis that is currently affecting Formosan landlocked salmon fish populations is the loss of the fresh water habitat, which it is used to in Taiwan. The destruction of the fresh water living environment by human beings has become a major threat to the survival of the salmon species. Scientists have been able to explain that the general habitat needs of salmon are very simple. The Formosan landlocked salmon fish habitat needs include plenty of gravel in which they normally spawn, sufficiently cool and clean fresh water for swimming to escape the predators and also find food (Nilsen, Ebbesson, Kiilerich, Björnsson, Madsen, McCormick & Stefansson, 2008). The other additional requirement is enough vegetation along the banks of rivers for prevention of erosion or even sedimentation. This vegetation is also needed for the purpose of adding nutrients into the water. Vegetation in the fresh water rivers also helps in providing the woody debris, which then gives the salmon fish the much needed shelter from the strong currents. 

Over the past many years, activities like mining, timber harvesting along the river banks, urban development and livestock grazing have all added to the destruction of the Formosan landlocked salmon habitat. The evidence of this destruction caused by human activities along the fresh water river banks is the very small number of Formosan landlocked salmon fish in the degraded parts of Taiwan than within the pristine ones (Tung, Lee & Yang, 2006). It is important to note that this habitat loss and destruction causes reduction of the genetic diversity and possible extinction of the whole salmon species population. Therefore, Formosan landlocked salmon fish population is now nearing extinction because of the degradation of the habitat in which it spawns.

Damage from dams 

The development of dams has a very huge adverse impact on the survival of the salmon fish populations. Through research, it has been established that the construction of extensive hydropower on major rivers in Taiwan has disrupted the Formosan landlocked salmon population (Gwo, Ohta, Okuzawa & Wu, 1998). Along the Tachia River basin, in Taiwan, there are major dams constructed to generate hydropower. This river has been a major habitat for the Formosan landlocked salmon population that is largely located in its Chichiawan and Kaoshan streams. These dams usually block off a large space of the original fresh water habitat for this Formosan landlocked salmon species. 

The damaging impact of the dams varies significantly. The major impact of the dams is reducing the number of salmon moving within the fresh water habitats to spawn. However, there are dams that have allowance for the salmon fish to pass over. Another threat of these dams is reduction of the level of biodiversity for the Formosan landlocked salmon species. The dams may cause a selective pressure that favors the salmon species that do not migrate (Battle, Chang, Tzeng & Lin, 2016). In this case, the Formosan landlocked salmon species that migrate will reduce in number because of the harmful dams while those that do not migrate will be under no significant effect from the dams.

Hatcheries 

In a bid to preserve the withering Formosan landlocked salmon fish species population in the fresh water river basins of Taiwan, hatcheries are being used. In this practice, breeds of Formosan landlocked salmon are introduced into the river so that their number can be increased. Scientists have established that this hatchery Formosan landlocked salmon species has characteristics that are significantly different from those of the wild ones. The two kinds of salmon populations live in the same habitats thus there are high chances of straying during mating. It must be noted that the artificial hatchery salmon species has weak features that reduce their chances of surviving in the wild water habitat. For instance, the hatchery-reared Formosan landlocked salmon fish species are weak at avoiding and escaping the predators and their degree of wildness is very small (Carruth, Dores, Maldonado, Norris, Ruth & Jones, 2000). Therefore, when they stray and mate with the wild salmon, the produced offspring have the weak characteristics of the hatchery-reared ones. The implication of this situation is that the new generations produced are not fit to survive, especially in the wild river environment. Rearing fish in a hatchery with the intention of increasing the populations of salmon has counter-effects. The result of this practice is simply an increased number of Formosan landlocked salmon fish population falling in the fresh river waters. It simply means that hatchery increases the level of risk and threat on the survival of the Formosan landlocked salmon fish population.

Biodiversity

The lack of certainty over the significance of the local adaptation and small spatial scale regarding the rate of adaptive evolution of the Formosan landlocked salmon fish species is reason for the need of continued research in this area. There are those scientists who have sought to explain that biodiversity does not have any relationship with the ability of a species to survive in its habitat. According to argument presented in this perspective, scientists reason that there are many verifiable species whose biodiversity has been reduced greatly but still survive (Hsu, Takata, Onozato & Gwo, 2015). The issue of biodiversity crisis has got huge attention in this case because it has been established that the lack of it is the reason for the continued decline of the whole species. 

Although there may be truth in the argument that biodiversity has no consequence on the survival fitness of a given species, it is vital to note that this concept has huge relevance when it comes to the Formosan landlocked salmon fish population (Levin & Schiewe, 2001). Therefore, this biodiversity of the Formosan landlocked salmon fish species is very essential to its survival and existence. Reduction in biodiversity is detrimental to the survival of the Formosan landlocked salmon fish species population and may lead to its extinction (Levin & Schiewe, 2001).

Conclusion

The Formosan landlocked salmon fish species, which is only found in Taiwan, is at a very high risk of extinction. This salmon species has been included in the IUCN Red List of Threatened Species. There are various factors that are leading to the biodiversity crisis for this species and the resultant decline in their populations. The solution to this problem is simply controlling and limiting the human activities by governments. River basin banks must be protected by governments in order to save this important salmon species.

References

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Carruth, L. L., Dores, R. M., Maldonado, T. A., Norris, D. O., Ruth, T., & Jones, R. E. (2000). Elevation of plasma cortisol during the spawning migration of landlocked kokanee salmon (Oncorhynchus nerka kennerlyi). Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology ,  127 (2), 123-131.

Chen, J. P., Wen, C. K. C., Meng, P. J., Cherh, K. L., & Shao, K. T. (2015). Ain’t no mountain high enough: the impact of severe typhoon on montane stream fishes.  Environmental biology of fishes ,  98 (1), 35-44.

Gwo J-C, Ohta H, Okuzawa K, Wu H-C. (1998). Cryopreservation of sperm from the endangered Formosan landlocked salmon (Oncorhynchus masou formosanus) . Theriogenology . 51:569–582.

Healey, M., Kline, P., & Chu-Fa, T. (2001). Saving the endangered Formosa landlocked salmon.  Fisheries ,  26 (4), 6-14.

Hsu C-B, Tzeng C-S, Yeh C-H, Kuan W-H, Kuo M-H, Lin H-J. (2010). Habitat use by the Formosan landlocked salmon Oncorhynchus masou formosanus. Aquatic Biology .10:227–239.

Hsu, T. H., Takata, K., Onozato, H., & Gwo, J. C. (2015). Causes of the drastic loss of genetic variation in the Critically Endangered Formosa landlocked salmon of Taiwan.  Endangered Species Research ,  27 (3), 277-287.

Levin, P. S., & Schiewe, M. H. (2001). Preserving salmon biodiversity: The number of Pacific salmon has declined dramatically. But the loss of genetic diversity may be a bigger problem.  American Scientist ,  89 (3), 220-227.

Lin, J. Y., Tsao, E. H., Lee, T. C., & Shaw, L. Y. (2004). Stream physical parameters and habitat requirement: the case of the Formosan salmon. Ecological Engineering ,  22 (4), 305-309.

Nilsen, T. O., Ebbesson, L. O., Kiilerich, P., Björnsson, B. T., Madsen, S. S., McCormick, S. D., & Stefansson, S. O. (2008). Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): seasonal development and seawater acclimation.  General and comparative endocrinology ,  155 (3), 762-772.

Tung, C. P., Lee, T. Y., & Yang, Y. C. (2006). Modelling climate‐change impacts on stream temperature of Formosan landlocked salmon habitat. Hydrological Processes ,  20 (7), 1629-1649.