Oncorhynchus masou formosanus
[6] As a result, methods such as loop-mediated isothermal amplification and PCR-derived tests are used to differentiate similar-looking species and sexes for conservation and management purposes.[7] However, there is one key sexual dimorphism, which presents in a secondary sex characteristic of males during mating season, during which the lower portion of the jaw becomes upturned.They were found to have migrated into Taiwan by way of the Tsushima Strait, a channel in the Japan Sea between 10 and 80 million years ago, as demonstrated by analysis of mitochondrial DNA samples.In the Chichiawan Stream, an important and large portion of the Formosan landlocked salmon range, habitat selection was found to be significantly different in summer versus winter months.[10] However, hydrological alterations, damming, and land development for agricultural purposes has degraded the habitat, resulting in a drop in abundance to approximately 200 individuals in 1984.It is a relictual subspecies of the once more widespread masu salmon, landlocked into the highland valleys by the warming of lower Dajia River after the end of the Last Ice Age.[2] This species reaches sexual maturity before two years of age, and undergoes its growth in physical size and biomass early in its life cycle.These ecosystem services are helpful in facilitating the biological functions of the salmon, including reproduction, and protecting the habitat against the impacts on flow regimes due to climate change as well as agricultural development.[11] The base of the trophic system in the Formosan landlocked salmon’s habitat is primarily C3 riparian plants, which comprise the diet of aquatic insects in the filter and gatherer functional feeding groups.These include the degradation and destruction of habitat due to human activities such as agricultural development, overexploitation of riparian resources, water and air pollution, and the consequences of climate change and global warming.Over the next 20 years, the Taiwanese government, the Shei-Pa National Park Administration, as well as effective conservation efforts in Taiwan, restored the fish population to historical high of 12,587 in 2020.[20][21] Despite the protections already in place, it is critical that future conservation efforts continue to support the growth of Formosan landlocked salmon populations in Taiwan.The upstream watersheds of the Tachia River are in alpine environments, so they are particularly vulnerable to the increased temperatures due to the high degree of solar radiation.[22] As a result, it will be important to monitor salmon populations as water temperatures rise and to implement strategies to mitigate the consequences of climate change.