|Scientific Name:||Takifugu obscurus|
|Species Authority:||(Abe, 1949)|
Fugu obscurus (Abe, 1949)
Sphoeroides ocellatus subspecies obscurus Abe, 1949
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Hardy, G., Matsuura, K., Shao, K., Jing, L., Leis, J.L. & Liu, M.|
|Reviewer(s):||Zapfe, G. & Lyczkowski-Shultz, J.|
Takifugu obscurus is known from the Yellow Sea, East China Sea and South China Sea to the Korean Peninsula. It is found in rivers in China. It is found at depths ranging from one to at least 20 m. This is a euryhaline species which lives in the bottom layer of inshore and inland waters. Spawning occurs in estuaries, and this species is known to migrate into freshwater to spawn. It is a commercial species which is considered highly-valued, however there is little information available to characterize the fishery. This species has been bred in captivity, and it is unclear whether or not this effort has been for the purposes of stock enhancement. There is little species-specific population information available. This species' dependence on freshwater systems to spawn and its predictable, seasonal mass spawning migrations into freshwater systems render it particularly vulnerable to overfishing. Seasonal fishing prohibitions and the presence of both fresh and marine water preserves in parts of its range may offer this species some protection. Takifugu obscurus is assessed as Least Concern.
|Range Description:||In the Western Pacific, Takifugu obscurus is known from the Yellow Sea, East China Sea and South China Sea south to the Korean Peninsula. It is found in rivers in China (Nakabo 2002). It is found to depths of at least 20 m, and may be found deeper.|
Native:China; Japan; Korea, Democratic People's Republic of; Korea, Republic of
|FAO Marine Fishing Areas:||
Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There is little species-specific population information available for wild populations of T. obscurus.|
|Habitat and Ecology:||
Takifugu obscurus is a demersal, anadromous species which undergoes annual seasonal migrations into freshwater systems to spawn. In the Yangtze River basin, the spawning period for T. obscurus is from March until April. This species maintains a sex ratio of approximately 1: 1. This species reaches sexual maturity between 25 and 28 cm (SL). The ovaries and blood are extremely toxic, while the liver, skin, and intestine are highly toxic. The flesh and testes are innocuous (Nakabo 2002).
|Use and Trade:||
Takifugu obscurus is a popular food fish in China and fetches a premium price owing to its high quality meat (Yang and Chen 2008). This is a species of interest for intensive aquaculture in China (Zhou and Jia-Xin 2003).
There have been no confirmed population declines in T. obscurus. However, it is likely to be impacted by the following:
The Fugu fishery is acknowledged to have undergone significant declines throughout East Asia. Highly effective fishing gear, including modified long-lines and nets with small mesh sizes, rather than excessive fishing effort, have been implicated in the depletion of Takifugu pufferfish resources in parts of East Asia. In Japan, initial efforts to regulate the fishery in the mid-2000s had not achieved desired results by 2010, and were subsequently re-evaluated (Kawata 2012). Although the species-specific effects of the Fugu fishery on T. obscurus are unknown, it is likely that populations of this minor commercial species are impacted by this fishery.
Genetic effects of cultured fish on natural populations
Fishes of the genus Takifugu have become the focus of increasing aquaculture efforts throughout East Asia. Aquacultured Takifugu are used to meet increasing demand for pufferfish products and to enhance natural populations which have been depleted throughout the region (Kawata et al. 2012). As culture fish are genetically distinct from natural populations, the release of aqua-cultured fish can result in a range of genetic outcomes, from no detectable effect to complete introgression or displacement of wild populations (Hindar et al. 1991). Fishes of the genus Takifugu are relatively recently diverged, and each combination of Takifugu species is expected to produce fertile hybrid crosses (Yamanoue et al. 2008). It is therefore likely that the effect of intentional and unintentional release of cultured Takifugu on the genetic integrity of wild populations is significant.
Regional threats: environmental degradation and over-fishing
Major threats to biodiversity of the China seas include over-exploitation of fishery resources and environmental deterioration. The China Seas have faced severe environmental degradation due to a range of anthropogenic activities within a relatively recent and short time frame (Daoji and Daler 2004). The degradation of estuarine environments due to pollution and coastal production is of particular concern, as these areas are characterized by high productivity and represent spawning and nursery areas for many species (Liu 2013). Large areas of the China Seas (Liu 2013) and the Gulf of Thailand (Blaber 2000) are considered to be heavily overfished. Additionally, heavy bottom-trawling in the 1980s and the widespread use of modified driftnets for multi-species fisheries in the Bohai Sea, combined with other anthropogenic stresses, have been implicated in the steady decrease in fish landings in this area (Xianshi 2004). In the Yellow Sea, previously dominant large demersal species became the targets of heavy fishing pressure during the 1950s and 1960s and greatly declined in abundance. By the 1980s, many large pelagic species were also showing great declines in abundance, and since that time the dominant species in the Yellow Sea have been small, planktivorous pelagic species, such as anchovies and sardines (Jin and Tang 1996). In the Yellow Sea, all ecological indexes such as the species number, species richness, species diversity and the evenness were lower in the year 2000 than in the year 1985 (Lin et al. 2005).
There are no known species-specific conservation measures in place for T. obscurus, however, it is possible that management efforts aimed at sustaining T. rubripes fisheries have benefited T. obscurus. Additionally, T. obscurus has been bred in captivity to meet increasing demand and to enhance existing stocks.
In order to sustain fisheries of the East China Sea, the government of China has implemented a number of management and conservation measures. These include establishing a prohibited-fishing zone along the 50-m depth contour, the establishment of seventeen national nature reserves and five special marine protected areas, the creation of fishery protected areas which are annually closed to trawling, and a summer closed-fishing areas, which prohibit trawling and have been extended to the South China Sea, Yellow Sea, and Bohai Sea (Cheng et al. 2007).
Takifugu obscurus can be found in both freshwater and marine protected areas. According to the protection regulations for wetlands in the Poyang Lake of Jiangxi Province (2004) and the implementation of Chinese Fishery Lawin Jiangxi Province (1987), fishing is is banned from March 20th to June 20th every year in Poyang Lake. This corresponds with the spawning migration of this species in China, although whether or not this species spawns in the lake is unknown. Fishing has also been banned for two months from June 1st to July 31st each year since 1987 along the Xiajiang reach, Xingan reach, Jishui reach and Jian reach of the Ganjiang River, where this species has been recorded. However, this does not correspond to the freshwater spawning migration of this species (Huang et al. 2010).
|Citation:||Hardy, G., Matsuura, K., Shao, K., Jing, L., Leis, J.L. & Liu, M. 2014. Takifugu obscurus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 28 November 2014.|
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