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).
This species lives in the bottom layer of inshore and inland waters, and grows 2040 cm in length. Most of the growth takes place in the sea but they spawn in brackish and fresh water. During the spawning season, which is from late spring to early summer, the sexually mature fish run into river estuaries and spawn in inland waters including rivers, lakes, and ponds. The fingerlings grow in the inland water and either return to the sea the next spring or they there for a few months before returning to the sea. In the sea they grow to sexually mature fish over several years, and then return to the inland water again to spawn (Kato et al. 2005).
Molecular Biology and Genetics
Barcode data: Takifugu obscurus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
-- end --
Download FASTA File
Statistics of barcoding coverage: Takifugu obscurus
Public Records: 7
Specimens with Barcodes: 7
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
- 2009Least Concern (LC)
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 onT. obscurusare 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 genusTakifuguhave become the focus of increasing aquaculture efforts throughout East Asia. AquaculturedTakifuguare used to meet increasing demand for pufferfish products and to enhance natural populations which have been depleted throughout the region (Kawataet 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 (Hindaret al. 1991). Fishes of the genusTakifuguare relatively recently diverged, and each combination ofTakifuguspecies is expected to produce fertile hybrid crosses (Yamanoueet al. 2008). It is therefore likely that the effect of intentional and unintentional release of culturedTakifuguon 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 (Linet al. 2005).
There are no known species-specific conservation measures in place forT. obscurus,however, it is possible that management efforts aimed at sustainingT. rubripesfisheries have benefitedT. obscurus. Additionally,T. obscurushas been bred in captivity to meet increasing demand and to enhance existing stocks.
The Fugu fishery is acknowledged to have undergone significant declines. Japan, South Korea and China previously operated their fisheries under a policy which prevented the regulation of foreign fishing vessels and treated the open sea in East Asia as common property. Since 1999, with the ratification of the United Nations (UN) Convention on the Law of the Sea and new fishery agreements between these nations, this policy has shifted to enable coastal countries to regulate foreign fishing vessels. As a result of this policy shift, Japan announced the Plan for Rebuilding Puffer Resources in April 2005, which set dates for an off-fishing season, restrictions on minimum body size, support for stock-enhancement programs, improvements to fishing grounds, and mandated the release of small fishes. As of 2010, stocks had not fully improved, prompting a re-assessment of the program. Several recommendations have been made in order to ensure its continued existence, particularly in light of socio-economic constraints which limit the possibility of developing alternative fisheries. Recommendations include gear restrictions and mandating that fishers catch older and heavier fish by postponing the beginning of the fishing season (Kamara 2012).
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 (Chenget al.2007).
Takifugu obscuruscan 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 (Huanget al.2010).
The economically important genusTakifuguhas been recommended for further taxonomic studies based on morphological and molecular analyses (Yamanoueet al.2008), and we support this recommendation.
Relevance to Humans and Ecosystems
EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.
To request an improvement, please leave a comment on the page. Thank you!