Conservation of the horseshoe crab at Kinmen, Taiwan: strategies and practices

Chen, Chang-Po; Yeh, Hsin-Yi; Lin, Po-Fen

doi:10.1023/b:bioc.0000035868.11083.84

Cited by 95 publications

(67 citation statements)

References 17 publications

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Section: Growthsupporting

confidence: 84%

“…A comparison of the prosomal width of different instars is shown in Table 2. Sizes of instars obtained from field and laboratory studies by Chen et al (2004) were similar to ours, but those obtained in a laboratory study by Sekiguchi (1988) were smaller.Unusually fast growth was recorded in the present study. In contrast to general growth events with 6 ecdyses in the first 3 yr after hatching (Rudloe 1981, (Shuster 1954, 1958, 1982, Mikkelsen 1988, Sekiguchi 1988, Chatterji 1994, juvenile Tachypleus tridentatus in our study experienced 6 ecdyses within a year (including approximately 2 mo before hatching), and 2 more ecdyses in the following 4 mo.…”

supporting

confidence: 84%

“…There are 4 living horseshoe crab species, including one American species, Limulus polyphemus (Linnaeus, 1758), and 3 Asian species, Carcinoscorpius rotundicauda (Latreille, 1802), Tachypleus tridentatus (Leach, 1819) and T. gigas (Müller, 1785). Horseshoe crab populations are rapidly declining around the world, as has been reported in the USA (Botton & Haskin 1984, Bell & Henderson 1993, Smith et al 2009), Japan (Itow 1998), Taiwan (Chen et al 2004), Singapore (Hong 2004) and the Philippines (Schoppe 2002). Horseshoe crabs were known to occur in great numbers in Hong Kong some 30 yr ago, but now, they can only be found in much lower numbers (Chiu & Morton 1999, Li 2008).…”

Section: Introductionmentioning

confidence: 89%

“…In Taiwan, more than 10 000 individuals of second-instar juvenile Tachypleus tridentatus produced artificially in the laboratory were released in the protected area in Kinmen in 2002(Chen et al 2004), while about 40 000 juveniles were released in the wild in Xiamen, China, in the same year. A successful restocking program relies heavily on an adequate supply of juveniles from artificial breeding, as juveniles released in the wild may suffer high mortality from predation, diseases, food availability, etc.…”

Section: Abstract: Horseshoe Crab · Tachypleus Tridentatus · Juvenilmentioning

confidence: 99%

“…Low temperatures reduce molting hormone levels to a critical level in Limulus polyphemus and hence suspend the ecdysis at temperatures < 20°C (Jegla & Costlow 1982). Chen et al (2004) suggested that 28 to 31°C is the most suitable temperature for incubating eggs and rearing juveniles. The present study showed that the growth of Tachypleus tridentatus could proceed throughout the year, provided that the seawater temperature was optimal (28 to 30°C).…”

mentioning

confidence: 99%

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Enhanced growth of juvenile Tachypleus tridentatus (Chelicerata: Xiphosura) in the laboratory: a step towards population restocking for conservation of the species

Cai¹,

柯才焕

2010

Aquat. Biol.

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Juveniles of artificially bred Tachypleus tridentatus were reared in the laboratory for 15.5 mo. Fast growth (at least 3 times faster than in previous studies) and low mortality were observed, with juveniles reaching the 9th instar stage and having a cumulative mortality of 61.3% at the end of the rearing period. Such enhanced growth can potentially be attributed to high seawater temperature, sufficient living space and constant water flow. Isometric growth of prosomal width and other growth parameters including opisthosoma width, eye distance and prosomal length was found. Two distinct growth phases were detected for the opisthosoma length, with zero growth from the 1st to 2nd instar but isometric growth from the 2nd to 9th instar stage. Growth in telson length was positively allometric from the 1st to 3rd instar and isometric from the 3rd to 9th instar stage. The increase in wet weight and prosomal width was isometric throughout the 9 developmental stages. Based on the allometric growth patterns, the juveniles can reach adult size within 4 yr. The results may serve as a basis for the large-scale culture of this species for the purposes of restocking and restoration of natural populations. KEY WORDS: Horseshoe crab · Tachypleus tridentatus · Juvenile growth · AllometryResale or republication not permitted without written consent of the publisher Aquat Biol 11: 37-46, 2010 Use of captive breeding for population enhancement in animal conservation has increased markedly in the last decade (Olney et al. 1994). In Taiwan, more than 10 000 individuals of second-instar juvenile Tachypleus tridentatus produced artificially in the laboratory were released in the protected area in Kinmen in 2002(Chen et al. 2004), while about 40 000 juveniles were released in the wild in Xiamen, China, in the same year. A successful restocking program relies heavily on an adequate supply of juveniles from artificial breeding, as juveniles released in the wild may suffer high mortality from predation, diseases, food availability, etc. The problems with juvenile horseshoe crabs in culture include low fertilization success, high juvenile mortality and slow growth of the instars (Sekiguchi et al. 1988, Chatterji 1994. The most extensive study of horseshoe crab growth was conducted by Sekiguchi (1988) on the juveniles of Limulus polyphemus and T. tridentatus, which required 9 yr to develop into 14th and 10th instars, respectively. The study itself, however, may not be representative because of both low numbers of specimens and survivors in the study, as an initial number of 44 and 33 ind. were used for L. polyphemus and T. tridentatus, respectively, and only one individual of each species survived at the end of the experiment.The actual life span and exact number of ecdysis events in horseshoe crabs are unknown (Tanacredi 2001, Carmichael et al. 2003, Lee & Morton 2005, as it is difficult to accurately assess age in horseshoe crabs (Botton & Ropes 1988). Goto & Hattori (1929) suggested that Tachypleus tridentatus molts 12 to 13 t...

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Section: Growthsupporting

confidence: 84%

supporting

confidence: 84%

Section: Introductionmentioning

confidence: 89%

Section: Abstract: Horseshoe Crab · Tachypleus Tridentatus · Juvenilmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Enhanced growth of juvenile Tachypleus tridentatus (Chelicerata: Xiphosura) in the laboratory: a step towards population restocking for conservation of the species

Cai¹,

柯才焕

2010

Aquat. Biol.

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Nursery habitat for Asian horseshoe crabs along the northern Beibu Gulf, China: Implications for conservation management under baseline gaps

Xie

Wang

et al. 2019

Aquatic Conservation

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Identification, protection and enhancement of essential habitats are priority issues for management and restoration of exploited species. The shores utilized by Asian horseshoe crabs as nurseries were surveyed and the coastal habitat characteristics were described in the northern Beibu Gulf of China. Regression models were applied to explore species‐habitat relationships. Fourteen and ten nursery sites were identified for Tachypleus tridentatus and Carcinoscorpius rotundicauda populations, respectively. Xiacun and Jinhaiwan in the eastern region of the northern Beibu Gulf were the essential nurseries for T. tridentatus, whereas Shanxin and Jiaodong in the western part were the primary nursery shores for C. rotundicauda. These shores supported high densities (4–6 individuals/100 m2) of juvenile horseshoe crab populations. Mangrove and seagrass coverage area, coupled with sediment physico‐chemical parameters, particularly grain size, and the environmental heterogeneity of nursery habitats explained the distribution pattern of juvenile populations. Most juvenile populations were found along the outer fringe of mangroves in the small shallow estuary, particularly near outflows of tidal creeks with generally higher chlorophyll a and organic carbon contents. The distribution of high‐density juvenile populations of both species also overlapped with areas of seagrass patches. These findings highlight the importance of mangroves and seagrasses in the nursery habitat use of Asian horseshoe crabs. Preserving the estuarine habitats with these vegetation types and identifying the high‐use nursery sites should be prioritised in China and other Asian places to conserve the declining Asian horseshoe crab populations.

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Spawning habitat suitability maps for the conservation of the tri‐spine horseshoe crab Tachypleus tridentatus in Tsuyazaki Cove, Fukuoka, Japan

Itaya

Koyama

Shuuno³

et al. 2023

Aquatic Conservation

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The suitable spawning habitat of Tachypleus tridentatus was estimated and mapped for the first time using scientific modelling in Tsuyazaki, Fukuoka, Japan. A total of 43 nests were found at five sites from 2018 to 2019. Of these 43 nests, the location information of nine nests at one of the sites was used as ‘Training data’ for constructing the models. A series of procedures was employed to determine the relationship between the biological data and their physical parameters to estimate the suitable spawning habitat. First, the contribution rates of the physical parameters (beach elevation, slope and sediment) to nest locations were evaluated. Second, physical parameters that showed significant contribution rates were chosen to estimate suitable spawning habitats. It was found that the beach elevation was the most significant parameter for estimating suitable spawning habitats. Mean high water neap to mean higher high water was estimated as suitable spawning habitat, and 74% of the nests were fitted in an area assessed as suitable. The result was consistent with previous studies. The area of suitable spawning habitat was estimated to be only 476 m2 out of 1943 m2, comprising 24% of the sandy beach in the study site. Therefore, it was concluded that the conservation and restoration of spawning grounds is a high‐priority and urgent issue at the site. It is proposed that scientific modelling of nest/egg occurrence and beach elevation can effectively determine suitable spawning habitats. Thus, it is possible to quickly establish the habitat most suitable for spawning in coastal environments and help plan conservation strategies for this globally endangered species.

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Conservation of the horseshoe crab at Kinmen, Taiwan: strategies and practices

Cited by 95 publications

References 17 publications

Enhanced growth of juvenile Tachypleus tridentatus (Chelicerata: Xiphosura) in the laboratory: a step towards population restocking for conservation of the species

Enhanced growth of juvenile Tachypleus tridentatus (Chelicerata: Xiphosura) in the laboratory: a step towards population restocking for conservation of the species

Nursery habitat for Asian horseshoe crabs along the northern Beibu Gulf, China: Implications for conservation management under baseline gaps

Spawning habitat suitability maps for the conservation of the tri‐spine horseshoe crab Tachypleus tridentatus in Tsuyazaki Cove, Fukuoka, Japan

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