Using Applied Statistics for Accurate Size Classification of the Endangered &lt;i&gt;Tachypleus tridentatus&lt;/i&gt; Horseshoe Crab

Mohamad, Rozihan; Paul, Nur Alisa; Isa, Nor Syuhaida; Damanhuri, Joni Haryadi; Shahimi, Salwa; Pati, Siddhartha; John, Akbar; Nelson, Bryan Raveen

doi:10.12911/22998993/132432

Cited by 7 publications

(8 citation statements)

References 11 publications

(15 reference statements)

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“…Despite an imbalance in sample yield for this population, the findings are conclusive that prosomal length and interorbit distance are useful to develop accurate allometry for the male and female T. gigas, respectively. In contrast, the first attempt was made on T. tridentatus from three localities with sample sizes <40 per population [Mohamed et al 2021]. Still, it should not be misunderstood that statistically-validated allometry has neglected the application of descriptive analysis.…”

Section: Discussionmentioning

confidence: 99%

“…A later examination on T. tridentatus was integrated with statistics and descriptive analysis and the use of Spearman's correlation to select suitable size indicators [Mohamed et al 2021]. The findings were conclusive that male and female horseshoe crabs have unique size indicators aside from the agreement that telson length was part of the inclusion criteria.…”

Section: Introductionmentioning

confidence: 98%

“…Now, with the objective to develop accurate gender-specific allometry for a large number of samples, the present work compared the differences between conventional (descriptive) and statistical outputs c.a. [Mohamed et al 2021] and concluded on an accurate (traditional) allometry census c.f. [Vijayakumar et al 2000] for a population of T. gigas in Sungai Merlimau Melaka.…”

Section: Introductionmentioning

confidence: 99%

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From Descriptive to Accurate Horseshoe Crab Size Variations in Wild Populations

Chan¹,

John²,

Shahimi³

et al. 2022

J. Ecol. Eng.

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Horseshoe crabs have survived until Holocene, but their persistence beyond the Anthropocene is challenged by drastic environment changes that entail impoverishments and the resultant unusual growth sizes. Previously, allometry via morphometric ratio was introduced to classify horseshoe crabs into normal-abnormal growth. However, the descriptive size and weight analysis indicated a considerable portion of Tachypleus gigas with normal allometry. This error was caused by the median sorting of values. Therefore, the same data was treated with correlation before generating a linear equation. By being sexual dimorphs, these arthropods actually have gender-specific morphology indicators which could generate a functional allometry. Since the assessed arthropods were mature, the 19 % yield of smaller female T. gigas was possibly due to degradation effects from poor diets or stress. Yet, for this population, an added risk was female-only harvest. Perhaps, close sizing to male counterparts could be perceived a survival strategy by the female T. gigas. More evidence is needed to strengthen this opinion but for now, this assessment method is novel for accurate allometry assessments in the species with sexual dimorphism. Overall, capture fisheries could have negative impacts and when made severe by sex-specific harvest, the unaccounted practices could collapse sustaining populations.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

From Descriptive to Accurate Horseshoe Crab Size Variations in Wild Populations

Chan¹,

John²,

Shahimi³

et al. 2022

J. Ecol. Eng.

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“…All measurements data were pooled according to females and males then inserted into Microsoft Excel. These data were transformed using a square root (Mohamed et al 2021). The Kolmogorov-Smirnov test was applied to verify a normal distribution.…”

Section: Discussionmentioning

confidence: 99%

Morphometric variation of the horseshoe crab Tachypleus gigas (Xiphosura: Limulidae) from the Banyuasin estuarine of South Sumatra, Indonesia

et al. 2021

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Abstract. Fauziyah, Mustopa AZ, Fatimah, Purwiyanto AIS, Rozirwan, Agustriani F, Putri WAE. 2021. Morphometric variation of the horseshoe crab Tachypleus gigas (Xiphosura: Limulidae) from the Banyuasin estuarine of South Sumatra, Indonesia. Biodiversitas 22: 5061-5070. Morphological studies are essential for fish resource management, ecology, conservation, and stock assessment. This research was conducted to characterize the morphological variation of the coastal horseshoe crab (Tachypleus gigas) from the Banyuasin estuarine, South Sumatra, Indonesia. The body weight (BW), prosoma width (PW), carapace length (CL), telson length (TEL), and total length (TL) were measured for describing the morphometric variability of T. gigas. A total of 70 T. gigas (32 females and 38 males) were found using trammel net fishing and bottom gillnet during the survey. Multivariate and allometric methods analyzed their morphometric characters. Based on Kruskal- Wallis tests, the result showed a significant difference in somebody measurements (TL and CL) between males and females. The principal component analysis (PCA) results showed that all morphometric characters had a strong correlation in both sexes, so the first principal component (PC1) values were 92% and 72%. In comparison, the second principal component (PC2) values were 5% and 20% in females and males, respectively. The results of discriminant function analysis (DFA) suggested that only one (BW) of the five morphometric characters was significant in separating both sexes. Both sexes were also revealed variations in growth patterns based on the allometric analysis results. These results were expected to be used as a basis for managing the horseshoe crab population-based conservation.

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“…Two species of the horseshoe crab namely; Tachypleus gigas (Müller) and Carcinoscorpius rotundicauda (Latreille) are abundantly found throughout the year along the north-east coast of India. Extensive studies have been conducted on various aspects of Atlantic and Asian species of the horseshoe crabs [Chatterji, 1999; Mohamad et al, 2021]. However, the phenomenon of sex reversal in horseshoe crab has not been reported so far.…”

Section: Introductionmentioning

confidence: 99%

Is Sex Reversal Common Phenomenon in Horseshoe Crabs Too?

Tudu¹,

Sarkar²,

Satyanarayana³

et al. 2021

Ecol. Eng. Environ. Technol.

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The capacity of organisms to change their sex has evolved independently in several species. Sex change has been widely studied, but research approaches have differed and conclusions have often been specific. Although sex allocation theory provides a unifying framework for the study of sex change, this unity has not always been appreciated, Environmental sex reversal (ESR), which results in a mismatch between genotypic and phenotypic sex, is well documented in numerous species and may be induced by chemical exposure. In the present study, an attempt was made to hypothesize the phenomenon of sex reversal in both Asian species (Tachypleus gigas and Carcinoscorpius rotundicauda) of the horseshoe crab in accordance with the size of the animals. Our findings suggest that both Asian species of horseshoe crabs ultimately show a positive sign of sex reversal phenomenon, however, this hypothesis needs further confirmation by studying the hormonal changes at all moulting stages of the horseshoe crab.

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Using Applied Statistics for Accurate Size Classification of the Endangered <i>Tachypleus tridentatus</i> Horseshoe Crab

Cited by 7 publications

References 11 publications

From Descriptive to Accurate Horseshoe Crab Size Variations in Wild Populations

From Descriptive to Accurate Horseshoe Crab Size Variations in Wild Populations

Morphometric variation of the horseshoe crab Tachypleus gigas (Xiphosura: Limulidae) from the Banyuasin estuarine of South Sumatra, Indonesia

Is Sex Reversal Common Phenomenon in Horseshoe Crabs Too?

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