Mohammadpur, Dhaka |

Morphometric Characterization and Length-length Relationship of Jagora spp. Collected from Tilapia Pond

Editor Chief

Published on:

Updated on:

Spread the love

Reyes, A. T.; De Dios, J. P.; Macasaquit, A. L.; dela Cruz, J. A. D.

College of Fisheries, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines

Article history: 
Received: 27.07.2021 
Accepted: 06.09.2021 
*Corresponding author: 

Length-length relationship Morphometrics 
Fifty (50) pieces of Jagora spp. collected from tilapia pond in General Tinio, Nueva Ecija, Philippines were subjected to shell morphometrics in order to evaluate its length-length relationship. The shell morphometrics were presented as average: Shell length (SL) = 38.40±4.06 mm, Aperture length (AL) = 12.34±1.41 mm, Whorl height 1 (WH1) =  7.96±1.26 mm, Whorl height 2 (WH2) = 5.84±0.83 mm,  Whorl height 3 (WH3) = 4.58±0.57 mm, Aperture width  (AW) = 6.40±0.89 mm, Whorl width 1 (WW1) = 7.96±1.48  mm, Whorl width 2 (WW2) = 10.60±1.56 mm, Body whorl width (BWW) = 13.12±1.86 and Interior aperture length  (AILL) = 8.52±1.00 mm. The correlations of SL to all of the considered morphometrics were strong or the r-value is from 0.6 to 0.8. The first three highest r values were recorded between SL-AL, SL-WH1, and SL-AW, thus, the value of AL, WH1, and AW could be best predicted given that SL is known.  


Our country is considered a major ‘hot spot’  of species richness with a very high degree of endemism (Department of Environment and  Natural Resources, 1997; Myers et al. 2000;  Mittermeier et al., 2000). For example, a  total of 519 vertebrate species are endemic to the Philippines, 64% of them are mammals  (Heaney, 1998).

However, the documentation of the Philippine biodiversity is still continuing, in particular of invertebrate taxa. There is a scarcity of ecological,  biogeographical, or evolutionary information for most representatives of the Philippine fauna and flora. At the same time, this rich biota is under severe threat due to the accelerating destruction of natural habitats  (Dudgeon, 2000). 

One of these limnetic groups is Cerithioidea,  a basal caenogastropod superfamily with about 17 predominantly marine, but also some brackish and freshwater families. In approximation, this superfamily has 200  genera and several thousand species. This superfamily is of great ecological importance as grazers and detritus feeders in most tropical to subtropical aquatic ecosystems  (Glaubrecht, 1996; Kohler and Glaubrecht,  2001). 

One of the freshwater species under the  superfamily Cerithioidea is Jagora spp. that is  recorded in the northern part of  the Philippines. It can grow up to 50 mm in  length and 18 mm in width. Its shell is highly towered, usually dark brown in color. The body is gray to black with filiform antennae.

Jagora spp. is characterized by a  unique reproductive system, including a long  sperm gutter, a very  short spermatophore bursa, and a  prominent lateral ridge working as a seminal  receptacle. Females carry eggs and juvenile stages within their mantle cavity. This snail feeds primarily on detritus and algae (Kohler  and Glaubrecht, 2003; Kohler and Dames,  2009). 

Morphological and morphometric studies in  snails are important for species identification  even in the advent of molecular tools (Prioli  et al. 2002). Morphological measurements  such as shell length, shell width, body whorl  length, penultimate whorl width, aperture  length, and aperture width are commonly  used in the process of snail identification  (Hamli et al. 2020).

The length-length relationship studies are practically used in the study of population dynamics, ecology,  taxonomic differences, life history events, and stock management (Le Cren, 1951; Lagler et al. 1962; Abdoli et al. 2008; Ferreira et al.  2008; Vaslet et al. 2008; Epler et al. 2009).  

This study aimed to morphologically  characterize the shell of Jagora spp. that was  collected from a tilapia pond in General Tinio,  Nueva Ecija, Philippines and to eventually use  these measurements to assess the length length relationship. 


Collection and preparation of samples  

Fifty (50) pieces Jagora spp. were collected from a tilapia pond with 5 m in width and 10  m in length in General Tinio, Nueva Ecija.  Snail samples were brought home for cleaning and visceral mass removal. The gastropod shell was photographed using a  digital camera.  

Measurement of shell 

A total of 10 shell morphometrics were measured using a Vernier caliper based on the works of Sherely (1996) (Figure 1). The detailed shell morphometrics and characteristics are shown in Table 1. 

Gxn1xrD3maPxJBdO7o1Al ww tkRXEvOoz fqDT1GyEiMhP e

Figure 1. Shell characteristics that are used  in this study (Sherely, 1996) 

Determinination of the degree of  association between morphometrics  

The degree of associations between the shell length (SL) and aperture length (AL), whorl heights (WHS), aperture width (AW), whorl widths (WWs), body whorl width (BWW), and interior aperture length (AINL) was based on the computed correlation coefficient (r)  using trendline analysis in Microsoft (MS)  Excel.  

Estimation of length-length relationship 

The length-length relationship of the snail  samples was estimated using the formula: X  = ea(SLb).  


SL = shell length in mm 

W = the other length in mm (AL, WH, AW,  WW, BWW, and AINL) 

a = intercept 

b = slope 

Table 1. Abbreviations and descriptions of Pachychilidae shell morphometrics (Sherly, 2006) 

Measurement  number 

Abbreviation Description 

C1 SL Shell length: maximum length of the shell C2 AL Aperture length: the maximum outside dimension of the  aperture measured along an offset line to the right of the  

long axis of the shell 

C3 WH1 Whorl height: measured from the intersection of the  outside margin of the apertural lip and the edge of the  

periostracum on the first whorl that meets the apertural  

lip to the suture between adjacent whorls 

C4 WH2 Whorl height: between the top and bottom sutures of  adjacent whorls 

C5 WH3 Whorl height: between the top and bottom sutures of  adjacent whorls 

C6 AW Aperture width: maximum width of the aperture  measured from the line demarcating the edge of the  

periostracum on the columella to the outer edge of the  

apertural lip 

C7 WW1 Whorl width: dimensions were taken along lines parallel  to the sutures from the midpoints of arcs formed by the  

outer edges of successive whorls 

C8 WW2 Whorl width: dimensions were taken along lines parallel  to the sutures from the midpoints of arcs formed by the  

outer edges 

of successive whorls 

C9 BWW Body whorl width: dimensions were taken along lines  parallel to the sutures from the midpoints of arcs formed  

by the outer edges of successive whorls 

C10 AINL Interior aperture length: maximum interior length of the  aperture measured from the interior edges of the  apertural lip 

image 9
Morphometric Characterization and Length-length Relationship of Jagora spp. Collected from Tilapia Pond 6


Shell morphometrics  

In Table 2, the shell measurements of 50  pieces of Jagora spp that were collected in a  tilapia pond in General Tinio, Nueva Ecija,  Philippines are presented. Ten (10) shell measurements were considered in this study,  namely shell length (SL), aperture length (AL),  whorl height 1 (WH1), whorl height 2 (WH2),  whorl height 3 (WH3), aperture width (AW),  whorl width 1 (WW1), whorl width 2 (WW2), body whorl width (BWW) and interior aperture length (AILL). 

Table 2. Average shell measurements of Jagora spp. that were collected in tilapia a pond in  Gneral Tinio, Nueva Ecija, Philippines 

Shell morphometrics Average measurement (mm)
Shell Length (SL) 38.40±4.06
Aperture Length (AL) 12.34±1.41
Whorl Height 1 (WH1) 7.96±1.26
Whorl Height 2 (WH2) 5.84±0.83
Whorl Height 3 (WH3) 4.58±0.57
Aperture Width (AW) 6.40±0.89
Whorl Width 1 (WW1) 7.96±1.48
Whorl Width 2 (WW2) 10.60±1.56
Body Whorl Width (BWW) 13.12±1.86
Interior Aperture Length (AILL) 8.52±1.00

The snail SL ranged from 30 to 48 mm  (38.40±4.06 mm) with 35 and 40 mm as the  most common. AL was from 10 to 18 mm  (12.34±1.41 mm) with 12 mm as the most frequent. WH1 was from 6 to 10 mm  (7.96±1.26 mm) with 9 mm as the dominant.  WH2 fluctuated from 4 to 8 mm (5.84±0.83  mm) with 6 mm as the foremost. WH3  ranged from 4 to 6 mm (4.58±0.57 mm) with  4 mm as the most frequent.

AW was  recorded from 5 to 8 mm (6.40±0.89 mm)  with 6 mm as the dominant width. WW1  ranged from 4 to 12 mm (7.96±1.48 mm)  with 7 mm as the leading width. WW2 ranged  from 5 to 14 mm (10.60±1.56 mm) with a  width of 10 mm as the most common. BWW  was from 7 to 19 mm (13.12±1.86 mm) with  12 mm width as the most frequent. AILL  varied from 7 to 11 mm (8.52±1.00 mm) with  9 mm as the most dominant (Table 2). 

According to several studies, the shell measurements are influenced by ecological factors such as latitude, depth of distribution,  tidal excursion or shore level, water movements such as waves, turbulence and currents, type of sediment, and trophic conditions (Fiori and Defeo, 2006; Claxton et al. 1998; Franz, 1993; Akester and Martel,  2000; Nagarajana et al. 2006). In Jagora spp.,  there are no available morphometrics studies  on the various factors that might influence  shell morphometrics. This present study only provides basic information on the shell morphometry of Jagora spp. that was only collected from a tilapia pond. 

Degree of association between shell length  and the rest of shell morphometrics 

A correlation coefficient measures the  statistical relationship between two  variables: the correlation between SL and the  rest of the shell morphometrics. The correlations of SL to all of the morphometrics were strong or r value is from 0.6 to 0.8 (SL AL = 0.785, SL-WH1 = 0.782, SL-WH2 = 0.628, SL-WH3 = 0.605, SL-AW = 0.769, SL-WW1 =  0.756, SL-WW2 = 0.699, SL-BWW = 0.653 and  SL-AILL = 0.741).

All paired variables showed  direct relationship as indicated by positive b values (SL-AL = 0.803, SL-WH1 = 0.211, SL WH2 = 0.855, SL-WH3 = 0.698, SL-AW =  1.017, SL-WW1 = 1.370, SL-WW2 = 1.069, SL BWW = 0.895 and SL-AILL = 0.815), thus, an increase of 1 unit in the X variable will result to a certain unit of increase in the Y variable  (Table 3).

The first three highest r values  were recorded between SL-AL, SL-WH1, and  SL-AW, thus, the value of AL, WH1, and AW  could be best predicted given that SL is known. The computed values of r and b in this present study are impossible to compare because of the unavailability of literature about Jagora spp. 

Table 3. Intercept (a), slope (b), coefficient of determination (r2), and correlation coefficient  (r) of the paired shell morphometrics.  

Paired variables r2r
SL-AL -0.182 0.803 0.617 0.785
SL-WH1 -0.030 0.211 0.612 0.782
SL-WH2 -0.590 0.855 0.394 0.628
SL-WH3 -0.447 0.698 0.366 0.605
SL-AW -0.807 1.017 0.592 0.769
SL-WW1 -1.274 1.370 0.571 0.756
SL-WW2 -0.671 1.069 0.489 0.699
SL-BWW -0.302 0.895 0.427 0.653
SL-AILL -0.361 0.815 0.549 0.741

Length-length relationship equation 

In Table 4, the summary of length-length equations is provided. These equations could be used to predict the value of AL (0.834  SL0.803), WH1 (0.970 SL0.211), WH2 (0.554  SL0.855), WH3 (0.640 SL0.698), AW (0.446  SL1.017), WW1 (0.280 SL1.370), WW2 (0.511  SL1.069), BWW (0.739 SL0.895) and AILL (0.697  SL0.815) if SL is given. The first three highest r value was recorded in pairs SL-AL, SL-WH1, and SL-AW. The values of AL, WH1, and AW could be best predicted given that SL is known. 

The length-length relationship studies are practically used in the study of population dynamics, ecology, taxonomic differences,  life history events, and stock management  (Le Cren, 1951; Lagler et al. 1962; Abdoli et al. 2008; Ferreira et al. 2008; Vaslet et al.  2008; Epler et al. 2009).  

Table 4. Length-length relationship (LLR) equation of the paired shell morphometrics. 

Paired variables LLR equation
SL-AL AL = 0.834 SL0.803
SL-WH1 WH1 = 0.970 SL0.211
SL-WH2 WH2 = 0.554 SL0.855
SL-WH3 WH3 = 0.640 SL0.698
SL-AW AW = 0.446 SL1.017
SL-WW1 WW1 = 0.280 SL1.370
SL-WW2 WW2 = 0.511 SL1.069
SL-BWW BWW = 0.739 SL0.895
SL-AILL AILL = 0.697 SL0.815


The correlations of SL to all the morphometrics were strong or the r value is from 0.6 to 0.8. The first three highest r values were recorded between SL-AL, SL WH1, and SL-AW, thus, the value of AL, WH1, and AW could be best predicted provided  that SL is known.

The following were  recommended for the improvement of  future studies: (1) compare the shell  morphometrics and LLR equation of Jagora  spp. collected from ponds, streams and  rivers, and irrigation canals; (2) consider the  influence of sex in the shell morphometrics and LLR equation of Jagora spp.; and (3)  increase the frequency of sampling. 


Abdoli, A.; Rasooli, P.; Mostafavi, H. Length weight relationships of Capoeta capoeta capoeta (Guldenstaedt, 1772) in the  Gorganrud River, South Caspian Basin.  Journal of Applied Ichthyology. 2009, 24,  96-98. 

Akester, R.; Martel, A. Shell shape, dysodont tooth morphology, and hinge-ligament thickness in the bay mussel Mytilus trossulus correlate with wave exposure.  Canadian Journal of Zoology. 2020, 78(2),  240-253. 

Department of Environment and Natural  Resources. Philippine biodiversity: An assessment and action plan. United  Nations Environment Programme. Makati  City: Bookmark, Inc., 1997, 1-40 pp. 

Dudgeon, D. Ecological strategies of Hong  Kong Thiaridae (Gastropoda: Prosobranchia). Malacological Review.  2020, 22, 39-53. 

Epler, P.; Nowak, M.; Popek, W. Growth rate of the chub (Squalius cephalus) and the nase (Chondrostoma nasus) from Raba,  Dunajec and Poprad river. AACL Bioflux.  2009, 2, 1-8. 

Franz, D. R. Allometry of shell and body weight in relation to shore level in the intertidal bivalves Geukensia demissa (Bivalvia: Mytilidae). Journal of  Experimental Marine Biological and  Ecological. 1993, 174(2), 193-207. 

Ferreira, S.; Sousa, R.; Delgado, J.; Carvalho  D.; Chada, T. Weight-length relationships  for demersal fish species caught off the  Madeira archipelago (eastern-central  Atlantic). Journal of Applied Ichthyology.  2008, 24, 93-95. 

Fiori, S.; Defeo, O. Biogeographic patterns in life-history traits of the yellow clam,  Mesodesma mactroides, in Sandy Beaches of South America. Journal of Coastal  Research. 2006, 224, 872-880. 

Glaubrecht, M. Evolutionsökologie und  Systematik am Beispiel von Süß- und  Brackwasserschnecken (Mollusca:  Caenogastropoda: Cerithioidea):  Ontogenese-Strategien, paläontologische  Befunde und historische Zoogeographie. Leiden: Backhuys, 1996, 1-230 pp. 

Hamli, H.; Hamed, N. A.; Azmai, S. H. S.; Idris,  M. H. Conchology variations in species identification of Pachychilidae (Mollusca,  Gastropoda, Cerithiodea) through multivariate analysis. Tropical Life  Sciences Research. 2020, 31(2), 145-158. 

Heaney, L. R. A. Synopsis of the mammalian fauna of the Philippine Islands. Fieldiana:  Zoology. New Series. 1998, 28, 1-61. 

Köhler, F.; Dames, C. Phylogeny and systematics of the Pachychilidae of mainland Southeast Asia – Novel insights from morphology and mitochondrial DNA  (Mollusca, Caenogastropoda,  Cerithioidea). Zoological Journal of the  Linnean Society. 2009, 157, 679-699. 

Köhler, F.; Glaubrecht, M. Morphology,  reproductive biology and molecular genetics of ovoviviparous freshwater gastropods (Cerithioidea: Pachychilidae)  from the Philippines, with description of the new genus Jagora. Zoologica Scripta.  2003, 32(1), 35-59. 

Köhler, F.; Glaubrecht, M. Toward a  systematic revision of the Southeast Asian freshwater gastropod Brotia H. Adams,  1866 (Cerithioidea:Pachychilidae): An  account of species from around the South  China Sea. Journal of Molluscan Studies.  2001, 67, 281-318. 

Lagler, K. F.; Bardach, J. E.; Miller, R. R.  Ichthyology. John Wiley and Sons, Inc.,  New York, 1962, 1-546 pp. 

Le Cren, E. D. The length-weight relationships and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis).  Journal of Animal Ecology. 1951, 20, 201- 219. 

Mittermeier, R. A.; Myers, N.; Mittermeier, C.  G. Hotspots: Earth’s biologically richest  and most endangered terrestrial  ecoregions. Chicago: University of Chicago  Press, 2000, 1-345 pp. 

Myers, N.; Mittermeier, R. A.; Mittermeier,  C. G.; da Fonseca, G. A. B.; Kent, J. Chicago:  Biodiversity hotspots for conservation priorities. Nature. 2000, 403, 853-858. 

Nagarajana, R.; Lea, S.; Goss-Custard, J. Seasonal variations in mussel, Mytilus edulis L. shell thickness and strength and their ecological implications. Journal of Experimental Marine Biology and Ecology.  2006, 339(2), 241-250. 

Prioli, S. M.; Prioli, A. J.; Julio, H. F.; Pavanelli,  C. S.; Oliveira, A. V.; Carrer, H.; Prioli, L. M.  Identification of Astyanax altiparanae (Teleostei, Characidae) in the Iguaçu.  Genetic and Molecular Biology. 2002,  25(4), 421-430. 

Sherely, G. Morphological variation in the  shells of Placostylus species (Gastropoda:  Bulimulidae) in New Zealand and  implications for their conservation. New  Zealand. Journal of Zoology. 1996, 23(1),  73-82. 

Vaslet, A.; Bouchon-Navaro, Y.; Louis, M.;  Bouchon, C. Weight-length relationships for 20 species collected in the mangroves of Guadeloupe (Lesser Antiles). Journal of  Applied Ichthyology. 2008, 24, 99-100. Protection Status