PJZ_58_3_1055-1067

INTRODUCTION

Malacofauna means molluscs of an area. Molluscs are benthic macro invertebrates which play an important part in intertidal ecosystem (Rajendra and Sivaperuman, 2020). They are found in many parts of the biosphere such as ocean, brackish, freshwater and terrestrial areas. Molluscs are one of the leading groups of ocean communities contributing mainly to the local biodiversity (Rueda et al., 2009; Rubal et al., 2018). Molluscs are one of the most diverse phylum in terms of species diversity, showing a diverse variety of form, size, colour and shape. They provide a vital source of protein for human after fish (Khan and Liu, 2019). Besides food they are also valuable in different industries such as jewelry, medicine, dyes and cement.

Woodwards (1856) was probely the first to report marine molluscs from Pakistan. In the recent past several reports have appeared on the molluscs from the coastline of Pakistan (Tirmizi and Zehra, 1982; Moazzam and Ahmed, 1994; Kazmi and Naushaba, 2004; Kazmi et al., 2019; Barkati and Rehman, 2005; Khanum et al., 2020), through the information on molluscs from Balochistan coast is limited (Khan and Dastagir, 1971; Tirmizi and Zehra, 1982; Afsar et al., 2012; Ghani and Afsar, 2017; Gondal et al., 2020).

The aim of this study to initiate study the diversity of Mollusca from Balochistan coast. This study will help to develop a plan to conserve marine molluscan diversity from Balochistan. The information should be useful for fisheries biologists as well as shell fisheries managers to determine the fishing efforts for this shellfishery from Pakistani waters.

MATERIALS AND METHODS

Samples were collected from coast of Gaddani (25° 07’ N, 66° 43’ E) Balochistan frequently visiting at low tide on monthly basis from June 2022 to November 2022. The sites were thoroughly investigated for molluscan diversity and their distribution pattern. Samples of molluscs were collected as epifauna, and as infauna by using hand picking method. The tools like hammer, forceps, sieves, chisels were used to detach species from their substratum. Samples was sorted and preserved in 70% alcohol. The samples were properly labled and then frozen until further investigation.

Identification of molluscans

Molluscan samples were identified on the basis of chonchological characteristics such as shell characters, color and shape (Baharuddin et al., 2018) also spire length and shape, mouth opening, opercula shape, umbilicus shape and size colour, and ornamentation of the shell were primarily used to identify the gastropoda. For bivalves shell, characters such as adductor muscle scars, pallial line and no of lateral tooth were noticed to identify the species using references of Roberts et al. (1982), FAO (1998) and Kazmi et al. (2019). The index of world register of marine species (WoRMS) and Marine Molluscan fauna of the Pakistani coastal waters, was checked for the authenticity of species taxonomy and identification.

Data analysis

Quantitative analysis were conducted for the study of occurrence and diversity. For this purpose, randomly three replicates quadrates of 1x1m2 from each site was set, to detect the distribution and occurrence pattern of malacofauna in different coastal areas of Balochistan. Simpson’s Diversity Index was calculated by Simpson diversity index equation as:

D = 1-Σni (ni-1) / N (N-1)

where, D is diversity Index, ni is number of organisms of a particular species, N is total number of organisms of all species.

RESULTS AND DISCUSSION

Diversity of Malacofauna in Gaddani

During study period 1930 specimens of 216 species of 38 families of gastropods were collected while 1059 specimens of 134 species of 24 families of Bivalvia, were reported. Seven specimens of one species of one family of Cephalopodes were collected while only one specimen of class polyplacophora was collected from Gaddani site (Fig. 1).

Simpson’s Diversity Index (SDI) of families of Gastropoda from Gaddani was about 0.893 which shows the high diversity of families of Gastropoda of this area. While Simpson’s Diversity Index (SDI) of Bivalvia from Gaddani was about 0.869 which shows less high diversity of Bivalvia of this site as compared to Gastropoda. Species richness of Gastropoda and Bivalvia were about 216 and 134, respectively, which was very high in this area. Month wise highest SDI of gastropods was observed in June 2022 which was about 0.9103 and least high SDI in July about 0.8552. SDI in September with 0.8638, in August was about 0.8658; 0.8740 in October and 0.8794 in November 2022. SDI of families of class Bivalvia was observed in June about 0.894, 0.882 in July, 0.880 in August, 0.828 in September, 0.843 in October and 0.826 in November. Which was shown the highest SDI in June while least high SDI in November 2022 (Fig. 2).

Class Gastropoda

Gastropods were reported in highest percentage of occurrence about 64% of total collection of malacofauna from Gaddani. Table I shows the name of species and families of Gastropoda which were collected which Table II shows % abundance of individuals and species of different families of Gastropoda in different months from June, 2022 to November 2022. Figure 3 shows the % of occurrence of 38 families of class Gastropoda. Species richness showed that much diversified class which were about 216 species. SDI of families of Gastropoda from Gaddani was about 0.893 which shown the high diversity of families of Gastropoda of this area. Family Littorinidae was found in highest % of abundence which about of (19%) out of 370 specimens of total collection of Gastropoda. Only one species Nodilittorina sp. of this family was collected in every month in high quantity. Out of 1815 highest number of species of any family 42 specimens of 28 species of family Trochidae Rafinesque, out of 1815 collected only during three months (June–August 2022) (Table I).

Table I. Gastropoda, 38 Families and 216 species collected from Gaddani coast.

Families/ Species

Patellidae Rafinesque, 1815

Patella Swakopmundensis W. Massier, 2009

P. candei d’ Orbigny, 1758

P. vulgata Linnaeus, 1758

Eoacmaeidae Nakano andOzawa, 2007

Eoacmaea omanesis (Christaens,1975)

Lottiidae Gray, 1840

Niveotecura pallida A.A.Gould,1859

Erginus rubellus (Fabricius,1780)

E. sybariticus (W.H.Dall,1839)

Scurria parasitica d(’Orbigny,1841)

S. variabilis Sowerby,1839

Nacellidae Thiele, 1891

Cellana denticulate (Martyn,1784)

C. flava (Hutton,1873)

C. radians (Gmelin,1791)

C. tramoserica (Holten, 1802)

C. pricei A.W. B Powell,1973

C. synonymss (L.A.Reeve,1854)

C. radiata (Born, 1778)

Neritidae Rafinesque, 1815

Nerita albicilla Linnaeus, 1758

N. versicolor Gmelin, 1791

N. chamaeleon Linnaeus, 1758

N. peloronta Linnaeus, 1758

N. funiculata Menke, 1850

N. olivaria Le Guillou, 1841

Neripteron (Dostia) bensoni (Récluz, 1850)

Nerita debilis Dufo, 1840

Fissurellidae Fleming, 1822

Diodora arcuata Sowerby,1862

D. bombayana Sowerby,1862

D. calyculata (Sowerby,1835)

D. cayenesis (Lamarck,1822)

D. demartiniorum Buzzurro and Russo, 2005

D. dorsata (Monterosato,1878)

D. galeata (Helbing,1779)

D. inaequalis Sowerby,1835

Table continues on next page..............

Families/ Species

D. italica (Defrance,1820)

D. occidua (Cotton,1930)

D. occitanic (C.A.Receluz,1843)

D. aspera (Rathke, 1833)

D. occultata Poppe andTagaaro 2020

D. philippiana (Dunker,1846)

D. product (Monterosato,1880)

D. singaporensis (Reeve,1850)

D. multifida (Deshayes, 1830)

Montfortia subemarginata (Blainville,1819)

M. emarginata (Blainville,1825)

Cemoria flemingiana Leach, 1852

Lepetelloidea Dall, 1882

Lepetella espinosae Dantar and Luque ,1994

L. barrajoni Dantar and ALuque, 1994

L. sierra Dantar t and Luque, 1994

L. tubicola Verrill and Smith,1880

L. wisshaki Hoffman,2018

L. ionica F.Nordsieck,1997

Pseudococculinidae Hickman, 1983

Kaiparapelta askewi J.H.McLean and Harasewych, 1995

Calyptraeidae Lamarck, 1809

Crepidula moulinsii Michaud,1829

Crucibulum umbrella Deshayes, 1830

C. guiriguinae Lesson,1830

C. auricular Gmelin,1790

Crepidula walchi (Reeve, 1859)

Trochidae Rafinesque, 1815

Austrocochlea constricta (Lamarck, 1822)

Bankivia fasciata (Menke, 1830)

Cantharidus dilatatus (G.B.Sowerby II, 1870)

C. opalus (Martyn, 1784)

Clanculus flagellatus (Philippi, 1849)

C. undatus (Lamarck, 1816)

C. floridus (Philippi, 1850)

C. plebejus (Philippi, 1851)

C. limbatus (Quoy and Gaimard, 1834)

C. consobrinus Tate, 1893

C. maugeri (W.Wood, 1828)

Coelotrochus tiaratus (Quoy and Gaimard, 1834)

C. oppressus (F.W.Hutton, 1878)

Table continues on next column..............

Families/ Species

C. viridis (Gmelin, 1791)

Calliostoma zizyphinum (Linnaeus, 1758)

Diloma subrostratum (Gray, 1835)

Elaphriella eukhonikhe Vilvens and Williams, 2016

Gibbula magus (Linnaeus, 1758)

Jujubinus exasperatus (Pennant, 1777)

Oxystele impervia (Menke, 1843)

Prothalotia pulcherrima (W.Wood, 1828)

P. ramburi (Crosse, 1864)

Pomaulax gibberosus (Dillwyn, 1817)

Steromphala rarilineata (Michaud, 1829)

S. umbilicalis (da Costa, 1778)

Spectamen bellulum (Angas, 1869)

Trochus rota Dunker, 1860

Zethalia zelandica (Hombron and Jacquinot, 1848)

Turbinidae Rafinesque, 1815

Megastraea undosa (Wood, 1828)

Lunella (Subninella) undulata (Lightfoot) 1786

L. smaragda (Gmelin, 1791)

Turbo canaliculatus Hermann, 1781

Bolma rugosa (Linnaeus, 1767)

Pomaulax gibberosus (Dillwyn, 1817)

Turbo intercostalis Menke, 1846

Triphoridae Gray, 1847

Marshallora nigrocincta (Adams, 1839)

Magnosinister hedleyi Laseron, 1954

Nototriphora regina (Hedley, 1903)

Bouchetriphora pallida (Pease, 1871)

Monophorus angasi (Crosse andFischer, 1865)

Inella rossiteri Jousseaume, 1884

Coriophora fusca (Dunker, 1860)

Monophorus monachus (Hervier, 1898)

Viriola morychus Jousseaume, 1898

Nototriphora regina (Hedley, 1903)

Talophora subulata (Laseron, 1958)

Litiopidae Gray, 1847

Diffalaba opiniosa Iredale, 1936

Alaba monile A.Adams, 1862

Dalliella brusinai Cossmann, 1895

Alaba culliereti (Dautzenberg, 1890)

Styliferina goniochila A.Adams, 1860

Table continues on next page..............

Families/ Species

Alaba guayaquilensis Bartsch, 1928

Alaba incerta (d'Orbigny, 1841)

Styliferina translucida (Hedley, 1905)

Litiopa bombix Kiener, 1833

Gibborissoia virgata (Philippi, 1849)

Thiaridae Gill, 1871 (1823)

Melanoides (Melanoides) tuberculata (O.F.Müller, 1774)

Melania furfurosa A.Gould, 1847

Potamididae Adams and Adams, 1854

Telescopium telescopium (Linnaeus, 1758)

Pirenella cingulata (Gmelin, 1791)

Vermetidae Rafinesque, 1815

Vermetus triquetrus Bivona-Bernardi, 1832

Thylacodes sipho (Lamarck, 1818)

T. adamsii (Mörch, 1859)

Eualetes tulipa (Rousseau, 1843)

Thylacodes squamigerus (Carpenter, 1857)

Littorinidae Children, 1834

Nodilittorina pyramidalis (Quoy and Gaimard, 1833)

Rostellariidae Gabb, 1868

Tibia insulaechorab Röding, 1798

T. curta (G.B.Sowerby II, 1842)

T. fusus (Linnaeus, 1758)

T. delicatula (G.Nevill, 1881)

Rostellaria palliata Forbes, 1846

Calyptraeidae Lamarck, 1809

Crepidula walchi (Reeve, 1859)

Aclididae G. O. Sars, 1878

Austrorissopsis consobrina (Tate and May. 1900)

Cypraeidae Rafinesque, 1815

Naria ocellata (Linnaeus, 1758)

N. turdus (Lamarck, 1810)

Purpuradusta gracilis (Gaskoin, 1849)

Naria boivinii (Kiener, 1844)

Mauritia arabica (Linnaeus, 1758)

Palmadusta clandestina (Linnaeus, 1767)

Erronea xanthodon (Gray, 1832)

Naria nebrites (Melvill, 1888)

Palmadusta humphreyii (Gray, 1825)

Naria spurca (Linnaeus, 1758)

Cypraeovula algoensis (Gray, 1825)

Table continues on next column..............

Families/ Species

Notocypraea declivis (Sowerby II, 1870)

Melicerona felina subsp. fabula (Kiener, 1844)

Naria lamarckii (Gray, 1825)

Lyncina vitellus (Linnaeus, 1758)

Erronea errones (Linnaeus, 1758)

Erronea (Erronea) ovum (Gmelin, 1791)

Palmadusta androyensis subspecies Consanguinea Blöcher and Lorenz, 2000

Naticidae Guilding, 1834

Polinices mammilla (Linnaeus, 1758)

Polinices peselephanti (Link, 1807)

P. panamaensis (Récluz, 1844)

P. candidissimus (Le Guillou, 1842)

P. jukesii (Reeve, 1855)

Neverita josephinia Risso, 1826

Natica vitellus (Linnaeus, 1758)

Bursidae Thiele, 1925

Tutufa rubeta (Linnaeus, 1758)

Tutufa tenuigranosa (E.A.Smith, 1914)

Bufonaria echinata (Link, 1807)

Bufonaria rana (Linnaeus, 1758)

B. crumena (Lamarck, 1816)

B. elegans (Sowerby II, 1836)

Cymatidae Iredale, 1913

Cabestana tabulata (Menke, 1843)

C. spengleri (Perry, 1811)

Monoplex pilearis (Linnaeus, 1758)

Epitoniidae Berry, 1910

Epitonium clathrus (Linnaeus, 1758)

Muricidae Rafinesque, 1815

Purpura persica (Linnaeus, 1758)

P. bufo Lamarck, 1822

Purpura Bruguière, 1789

Rapana venosa (Valenciennes, 1846)

Indothais lacera (Born, 1778)

Hexaplex (Trunculariopsis) trunculus (Linnaeus, 1758)

Dicathais orbita (Gmelin, 1791)

Ocenebra erinaceus (Linnaeus, 1758)

Indothais malayensis (Tan and Sigurdsson, 1996)

Thais tricolorata Bozzetti, 2010

Thais bufo (Lamarck, 1822)

Table continues on next page..............

Families/ Species

T. ambustulata Hedley, 1912

Murex (Murex) spinastreptos Houart, 2010

T. tricolorata Bozzetti, 2010

Murex (Murex) aduncospinosus Sowerby, 1841

Murex carbonnieri (Jousseaume, 1881)

M. falsitribulus Ponder and Vokes, 1988

Murex (Tribulus) acanthostephes Watson, 1883

Murex (Murex) queenslandicus Ponder and Vokes, 1988

Murex trapa Röding, 1798

Murex (Murex) indicus Houart, 2011

Turbinellidae Swainson, 1840

Vasum muricatum (Born, 1778)

Turbinella pyrum (Linnaeus, 1767)

Vasum caestus (Broderip, 1833)

Babyloniidae Habe and Oyama, 1971

Babylonia valentiana (Swainson, 1822)

B. spirata (Linnaeus, 1758)

Melongenidae Gill, 1871

Pugilina cochlidium (Linnaeus, 1758)

Nassariidae Iredale, 1916(1835)

Nassarius persicus (Martens, 1874)

Columbellidae Swainson, 1840

Pyrene filmerae (Sowerby Iii, 1900)

Olividae Latreille, 1825

Oliva reticularis Lamarck, 1811

O. mustelina Lamarck, 1811

O. sayana Ravenel, 1834

O. julieta Duclos, 1840

O. incrassata (Lightfoot) 1786

O. bulbosa (Röding, 1798)

O. polpasta Duclos, 1833

O. australis Duclos, 1835

O. truncata Marrat, 1867

O. carneola (Gmelin, 1791)

O. concavospira Sowerby, 1914

Conidae Fleming, 1828

Conus mus Hwass, 1792

C. daucus Hwass, 1792

C. anemone Lamarck, 1810

C. angasi Tryon, 1884

Turridae Adams and Adams, 1853

Turricula javana (Linnaeus, 1767)

Pyramidellidae Gray, 1840

Turbonilla (Turbonilla) Risso, 1826

Table continues on next column..............

Families/ Species

Architectonicidae Gray, 1850

Architectonica nobilis Röding, 1798

A. perdix (Hinds, 1844)

PupillidaeTurton, 1831

Pupoides albilabris (Adams, 1841)

Onchidiidae Rafinesque, 1815

Onchidella steindachneri (Semper, 1882)

Onchidium typhae Buchannan, 1800

Peronia peronii (Cuvier, 1804)

Siphonariidae Gray, 1840

Siphonaria denticulata Quoy and Gaimard, 1833

Second abundant family was Muricidae with 342 (17.72%) specimens of 20 species. Highly abundant species was Hexaplex (Trunculariopsis) trunculus with 170 specimens were collected all months except Sep. and Oct., 2022.

Twenty two specimens of 20 species of family Fissurellidae Fleming, 1822 were collected. One specimen of Cemoria flemingiana Leach, 1852, Diodora 17 species (Reeve, 1850), Montfortia subemarginata (Blainville, 1819)and Montfortia emarginata (Blainville, 1825) was found while 2 specimens of Diodora occultata Poppe and Tagaro, 2020 and Diodora bombayana Sowerby, 1862 were collected.

Family Cypraeidae Rafinesque, 1815 was found with 157 (8.13%) speciemns of 18 species. 85 specimens of Naria nebrites were found every month, which was highly abundant species.

Eleven species of Oliva from family Olividae was found in 14% (278 specimens) of abundance of total collection of gastropoda from Gaddani. 65 and 57 specimens of O. sayana and O. julieta were collected from all months of collection.

Family Potamididae was found in relatively less abundance about (6. 94%) 134 specimens of 2 species of gastropoda. 124 specimens of Telescopium telescopium (Linnaeus, 1758) were collected every month of collection while 10 specimens of Pirenella cingulata (Gmelin, 1791) were found only June 2022. 87 specimens of 7 species of Cellana of family Nacellidae was found in 4.51% of abundance. Highly abundant species C. tramoserica was found in every month of collection. Twenty specimens of 11 species of family Triphoridae Gray, 1847 was found in 1.02% of abundance.

Family Litiopidae Gray, 1847 were collected with 49 specimens of 10 species, only in two-month June and July 2022.

Table II. SDI (Simpson’s Diversity Index), Number and % of abundance of individuals (Indi.) and species (spp.) of different families of class Gastropoda in different months from June 2022 to November 2022.

Families	Jun. 22	Jul. 22	Aug. 22	Sep. 22	Oct. 22	Nov. 22	Total No. of Indi.	%	No. of Spp.	%
Patellidae Rafinesque, 1815	0	0	1	1	1	0	3	0.15	3	1.389
Eoacmaeidae Nakano and Ozawa, 2007	0	0	3	0	0	0	3	0.15	1	0.463
Lottiidae J. E. Gray, 1840	1	0	2	11	2	6	22	1.14	5	2.315
Nacellidae Thiele, 1891	16	13	17	21	7	13	87	4.54	7	3.241
Neritidae Rafinesque, 1815	17	1	0	0	21	7	46	2.38	8	3.704
Fissurellidae Fleming, 1822	5	2	0	0	5	10	22	1.14	20	9.259
Lepetelloidea Dall, 1882	1	0	0	1	1	9	12	0.62	6	2.778
Pseudococculinidae Hickman, 1983	0	0	0	0	0	1	1	0.05	1	0.463
Calyptraeidae Lamarck, 1809	2	2	2	1	1	8	16	0.83	5	2.315
Trochidae Rafinesque, 1815	37	3	2	0	0	0	42	2.23	28	12.96
Turbinidae Rafinesque, 1815	10	3	1	0	0	0	14	0.72	7	3.241
Triphoridae Gray, 1847	10	5	2	1	1	1	20	1.03	11	5.093
Litiopidae Gray, 1847	47	2	0	0	0	0	49	2.53	10	4.630
Thiaridae Gill, 1871 (1823)	2	3	3	2	1	1	12	0.62	2	0.926
Potamididae Adams and Adams, 1854	23	20	35	7	41	8	134	6.94	2	0.926
Vermetidae Rafinesque, 1815	5	3	0	0	0	0	8	0.41	5	2.315
Littorinidae Children, 1834	80	75	65	45	70	35	370	19.17	1	0.463
Rostellariidae Gabb, 1868	17	12	19	13	8	7	76	3.94	5	2.315
Aclididae G. O. Sars, 1878	2	2	2	2	2	2	12	0.63	1	0.463
Cypraeidae Rafinesque, 1815	26	29	24	18	18	42	157	8.13	18	8.333
Naticidae Guilding, 1834	3	1	4	5	12	5	30	1.51	7	3.241
Bursidae Thiele, 1925	5	0	0	1	1	1	8	0.41	6	2.778
Cymatidae Iredale, 1913	4	3	2	2	1	2	14	0.72	3	1.389
Epitoniidae Berry, 1910	1	0	0	0	0	0	1	0.05	1	0.463
Muricidae Rafinesque, 1815	52	71	70	62	49	38	342	17.72	20	9.722
Turbinellidae Swainson, 1840	5	4	2	2	1	3	17	0.88	3	1.389
Babyloniidae Kuroda, 1971	3	6	11	5	2	2	29	1.51	2	0.926
Melongenidae Gill, 1871	1	0	0	0	0	0	1	0.05	1	0.463
Nassariidae Iredale, 1916	1	0	0	0	0	0	1	0.05	1	0.463
Columbellidae Swainson, 1840	6	1	2	3	2	1	15	0.77	1	0.463
Olividae Latreille, 1825	56	48	47	41	41	69	278	14.4	11	5.093
Conidae Fleming, 1828	4	4	3	3	2	8	24	1.24	4	1.852
Turridae H. Adams and Adams, 1853	1	0	0	0	0	0	1	0.05	1	0.463
Pyramidellidae Gray, 1840	1	1	1	1	1	2	7	0.36	1	0.463
Architectonicidae Gray, 1850	7	5	2	3	7	7	31	1.63	2	0.926
Pupillidae Turton, 1831	1	1	1	1	1	1	6	0.32	1	0.463
Onchidiidae Rafinesque, 1815	3	3	3	3	3	3	18	0.93	3	1.389
Siphonariidae Gray, 1840	1	0	0	0	0	0	1	0.05	1	0.463
Total	452	319	323	252	300	284	1930	100	216	100
SDI	0.910	0.855	0.866	0.864	0.874	0.879	0.893		0.995

Family Turbinidae Rafinesque, 1815 and Naticidae Guilding, 1834 both were found with 7 species each and 14 and 30 specimens, respectively.

Family Rostellariidae was found in 3.94 % of abundance. 74 specimens of 5 species were found, among them 4 species of Tibia were collected.

Twelve families of Gastropoda from Gaddani had only one species with different number of specimens i.e., 374 individuals of Nodilittorina pyramidalis of family Littorinidae, 15 individual of Pyrene filmerae of family Columbellidae, 12 individuals of Austrorissopsis consobrina of family Aclididae, 7 individuals of Turbonilla sp. of family Pyramidellidae, 6 specimens of Pupoides albilabris of Pupillidae anf 3 individuals of Eoacmaea omanensis of family Eoacmaeidae were recorded. Remaining 6 families namely: Pseudococculinidae, Epitoniidae, Melongenidae, Nassariidae, Turridae, and Siphonariidae had only one specimen of species Kaiparapelta askew, Epitonium clathrus, Pugilina cochlidium, Nassarius persicus, Turricula javana and Siphonaria denticulate respectively. The lowest % of occurrence was found in Pseudococculinidae, Epitoniidae, Melongenidae, Nassariidae, Turridae and Siphonariidae which was about 0.05% (only one specimen).

Class Bivalvia

Second highest abundant class was Bivalvia which were about 34 % of total collection of mollusca from Gaddani. 1059 specimens of 134 species of 24 families of bivalvia were collected during study from Gaddani (Table III). SDI of bivalvia from Gaddani was about 0.8693 which shows the less high diversity of Bivalvia at this site compared to gastropodas.

Figure 4 revealed the % of occurrence of 24 families of class Bivalvia. Out of 24 families, 15 families were found throughout study period. Out of 134 species, 93 (69%) species belonged to 6 families and remaining 41 (31%) of species were other 18 families (Table IV). Family Ostreidae was highly abundant family with 28% of abundance (296 specimens of 11 species). These 11 species belonging to 4 genera. Family Carditidae was second abundant family about 13 % of total bivalve’s collection from Gaddani. Only one species Cardites floridanus of the family Cartididae was collected every month in high quantity.

Family Veneridae was highly diversified family which had 25 species (19%) with 81 specimens (7.56%) of total collection of Bivalvia. 19 species of Genus Dosinia and one species of 6 genus namely Leukoma, Sunetta, Venerupis, Petricola, Callista and Paphia of family Veneridae were collected. 12 speciemens of Dosinia exoleta was collected during study in this site. Second diversified family

Table III. Bivalvia, 24 Families and 134 species collected from Gaddani coast.

Families/ Species

Yoldiidae Dall, 1908

Yoldia lanceolata (Soweby, 1820)

Y. nitida (Brocchi, 1814)

Mytilidae Rafinesque, 1815

Mytilus edulis Linnaeus, 1758

M. californianus Conrad, 1837

Perna canaliculus (Gmelin, 1791)

Solamen glandula (Totten, 1834)

Noetiidae Stewart, 1930

Noetia ponderosa (Say, 1822)

Striarca lactea (Linnaeus, 1758)

Arcidae Lamarck, 1809

Barbatia barbata (Linnaeus, 1758)

B. novaezealandiae (E.A.Smith, 1915)

B. foliata (Forsskål, 1775)

B. obliquata (W. Wood, 1828)

B. mytiloides (Brocchi, 1814)

B. domingensis (Lamarck, 1819)

B. lacerata (Bruguière, 1789)

B. reeveana (d'Orbigny, 1846)

B. pistachia (Lamarck, 1819)

Arca natalensis Krauss,1848

Anadara corbuloides (Monterosato, 1881)

A. kagoshimensis (Tokunaga, 1906)

A. auriculata (Lamarck, 1819)

A. brasiliana (Lamarck, 1819)

A. (Scapharca) natalensis (Krauss, 1848)

A. pilula (Reeve, 1843)

Glycymerididae Dall, 1908

Tucetona laticostata (Quoy and Gaimard, 1835)

Pteriidae Gray, 1847

Pteria colymbus (Röding, 1798)

Isognomon alatus (Gmelin, 1791)

I. legumen (Gmelin, 1791)

I. radiatus (Anton, 1838)

I. perna (Linnaeus, 1767)

I. nucleus (Lamarck, 1819)

Ostreidae Rafinesque, 1815

Magallana gigas (Thunberg, 1793)

Table continues on next page.................

Families/ Species

Dendostrea cristata (Born, 1778)

D. folium (Linnaeus, 1758)

D. frons (Linnaeus, 1758)

D. vespertina (Conrad, 1855)

D. frons (Linnaeus, 1758)

Saccostrea scyphophilla (Peron and Lesueur, 1807)

S. glomerata (Gould, 1850)

S. cucullata (Born, 1778)

Ostrea edulis Linnaeus, 1758

O. chilensis Küster, 1844

Gryphaeidae

Parahyotissa inermis (Sowerby, 1871)

Pododesmus macrochisma (Deshayes, 1839)

Limidae Rafinesque, 1815

Lima vulgaris (Link, 1807)

Pectinidae Rafinesque, 1815

Mimachlamys varia (Linnaeus, 1758)

Anomiidae Rafinesque, 1815

Anomia simplex d'Orbigny, 1853

A. ephippium Linnaeus, 1758

A. peruviana d'Orbigny, 1846

A. trigonopsis F.W.Hutton, 1877

Spondyliidae Gray, 1826

Spondylus sp.

Plicatulidae Gray, 1854

Plicatula complanata Deshayes, 1863

Euanodontia ovum (Reeve, 1850)

Lucinidae Fleming, 1828

Arcinella cornuta Conrad, 1866

Loripes clausus (R.A. Philippi, 1849)

Carditidae Férussac, 1822

Cardites floridanus (Conrad, 1838)

Chamidae Lamarck, 1809

Chama buddiana C.B.Adams, 1852

C. arcana F.R.Bernard, 1976

C. congregata Conrad, 1833

C. gryphoides Linnaeus, 1758

C. asperella Lamarck, 1819

C. buddiana C.B.Adams, 1852

C. coralloides Reeve, 1846

C. florida Lamarck, 1819

Table continues on next column.................

Families/ Species

C. macerophylla Gmelin, 1791

C. crassa Chenu, 1846

C. pacifica Broderip, 1835

C. limbula Lamarck, 1819

C. dunkeri Lischke, 1870

C. brassica Reeve, 1847

Pseudochama gryphina (Lamarck, 1819)

P. exogyra (Conrad, 1837)

Arcinella cornuta Conrad, 1866

Cardiidae Lamarck, 1809

Vasticardium flavum (Linnaeus, 1758)

V. berschaueri Thach, 2014

V. vertebratum (Jonas, 1844)

V. assimile (Reeve, 1844)

Acrosterigma fidele Vidal, 1992

Papyridea soleniformis (Bruguière, 1789)

Dinocardium robustum (Lightfoot) 1786

Microfragum festivum (Deshayes, 1855)

Serripes groenlandicus (Mohr, 1786)

Fulvia (Fulvia) fragilis (Forsskål, 1775)

Mactridae Lamarck, 1809

Mactra stultorum (Linnaeus, 1758

M. chinensis Philippi, 1846

M. isabelleana d'Orbigny, 1846

M. olorina Philippi, 1846

Mactra eximia Reeve, 1854

Spisula trigonella (Lamarck, 1818)

Pharidae Adams and Adams, 1856

Ensiculus cultellus (Linnaeus, 1758)

Tellinidae Blaninville, 1814

Macoma inexpectata Cosel, 1995

Macomangulus tenuis (da Costa, 1778)

Hanleyanus vestalioides (Yokoyama, 1920)

Angulus tenuis (da Costa, 1778)

Pseudomacalia antillarum (d'Orbigny, 1853)

Tellina parvula Bertin, 1878

T. cruciata (Spengler, 1798)

Semelangulus boucheti Huber, 2015

Gari depressa (Pennant, 1777)

Limecola balthica (Linnaeus, 1758)

Quidnipagus palatam Iredale, 1929

Table continues on next page.................

Families/ Species

Serratina aequistriata (Say, 1824)

Paphia crassisulca (Lamarck, 1818)

Donacidae Fleming, 1828

Donax scortum (Linnaeus, 1758)

Hecuba scortum (Linnaeus, 1758)

Veneridae Rafinesque, 1815

Dosinia subrosea (Gray, 1835)

D. lupinus (Linnaeus, 1758)

D. sculpta (Hanley, 1845)

D. discus (Reeve, 1850)

D. exoleta (Linnaeus, 1758)

D. erythraea Römer, 1860

D. concentrica (Born, 1778)

D. tumida (Gray, 1838)

D. afra (Gmelin, 1791)

D. (Pectunculus) maoriana Oliver, 1923

D. labiosa Römer, 1862

D. (Austrodosinia) anus (Philippi, 1847)

D. hepatica (Lamarck, 1818)

D. japonica (Reeve, 1850)

D. mactracea (Broderip, 1835)

D. orbignyi (Dunker, 1845)

D. alta (Dunker, 1849)

D. (Austrodosinia) anus (Philippi, 1847)

D. fibula (Reeve, 1850)

Leukoma staminea (Conrad, 1837)

Sunetta bruggeni Fischer-Piette, 1974

Venerupis corrugata (Gmelin, 1791)

Petricola (Rupellaria) bicolor G.B.Sowerby II, 1854

Callista chione (Linnaeus, 1758)

Paphia semirugata (Philippi, 1847)

Myidae Lamarck, 1809

Mya truncata Linnaeus, 1758

Periplomatidae Dall, 1895

Periploma (Periploma) planiusculum Sowerby, 1834

was Chamidae which had 17 species (12.68%) with 106 (10.01%) speciemens. 3 Genus namely Chama, Pseudochama and Arcinella were collected of this family. 14 species of genus Chama were reported during study. Family Arcidae with 16 species (11.94 %) with 81 specimens (7.65%) were reported. One species of Arca, 6 species of Anadara and 9 species of Barbatia were collected of this family.

Family Tellinidae with 86 speciemens of 12 genus and 13 species were collected during this study. Family Ostreidae with 11 species of 4 genus and 296 specimens while family Cardiidae with 11 species of 6 genus and 30 speciemens were reported.

Eight families of Bivalvia from Gaddani were reported only one genus and one species with different number of specimens i.e., 140 individuals of Cardites floridanus of family Carditidae, 5 specimens of Ensiculus cultellus of family Pharidae, 2 individuals of Mya truncate of Myidae, Mimachlamys varia of Pectinidae and Loripes clausus of Spondyliidae were collected. Only one specimen Tucetona laticostata, Lima vulgaris and Periploma (Periploma) planiusculum of family Glycymerididae, Limidae and Periplomatidae was collected in June 2022, respectively.

Class Cephalopoda

Seven specimens of one species (Sepia officinalis) of family Sepiidae Keferstein, 1866 was collected whole study period except July 2022. 3 specimens of S. officinalis were found in Oct. 2022 from the coast of Gaddani (Table V).

Class Polyplacophora

Only one specimen of Chiton lamyi of family Chitonidae Rafinesque, 1815 of class Polyplacophora, was collected in June 2022 (Table V).

Table IV. SDI (Simpson’s Diversity Index), Number and % of abundance of individuals (Indi.) and species (spp.) of different families of class Gastropoda in different months from June 2022 to November 2022.

Families	Jun. 22	Jul. 22	Aug. 22	Sep. 22	Oct. 22	Nov. 22	Total No. of Indi.	%	No. of Spp.	%
Yoldiidae Dall, 1908	2	1	1	1	1	0	6	0.58	2	1.49
Mytilidae Rafinesque, 1815	9	3	1	4	3	2	22	2.08	4	2.99
Noetiidae Stewart,1930	8	6	7	6	5	12	44	4.15	2	1.49
Arcidae Lamarck, 1809	35	15	9	6	12	4	81	7.65	16	11.94
Glycymerididae Dall, 1908	1	0	0	0	0	0	1	0.09	1	0.75
Pteriidae Gray, 1847	13	3	4	2	7	9	38	3.59	6	4.48
Ostreidae Rafinesque, 1815	59	34	27	51	64	61	296	27.95	11	8.21
Gryphaeidae Vyalov, 1936	4	3	1	3	5	7	23	2.17	2	1.49
Limidae Rafinesque, 1815	1	0	0	0	0	0	1	0.09	1	0.75
Pectinidae Rafinesque, 1815	0	0	0	1	0	1	2	0.19	1	0.75
AnomiidaeRafinesque, 1815	29	6	4	4	4	4	51	4.82	5	3.73
Spondyliidae Gray, 1826	0	0	0	0	2	0	2	0.19	1	0.75
Plicatulidae Gray, 1854	2	0	0	0	0	0	2	0.19	2	1.49
Lucinidae Fleming, 1828	1	1	1	1	3	1	8	0.75	2	1.49
Carditidae Férussac, 1822	15	30	15	30	20	30	140	13.22	1	0.75
Chamidae Lamarck, 1809	22	18	14	23	20	9	106	10.01	17	12.69
Cardiidae Lamarck, 1809	12	2	2	1	10	3	30	2.83	11	8.21
Mactridae Lamarck, 1809	5	2	1	1	4	0	13	1.23	6	4.48
Pharidae Adams, 1856	1	4	0	0	0	0	5	0.47	1	0.75
Tellinidae Blaninville, 1814	11	15	9	14	22	15	86	8.12	13	9.7
Donacidae Fleming, 1828	4	4	5	1	2	2	18	1.7	2	1.49
Veneridae Rafinesque, 1815	34	11	6	9	6	15	81	7.65	25	18.66
Myidae Lamarck, 1809	2	0	0	0	0	0	2	0.19	1	0.75
Periplomatidae Dall, 1895	1	0	0	0	0	0	1	0.09	1	0.75
Total	271	158	107	158	190	175	1059	100	134	100
SDI	0.894	0.882	0.88	0.828	0.843	0.826	0.869		0.905

Table V. Abundance of family Sepiidae of Class Cephalopoda family Chitonidae of Class Polyplacophora from months of June 2022 to November 2022 from Gaddani coast.

Class	Family	Jun. 22	Jul. 22	Aug. 22	Sep. 22	Oct. 22	Nov. 22	Total
Cephalopoda	Sepiidae	1	0	1	1	3	1	7
%		14.28%	0.00%	14.28%	14.28%	42.86%	14.28%	100
Polyplacophora	Chitonidae	1	0	0	0	0	0	1

Discussion

This study was carried out to evaluate the occurrence and abundance molluscan fauna specially gastropoda and bivalvia in intertidal region of Gaddani Coast, Balochistan. The surveys were conducted at three sampling sites, which were revealed 216 species of Gastropoda and 134 species of Bivalvia, that are commonly inhabit in coast. It is very difficult to assess the total number of molluscan species from the previously-published literature because many studies did not describe any taxonomic detail, nor provided illustrations or images. The usage of different and older synonyms is also a problem. A previous study on the total number of species recorded from Pakistan by Kazmi et al. (2019) reported 713 species of Gastropoda, 349 species of Bivalvia from the Pakistan coast and concluded that the Balochistan coast was highly diverse with respect to molluscan community but not studied in detailed.

Present study, gastropods were reported in highest percentage of occurrence about 64% of total collection of malacofauna from Gaddani. Out of 216 species of gastropoda, 50% of species were belonged to 6 families and remaining 50% species were other 211 families. One species Nodilittorina sp. of family Littorinidae was collected in every month in highest % of abundance, of total collection of gastropoda. During the present study it was observed that 42 specimens of 28 species of family Trochidae Rafinesque, 1815, were collected which was the highest number of species of any family of gastropoda.

Simpson’s Diversity Index (SDI) of families of gastropoda was about 0.893 which shown the high diversity of families of gastropoda of this area. While 134 species of 24 families of Bivalvia, were reported from this site. Out of 134 species, 93 (69%) species were belonging to 6 families and remaining 41 (31%) of species were other 18 families. Family Carditidae was second abundant family about 13 % of total bivalve’s collection from Gaddani. Only one species Cardites floridanus of the family Cartididae was collected every month in high quantity. 8 families of bivalvia from Gaddani were reported only one genus and one species with different number of specimens. SDI of bivalvia from Gaddani was about 0.869 which shown the less high diversity of bivalvia of this site as compared to gastropoda.7 specimens of one species of one family of Cephalopodes were collected while only one specimen of class polyplacophora was collected from Gaddani site.

The current findings of Cerithium spp. and Thais spp. were like the findings of Ghani and Afsar (2017), who found these species in Jiwani, Balochistan. These were also reported by Gondal et al. (2012) from Sonmiani Bay in Balochistan. Khan and Dastagir (1971) reported Telescopium telescopium (Potamididae) from Pakistan. Molluscan species like Tibia spp., Andara spp., Marcia spp., and Gari spp. have been discovered in Balochistan’s Sonmiani Bay, Ormara, Kalmar Hor, and Pasni Bay (Gondal et al., 2012; Moazzam and Ahmed, 1994). Marcia species have been found in the mangroves of Karachi, according to Barkati and Tirmizi (1986). Those of Gari spp. were identified by Kazmi and Khan (2014). Gondal et al. (2012) identified Veneridae spp. from Sonmiani, Balochistan. In present study family Veneridae was highly diversified family which had 25 species (19%) with 81 specimens (7.56%) of total collection of Bivalvia.

Conservation of biological diversity is one of the major goals for sustainable management of marine renewable resources. The species diversity has a good relationship with species richness and evenness and diversity index is maximum with high number of species and minimum with low number of species (Srinivasan, 1999). Data obtained from this study represents an important step to gain a better understanding of molluscan habitats and their essential role as habitat provider to other species.

Declaration

Acknowledgement

Authors acknowledge the colleagues of Department of Marine Sciences, LUAWMS for constructive comments on this research and fruitful discussion.

Funding

Author received no financial support for research, authorship and publication of this article.

IRB approval

This article is part of the M.Phil. Research work of Nazeer Ahmed. Their M.Phil. Dissertation was approved by the Departmental Appraisal Committee, external and Internal examiner.

Ethical statement

We ensured that all research was conducted in accordance with ethical principles. Neither human was the subject in research nor such kind of animal, which required any administrative approval.

Statement of conflict of interest

The authors have declared no conflict of interest.

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