FISHES OF THE GENUS ILISHA RICHARDSON, 1845 FROM VISAKHAPATNAM

BY S. DUTT* (Department of Zoology, Andhra University, Waltair) Recoived September 29, 1967 (Communicated by Prof. P. N. Ganapati, V.A.SC.)

ABSTRACT Twelve species of genus llisha Richardson, I846 are recognised to date. The genus and constituent species are badly in need of revision. Five of the twelve species have so far not been recorded from India. Of the seven species recorded from India, the type locality of two species llisha indiea (Swainson) and I. megaloptera (Swain.), is Visakha- patnam and of a third species I. filigera (Val.) is Coromandel Coast. Descriptions of these three species based on new material frcm Visakl=a- patnam are given, because earlier descriptions me inadequate or partially incorrect. The salient features of the posterior frontal fontanelles and the vertebral column are given.

INTRODUCTION THE genus Ilisha is badly in need of revision as has been pointed out by White- head 0965). Species of this genus are widely distributed in Indian waters and although never abundant, they occur in fair numbers at some places, e.g., Kakinada on east coast. Fowler (1941) inclu&d thirteen species in genus llisha, seven of which were earlier descril~d by Day (1878) in genus Pellona; of these thirteen species, Whitehead et aL (1966) have recently shown I. amblyuroptera (Blkr.), 1852 to be the same as I. pristigastroidea (Bleeker), 1852. Thus of the twelve species recognised to date,five species have not been so far reported from India; one of these latter~ Peilona ( = Ilisha) sladeni included by Day (1878) in his Fishes of India is from river Irrawady at Mandalay, Burma, which at that time formed part of British India; the type localities of the other four species are in indo-Malayan Archipelago. Con- sldering the similarity in the fish fauna of the latter region and the coasts of

* Present address: D~partmvnt of Zoology, Andhra University Post.Graduate Centre, Ouatur. 2O6 Fishes of the Genus Ilisha Richardson, 1846 front Visakhapatnam 207

India, it should not be surprising if one or more of the five species not so far recorded from India, do occur in Indian waters. Of the seven species of Ilisha from India, three species occur at Visakha- patnam. The type locality of two of them: Ilizha indica (Swainson), 1938 (based on Ditchoee Russell, 1803) and Ilisha megaloptera (Swainson), 1839 (based on Jangarloo Russell, 1803) is Vizagapatam (=Visakhapatnam). The type locality of the third species Ill,ha filigera (Val.), 1847 is given as Coromandelt and Bombay (Fowler, 1941). It is interesting to note that these clupeids occur more in boat seines operated from non-mechanised cattamarams working in pairs and in trawl catches, albeit in small number, rather than in drift nets and shore seines which are operated mainly for clupeoids. Other clupeoids which are pelagic, do appear in boat seine and trawl catches but not so regularly, and in such small numbers that their occur- ence could be attributed to chance capture as the net is haukd up. The regularity with which lli~ha species occur in boat seine arid trawl catches suggests that they frequent relatively deeper waters within reach of the trawl mouth. The area traversed by trawlers here does not normally extend beyond a depth of about 70 m. The classification adopted here is from Whitehead (1965). For synonymy of species described here, vide Fowler (1941) ar.d Whitehead (1965).

MATERIAL AND METItODS Samples of llisha spp. were collectcd from trawl catches and bottom-set gill nets operated by the Central Offshore Fishing Station, Visakhapatnam, and from boat seines operated from non-mechanised cattamarams operated by local fishermen; they occur rarely in the relatively small-mesh drift nets and hardly ever in shore seines. Among body measurements and meristic data taken mention may be made of the following: 1. Standard length.--From snout tip to base of middle caudal rays. 2. Head length.--Snout tip to posteriormost limit of opcrculum. 3. Snout.~Snout tip to middle of anterior border of eye.

Visakhapatnam is in the northern half of Coromandel Coast, a term used in 18th and 19tb centuries for the northern part of the east coast of Madras Presidency, but its limits were not clearly defined. Apart from Visakhapatnam, the coastal fishing towns of Cccanada (=Kakinada) and Masulipatam (~ Machilipatnam) which are all now in Andhra State wcre included in it. 208 S. DUTT

4. Eye diameter.--t-IorizontaIly, in middle of eye. 5. Predorsal, prepectoral, preventral and pre-anal distance.--Linear measurement from snout tip to base of anteriormost ray of the concerned fin. 6. In counting pectoral and ventral fin rays and gill takers on first arch, only those of the left side were taken. 7. In vertebral count, the urostyle is included as one vertebra. Suborder: CLUPEOIDEI. Superfamily: CLUI~EO IDA,E. Family: CLUPEID^E. llisha Richardson, t846.

lliska indica (Swainson), 1839 Description.--Based on 26 fishes in fresh condition, 177-218 ram. st. 1., from Visakhapatnam, type locality. In percentages of standard length: body depth 32.6-36.2, head 24.1-26.4, snout length 6.6-7.8, ey.z diameter 7.7-9.0, predorsal distance 46.4--48.8, prepectoral distance 25.6-27.2, preventral distance 44.9-48.6, preanal distance 61.6-67.8, dorsal base 11.8-14.1, anal base 28.7-32.2, pectoral length 16.3-18.1, ventral length 6.0-7.0. Dorsal profile slightly convex, ventral profile distinctly convex. Maxilla extends to 2/5 or ½ horizontal eye diameter. Caudal fin longer than head. Dorsal origin nearer to snout than to caudal base. Pectoral does not reach ventral origin (cf. I. megaloptera). Ventral origin in front 6f dorsal origin, but ventral rays extend to below 4th or 5th dorsal ray. Anal origin behind dorsal base, about midway below last dorsal ray when latter is depressed (pressed back to lie horizontally). Dorsal iii 13-15, pectoral i 15-16, ventral i 6, anal iii 37-42. Abdominal scutes 18-21 preventral, 8:10 postventral, total 26-30. Gill rakers on first arch 10-12 -t- 24-26, total 34-38. Vertebrae l0 +32, 11 + 31 or 12 -t- 30, total 42. Scales caducous, in median lateral series: 30-40 to caudal base, 4 on latter (Fowler, 1941). Colour.--In fresh specimens, back steel-blue, glistening, when scales present; a drab blue-grey without scales, turning coppery after a few hours; flanks and belly silvery-white. Dorsal side of snout and of protruding lower jaw dark with melanophores. Dorsal fin faint yellow with small melano- Fishes of the Genus Ilisha Richardson, 1846 from Visakhapatnam 209 phores dispersed all over; first three rays dark, as also upper edge. Caudal pale yellow with dark edge. Upper half of pectoral faint yellow with few tiny melanophores on upper rays, lower half hyaline. Ventrals and anal largely hyaline, but anal may be faint yellow, with few tiny discrete melano- phores. Notes.--In adults only the left gonad is fully developed; in females, the right ovary is very thin, shorter than left ovary but with developing eggs. They spawn in the early part of the year: January-March. The number of anal fin rays iii 37-42 is higher than that given by Day (1878): 39-40, and Fowler (I941): 36-39. Fowler's meristic data repeated by Munro (1955) are not quite in agreement with those of specimens from the type locality. Fowler (1941: 653) states that the maxilla reaches 113 in eye and that teeth are obsolete or absent. Re-examination of specimens in U.S.N.M. and A.N.S.P., on which Fowler based his description, is desirable. The data of Chu and Tsai (1958) for specimens from Taiwan are close to the present data. The meristic data given by Whitehead (1965) for specimens from Persian Gulf are within the range for specimens from Visakhapatnam, except for the number of dorsal fin rays which is higher in specimens from Persian Gulf. (llisha filigera Valenciennes), 1847 Description.--Based on 15 specimens in fresh condition, 208-26~ st. 1., from Visakhapatnam. In percentages of standard length.--Body d¢pth 31.5-34.4, head 25.2-26.7, snout 6.2-7.3, eye diameter 7.7-8.7, predorsal distance 49.4-53.3, prepectoral distance 24.9-27.0, preventral distance 44.0-47.5, pre-anai distance 55-9--63.0, dorsal base I0.1-11-2, anal base 33.6-36.6, pectoral length 18.4-20.2, ventral length 5.1-6.3. Dorsal profile only slightly convex, ventral profile convex. Maxilla extends to below middle of eye. Caudal fin longer than head. Dorsal origin about midway between snout and caudal base or slightly nearer snout tip. Pectoral reaches base of ventral. Ventrals entirely in front of dorsal. Anal origin below last third or fourth dorsal ray. Dorsal iii 13-15, pectoral i 15-17, ventral i 5, anal iii 42--46. Abdominal scutes 20-23 preventral, 9-10 postventrat, total 312-32. Gill rakers on first arch 9-10 q- 19-21, total 28-31. Vertebrae 15 ÷ 31, 14 ÷ 33 or 15 + 32, total 46 or mostly 47. Scaks caducous, in median lateral series 50, in transverse series 15 or 16 (Fowkr, 1941). 210 S. DUTT Colour.--In fresh specimens, back drab blue-grey with scales shed, flanks and belly silvery white. Dorsal side of snout and of protruding lower jaw dark with melanophores. Anterior and dorsal edges of dorsal fin dark grey otherwise hyaline. Caudal pale yellow, with dorsal azd posterior edges dark. Anal base hyaline, distal ~ yellow, edge dazk. Vcntrals hyaline Upper half of pectorals yellow, lower half hyaline, posterior ~ dotted with melanophores arranged more densdy toward posterior edge; first (upper ray) dark. Golden tinge on operculum and sides of mouth. Notes.--This species is more common in trawl than in boat seine catches. The range for dorsal fin rays and abdominal scutes given by Day (1878), Fowler (1941) and Munro (1955) is rather high, and that for gill rakers on lower arm of first arch given by latter two authors, rather low. The number of ventral fin rays is 6 and not 8 (cf. Day, 1878). llbka megaloptera (Swain~n), 1839 Description.--Based on eight specimens in fresh condition~ 83-139mm. st. 1., from Visakhapatnam, type locality. In percentages of standard length.--Bedy depth 34.6-37.5, head 23.6-26.4, snout 5.8-6.8, eye diameter 8.6-9.9, predorsal distance 43.3-47.5, prepectoral distance 26.1-28.8~ preventral distance 44.0-47.1, pre-anal distance 57.0--60.7, dorsal base 10.8-12.8, anal base 37.0-43.8, pectoral length 16.5-19.8, ventral length 5.5-8.1. Dorsal profile slightly convex, more ,so between head and dorsal origin; faint concavity on posterior half of head; ventral profile deep convex. Maxilla extends to ~r eye diameter. Caudal fin longer than head. Dorsal origin nearer to snout than to caudal base. Pectorals reach ventral origin or slightly beyond. Ventral origin in front of dorsal, dorsal arising above ventral tip or slightly in front. Anal origin approximately below one of last three dorsal rays. Dorsal iii 13-14, pectoral i 14-17, ventral i 6, anal iii 40-43. Abdominal scutes 20 preventral, 8-9 postventral, total 28-29. Gill rakers on first arch 10--11 + 21-22, total 31-33. Vertebrae 10 + 33 or 11 + 32, total 43. Scales caducous, in median lateral series: 50 to caudal base, 20 transversely, 21 predorsal (Fowler, 1941). Colour.--In fresh specimens, back glistening pearl-grey (drab blue-grey with scales shed), flanks and belly silvery white, with diamond-blue iridescence by reflected light. Dorsal side of snout and of lower jaw black. Ant~ro- ventral side of lower jaw pale yellow with two short bands of melanophores. Fishes of the Genus Ilisha Richardson, 1846 from Visakhapatnam 211

Inside of lower jaw yellow. Dark band between head and dorsal and narrower band between dorsal and caudal. Upper part of opereulum, above 2/3 vertical diameter of eye, grey; golden tinge behind eye. Anterior ~r to ½ of dorsal plae yellow, rest hyaline; fine melanophores all over dorsal; anterior and dorsal edges dark. Caudal yellow, fine melanophores all over, edge dark. Basal half of anal hyaline, distal half pale yellow, grey narrow edge. Ventrals hyaline. Upper half of pectoral pale yellow, rest hyaline. Notes.--The number of preventral scutes given by Day (1878) and Fowler (1941) is too high. The number of gill rakers on lower arm in these specimens from type locality: 21-22 is slightly higher than that given by Fowler (1941):20.

POSTERIOR FRONTAL FO~TA~r~tLV-Sn~ llisha SrP. Whitehead (1963) has drawn attention to the value of the pair of dorsal fontanelles at the hind end of the skull, in the classification of clupeoid fishes. According to him, in Clupeidae and Dorosomatidae, the fontanelles which are present in the juveniles become dosed in the genera containing large adults, like Clupea, Sardinella, etc. The present studies show that genus llisha constitutes an exception because, although the adults grow to a large size (at least 320 ram. t.1. in L filigera), the fontanelles remain distinct in juveniles as well as in adults. The fontanelles are broad anteriorly and narrower posteriorly. The fontanelles together present a pear-shaped outline,

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Flos. 1-2. Fig. 1. Dorsal view of post-orbital region in skull of L indica (Swain.), 202 mm. st. 1. showing posterior frontal fontanelles (black) bounded by frontals (vertical hatching), parietals (horizontal hatching) and supra-occipital (stippled) ; the anterior extension of latter hi unshaded as also supra-occipital ridge behind it. Fig. 2. Third and fourth vertebrae of I. indicao 202 mm. st. 1, to show broad wing-like transverse processes of third vertebra. with the narrow end directed backward. Figure 1 shows the shape and position of the posterior frontal fontanelks in L ir,dica. Anteriorly and B3 212 S. DUTT antero-laterally (to about 2/5 the length) they are bounded by the thin frontals, laterally by the parietals, postero-Iaterally and posteriorly by the supra- occipital. Extending forward from the supra-occipital is a narrow anterior extension which extends almost to the anterior end of the frontals. In fact the midfrontal suture rests on it. Just behind the fontanelles there is a narrow anteriorly directed supra-occipital ridge.

V~RT~BRAL COLUMN The number of vertebrae shows little variation, unlike in many other clupeoids like Sardinella spp., Stolephorus spp., Thryssa spp., etc., in which there is a range of 2 to 3 in the total number of vertebrae of each species. In all the three species of Ilisha examined, the first vertebra is narrow. The third vertebra has wing-like transverse processes (Fig. 2) which are con- spicuously larger than those of the preceding two as well as succeeding vertebrae.

ACKNOWLEDGEMENTS The author expresses his grateful thanks to Prof. P. N. Ganapati for encouragement and for providing excellent facilities. It is a pleasure to acknowledge help rendered by Dr. R. N. Bhattacharya, Deputy Director, Central Offshore Fish/ng Station, Visakhapatnam, and the crew of the trawlers, in collection of material.

REFERENCES

Blegvad, H. _ "Fishes of the Iranian Gulf," Danish Sci. Invest. Iran, 1944, Part 3, 67. Chu, K.-Y. and Tsai, C. I". -- "A review of the ¢lupooid fishes of Taiwan, with descriptions of newspecies," Quart. J. Taiwan Mus., 1958, 11(1-2), 119. Day, F. - The Fishes of India, 1878, 1, 642--46; 2, pl. 164, Fig. 4; pl. 165, Figs. 2 and 4. (Reprinted 1958, by William Dawson & Sons Ltd., London). Fowler, H. W. - "Contributions to the biology of the Philippine Archipelago and adjacent regions," Bull. U.S. nat. Mus., No. 100, 1941, 13, 650-63. Munro, I. S. R. h. The Marine and Freshwater Fishes of Ceylon, Dept. Ext. Affairs, Canberra, 1955, 27. Norman, J. R. •. "A revision of the Clupeid Fishes of Genus llisha and allied Genera," Ann. Mag. nat. Hist., Ser. 9, 1923, 11 (61), 1--22. Fishes of the Genus Ilisha Richardson, 1846 from gisakhapatnam 213 Description and Flpres af ~r~¢o Hundred Fishes Colleoted Russoll,P. at Vlzagapatam on the Coast of Coromandal, W. Bulme, & Co., London, 1803. Whitehead, P. J. P. "A contribution to the classification of Clupeoid fishes," Ann. Mag. nat. Hist., Ser. 12, 1963, S, 737-50. "'A Review of the Elopoid and Clupeoid Fishes of the Red Sea and adjacent regions," Bull. Brit. Mus. nat. Hist. (ZooL), 1965, 12 (7), 260-61. "The Types of Bleeker's Indo-Pacific Elopoid and Clupeoid Boeseman, "M. and Fishes." ZooL VerhandeL, Leiden, 1966, No. 84, 93-103, Wheeler, A.C. pl. I1, Fig. 3; pl. 13, Fig. 2.