View metadata, citation and similar papers at core.ac.uk brought to you by CORE

provided by CMFRI Digital Repository

Indian J. Fish., 45(3) : 257-264, Jul.-Sep., 1998

Maturation process and reproductive cycle in two marine crabs, Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) along the Karnataka coast K.K. SUKUMARAN1 AND B. NEELAKANTAN School of Ocean Sciences, Kodibag, Karwar - 521 303, India

ABSTRACT

In the development of ovary of Portunus (Portunus) sanguinolentus and P. (P.) pelagicus, six maturity stages have been recognised by gross exami­ nation, i.e., immature virgins, immature resting, early maturing, late maturing, mature and spent. By microscopical studies, nine arbitrary stages have been identifed in the maturation process of ovary. In the development of testis, three maturity stages have been discernible, i. e., immature, maturing and mature. The spawning season is exended from August to May in both the species with intensive activity during December-February in the former and during January-February and September in the latter species.

Introduction Nayak (1961), Ryan (1967, 1967 a), , , ,. . T ,. Pillai and Nair (1970, 1971, 1971a, The annual crab landings m India i976)) gukumarane*aZ. (1986), Sumpton from the marine sector is around 25, 000 gt ^ (igg9) and campbell and Fielder tonnes. The crab fishery is mainly (19g6) Mogt of thege studieg arg onJ supported by Portunus (Portunus) , • r , „ *. ^ i rr . , J , _ ._ . , . briel accounts on some aspects of rela- sangumolentus and P. (P.) pelagicus .. ., , , .. , ., °,, . , . ., tive growth, sexual maturity, maturity and these two species together contrib- . .. . • i i 6 nn r, „ , , , ,. stages, sex ratio, mating behaviour, ute to about 90 % or the crab landings t „,-. •, f „ b fecundity and spawning from various in the country. regions. More recently, Sukumaran and Notwithstanding the commercial im- Neelakantan (1996 and 1997) have portance of P. (P.) sanguinolentus and dealt with relative growth, sex ratio, P. (P) pelagicus in their distributional fecundity and reproductive potential in ranges, the information on the spawn- these two species from the Karnataka ing biology of these crabs is rather coast. The present study gives a fairly Presenfragmentart addressy an: d1 limiteMadrads Researcto the workh Centrs oef of Centracomprehensivl Marine eFisherie accouns Researct on thhe Institutematura,- MenoChennan (1952)i - 600, Prasa006, Indiad and. Tampi (1953, tion process and reproductive cycle of P. 1954), Chhapgar (1956), George and (P.) sanguinolentus and P. (P.) pelagicus K. K. Sukumaran & B. Neelakantan 258 from the Karnataka coast on the central ing and non-spawning crabs was estima­ west coast of India. ted monthwise by ascertaining the indi­ vidual gonad weight in relation to body Materials and methods weight and found out the percentage.

P. (P.) sanguinolentus and P. (P.) Results and discussion pelagicus caught by different gear were sampled from Mangalore, Malpe and Maturation process in female Karwar, three important fish landing centres in Karnataka, on a regular basis Structure of adult ovary : The and analysed for carapace width, sex ovary in both the species is paired and and maturity conditions. approximately H-shaped in form, lies dorsal to hepatopancreas and extend The gonadal developmental stages posteriorly upto the narrow abdomen were ascertained by the following meth­ along each side of the hind gut. Anterior ods: to heart, the ovaries join at a commis­ 1. By gross examination of gonads. sure just posterior to the stomach, with lobes that extend anteriolaterally around 2. By studying the ova diameter the gastric region and into the cephalo- frequency distributions. thorax on each side. Spermathecae, In the first method, developmental which arise from the mid lateral por­ stages have been assigned based on tion, extend ventrally to gonopores that oocyte size, colour or ovary size to open on the sixth thoracic somite. determine the reproductive condition. Maturity stages of ovary (gross The maturity in male crabs was deter­ examination) mined based on the thickness and colour of vas deferens. The following six stages of maturity In the second method, the oocyte dia­ have been recognised in the ovarian meter measurements were taken from development in P. (P.) sanguinolentus ovaries belonging to various develop­ and P. (P) pelagicus. mental stages and oocyte size frequency i) Immature virgins (Stage I) : The polygons were constructed with a view ovary is colourless, thread - like. to trace the development of ova from immature stage to mature condition. In ii) Immature resting I intermediate order to bring out the natural sequence (Stage II) : After ovulation, ovary of maturity stages through which the return to immature stage before ova pass before becoming fully mature, rematuration. The ovary in this the ova diameter measurements taken stage is thick and translucent or from individual ovaries were classified yellow orange or brown orange or according to the size - frequency distri­ brown tan in colour. Crabs having bution of ova and the position of the broader abdominal flaps with im­ mode of the most mature groups of ova mature ovary and measuring 100 as suggested by Devaraj (1977). mm carapace width and above are included in this stage. The gonadosomatic index (GSI) which is useful in determining the reproduc­ iii) Early maturing (Stage III) : The tive cycle and for separating the spawn­ ovary is slightly enlarged and char- Maturation process in marine crabs 259

acterised by an ivory or yellow flaccid and ivory or yellow orange or colour. tan in colour. Maturity stages in female (by iv) Late maturing (Stage TV) : The microscopical studies) ovary at this stage is swollen with pronounced lobulations often ob­ On the basis of ova diameter - scuring the antero-lateral portions frequency analysis of P. sanguinolentus of hepatopancreas. Colour varies and P. pelagicus nine arbitrary stages from yellow to orange. were recognised and designated serially from A to I (Fig. 1). A brief description v) Mature (Stage V) : Mature ovaries of the stages is given below. are deep orange in colour and the Immature : Clusters of primary/ greatly swollen anterior lobes com­ young oocytes present. pletely obscure the underlying Stage A : Mode at 3.03 urn; no ova hepatopancreas and extend into the beyond 4.4 um. available space in the haemocoel. Stage B : Mode at 3-4 um; no ova vi) Spent (Stage VI) : The ovary is very beyound 8.08 um. 0 : 0.

\ \ z\ s-^S- Z\^

. rt°aan?aa»- •>"V-

0 °°ft"rrrir"rT* 'Trynrtnonp—•••••, . , \^f^f^yn^^"5rf % ri • » » 1 ' » • * • i» A it ' A ii ft Aft ««i MICKOBIVIIIOM> aiv111o Mt t Fig. 1. Ova diameter frequency polygons showinowingg ththee developmendevelopmentt ooff ovova from immature to mature stage in P. (P.) sanguinolentus (S(S)) anandd PP.. (P.)(P.) pelagicuspelagicus (P)(P).. (For description of stages A - I, see the text). K. K. Sukumaran & B. Neelakantan 260

Early maturing : Oocytes with Stage I : No clear modes; no ova clear nucleus and are in various stages beyond 27 um. of development. Maturation process in male Stage C : The mode of the most Structure of adult testis (gross ex­ mature group of ova is 6.1 - 7.1 um; no amination) ova beyond 11 um. The male reproductive system con­ Stage D : The mode of the most sists of a pair of testes and vas deferens. mature group of ova is between 9.1-11.0 The paired testes are slender, white am and no ova beyond 18 urn. In P. convoluted tubes interconnected medi­ sanguinolentus, another secondary mode ally by a commissure. The vas deferens at 5.05 um also noticed. extends from the posterior end of testes Late maturing: Many of the oocytes and pass through the thoracic cavity are in late phases of vitellogenesis and and pereiopodal musculature of eighth exhibit a granular texture due to the thoracic segment where it ends in the accumulation of yolk granules obscuring penile papillae on the coxae of the fifth the nucleus completely. pereiopod. Stage E : The mode of the most The vas deferens is divided into four mature group of ova is between 13 and regions, the proximal vas deferens, mid 15 urn. No ova beyond 23 um. A minor vas deferens, distal vas deferens and mode at 7 um seen in P. pelagicus. ejaculatory duct. The proximal vas deferns is tightly coiled and dull-white Stage F : The mode of the most in colour and lies anterior to the mature group of ova is between 18 and pericardial region. The milky white mid 22 urn and a mode between 5 and 7 um; vas deferens is loosely coiled and consti­ no ova beyond 32 um. tute the largest part of the system. The Mature: Ovary is dominated by distal vas deferens is transparent and mature ova which are granular in highly convoluted partly extending into apprearance as the oocytes are com­ muscular ejaculatory duct. pletely filled with yolk material. Maturity statges of testis Stage G : The mode of the most In the present study, the following mature group of ova between 23 and 25 three stages have been recognised in the um and separated from the succeeding development of testis. group of ova by a deep trough. The mode at 7 um showed no sign of development; i) Immature (Stage I) : Testes and vasa no ova beyond 38 um. deferentia not clearly differenti­ ated; gonad small on either side of Stage H: The mode of the most stomach; vasa deferentia are thin, mature group of ova between 29 and 34 translucent straight tubes; sperma­ um. The minor mode at 7 um of stage tozoa absent. Gonad of males meas­ G become insignificant; no ova beyond uring below 80 mm CW were in this 47 um stage of development. Spent: Mature unspawned ova un­ ii) Maturing (Stage II) : Testes and vasa dergoing resorption are often present. deferentia well developed. Testes Maturation process in marine crabs 261

are large coiled tube spreading laterally and posteriorly in the gonadoaomatto Imtex A stomach. Vasa deferentia opaque or white coiled mass, about 0.5 - 1.0 mm thick extending to both sides of heart. Spermatophores present. ra iii) Mature (Stage III) : Testes showed

further enlargement. Vasa deferen­ 2- tia are very much swollen, 2-3 mm 1- thick and milky white mass extend­ f|llS 1 R R f f R R 1 _E;; 8 ing to fill most body cavity. I Spermatophores present. months

Gonadosomatic index (GSI) gonodoaomatto Indax The GSI in females showed clear cyclic pattern with high values during January-February in P. (P.) sangui- nolentus and during September and January-February in P. (P.) pelagicus (Figs. 2A and 2B) when the incidence of mature crabs were relatively high and low during the other months. Since the M O M D iiiyyIH P M A yU gonad index did not show any definite months pattern in males (Figs. 2A and 2B), the IM CD breeding potential of male could be assessed only by the morphological Fig. 2. A - Gonadosomatic index (GSI) for P. condition of the gonad. (P.) sanguinolentus during different months. B - Gonadosomatic index (GSI) for P. (P.) pelagicus during different months. Spawning May (Figs. 3B and 4B) suggesting pro­ It is seen that eventhough the spawn­ longed breeding in this species. ing season is prolonged from November to May, peak activity was recorded The occurrence of mature, spent and during December-February in P. (P.) berried crabs of P. (P.) sanguinolentus sanguinolentus as evident from high and P. (P.) pelagicus in large numbers incidence of mature and spent crabs particularly during peak breeding sea­ (Fig. 3A) along with maixmum values of son in the shrimp trawlers operating ovigerous females during this period within 40 m depth tends to suggest that (Fig. 4A). these crabs are breeding in the inshore waters itself. In the case of P. (P.) pelagicus, the Ovigerous females spawning activity was pronounced during January-February and in Sep­ The ovigerous females of P. (P.) tember eventhough mature, spent or sanguinolentus started appearing in the berried females were available practi­ fishery in December and steadily in­ cally in all the months from August - creased its abundance, attaining higher K. K. Sukiiinarcm & B - Neelakantan 262

only few crabs in berried state in April, mature/spent % May and August. In July, no berried crabs were taken in any gear. In September and October, the incidence of ovigerous females was observed to be high (Fig. 4B). The present study showed that the breeding activity in P. (P.) sanguino­ lentus and P. (P.) pelagicus was much reduced in the coastal waters during the peak monsoon months possibly due to the low saline conditions prevailing in the nearshore waters during that pe­ riod.

ovigerous females (%)

•imtun ES3 apart Fig. 3. A - Monthwise distribution of mature and spent stages of P. (P.) sanguinolentus females. B - Monthwise distribution of mature and spent stages of P. (P.) pelagicus females (data for Mangalore, Malpe and ovigerous females (%) Karwar pooled.)

values in December, January or Febru­ ary in the trawl catches during 1992-'93 and 1993-'94 seasons (Fig. 4A). In the following months, the proportion of ovigerous females was relatively low. It was found that berried crabs of this III . ,!i .. 1 species occurred in the catches in all the 8jl. MO N lD J S3F M A M J JL t a 0 N DJMiFt MAMA S months in various proportions except months June when there was no catch. ES3 Mangalore M Malpe EZ3 Karwar

In P. (P.) pelagicus, berried crabs Fig. 4. A - Monthwise distribution of started appearing in the catch in Au­ ovigerous females of P. (P.)sanguinolentus gust, steadily increased in January- at Mangalore, Malpe and Karwar. B - February in the trawl catches during Monthwise distribution of ovigerous fe­ 1992-'93 and 1993-'94 seasons and mar­ males of P. (P.) pelagicus at Mangalore, ginally reduced in March. There were Malpe and Karwar. Maturation process in marine crabs 263

The recruitment of younger juveniles Thesis. Madurai Kamaraj University, during October-April (November-April 337 pp. in P. (P.) pelagicus) suggests peak George, P.C. and K.R. Nayak 1961. Obser­ spawning activity during August-Feb­ vations on the crab fishery of ruary in these marine portunids, al­ Mangalore coast. Indian J. Fish., 8 though the incidence of ovigerous and (1) : 44-53. mature/spent females indicated peak Menon, M.K. 1952. A note on the bionomics activity only during December-Febru­ and fishery of the swimming carb ary in P. (P.) sanguinolentus and in Portunus sanguinolentus (Herbst) on September-October and January-Feb­ the Malabar coast. J. Zool. Soc. India, ruary in P. (P.) pelagicus. It is possible 4(2) : 177-184. that the adult population which has Pillai, K. Krishna and N.B. Nair. 1970. moved into deeper waters during mon­ Observations on the reproductive cy­ soon months due to low saline conditio­ cles of some crabs from the southwest ns prevailing in the nearshore waters, coast of India. J. mar. biol. Ass. India, may be breeding in the deeper waters 10(2) : 384-386. during monsoon months (August-Sep­ Pillai, K. Krishna and N.B. Nair 1971. The tember), where the hydrological condi­ reproductive cycles of three decapod tions may be more favourable resulting crustaceans from the southwest coast in recruitment of younger juveniles into of India. Curr. Sci., 40 (7) : 161-162. the fishery in October/November period. Pillai, K. Krishna and N.B. Nair 1971a. The The high incidence of ovigerous and annual reproductive cycles of Uca mature/spent females of P. pelagicus in annulepes, Portunus pelagicus and the samples obtained in September is Metapenaeus affinis (Decapoda, also in conformity with this view. Crustacea) from the southwest coast of India. Mar. Biol., 11(2) : 152-166. Acknowledgments Pillai, K. Krishna and N.B. Nair 1976. The first author (KKS) is thankful to Observations on the breeding biology the Director, Central Marine Fisheries of some crabs from the southwest Research Institute, Kochi for granting coast of India. J. mar. biol. Ass. India, him study leave during which period 15(2) : 754-770. this work was carried out. Prasad, R.R. and P.R.S. Tampi 1953. A contribution to the biology of the blue References swimming crab Neptunus pelagicus Campbell, G.R. and D.R. Fielder 1986. Size (Linnaeus), with a note on the zoea of at sexual maturity and occurrence of Thalamita crenata Latrelle. J. Bom­ ovigerous females in three species of bay Nat. Hist. Soc, 51 : 674-689. commercially exploited protunid crabs Prasad, R.R. and P.R.S. Tampi 1954. Some in S.E. Queensland. Proc. R. Soc. Qd., aspects of relative growth in the blue 97 : 79-87. swimming crab Neptunus pelagicus Chhapgar, B.F. 1956. On the breeding (Linnaeus). Proc. Natl. Inst. Sci. habits and larval stages of some India, 20(2) : 218-234. crabs. Rec. Indian Mus., 54(1) : Ryan, E.P. 1967. Structure and function of 33-52. the reproductive system of the crab Devaraj, M. 1977. The biology and fishery Portunus sanguinolentus (Herbst) for the seerfishes of India. Ph.D. (Brachyura : Portunidae). I. Male K. K. Sukumaran & B. Neelakantan 264

system. Proc. Sym. Crustacea. Mar. and Portunus (Portunus) pelagicus Biol. Ass. India, Part II : 506-521. (Linnaeus) along the southwest coast of India. Indian J. Fish., 43 (3) : 215- Ryan, E.P. 1967a. Structure and function of 223. the reproductive system of the crab Portunus sanguinolentus (Herbst) Sukumaran, K.K. and B, Neelakantan 1997. (Brachyura : Portunidae). II. Female Sex ratio, fecundity and reproductive system. Proc. Symp. Crustacea. Mar. potential in two marine portunid Biol. Ass. India, Part II : 522-544. crabs, Portunus (Portunus) sangui­ nolentus (Herbst) and Portunus Sukumaran, K.K., K.Y. Telang and O. (Portunus)pelagicus (Linnaeus) along Thippeswamy 1986. On the fishery the Karnataka coast. Indian J. Mar. and biology of the crab Portunus Sci., 26(1) : 43-48. sanguinolentus (Herbst) along the South Kanara coast. Indian J. Fish., Sumpton, W.D., G.D. Smith and A.M. Potter 33(2) : 188-200. 1989. Notes on the biology of the Sukumaran, K.K. and B. Neelakantan 1996. portunid crab Portunus sangui­ Relative growth and sexual maturity nolentus (Herbst) in the subtropical in the marine crabs, Portunus Queensland waters. J. Aust. J. Mar. (Portunus) sanguinolentus (Herbst) Freshw. Res.,. 40(6) : 711-717.