Short communication: Effects of induced spawning on early development in snout otter , philippinarum (Deshayes, 1854) (: )

Item Type article

Authors Bantoto-Kinamot, V.

Download date 30/09/2021 16:14:03

Link to Item http://hdl.handle.net/1834/37690 Iranian Journal of Fisheries Sciences 15(3)1230-1236 2016

Effects of induced spawning on early development in snout otter clam, Lutraria philippinarum (Deshayes, 1854) (Bivalvia: Mactridae)

Bantoto-Kinamot V.*

Received: December 2016 Accepted: May 2016

Department of Biology, Negros Oriental State University, Kagawasan Avenue, Dumaguete City 6200, Negros Oriental, Philippines. *Corresponding author’s Email: [email protected]

Keywords: Lutraria philippinarum, Bais Bay, Spawning induction, Embryonic development

Introduction 2012). This species is served as a Throughout the world, bivalves play an special dish in restaurants of the important role in the national economy Philippines and Vietnam making it of many countries. In 2005, the highly in demand. contribution of bivalves to the total A synergy between capture fisheries global trade of fish and fishery products and aquaculture through hatchery was approximately US$ 78.9 billion technology is considered as a (WHO, 2010). Though the contribution sustainable way to restore depleted of the overall bivalve production to stocks at the same time increase aquaculture increased, production from production to help meet the projected wild harvests exhibited a downward global demand for fishery resources. trend. Increased fishing efforts from Release of cultured juveniles serves as rapidly growing population, habitat a promising application to hatchery destruction, environmental changes, technology to augment the natural pollution, high seafood and shell trade supply of juveniles, restore global demand are the factors which overexploited species and provide lead to the decline of many mollusk substantial yields (Bell et al., 2008). In resources. One of the commercially the Philippine setting, this practice is important bivalves which showed a still to be carried out for most declining catch is Lutraria commercially important bivalves like L. philippinarum (Bantoto and Ilano, 1231 Bantoto-Kinamot, Effects of induced spawning on early development in snout otter clam, … philippinarum since most of its Manjuyod, Negros Oriental (9º38’ N; demands rely on wild harvesting. 123º08’ E). The collected were Spawning induction in sexually placed in an ice bucket containing matured broodstock is important in seawater and brought to the laboratory hatchery operations for the production for spawning induction. In the of seeds (Alagarwami and Dharmaraj, laboratory, the clams were placed in a 1983). Thus, the most effective method container with filtered seawater at room of spawning induction in species should temperature for 24 hrs to acclimate the be established. For instance, serotonin clam under laboratory conditions. After and sex steroids injection are mostly 24 hrs, each individual was cleaned used for the giant clam (Beckvar, 1981; individually to remove any encrusted Crawford and Lucas, 1986; Neo et al., epifauna and placed into separate 2011). In the case of Lutraria spawning bottles. philippinarum, a reliable method of During spawning induction, spawning induction and description of randomly selected clams were injected its larval development are yet to be with 2ml of KCl, NH4OH and H2O2 at developed. the foot. The concentrations of KCl Thus, this study deals with the used in this study were 0.5%, 2%, 4% stages of early development in Lutraria and 6% while for NH4OH and H2O2, the philippinarum and the effects of concentrations used were 0.5%, 1%, induced spawning on its early 2% and 3%. After injection, each clam development. Results of this study will was placed in a single spawning bottle add to the dearth of larval development with filtered seawater at room and biology literatures on L. temperature until they spawned. philippinarum. Description of L. As soon as the clam started to philippinarum larvae reared under spawn, the gametes were immediately laboratory conditions will also help in removed from the spawning bottle, the identification of the wild larvae transferred to a beaker and stirred since early larvae of bivalves are carefully to allow fertilization to occur. difficult to distinguish. A reliable The eggs or sperms released per clam method for spawning induction in sample after induction were counted Lutraria philippinarum for mass seed using a Neubauer haemocytometer propagation, stock enhancement, under a compound microscope. restocking and coastal rehabilitation of Fertilization success and early this resource will also be established. development were assessed under a compound microscope. Fertilized eggs Materials and methods were identified by active cell division Mature clams with estimated length into a blastula cell mass while ranging from 6cm to 12cm were undeveloped embryos were identified collected from North Bais Bay, by no cell division. Each phase of larval Iranian Journal of Fisheries Sciences 15(3) 2016 1232 development was identified and has been found to be better in the documented. alkaline medium of Tris. Alkalinity promotes both the peroxide activation Results and discussion and induction of spawning. In Pinctada It was observed in this study that only fucata, alkaline medium increases the high concentrations of the chemical proportion of oyster to spawn in stimulant used were able to induce response to a given concentration of spawning. Using NH4OH, 17% clam hydrogen peroxide. samples spawned with 2% NH4OH and Female clams released 5 42% with 3% NH4OH. For KCl, 17% approximately 1.5 to 8.0 x 10 eggs clam samples spawned with 6% KCl. with a mean diameter of 20µm (Fig. On the other hand, 33% spawned with 1B). Fertilization occurred 30 to 45 min

3% H2O2. The timing of spawning after while gradual protrusion of polar among the clams induced with KCl, body which marked the first cleavage

NH4OH and H2O2 did not differ. was observed after 1 hr (Fig.1C-D). Release of gametes by the clams Most of the 2-celled stage was observed induced by KCl, NH4OH and H2O2 after 2 hrs (Fig.1E). As cleavage occurred 10-15 min after induction progressed, the micromeres became (Table 1). concentrated in the pole. Eight- Lutraria philippinarum spawned in celled stage during 3rd cleavage was response to relatively high observed after 2hrs and 30 min concentrations of potassium chloride characterized by prominent micromeres

(KCl), hydrogen peroxide (H2O2) and and macromeres (Fig. 1H). The fifth ammonium hydroxide (NH4OH) KCl, cleavage occurred after 3hrs. The

H2O2 and NH4OH which stimulated embryo during this stage was one- muscle contraction during spawning. In celled thick and cells adhered to the addition, hydrogen peroxide has been neighboring cells (Fig. 1I). After 3 hrs found to activate the endogenous and 20min, the embryo underwent the enzymatic synthesis of prostaglandin 6th cleavage marked by the appearance related to spawning (Morse, D. 1984; of cilia and rotational movement (Fig Alagarwami and Dharmaraj, 1983). 1K). Trochophores were observed after Prostaglandins produced by nerve cells 24 hrs (Fig. 1L). are considered to play an important role in mollusk spawning. In the present study, though L. philippinarum spawned with H2O2, the percentage response was found to be relatively lower than that to NH4OH and KCl. According to Alagarwami and Dharmaraj (1983), peroxide induction 1233 Bantoto-Kinamot, Effects of induced spawning on early development in snout otter clam, …

Table 1: Timing of the early development of Lutraria philippinarum at 30 ºC and 35 ppt.

Stage Time after spawning induction (hr) Spawning 10-15 min Fertilization 30-45 min Perivitelline Membrane Formation 1 Polar Body Formation 1 1st cleavage 1-2 2nd cleavage 2 3rd cleavage 2 and 30 min 5th cleavage 3 hrs 6th cleavage 3 hrs and 20min Trochophore 24

Figure 1: Microscopic photograph of early development stages of Lutraria philippinarum, (A,B) sperms and egg, (C) zygote showing perivitelline membrane and polar body (D), zygote developing a polar lobe (E) 1st cleavage (F) 2nd cleavage; (G) 3rd cleavage, (H) prominent micromeres and macromeres, (I) 5th cleavage (J) morula (K) embryo with cilia that spin fast (L) trochophore. perivitelline membrane (pm); polar body (pb); polar lobe (pl) micromere (mi); macromere (ma); cilia (ci). 1234 Bantoto-Kinamot, Effects ofIranian induced Journal spawning of Fisheries on early Sciences development 15(3) in2016 snout otter clam, … 1234

The pattern of early embryonic Arctica islandica is best reared at 10°C- development of L. philippinarum was 15°C and a successful metamorphosis comparable with that of Pholas into shelled veliger requires above orientalis in Iloilo, Philippines along 10°C. At temperatures between 8.5°C- Guimaras Straight (Ronquillo and 10°C, development and metamorphosis McKinley, 2006). The embryos of L. become prolonged and settlement may philippinarum showed spiral cleavage. take 55days. In Macoma balthica, Cilia were observed in L. philippinarum trochophore larvae developed at 4ºC as it reached the 6th cleavage stage. within 2-3 days (Pekkarinen, 1986). However, each stage of embryonic According to Pekkarinen (1986), development in L. philippinarum during immature eggs released at high this study took longer than that in P. temperature will still develop into orientalis. The sixth cleavage occurred larvae but soon die. In this study, it was after 3 hrs and 20 min in L. possible that immature eggs of L. philippinarum while it took only 2hrs philippinarum were also released due to and 55 min in P. orientalis. high water temperature and fertilized Trochophore stage of L. but later died. philippinarum was observed after 24 Polyspermy stopped cell division in hrs versus 10-11 hrs in P. orientalis. fertilized eggs or produced malformed The eggs of L. philippinarum were embryos. In the study of Neo et al. smaller than that of P. orientalis. (2011) on Tridacna, it was found out Temperature may be considered as the that though giant clams release large confounding factor for the difference in amounts of gametes at each spawning, the timing of development as observed high larval mortality occurred before in Potamocorbula amurensis and P. completing metamorphosis. laevis (Nicolini and Penry, 2000); Concentrated sperm suspensions and Bathymodiolus childressi (Arellano and extracts can give rise to lytic activities Young, 2009) and Perna viridis (Wong against the egg membrane (Pekkarinen, and Arshad, 2013). 1986). In Mytilus edulis, embryonic Mortality of the larvae of L. development was reduced with high philippinarum during this study could egg density beyond a certain be due to water temperature, concentration during the embryonic polyspermy and bacterial infections. development (Wong and Arshad, Previous studies showed that water 2013). Bacterial infection in the temperature is a major factor of larval developing larvae also caused mortality development. In the larva of B. as observed in five-day old Tridacna childressi, more individuals developed squamosa veligers (Neo et al., 2011). shells when temperature was increased Thus, for future studies of L. to 12-14ºC than in cultures that philippinarum the effect of egg-sperm remained at 7-8 ºC (Arellano and ratio on fertilization success should be Young, 2009). The veliger stage of determined. 1235 Bantoto-Kinamot, Effects of induced spawning on early development in snout otter clam, …

The results of this study were Beckvar, N., 1981. Cultivation, encouraging because L. philippinarum spawning and growth of the giant was induced to spawn with chemical clams Tridacna gigas, T. derasa and stimulants and early larval stages T. squamosa in Palau Caroline developed under laboratory conditions. Islands. Aquaculture, 24, 21-30. Though more researches have to be Bell, J.K., Leber, H., Blankenship, L., conducted for hatchery operations and Loneragan, N. and Masuda, R., coastal rehabilitation of L. 2008. A new era for restocking, philippinarum, this study serves as stock enhancement and sea ranching benchmark to establish spawning of coastal fisheries resources. induction and complete larval rearing Reviews in Fisheries Science, 16(1- protocols. 3), 1-9. Crawford, C., Nash W. and Lucas, J., Acknowledgements 1986. Spawning induction and larval The author would like to thank Dr. and juvenile rearing of the giant Anthony Ilano and the anonymous clam, Tridacna gigas. Aquaculture, reviewers for their comments and 58 (3-5), 281-295. suggestions. The author also Morse, D., 1984. Biochemical and acknowledges the logistic support of genetic engineering for improved the University of San Carlos and production of abalone and other Negros Oriental State University. valuable mollusk. Aquaculture. 39(1-4), 263-282. References Neo, M., Todd, P., Chou, L. and Teo, Alagarswami, K. and Dharmaraj, S., S., 2011. Spawning induction and 1983. On controlled spawning of larval development in the fluted Indian pearl oyster Pinctada fucata giant clam, Tridacna squamosa (Gould). Proceedings of the (Bivalvia: Tridacnidae). Nature in Symposium on Coastal Aquaculture. Singapore, 4, 157-161. Vol. 2, 590-597. Nicolini, M. and Penry, D., 2000. Arellano, S. and Young, C., 2009. Spawning, fertilization and larval Spawning, development and the development of Potamocorbula duration of larval life in a deep-sea amurensis (: Bivalvia) from cold-seep mussel. Biology Bulletin, San Francisco Bay, California. 216,149-162. Pacific Science, 54(4), 377-388. Bantoto, V. and Ilano, A., 2012. The Pekkarinen, M., 1986. Notes on the reproductive biology of Lutraria spawning, egg cleavage and early philippinarum(Veneroidea:Mactrida) development of the bivalve Macoma and its fishery in the Philippines. balthica. Annales Zoologici Fennici, Revista de Biologia Tropica, 60(4), 23, 71-75. 1807-1818. Iranian Journal of Fisheries Sciences 15(3) 2016 1236

Ronquillo, J. and McKinley, R., 2006. World Health Organization (WHO), Developmental stages and potential 2010. Safe management of shellfish mariculture for coastal rehabilitation and harvest waters. Edited by G. of endangered Pacific angel wing Rees, K. Pond, D. Kay, J. Bartram clam, Pholas orientalis. and J. Santo Domingo. ISBN:9781843392255. Published by Aquaculture, 256, 180-191. IWA Publishing, London, Wong, N. and Arshad, A., 2013. K.http://www.who.int/water_sanitati Induced spawning and early on_health/emerging/ bivalves.pdf. development of Modiolus Retrieved date: 5 May 2014. philippinarum (Hanley, 1843) (Bivalvia:Mytilidae). Asian Journal of Animal and Veterinary Advances, 8(1), 100-107.