ILMU KELAUTAN Juni 2011. Vol. 16 (2) 111-118 ISSN 0853 -7291 Population Dynamics of the Indonesian Mantis Shrimp, Harpiosquilla raphidea (Fabricius 1798) (Crustacea: Stomatopoda) Collected from a MMMudMud FFFlat in Kuala Tungkal, Jambi Province , Sumatera Island Yusli Wardiatno* and Ali Mashar Department of Aquatic Resources Management, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University (IPB) Kampus FPIK -IPB, Darmaga, Bogor 16680 Email : [email protected] Abstrak Penelitian ini bertujuan untuk mengungkapkan struktur populasi, pertumbuhan, lama mass hidup, dan laju ekspoitasi dari udang mantis (Harpiosquilla raphidea Fabricius, 1798). Penelitian ini dilakukan secara periodik di Kuala Tungkal, Tanjung Jabung Barat, Jambi dari Juli 2009 hingga Juni 2010. Hasil penelitian memperlihatkan adanya dua kelom pok ukuran yang berbeda di daerah intertidal dengan di daerah subtidal. Ukuran panjang udang mantis yang hidup di daerah intertidal berkisar 25-233 mm dengan kelompok dominan berukuran 79-96 mm, sedangkan di daerah subtidal ukuran panjang udang mantis adalah 160-366 mm dengan kelompok dominan berukuran 193-258 mm. Koefisien pertumbuhan (K) adalah 0,14 untuk jantan dan 0,11 untuk betina; sementara L∞ kedua jenis kelamin adalah sama yakni 381,68 mm. Lamanya masa hidup jenis udang mantis ini diperkirakan antara 6,7 sampai 8,5 tahun. Nilai laju eksploitasi (E) sebesar 0,42 mengindikasikan laju yang belum optimum. Kata kunci: Udang mantis, pertumbuhan, laju eksploitasi, masa hidup, Kuala Tungkal Abstract This study aim was to reveal the population structure, growth, life span and exploitation rate of mantis shrim p (Harpiosquilla raphidea Fabricius, 1798). This research was conducted in Kuala Tungkal, Tanjung Jabung Barat, Jambi from July 2009 to June 2010 and partially carried out periodically. The results showed the difference in group size distribution between t he mantis shrimp caught in the intertidal and those caught in subtidal areas. The length of the mantis shrimps in the intertidal area ranged from 25 to 233 mm with the dominant length was 79- 96 mm, while in the subtidal area the length ranged from 160-366 with dominant length between 193-258 mm. Growth coefficient (K) was 0.14 for males and 0.11 for females; while L∞ was the same for the two sexes, i.e. 381.68 mm. The life-span of the shrimp was estimated to be 6.7 to 8.5 years. The value of exploitation ra te (E) was 0.42 indicating a not optimum exploitation rate of the shrimp. Key words ::: mantis shrimp, growth, exploitation rate, life -span, Kuala Tungkal Introduction raphidea lives on muddy bottoms in coastal waters around Indonesia. In a mudflat developed in the mouth In the fishery point of view, macrobenthic of Tungkal river of Province Jambi, the shrimp is communities of demersal invertebrates and fish in exploited commercially, mainly by small bottom-trawlers marine soft-sediment have contributed to the global and gill net due to its economical value. Live caught fishery, especially in Asia (Colloca et al ., 2003; Garces mantis shrimp by the fishermen costs around USD 3.5 et al ., 2006; Lui et al ., 2007). Of those communities, per individual with 7–9 inch size (Personal many species of mantis shrimp is commercially observations; 2009). The size of the shrimp may attain valuable species, such as Oratosquilla oratoria 335 mm (Manning, 1969; Moosa, 2000). The shrimp is (Kodama et al ., 2004), Squilla sp. (Musa & Wei, mostly exported to H ong Kong and Taiwan, and the 2008), and Harpiosquilla raphidea (Wardiatno & demand increases in years. Mashar, 2010). As fisheries product mantis shrimp can be found regularly in fish markets of several Research on orders stomatopoda has been countries, such as Spain, Italy, Egypt and Morocco done a lot for a long time, including on the ecology of (Abello & Martin, 1993). economically important stomatopoda (Lui, 2005), the behavior of mantis shrimp (Manfrin & Piccinetti, 197 0; The spearer mantis shrimp, Harpiosquilla Schiff, 1989; Heitler et al ., 2000), population dynamics *) Corresponding author www.ijms.undip.ac.id Diterima/Received:20-04-2011 Disetujui/Accepted:19-05-2011 ILMU KELAUTAN Juni 2011. Vol. 16 (2) 111-118 of Squilla mantis (Griffiths & Blaine, 1988 ; Abelló & mantis shrimp catch of fishermen using gill net s. While Martin, 1993), food habit (Froglia & Gianinni, 1989), the mantis shrimp samples from the intertidal areas the ecological function of the retina of the eye (Cronin were caught by the sweeping area method using et al ., 1994; Cronin et al ., 2000), the influence of sondong and mini trawl. environment on the distribution of the mantis shrimp (Abelló & Macpherson, 1990), and genetic population The total number of mantis shrimp are caught (Barber et al ., 2002). However, research on during the study was 2109 individuals, comprising Harpiosquilla raphidea has not been much done, if 1294 individuals caught by gillnet and 815 individuals any. Data and information about H. raphidea were caught with sondong and mini-trawlers. Collected limited to the taxonomy and morphology (Manning, shrimps were measured to obtain the Kubo’s body 1969; Moosa, 2000; Azmarina, 2007; Ahyong et al ., length [abbreviated as BL: from the base of the rostrum 2008), or reproductive biology (Wardiatno & Mashar, to the anterior edge of the median notch of the te lson 2010). This paper presents the information on the (Ohtomi et al ., 1992; Kubo et al ., 1959)]. biology of Harpiosquilla raphidea with a highlight to its Measurements were made to the nearest 0.1 cm using population dynamics. caliper. The weight was measured as well using a balance to the nearest 0.1 g. Sex was determined by the presence or absence of penis located at the base of Materials and Methods a pair of third pereiopods on the eighth thoracic seg- ment (Kubo et al ., 1959), unless evident by the Study area conspicuous presence of ovaries in females. The present study was carried out on an Data analysis intertidal mudflat developed at the mouth of Tungkal River, Tanjung Jabung Barat District, Province Jambi Length frequency distribution analysis is used (Figure 1). At extreme low spring tides the mudflat is to determine the distribution of the mantis shrimp is exposed for about 1 km seaward. Harpiosquilla based on group size. Frequency distribution analysis raphidea occurs over almost the entire mudflat. The was conducted with Battacharya method (Sparre & depth of the sediment column was at least 50 cm, Venema, 1999) using the program FISAT II. and could probably reach more than 2.0 meter. The water characteristics are as follows: temperature Analysis of the length-weight relationship is ranged from 28.2 to 30.5 oC, salinity ranged from 15 used to determine growth patterns of mantis shrimp to 19 psu, and oxygen concentration ranged from using regression tests following Effendie (1997). To 6.7–7.6 ppm. further strengthen the testing in determining the closeness of relations between the two parameters (b Sampling of Harpiosquilla raphidea value), t-test may be performed with the following formula by Walpole (1992). Mantis shrimp samples were taken from two sites, i.e. intertidal and sub-tidal areas. Mantis Ford-Walford plot was used for estimating shrimps of subtidal area were obtained from the growth parameters L ∞ and K from the von Bertalanffy mantis shrimp catch of fishermen using gill net s. equation with the same sampling time interval (King, Figure 111.1... Research location. Black box indicates the mudflat where the shrimps were collected (Adopted from Wardiatno & Mashar , 2010) . 11 2 Population Dynamics of the Indonesian Mantis Shrimp, H. raphidea (Y. Wardiatno & A. Mashar ) ILMU KELAUTAN Juni 2011. Vol. 16 (2) 111-118 Sampling of Harpiosquilla raphidea comparing the catch mortality (F) on total mortality (Z) (Beverton & Holt, 1957; Pauly, 1984; Pauly, 1980 in Mantis shrimp samples were taken from two Sparre & Venema, 1999 ). The exploitation rate is then sites, i.e. intertidal and sub-tidal areas. Mantis compared to the optimum rate according to Gulland shrimps of subtidal area were obtained from the (1971) in Pauly (1984) which is 0.5. mantis shrimp catch of fishermen using gill nets. While the mantis shrimp samples from the intertidal areas were caught by the sweeping area method using Results and Discussion sondong and mini trawl. Length frequency distribution of Harpiosquilla The total number of mantis shrimp are caught raphidea during the study was 2109 individuals, comprising 1294 individuals caught by gillnet and 815 individuals Number of mantis shrimp are caught during the caught with sondong and mini-trawlers. Collected study was 2109 individuals consisting o f 1294 shrimps were measured to obtain the Kubo’s body individuals (549 males and 745 females) that were length [abbreviated as BL : from the base of the captured in the subtidal area and 815 individuals (331 rostrum to the anterior edge of the median notch of males and 484 females) that were captured in the the telson (Ohtomi et al ., 1992; Kubo et al ., 1959)]. intertidal area (see Figure 2). By sex, number of female Measurements were made to the nearest 0.1 cm mantis shrimp are caught at the study site, both in using caliper. The weight was measured as well using intertidal and subtidal areas, is higher than the male. a balance to the nearest 0.1 g. Sex was determined by This condition is consistent with the results of Abello & the presence or absence of penis located at the base Martin (1993) and Hamano et al. (1987) who of a pair of third pereiopods on the eighth thoracic conducted a research on the mantis shrimp, Squilla segment (Kubo et al ., 1959), unless evident by the mantis . conspicuous presence of ovaries in females. Based on Figure 2 it seems that there are two Data analysis groups due to size distribution of the mantis shrimp Harpiosquilla raphidea with relatively similar pattern in Length frequency distribution analysis is used both males and females.