35 Vol. 21 No 1, February 2023, page 35-44 e-ISSN: 2580-0094; p-ISSN:1693-3931 DOI: 10.19184/bioedu.v21i1. 32294 jurnal.unej.ac.id/index.php/BIOED The Reveal of Growth Pattern and Condition Factors of Blue Swimming Crabs (Portunus pelagicus) in Coastal-Estuary Ecosystem of Labuhanbatu Regency, North Sumatera Nurjannah 1 , Rivo Hasper Dimenta 2 1,2 Biology Education, Faculty of Teacher Training and Education, Labuhanbatu University, Indonesia Article Info ABSTRACT Article history: Received July 6, 2022 Revised February 28, 2023 Accepted February 28, 2023 The blue swimming crab, Portunus pelagicus as one of the potential crabs from Portunidae family that have high economic value in Labuhanbatu regency. This study aimed to reveal the information on condition factors and growth pattern of P. pelagicus population in the coastal -estuary ecosystem of Labuhanbatu regency. This study was conducted from November 2021 to January 2022, using the purposive random sample method in determining the sampling points. In collecting the samples of P. pelagicus, the sapling process used fish traps called bubu with fresh fish as bait. Results showed that the growth pattern of P. pelagicus was allometric negative, in which values for males and females were 1.15 and 2.27, respectively. Furthermore, the results of the correlation analysis between the physic-chemical of waters to abundance of P. pelagicus indicated that positive correlation for water temperature (0.835), dissolved oxygen (DO) (0.778), and salinity (0.726) had an effect on the presence of P. pelagicus population. Keywords: Portunus pelagicus Growth Pattern Condition Factors Pearson Correlation Physic-Chemical Waters This is an open access article under the CC BY-SA license. . Corresponding Author: Rivo Hasper Dimenta, Biology Education, University of Labuhanbatu Jalan Sisingamangaraja No.126A Km 3,5 Aek Tapa, Rantauprapat, Kec Rantau Selatan, Kab. Labuhan Batu 21418, Indonesia Email: rivohd11@gmail.com 1. INTRODUCTION Indonesia is one of the crab-producing countries in Southeast Asia (Hargiyatno et al., 2013). one species crab from the Portunidae family that found in Indonesia is swimming crabs (Portunus pelagicus) (WoRMS, 2022). This species is live in the mangrove ecosystem, in which this ecosystem has the main ecological (as species supported on food chain), and economic functions (as food source of human) (Kamal, 2011; Usman, 2022). P. pelagicus in Indonesia is popularly known as rajungan. The local people in the coast of Labuhanbatu Regency call it renjong (one of which is the Sei Berombang community). In Situbondo Regency, East Java, it is known as kepiting terang bulan (Dewi et al., 2017). Furthermore, in the international market, it is called the swimming crab (Makahinda et al., 2018). Ihsan (2018) and Sunarto et al. (2010) informed that the swimming crabs (P. pelagicus) are the prima donna because their selling price can reach 200,000 IDR/kg in the Sei Berombang (personal communication with Mr. Harisman-2021). China is one of the potential markets for exporting the swimming crabs and other crabs from Indonesia. Concerning the nutritional content per 100 g, the meat of these crabs contains protein (16-17 g), carbohydrates (14.1 g), phosphorus (1.1 mg), calcium (210 mg), iron (200 SI), and vitamins A & B1 (0.05 mg) (Hadijah et al., 2021). In addition, their shells also contain high minerals, chitin, cytosine, and carotenoids which are used as raw materials for making food, cosmetics, medicine, and others. Related to their distribution, swimming crabs are spread in the Indo-West Pacific Ocean (the waters of China, Japan (Okinawa and Kyushu), and Indonesia), the Malacca Strait, the Indian Ocean, East & Southeast Asia (e.g., Singapore, the Philippines, Japan, Korea, China, and the Bay of Bengal), Turkey, Lebanon, Sicily, Syria, Cyprus, Australia, and the northern Antarctic region (Hadijah et al., 2021), specifically the coastal waters or mangroves ecosystem. Ghufran (2012) and Sipayung et al. (2021) revealed that the mangrove ecosystem as the main litter producer that produces detritus and support to increase the nutrient water quality and crabs’ population