Size structure, length-weight relationship, and sex ratio of silky sharks (Carcharhinus falciformis, Müller & Henle, 1839) in Prigi waters, East Java, Indonesia

Abstract

Silky sharks (Carcharhinus falciformis) are one of the shark species found in Prigi waters, East Java. According to the International Union for Conservation of Nature (IUCN), silky sharks are included in the near threatened species. The purpose of this study was to determine the size structure, length-weight relationship, sex ratio, and level of gonadal maturity of silky sharks in Prigi waters, East Java. This research was conducted at Pelabuhan Perikanan Nusantara in Prigi, using descriptive methods. The data used were total length data and weight of C. falciformis. The study took samples of 30 individuals, consisting of 19 males and 21 females. The size of C. falciformis ranged from 61-189 cm. The longest male sharks were around 76-103 cm and the longest female sharks were 81-100 cm. The weight of C. falciformis ranged from 3.5 kg to 55 kg with an average of 8.5 kg. The length-weight relationship of C. falciformis resulted in and equation of y = 2.4087x-9.0779. From this value, it can be concluded that the growth pattern has negative allometric where the growth of the body of the sharks is not balanced with their weight gain. The sex ratio between male and female is unbalanced, which is 0.45: 1.

Keywords

• Carcharhinus falciformis
• length-weight
• sex ratio
• Prigi