DIAN OKTAVIANI
Research Centre for Fisheries, Agency for Research and Human Resource of Marine and Fisheries. BRSDM KP II Building. Jl. Pasir Putih II, Ancol Timur, Jakarta 14430, Indonesia

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Biological aspects of Longfin Mojarra (Pentaprion longimanus, Cantor 1849) in north coast of Central Java, Indonesia DIAN OKTAVIANI; RIA FAIZAH; DUTO NUGROHO
Biodiversitas Journal of Biological Diversity Vol. 19 No. 2 (2018)
Publisher : Society for Indonesian Biodiversity

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/biodiv/d190248

Abstract

Oktaviani D, Faizah R, Nugroho D. 2018. Biological aspects of Longfin Mojarra (Pentaprion longimanus, Cantor 1849) in north coast of Central Java, Indonesia. Biodiversitas 19: 683-689. Longfin Mojarra (Pentaprion longimanus) locally named as rengganis, is a demersal fish species that is commonly caught in Scottish seine fisheries off the north coast of Java. The fisheries are in heavily harvest level since decades. The aim of this study was to observe the biological aspects of this species. Observations were made between August 2014-July 2015 from Tegal fishing port, western part of north coast central Java. General life-history parameters were measured, i.e., monthly length frequency for 1876 fishes, among them 573 specimens were observed for length-weight relationship, including 541 specimens for sex ratio and maturity stages. Fulton index, Gonadosomatic index, sex ratio and estimated length at first mature were analyzed. The result showed fish size ranged between 7.4 to 15.3 cmFL with the average length of 11.2+1.75 cmFL. We found that length-weight relationship tends to be isometric which statistically the body growth coefficient (b) is equal to 3 (tc = 0.53 < tab; p<0.05) . Monthly Fulton indexes ranged between 1.05-2.87 with an average of 1.90 + 0.17. Sex ratio during observation was not significantly different (p<0.05) from the expected ratio of 1: 1. Mature females occurred year-round with the highest percentage observed from January to April 2015. The estimated length at first maturity was 13.04 cm FL. These biological parameters will be used to support the population study of the future demersal fish species to improve conservation and management measures.
Length-weight, maturity, and condition factor of torpedo scads (Megalaspis cordyla Linnaeus, 1758) in the Java Sea, Indonesia Dian Oktaviani; Eko Prianto; Duto Nugroho
Biodiversitas Journal of Biological Diversity Vol. 21 No. 4 (2020)
Publisher : Society for Indonesian Biodiversity

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/biodiv/d210433

Abstract

Abstract. Oktaviani D, Priyanto E, Nugroho D. 2020. Length-weight, maturity, and condition factor of torpedo scads (Megalaspis cordyla Linnaeus, 1758) in the Java Sea, Indonesia. Biodiversitas 21: 1527-1534. The Java Sea comprises the most extensive ecosystem with high pressure on the biodiversity of marine fish species in Indonesia. Small pelagic fish is the main target among marine fish species in this area for decades to fulfill the need for animal protein for human consumption. Torpedo scads (Megalaspis cordyla Linnaeus, 1758) locally called as tetengkek is one of the common species caught in small pelagic seiners fisheries in the area. The significant increasing trend of annual fish landing could lead to unsustainable long-term harvesting. This study was performed to support baseline information on the biological characteristics of Torpedo scads. Measurements on length, weight, sex, maturity, and gonad weight are the main database that collected from February to December 2017 in the Tegal fishing port, north coast of central Java. A total of 2139 specimens were available for monthly length-frequency measurements, and 601 specimens among them specifically observed for length-weight, sex, maturity stage, and their gonad weight. The result showed that fish caught within a range of 16.0-35.4 cmFL and weight of 40-570 g. The length-weight relationship tends to be isometric with the equation of L = 7.e-03 W3.1511. The male and female ratio at 1.07: 1.0 with most of the fish caught at an immature stage (77% of males and 63% of females). Average Fulton condition factor (Kn) of 1.15­+0.09 (0.86-1.64). A wide range of GSI indicates that torpedo scads partially spawn at each month of the year.