scholarly journals IDENTIFIKASI STRUKTUR STOK IKAN CAKALANG (Katsuwonus pelamis Linnaeus, 1758) DI SAMUDRA HINDIA (WPP NRI 573) MENGGUNAKAN ANALISIS BENTUK OTOLITH

2017 ◽  
Vol 23 (2) ◽  
pp. 77
Author(s):  
Arief Wujdi ◽  
Bram Setyadji ◽  
Suciadi Catur Nugroho
Keyword(s):  
Indian Ocean ◽  
Canonical Analysis ◽  
Sampling Location ◽  
Discrete Wavelet ◽  
Stock Structure ◽  
Katsuwonus Pelamis ◽  
Multivariate Statistic ◽  
Otolith Shape ◽  
The Indian Ocean ◽  
Outline Analysis

Ikan cakalang (Katsuwonus pelamis Linnaeus, 1758) yang tersebar luas di Samudra Hindia selatan Jawa, Bali dan Nusa Tenggara telah dieksploitasi secara terus menerus dengan berbagai alat tangkap. Pengelolaannya saat ini belum rasional karena masih diasumsikan sebagai unit stok tunggal tanpa adanya bukti ilmiah sehingga rentan mengalami lebih tangkap. Penelitian ini bertujuan untuk mengindentifikasi struktur stok ikan cakalang dengan teknik analisis bentuk otolith. Sampel otolith (saggittae) dikumpulkan pada bulan April, Agustus, dan September tahun 2016 di 4 lokasi, yaitu: Binuangeun, Sadeng, Prigi, dan Labuhan Lombok. Rekonstruksi bentuk otolith dilakukan dengan pendekatan outline analysis menggunakan teknik transformasi discrete wavelet. Uji statistik multivariate dengan kluster analisis menggunakan canonical analysis ofprincipal (CAP) dan uji ANOVA-like permutation juga diterapkan untuk menentukan signifikansi antar populasi. Hasil penelitian menunjukkan bahwa analisis bentuk otolith dapat digunakan sebagai penanda yang akurat untuk mengidentifikasi struktur stok. Bentuk otolith ikan cakalang bervariasi khususnya pada bagian rostrum, namun tidak berbeda nyata antar populasi (p>0,001). Hal tersebut berarti struktur stok ikan cakalang di Samudra Hindia (WPP NRI573) terdiri dari 1 populasi yang bergerak mengikuti pola perubahan lingkungan perairan di sepanjang Samudra Hindia. Skipjack tuna (Katsuwonus pelamis Linnaeus, 1758) distributed vastly along the Indian Ocean south of Java, Bali and Nusa Tenggara. It has been exploited by various fishing gear yet it always assumed to be a single stock. It was not based on scientific evidence but merely based on “a scientific assumption”, so that vulnerable to subject of overfishing. This research aims to examine the alternative tool for identifying the stock structure based on the otolith shape. Sampling location took place in four regions, namely: Binuangen, Sadeng, Prigi and Labuhan Lombok. The otolith (sagittae) samples was collected during April, August, and September 2016. The otolith shape was reconstructed using outline analysis with discrete wavelet transformation technique. A multivariate statistic using canonical analysis of principal (CAP) and ANOVA-like permutation test were also used to determine the signification among populations. The result showed that skipjack’s otolith shape was varied from one and another, especially in the rostrum. But it was not statistically different among regions (p>0.001), which means a single stock for skipjack in the Indian Ocean (Indonesian territory of FMA 573). This study also proved that otolith shape can be useful marker tool to identify stock structure for management purpose.

scholarly journals Otolith chemical fingerprints of skipjack tuna (Katsuwonus pelamis) in the Indian Ocean: First insights into stock structure delineation

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0249327
Author(s):  
Iraide Artetxe-Arrate ◽  
Igaratza Fraile ◽  
Jessica Farley ◽  
Audrey M. Darnaude ◽  
Naomi Clear ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Indian Ocean ◽  
Equatorial Indian Ocean ◽  
Otolith Microchemistry ◽  
Stock Structure ◽  
Skipjack Tuna ◽  
Katsuwonus Pelamis ◽  
Nursery Areas ◽  
Chemical Signatures ◽  
The Indian Ocean

The chemical composition of otoliths (earbones) can provide valuable information about stock structure and connectivity patterns among marine fish. For that, chemical signatures must be sufficiently distinct to allow accurate classification of an unknown fish to their area of origin. Here we have examined the suitability of otolith microchemistry as a tool to better understand the spatial dynamics of skipjack tuna (Katsuwonus pelamis), a highly valuable commercial species for which uncertainties remain regarding its stock structure in the Indian Ocean. For this aim, we have compared the early life otolith chemical composition of young-of-the-year (<6 months) skipjack tuna captured from the three main nursery areas of the equatorial Indian Ocean (West, Central and East). Elemental (Li:Ca, Sr:Ca, Ba:Ca, Mg:Ca and Mn:Ca) and stable isotopic (δ13C, δ18O) signatures were used, from individuals captured in 2018 and 2019. Otolith Sr:Ca, Ba:Ca, Mg:Ca and δ18O significantly differed among fish from different nurseries, but, in general, the chemical signatures of the three nursery areas largely overlapped. Multivariate analyses of otolith chemical signatures revealed low geographic separation among Central and Eastern nurseries, achieving a maximum overall random forest cross validated classification success of 51%. Cohort effect on otolith trace element signatures was also detected, indicating that variations in chemical signatures associated with seasonal changes in oceanographic conditions must be well understood, particularly for species with several reproductive peaks throughout the year. Otolith microchemistry in conjunction with other techniques (e.g., genetics, particle tracking) should be further investigated to resolve skipjack stock structure, which will ultimately contribute to the sustainable management of this stock in the Indian Ocean.

Genetic analysis reveals two stocks of skipjack tuna (Katsuwonus pelamis) in the northwestern Indian Ocean

2011 ◽  
Vol 68 (2) ◽  
pp. 210-223 ◽  
Author(s):  
Sudath T. Dammannagoda ◽  
David A. Hurwood ◽  
Peter B. Mather
Keyword(s):  
Indian Ocean ◽  
Phylogenetic Reconstruction ◽  
Sri Lankan ◽  
Stock Structure ◽  
Skipjack Tuna ◽  
Microsatellite Data ◽  
Katsuwonus Pelamis ◽  
Genetic Groups ◽  
Breeding Grounds ◽  
The Indian Ocean

Skipjack (SJT) ( Katsuwonus pelamis ) is a medium-sized, pelagic, highly dispersive tuna species that occurs widely across tropical and subtropical waters. SJT constitute the largest tuna fishery in the Indian Ocean and are currently managed as a single stock. Patterns of genetic variation in a mtDNA gene and six microsatellite loci were examined to test for stock structure in the northwestern Indian Ocean. 324 individuals were sampled from five major fishing grounds around Sri Lanka and from single sites in the Maldive Islands and the Laccadive Islands. Phylogenetic reconstruction of mtDNA revealed two coexisting divergent clades in the region. Analysis of molecular variance (AMOVA) of mtDNA data revealed significant genetic differentiation among sites (ΦST = 0.2029, P < 0.0001), also supported by spatial AMOVA results. AMOVA of microsatellite data also showed significant differentiation among most sampled sites (FST = 0.0256, P < 0.001), consistent with the mtDNA pattern. STRUCTURE analysis of the microsatellite data revealed two differentiated stocks. While both marker types examined identified two genetic groups, microsatellite analysis indicates that the sampled SJT are likely to represent individuals sourced from discrete breeding grounds that are mixed in feeding grounds in Sri Lankan waters.

scholarly journals Comparison of handline tuna catches in Indian Ocean and Banda Sea waters

2021 ◽  
Vol 322 ◽  
pp. 03004
Author(s):  
Ignatius Tri Hargiyatno ◽  
Regi Fiji Anggawangsa ◽  
Moh. Natsir ◽  
I. Gede Bayu Sedana ◽  
Agustinus Anung Widodo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Average Length ◽  
Fishing Ground ◽  
Katsuwonus Pelamis ◽  
Thunnus Obesus ◽  
Significant Difference ◽  
Landing Sites ◽  
The Indian Ocean ◽  
Catch Composition ◽  
First Maturity

There are two essential landing sites for handline tuna in Indonesia: Palabuhanratu (in the Indian Ocean) and Kendari (in the Banda Sea). This paper analyzes handline catches from the Indian Ocean and Banda Sea waters as the main fishing ground. The catch composition of the handline tuna landed in Kendari is more varied than Palabuhanratu. Several species commonly caught are yellowfin tuna (Thunnus albacares), skipjack tuna (Katsuwonus pelamis), bigeye tuna (Thunnus obesus) as a target species, and some billfish species as bycatch. Mean CPUE for handline tuna landed in Palabuhanratu is lower than Kendari. A significant difference is based on the monthly mean CPUE variation between Palabuhanratu and Kendari landing sites (p < 0.001). Handline catches in Palabuhanratu had a more comprehensive range of length sizes than Kendari, using a two-sample K-S test showed significant differences (p < 0.001). The fish size landed in Kendari is relatively smaller than Palabuhanratu. The average length of fish caught by handline is smaller than the length at first maturity (Lm) value in both landing sites. The use of large size hook for hand lines is recommended for catching tunas in this area.

scholarly journals PENENTUAN UKURAN PERTAMA KALI MATANG GONAD (Lm) CAKALANG (Katsuwonus pelamis Linnaeus, 1758) DI SAMUDRA HINDIA SELATAN BALI

2019 ◽  
Vol 25 (2) ◽  
pp. 135
Author(s):  
Hety Hartaty ◽  
Gussasta Levi Arnenda
Keyword(s):  
Indian Ocean ◽  
Oocyte Development ◽  
Oocyte Diameter ◽  
Skipjack Tuna ◽  
Katsuwonus Pelamis ◽  
Multiple Spawner ◽  
The Indian Ocean ◽  
First Maturity ◽  
Paraffin Method ◽  
Immature Fish

Cakalang tergolong kelompok jenis ikan pelagis besar yang keberadaanya cukup melimpah di perairan Samudera Hindia termasuk perairan selatan Bali. Informasi biologi reproduksi sangat penting terutama untuk mengetahui kapan ikan tersebut memijah sehingga dapat digunakan sebagai dasar pengelolaannya. Cakalang memijah beberapa kali (multiple spawner), hal ini diketahui berdasarkan tingkat perkembangan oosit yang lebih dari satu tingkatan dalam satu gonad aktif. Sampel gonad cakalang betina diperoleh dari Pangkalan Pendaratan Ikan Kedonganan, Bali. Sebanyak 106 ekor cakalang betina dengan kisaran panjang cagak 37-71 cmFL dan kisaran bobot 902-7.214 gram yang teramati. Sampel gonad dalam keadaan segar langsung difiksasi menggunakan larutan buffer-formalin 10% kemudian dianalisis secara histologis menggunakan metode parafin dan pewarnaan HE (Harris-Haemotoxilin dan Eosin). Cakalang betina yang diklasifikasikan sebagai ikan yang belum dewasa (immature) memiliki karakteristik oosit unyolked (UY) yang lebih gelap pewarnaannya, memiliki diameter <156 µm dan Early yolked (EY) yang memiliki diameter 114-249 µm. Cakalang dewasa (mature) memiliki karakteristik perkembangan ovari berupa adanya oosit pada tingkat yang lebih tinggi yaitu advanced yolked (AY) dengan diameter oosit berkisar antara 180-448 µm, migratory nucleus (MN) 239-468 µm dan hydrated (Hy) dimana ukuran oositnya sangat besar yaitu sekitar 459-552 µm dan berbentuk seperti noda merah muda (pink stain). Cakalang betina di perairan Samudera Hindia selatan Bali memiliki perkembangan oosit yang asynchronous (tidak seragam) yang ditandai oleh munculnya beberapa tingkat perkembangan oosit dalam satu ovari. Ukuran panjang pertama kali matang gonad (Lm) cakalang betina yaitu 44,7 cmFL. Cakalang betina dewasa yang berstatus memijah aktif (actively spawning) ditemukan di setiap bulan pengamatan (April-September) dan diduga memijah sepanjang tahun. Skipjack tuna is classified as a large pelagic fish species and has abundant presence in the waters of the Indian Ocean including the waters of southern Bali. Information related to reproductive biology is very important especially to find out when the fish spawn so that they can be used as a basis for its management. Skipjack spawns several times (multiple spawner), this is known based on the level of oocyte development that was more than one level in one active gonad. Samples of female skipjack gonads were obtained from Kedonganan, Bali. A total of 106 female skipjack tuna with length range of 37-71 cmFL and weight range of 902-7,214 grams were observed. Gonad samples in fresh condition were immediately fixed using a 10% buffer-formalin solution then histologically analyzed using the paraffin method and HE staining (Harris-Haemotoxilin and Eosin). Female skipjack classified as immature fish has the characteristics of unyolked oocytes (UY) which are darker in coloration, have a diameter <156 ìm and Early yolked (EY) which has a diameter of 114-249 ìm. Adult skipjack (mature) has the characteristics of ovarian development in the form of oocytes at a higher level, namely advanced yolked (AY) with oocyte diameter ranging from 180-448 µm, migratory nucleus (MN) 239-468 µm and hydrated (Hy) where oocyte size is very large, which is around 459-552 µm and shaped like a pink stain. Female skipjack in the waters of the Indian Ocean south of Bali has an asynchronous (non-uniform) oocyte development which is characterized by the appearance of several levels of oocyte development in one ovary. Size at first maturity (Lm) of female skipjack in Indian Ocean southern Bali was 44.7 cmFL. Adult skipjack females with active spawning status are found every month of observation (April-September) and suspected to spawn throughout the year.

scholarly journals DUGAAN MUSIM PEMIJAHAN IKAN CAKALANG (Katsuwonus pelamis) DI PERAIRAN SAMUDRA HINDIA SELATAN JAWA DAN NUSA TENGGARA

2020 ◽  
Vol 12 (1) ◽  
pp. 1
Author(s):  
Yoke Hany Restiangsih ◽  
Anthony Sisco Panggabean ◽  
Erfind Nurdin
Keyword(s):  
Indian Ocean ◽  
Spawning Season ◽  
Katsuwonus Pelamis ◽  
Landing Sites ◽  
The Status ◽  
The Indian Ocean ◽  
Biological Sampling ◽  
Average Size ◽  
First Maturity ◽  
Somatic Index

Sumberdaya ikan cakalang (Katsuwonus pelamis) merupakan ikan ekonomis penting dan utama di Indonesia. Tingginya tingkat pemanfaatan ikan cakalang di Samudra Hindia menjadi hal yang sangat rawan dan perlu kehati-hatian dalam pengelolaannya. Tersedianya data dan informasi tentang musim pemijahan merupakan bagian dari pengetahuan yang diperlukan untuk mengetahui status sumberdaya bagi upaya pengelolaannya. Penelitian ikan cakalang dilakukan berdasarkan pengambilan contoh biologi dibeberapa tempat pendaratan ikan (Palabuhan Ratu, Prigi dan Labuhan Lombok). Penelitian dilaksanakan pada bulan Januari sampai dengan Nopember 2016. Pendugaan musim pemijahan menggunakan pendekatan indeks kematangan gonad (IKG) bulanan. Distribusi ukuran ikan yang tertangkap dengan menggunakan pancing tonda berkisar antara 24 – 66 cm. Ukuran rata-rata pertama kali tertangkap (Lc) pada panjang 41,6 cm, ukuran pertama kali matang gonad (Lm) 42,5 cm. Berdasarkan fluktuasi IKG musim pemijahan ikan diduga berlangsung pada bulan April dan Nopember.Skipjack tuna (Katsuwonus pelamis) are most important and economically fish in Indonesia. The highest exploitation skipjack in the Indian Ocean is very vulnerable are requires caution in its management. The availability of data and information about the spawning season is a part of the knowledge needed to determine the status of resources for management efforts. This research was carried out based on biological sampling at several fish landing sites (Palabuhanratu, Prigi, and Labuhan Lombok). This research was conducted from January until to November 2016. Estimating of the spawning season was used a monthly Gonado Somatic Index (GSI) approach. The range of size distribution from of fish caught using troll line were 24 until 66 cm. The average size of first caught (L50%) at a length was 41.6 cm, the size of the length of first maturity (Lm) was 42,5 cm. Based on the GSI fluctuation, spawning season was done in April and November.

scholarly journals Otolith microchemistry: a useful tool for investigating stock structure of yellowfin tuna (Thunnus albacares) in the Indian Ocean

2019 ◽  
Vol 70 (12) ◽  
pp. 1708 ◽  
Author(s):  
Iraide Artetxe-Arrate ◽  
Igaratza Fraile ◽  
David A. Crook ◽  
Iker Zudaire ◽  
Haritz Arrizabalaga ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Indian Ocean ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Stock Structure ◽  
North West ◽  
Natal Origin ◽  
Oxygen Stable Isotopes ◽  
West Indian Ocean ◽  
The Indian Ocean

A better understanding of the stock structure of yellowfin tuna (Thunnus albacares) in the Indian Ocean is needed to ensure the sustainable management of the fishery. In this study, carbon and oxygen stable isotopes (δ13C and δ18O) and trace elements (138Ba, 55Mn, 25Mg and 88Sr) were measured in otoliths of young-of-the-year (YOY) and age-1 yellowfin tuna collected from the Mozambique Channel and north-west Indian Ocean regions. Elemental profiles showed variation in Ba, Mg and Mn in YOY otolith composition, but only Mn profiles differed between regions. Differences in YOY near-core chemistry were used for natal-origin investigation. Ba, Mg and Mn were sufficiently different to discriminate individuals from the two regions, in contrast with carbon and oxygen stable isotopes. A linear discriminant analysis resulted in 80% correct classification of yellowfin tuna to their natal origin. Classification success increased to 91% using a random forest algorithm. Finally, a unique larval source was detected among age-1 yellowfin tuna. The signal of these fish resembled that of YOY from a north-west Indian Ocean origin, highlighting the importance of local production. The present study supports the use of otolith chemistry as a promising approach to analyse yellowfin stock structure in the Indian Ocean.

scholarly journals BIOLOGI REPRODUKSI IKAN CAKALANG (Katsuwonus pelamis) DI SAMUDERA HINDIA BAGIAN TIMUR

2015 ◽  
Vol 7 (2) ◽  
pp. 87
Author(s):  
Irwan Jatmiko ◽  
Hety Hartaty ◽  
Andi Bahtiar
Keyword(s):  
Indian Ocean ◽  
Histological Analysis ◽  
Gonadosomatic Index ◽  
Fork Length ◽  
Maturity Stage ◽  
Skipjack Tuna ◽  
Katsuwonus Pelamis ◽  
The Indian Ocean ◽  
The One ◽  
First Maturity

Cakalang (Katsuwonus pelamis) adalah salah satu hasil tangkapan penting bagi nelayan di Samudera Hindia. Penelitian ini bertujuan untuk mengetahui perkembangan gonad dan panjang pertama kalimatang gonad cakalang di Samudera Hindia. Sampel cakalang dikumpulkan dari beberapa tempat di Pantai Selatan Jawa yaitu: Palabuhanratu, Cilacap, Pacitan, Sendang Biru, Kedonganan, Tanjung Luar, Labuhan Lombok dan Oeba dari bulan April 2012 sampai November 2013. Panjang cagak dari 136 sampel berkisar antara 35-68 cm. Tingkat kematangan gonad (TKG) diamati secara histologi dan analisis Gonadosomatic index (GSI). Hasil penelitian ini menunjukkan bahwa TKGcakalang didominasi oleh TKGIV sebesar 43%, diikuti dengan TKG III (21%), TKG I (17%), TKG II (16%) dan TKG V (2%). Panjang pertama kali matang gonad terjadi pada ukuran 42,9 cm. Skipjack tuna (Katsuwonus pelamis) is the one of the important catch for fishermen in the Indian Ocean. The objectives of this research are to investigate gonad maturity and length at first maturity for female cakalang in Indian Ocean. Skipjack tuna were sampled from several places in South Coast of Java i.e.: Palabuhanratu, Cilacap, Pacitan, Sendang Biru, Kedonganan, Tanjung Luar, Labuhan Lombok and Oeba from April 2012 to November 2013. Fork length of the sampled 136 fish ranged from 35 to 68 cm.Maturity stage (TKG) investigate using histological analysis and Gonadosomatic index (GSI) calculation. The results showed that maturity stage of skipjacktuna dominated by TKG IV with 43%, followed by TKG III (21%), TKG I (17%), TKG II (16%) dan TKG V (2%). Length at first maturity occurred at 42.9 cm.

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