Abstract. Indarjo A, Salim G, Zein M, Septian D, Bija S. 2020. The population and mortality characteristics of mangrove crab (Scylla serrata) in the mangrove ecosystem of Tarakan City, Indonesia. Biodiversitas 21: 3856-3866. The mangrove crab is an iconic species of Tarakan City and is often is used as a souvenir. However, the high demand for this species can cause its population to decline. This study aimed to characterize the mangrove crab (Scylla serrata) population in the mangrove ecosystem of Tarakan City, North Kalimantan, Indonesia. This study was designed using a quantitative descriptive method with a case study model. The samples of mangrove crabs were obtained from 6 different stations using a purposive sampling method. The mangrove crab specimens were caught using 35-50 units of crab traps known as the ambau brackets. The primary data included carapace length, carapace width, carapace thickness, sex, and the total weight of each mangrove crab specimen. The results showed that male mangrove crabs have positive allometric growth when the condition index was fat. However, female crabs exhibited negative allometric growth when the condition index was thin. The Von Bertalanffy growth model analysis showed that the maximum carapace length of male mangrove crab in the mangrove ecosystem of Tarakan City was approximately 11.1118 cm for 189 days, while the female length was 9.6474 cm for 80 days. The total mortality value of male and female crabs was 120.01% and 154.94%, the mortality due to fishing was 84.69% and 135.75%, and natural mortality was 35.32% and 19.2%, respectively. The estimated rate of exploitation of both male and female crabs was 70.57% and 87.61%, respectively. The exploitation of S. serrata in the mangrove ecosystem of Tarakan City was evident, hence, conservation efforts are urgently required.
Abstract. Indarjo A, Salim G, Nugraeni CD, Zein M, Ransangan J, Prakoso LY, Suhirwan, Anggoro S. 2021. Length-weight relationship, sex ratio, mortality and growth condition of natural stock of Macrobrachium rosenbergii from the estuarine systems of North Kalimantan, Indonesia. Biodiversitas 22: 846-857. Giant prawns (Macrobrachium rosenbergii) in North Kalimantan Province, Indonesia are commonly found inhabiting estuarine areas in Salimbatu Village (Bulungan District), Tepian Village (Nunukan District) and Buong Baru and Sesayap Villages (Tana Tidung District). The present study was conducted to analyze the relationship between length and weight, sex ratio, mortality, and growth condition index of the naturally occurring giant prawns in three districts namely Bulungan, Nunukan, and Tana Tidung in the North Kalimantan Province, Indonesia. The samplings were carried out for a period of seven months beginning April to November 2020. The results revealed that the giant prawns in Buong Baru Village, Sesayap Village, and Salimbatu Village were characterized to have negative allometric growth patterns. Interestingly, the male giant prawns in Tepian Village were observed to exhibit positive allometric growth pattern. The ratio sex analysis of the giant prawns in the four villages indicated that female prawns were more than male. In terms of size distribution, Salimbatu Village exhibited 60.1% of prawns measured at 14.02-17.74cm (size range of 10.3-47.5 cm). In Tepian Village, 32.9% of the prawns were observed to measure between 11.20-12.80 cm (size range of 8.0-24.0 cm). In Buong Baru Village, it was observed 18.5% of the prawns measured 22.0-25.5 cm and 29.0-32.5 cm (size range of 15.0-50.0 cm), respectively. Finally, 28.3% of the prawns in Sesayap Village was observed to measure at 12.19-14.02 cm from the overall size distribution between 6.7-25.0 cm. Relative condition factor of giant prawns found in the waters of Salimbatu Village, Tepian Village, and Buong Baru Village waters and Sesayap Village waters was characterized by thin body shape. The maximum length of male prawns was higher than female prawns in Salimbatu Village, Desa Tepian and Sesayap Village, except in Buong Baru Village where female was longer than male. The exploitation rate and fishing mortalities of prawns were higher in Buong Baru Village, Tana Tidung District. Giant prawn fishery contributes to the socio-economic development of the people in North Kalimantan. Hence, sustainable fishery management of this species, particularly in Buong Baru Village is urgently needed so that it can continue to provide livelihoods to the fishermen in the area.
The Mudskipper (P. barbarus) lives in intertidal mud flats and it becomes an indicator of water quality. The transformation of construction and water pollution in this area is important to investigate due to interaction of fishery industry, home residence, and market area surrounding areas. The aim of this research was to analyze the characteristic of Von Bertalanffy growth, allometric, condition index, and mortality of the P. barbarus in KKMB, Tarakan city. The research was designed by using descriptive quantitative method. The sampling process used purposive sampling. The sampling was conducted for 12 times plot.transect-1 in the extension area of KKMB, Tarakan city with a total area is 12 Ha, plot.transect-1area is 10x10 m2, and distance between each transect is 10 m2. Sampling was carried out in survey area and laboratory to identify the gender and calculate total length and weight. The result showed the growth of male mudskipper (L∞ = 26.545 cm) and female (L∞ = 17.594 cm). Their size and the total population was decreased. The characteristic of male mudskipper growth was positive allometric, then female was negative allometric. The natural mortality and the catch of male mudskipper were higher than female.
Awal mula proses domestikasi pada hewan diperkirakan sudah terjadi pada zaman Mesolitikum (10.000 SM). Berdasarkan bukti sejarah, hewan pertama yang didomestikasi didaerah Asia Timur adalah anjing. Tentu saja hal ini diperkuat setelah ditemukan kerangka-kerangka anjing yang berusia 7000 dan 8000 SM. Disamping itu kerangka kucing yang berusia 6000 SM juga ditemukan didaerah Siprus. Selain peliharaan manusia zaman dahulu juga sudah mulai mendomestikasi hewan liar yang bisa dimakan dan memenuhi kebutuhan mereka untuk dijadikan hewan ternak seperti kambing dan domba yang diperkuat dengan ditemukannya kerangka kedua hewan tersebut pada tahun 7000 SM. Proses domestikasi hewan yang banyak dilakukan di negeri kita yaitu proses mendomestikasi hewan ternak yang memiliki kaitan penyediaan kebutuhan pangan juga sandang seperti rambut dan kulitnya bisa digunakan untuk membuat pakaian. Hingga saat ini spesies hewan yang telah berhasil dilakukan proses domestikasi masih terbilang sangat sedikit. Hal ini dikarenakan proses domestikasi yang bersifat cukup kompleks dan pelaksanaannya yang harus bertahap sehingga mampu mengubah sifat dan karakteristik tetuanya. Selain itu tekanan juga kondisi yang menjadi penyebab proses domestikasi masihlah tidak nampak jelas serta bervariasi proses dari satu melalui area geografis menuju ke daerah disertai satu organisme ke organisme lainnya. Proses domestikasi sendiri mulai berakhir pada zaman Pleistosen, dimana perubahan iklim saat itu sangat sulit untuk diprediksi apakah akan semakin dingin atau berubah (dengan cepat) kembali menjadi dingin. Hal ini tentu menjadi pembatas dalam penyebaran baik itu populasi manusia dan spesies lainnya. Sebanyak 148 spesies non karnivora namun hanya 15 spesies yang telah berhasil dilakukan domestikasi. Berdasarkan gambaran tersebut menandakan bahwa proses domestikasi sangat sulit untuk dilaksanakan dan harus benar-benar bertahap agar mendapatkan hasil yang mewakili spesies serta memiliki sifat adaptasi yang cukup baik.
Coastal areas are highly vulnerable to disasters, as they are affected by events occurring both on land and at sea. In the development of cities in these areas, information on vulnerability levels is needed as a consideration in determining policy. This study aims to identify potential vulnerability of Semarang city, and to investigate the potential of hazard and disaster risk levels of the city. The study was conducted in 17 villages in the northern coastal area of Semarang. The assessment approach used was score analysis to some variables, i.e geomorphology, erosion, coastal slope, waves and socio-economic aspects. The research showed that the highest level of coastal vulnerability in the Semarang city were at three villages i.e.Terboyo Kulon, Terboyo Wetan and Trimulyo with value of 4.5; while the lowest level were at the Maron beach, Marina beach and Tanah Mas with value of 2.8. The highest potential coastal hazard in the Semarang city were at two villages i.e. Tanjung Mas and Tambak Lorok with value of 4.5; and the lowest value were in the village of Randugarut, Karanganyar, Tugurejo, Marina beach and Tanah Mas with value of 1.25.The highest level of coastal risk in the Semarang city were in the Trimulyo village with value of 3.13; and the lowest level were in the Marina beach and Tanah mas with value of 1.32.
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