Sungai Jajar merupakan salah satu sungai besar yang aliran sungainya banyak dimanfaatkan penduduk sekitar. Kondisi ini akan berdampak terhadap kualitas perairan yang dapat mengakibatkan suatu pencemaran. Makrozoobentos merupakan hewan yang hidup di dasar perairan dan dapat dijadikan sebagai bioindikator karena habitat hidupnya relatif menetap. Tujuan dari penelitian ini adalah untuk mengetahui tekstur sedimen, kandungan bahan organik, kelimpahan makrozoobentos, hubungan tekstur sedimen dengan bahan organik; tekstur sedimen dengan kelimpahan makrozoobenthos; dan hubungan bahan organik dengan kelimpahan makrozoobenthos. Penelitian dilaksanakan pada bulan Maret-April 2018 menggunakan teknik purposive random sampling dengan total 6 stasiun. Sampel yang diambil adalah substrat dan makrozoobenthos. Hasil penelitian menyatakan bahwa nilai fraksi sand berkisar antara 3,66 -8,40%; fraksi silt berkisar antara 1,29-1,80% dan fraksi clay berkisar antara 89,89-94,81%. Jenis makrozoobentos yang ditemukan dikelompokkan dalam 3 kelas, yaitu: Gastropoda (Cerithidea sp, Terebra sp, Pila sp, Murex sp, Urosalpinx sp, Filopaludina sp dan Telescopium sp), Bivalvia (Anadara sp, Mesodesma sp, Mytillus sp) dan Polychaeta (Nereis sp). Kelimpahan individu berkisar antara 280-2320 ind/m2 dengan kelimpahan tertinggi terdapat pada stasiun III dan kelimpahan terendah pada stasiun I. Kandungan bahan organik berkisar antara 6,73-9,4 %. Hubungan bahan organik dengan tekstur sedimen memiliki korelasi yang cukup erat. Hubungan antara tesktur sedimen dengan kelimpahan makrozoobenthos memiliki korelasi yang rendah. Hubungan bahan organik dengan kelimpahan makrozoobenthos menunjukkan hubungan yang cukup erat dengan nilai koefisien korelasi sebesar 0,557.                 Sungai Jajar is one of the major rivers where the river flows are widely used by local people. This condition will have an impact on water quality which can cause a pollution. Macrozoobenthos are organism that live in the bottom of the water and can be used as bioindicators because their habitat is relatively sedentary. The purpose of this study was to determine sediment texture, organic matter, abundance of macrozoobenthos, sediment textures relationship with abundance of macrozoobenthos; relationship of organic matter with sediment texture; and the relationship of organic matter with abundance of macrozoobenthos. The study was conducted in March-April 2018 using purposive random sampling method technique with a total of 6 stations. The samples taken were substrate and makrozoobenthos. The result refers that sand fraction value ranged from 3,66%-8,40%; Silt fraction ranged from 1,29%-1,80% and clay fraction ranged from 89,89%-94,81%. Macrozoobenthos found in three classes are: Gastropods (Cerithidea sp, Terebra sp, Pila sp, Murex sp, Urosalpinx sp, Filopaludina sp and Telescopium sp), Bivalvia (Anadara sp, Mesodesma sp, Mytillus sp) and Polychaeta (Nereis sp). Individual abundance ranged from 280-2320 ind/m2 with the highest abundance found at station III and the lowest abundance at station I.  The content of organic material ranges from 6,73% -9,4%. The relationship of organic matter with sediment texture has moderate correlation. The relationship between sediment texture and abundance of macrozoobenthos has low correlation. The relationship of organic matter with abundance of makrozoobenthos shows a fairly strong relationship with a correlation coefficient of 0,557.

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Indian scad is a small pelagic fish that has important economical value. Indian scad caught by mini purse seine which is the most dominant fishing gear in Tasikagung Fishing Port of Rembang. The high demand of Indian scad, in fishermen enlarging their effort. The purpose of this research is to know the growth, mortality rate, exploitation rate and reproduction aspects including gonad maturity level and gonad maturity index of Indian scad. The research was conducted in January – April 2019. The method used was systematic random sampling. Data collected were size of fish (mm), weight (gram), weight of gonads (g) and catching area. The samples were collected twice a month. The length of fish ranged from 102 - 185 mm. The length-weight relationship analysis obtained equation W = 0.0000546TL2.73 and L50% 155 mm. Estimation of Von Bertalanffy growth equation is L∞ = 221 mm, K = 1.7 year−1, and the time of zero length (t0) = -0.322 year. Total mortality (Z) of indian scad was 2.91 year−1, natural mortality (M) was 1.48 year−1 and the fishing mortality (F) was 1.43 year−1. This indicates that the rate of exploitation of indian scad amounted 0.49 year−1. The pick recruitment occurred in August and September. The average Indian scad caught in the condition of maturity on gonad maturity level III and IV. Gonad maturity index of male Indian scad was 1.47 and females was 1.59.

Abstract. Saputra SW, Solichin A, Taufani WT, Rudiyanti S, Widyorini N. 2019. Growth parameter, mortality, recruitment pattern, and exploitation rate of white shrimp Penaeus indicus on the northern coast of Central Java, Indonesia. Biodiversitas 20: 1318-1324. The aims of this study were to know the growth parameters, first lenght captured (Lc), mortality, recruitment pattern, and the exploitation rate of white shrimp (Penaeus indicus H.Milne Edwards, 1837) in the Western Coastal North Central Java Sea, Indonesia. Samples were collected from May 2016 to July 2017 using survey method and direct observations on fishing unit areas. The results showed that the relationship of the carapace length and weight is allometric. Based on the estimates of von Bertalanffy growth equation to the carapace length, the growth parameters of CL∞ and K values in male were 37 mm and 0.97, while in female were 38.5 mm and 0.85. While, the rates of total mortality (Z), natural mortality (M), and fishing mortality (F) were 3.5, 1.67, and 1.84 for males, and 5.03, 1.51, and 3.52 for females, respectively. The exploitation rate (E) of male shrimp was 0.52 and of female was 0.7 indicating that female shrimp get higher capture pressure than the males. It also showed that the rate of exploitation has to exceed the optimum sustainable yield (E>0.5). Time recruitment occurred throughout the year, with two peak seasons, i.e., in April-June and September-November. Moreover, the length of the carapace during recruitment was 15-20 mm. While the carapace length of the first caught (CL∞50) was 18.3 mm for male and 17.6 mm for female indicating that the P. indicus caught was still in the small size, as well as below the first mature gonad (CLm50 = 22-39 mm). This is because the mesh size of cod-end is 0.75 inches or about 2 cm.

One of the most-caught shrimp in north coast of Central Java is Penaeus merguiensis. However, little is known on the population biology of the organisms. This study was aimed to investigate length-weight relationship, growth, length at first capture (Lc50), mortality rate, and exploitation rate of P. merguiensis in Western part of Central Java’s northern coastal waters. The study was conducted from May 2016 to July 2017 using survey method. Samples were taken for 15 times (month) from 9 coastal fishing ports. The result shows that the relationship of the carapace length and weight is negative allometry. The growth parameters of CL∞ and K were 52.5mm and 1.3 y-1 (male) and 57.25mm and 1.2 y-1 (female). Total mortality rate (Z), natural mortality rate (M), and fishing mortality rate (F) were 4.51 y-1, 1.86 y-1 and 2.65 y-1 (male), and 5.36 y-1, 1.72 y-1, and 3.64 y-1 (female), respectively. The exploitation rate (E) of male banana shrimp was 0.59, and for female shrimp was 0.68. The result shows that the exploitation level has exceeded the optimum level (E>0.5). Recruitment of P. merguiensis may occur the whole year, but it peaks were in March and August (male), April and August (female). Carapace length of first captured (CLc50) was 20.63mm (male) and 18.28mm (female). It means that the sized of captured P. merguiensis is less than the size of first mature (CLm50) or growth overfishing and as a result, disrupting the availability of adult shrimp. The condition occurs due to the size of cod-end mesh measured 0.75inc.