No abstract

<p class="abstrakindo">Dinas Hidro-Oseanografi TNI AL merupakan salah satu lembaga yang memiliki tugas menyediakan Peta Laut untuk kepentingan keselamatan pelayaran. Teknologi penginderaan jauh memberikan peluang untuk pemetaan batimetri perairan dangkal secara efektif dan efisien, terutama di daerah yang memiliki tingkat perubahan kedalaman yang relatif cepat. Tulisan ini membahas studi akurasi ekstraksi kedalaman laut dengan metode Lyzenga dan modifikasinya dengan menggunakan Data SPOT-7, sehingga pada penelitian ini dikaji tingkat ketelitian batimetri yang diekstrak menggunakan Data SPOT-7 dengan resolusi spasial 6 meter di Perairan Teluk Belangbelang Mamuju Sulawesi Barat. Data lapangan yang digunakan adalah data survei hidrografi untuk pendaratan amphibi di Teluk Belangbelang Mamuju. Metode yang dikaji dalam penelitian ini adalah metode yang dikembangkan oleh Kanno dkk. (2011) yang dimodifikasi dari Metode Lyzenga (2006) yang terdiri dari 4 jenis yaitu Lyzengga (2006) murni (LYZ), KNW dengan pengembangan dari LYZ dengan penyeragaman asumsi pengaruh kolom air dan atmosfir, SMP yaitu dengan menambahkan regresi semi-parametrik, STR (Spatial Trend) dengan mengkoreksi faktor error pada koordinat pixel, dan TNP yaitu gabungan dari ketiga metode antara lain: KNW, SMP dan STR. Hasil terbaik dengan ketelitian hampir 70% pada keseluruhan data didapatkan melalui metode TNP pada orde 2. Begitu juga persentase terkecil yang tidak masuk orde ketelitian adalah metode TNP dengan nilai 30,32%. Ketelitian pendugaan kedalaman dengan metode STR untuk kedalaman &lt;0 m adalah 0,11 m, 0 - 2 m adalah 0,25 m, 2,1 - 5 m adalah 0,68 m.</p>

Successful adaptation of invasive crayfish influence by environmental factors and biological factors, especially reproduction. Therefore needed important to collect and evaluate crayfish biology data, particularly the length, reproduction, and selectivity parameter. This parameter is also helpful in data-poor management in fisheries because it can be connected to management’s tactical strategy. The invasive crayfish data collect in 5 five locations in Java island, i.e., Cirebon, Semarang, Surabaya, Yogyakarta, and Cilacap. SPR analysis using application link to http://barefootecologist.com.au/lbspr after maturity, size capture, and length-frequency analysis. The result of these research shows average length in Cirebon (71 ±18,38), in Semarang (53 ±0,00), in Surabaya (83 ±3,54), in Yogya (87,5 ±15,91), and Cilacap (65 ±6,36) mm. Spawning potential ratio in Cirebon 68%, in Semarang 37%, in Surabaya 100%, in Yogyakarta 81%, and Cilacap 0,62%, with the total average in five-station is 62%. The first maturity at 50% population, Selectivity length (50%) in Cirebon 38,72 mm, Semarang 49,68 mm, Surabaya 37,96 mm, Yogya 37,68 mm and Cilacap 42,29 mm. SPR result that more than 40% shown that successfully spawning in Java relatively high and spread, and adaptation is also going well. The distribution in wild habitat potential influences native species, and it even causes extinction. Therefore it is necessary to prepare management steps to protect native species from invasive crayfish.

Cherax quadricarinatus is a parastacid crayfish native to parts of north-eastern Australia and southern New Guinea. It is a relatively large and highly fecund species in comparison with other crayfish of this genus. Since C. quadricarinatus was previously assessed as an invasive species in Indonesia, further monitoring of this species in this region was recommended. Detailed understanding of its spatial behaviour can be the basis for further research aimed at improved management. Field sampling was performed outside its native range in Java, Indonesia from 2019–2020, resulting in data useful for modelling the species' spatial distribution. The occurrence of the species was confirmed in 66 of 70 surveyed localities with 51 new records for Indonesia. Future investigations focused on the relationship between the spatial distribution and dispersal pattern of C. quadricarinatus and its interactions with native biota and entire ecosystems were recommended.

Increasing of fishing productivity is an indicator of fishing intensity. The increasing productivity dominated by a small and immature population also as an indicator of vulnerability stock in the sea. Therefore, fishing productivity research is important as the basis of the study of the efficiency and vulnerability of fish stocks. This research was conducted in the Sunda strait using landing fish data in Labuan Landing Port from February until July 2018. Evaluation of the effectivity and intensity of fishing pressure was determined by a descriptive statistic from average and deviation of the fishing number. The results of the research showed that the productivity of purse seine, beach seine, mini purse seine, mini trawl higher than that of other gears. The average productivity value purse seine, beach seine, mini purse seine, mini trawl was 100.63, 84.16, 25.5 and 31. 6 kg per unit per trip, respectively. These gears were more effective compared to other fishing gears. These results can be used as an indicator and basis to evaluate the vulnerability stock from fishing activity.