SIZE AT FIRST MATURITY OF THE BLUE SPOTTED MASKRAY, Neotrygon kuhli lN INDONESIAN, WATERS

Abstract

The biue spotted maskray, Neotrygon kuhtii is the most common rays occurred in Indonesian waters. This species is often caught as bycatch in trawl fisheries targeting demersal fishes and shrimps. The unselected ancl intensive catches of this species can influence to its sustainable in the future. A study on this species was conducted at several areas in Indonesia from 2003 to 2006. A total of 1,122 individuals, consisting of 523 females and 599 males were measured from some areas in western lndorresia including the Java Sea, the Malacca Strait, South Java, East Sumatera, West Kalimantan, and South Natuna waters. Size ranges o'f Neotrygon kuhlii were varied among regions.In general, mature individuals were caught more often than neonates in all areas. The minimtlm size was 130 mm disc width and maximum size was 415 mm disc width. Females usually produce one pup in its reproduction cycle and the smallest recorded pregnant female was 240 mm disc width, while the largest was 317 mm disc width. Males attain maturity at size between 215 and 295 mm disc width. There were also differences in size at first maturity lor Neotrygon kultlii caught from each area.The rays seemed to be mature earlier at the Java Sea, West Kalimantan, East Sumatera and the Malacca Strait, as an indication of the plasticity in their life histories to cope with fishing pressure and environmental degradations in their habitats.

Molecular Identification of Stingrays (Dasyatidae) from Gresik, East Java

“…While the specimen code GRPI02 Neotrygon kuhlii (Spotted Stingray) with a sequence similarity level of 100%. Regarding the habitat of N. kuhlii, population from Java and Bali not significat different due to the sama in Java Sea (Fahmi et al, 2017). The high percentage value indicates that the sample sequences are identical to the species sequences in the database, which is the highest percentage of BLASTN analysis results in each sample.…”

Size at sexual maturity, seasonal variation by maturity stages, and fecundity of the spotted round ray (Urobatis maculatus) and the thorny stingray (Urotrygon rogersi) from the northern tropical eastern Pacific

“…However, other factors could have also influenced these observed differences in the DW 50 between regions, for example, the sample size (Bellodi et al, 2016; Da Silva et al, 2018), the structure of the data concerning the proportion of mature individuals in each size class (Chen & Paloheimo, 1994; Molina & Cazorla, 2015; Trippel & Harvey, 1991), the criteria for assigning maturity, mainly when performing macroscopic observation of reproductive structures (Martin & Cailliet, 1988; Oviedo‐Pérez et al, 2014; Tagliafico et al, 2016) or selectivity of the fishing gear (Estalles et al, 2017; Martins et al, 2018; Tagliafico et al, 2012). The differences could also be related to the existence of subpopulations with different natural variability in maturity (Alkusairy & Saad, 2017; Araújo et al, 2016; Da Silva et al, 2018; Snelson Jr. et al, 2008), caused by different oceanographic and environmental conditions (Girard & Du Buit, 1999; Saadaoui et al, 2015; Yamaguchi et al, 2000), or even fishing pressure (Aranha et al, 2009; Fahmi et al, 2009; Serra‐Pereira et al, 2015).…”

Histopatologi Lumba-Lumba Fraser (Lagenodelphis hosei) yang Terdampar di Pandeglang, Banten

“…Mamalia laut yang terdampar ditemukan dalam berbagai kondisi baik secara tunggal ataupun kelompok (Andrimida, 2021). Berbagai faktor dapat menjadi penyebab terdamparnya mamalia laut seperti topografi perairan, arus, angin, suhu perairan, kurangnya ketersediaan pakan, kelaparan, blooming alga, terkena kapal ataupun alat pancing dan penyakit termasuk parasit (Fahmi et al, 2014;Grant et al, 2018).…”