Estimating the spawning and growth of striped snakehead Channa striata Bloch, 1793 in Lake Rawa Pening Indonesia.

The striped snakehead (Channa striata Bloch, 1793) is a commercially important fish in Lake Rawa Pening, central Java, Indonesia. This study aims were to investigate their age, growth, and recruitment pattern, through a sampling that was performed monthly, from November 2017 to August 2018. The individual fish was measured for length and weight, and sex was determined. The otoliths were collected, cleaned, and placed on molds to pour epoxy resin. The otoliths were cut to obtain slices and observed under a microscope at 100 × magnification. Subsequently, the age was determined by counting the number of daily rings. It was established that the snakehead spawned every month, with a comparably higher frequency in the new moon than in other phases, and mostly were 3-10 months old, characterized by bigger and older sizes during the rainy season. Furthermore, the average growth rate was observed to be faster during the rainy season in contrast with the dry season. Hence, the parameters of von Bertalanffy growth functions were estimated by back-calculated length, and the pattern in female was Lt = 56.09 (1 - e- 0.81 (t + 0.07)), while male Lt = 59.36 (1 - e- 0.71 (t + 0.09)), and total Lt = 60.32 (1 - e- 0.71 (t + 0.14)), respectively.

Occurrence and identification of Anisakis spp. (Nematoda: Anisakidae) isolated from chum salmon (Oncorhynchus keta) in Korea.

The prevalence of infection and the identification of anisakid larvae in chum salmon (Oncorhynchus keta) from the Namdae River, the east coast of Korea, were investigated. In total, 8,358 larvae were collected from 120 fish samples (male = 58 fish, female = 62 fish) in 2008. Fish samples were collected during October and November 2008. All the chum salmon samples (120/120, 100%) caught were infected with anisakid larvae with a high intensity (69.65 ± 48.58 larvae/host). They were mostly found in muscles (98.00%). Based on the morphological and the molecular analysis of PCR-RFLP and sequencing of mitochondrial DNA cox2 gene markers, these nematodes were identified as Anisakis simplex (sensu stricto) third-stage larvae. This is the first report on the molecular identification of anisakid worms from salmonid fishes in Korea. The high occurrence of anisakid worms in chum salmon may pose considerable food safety problems if they were consumed as raw or undercooked, although their commercial value is relatively lower than other salmonid species.