Iranian Journal of Ichthyology
Volume:9 Issue: 4, Dec 2023

Mudskippers (Oxudercidae) are euryhaline fish found in mudflats, sandy beaches, and mangrove swamps. Owing to the high abundances of mudskipper species in Peninsular Malaysia, the identification process is found challenging. The purpose of this study was to identify selected species of mudskipper from selected mangroves in Terengganu, east coast of Peninsular Malaysia according to morphometrical variations and development of key pictorial of mudskipper. A total of 63 mudskippers were collected using a fish net in Marang (n= 30) and Setiu (n= 33). Quantitative data on the morphometric characteristics of each individual were identified namely Periophthalmus gracilis, P. variabilis and P. argentilineatus. One-way analysis of variance showed significant differences (P<0.05) in 10 out of 16 morphometric characteristics among the three species. In the casewise statistics analysis, 92.1% of the mudskippers were correctly classified into their original groups on average. The canonical variate analysis (CVA) scatter plot showed the segregation of three identified mudskipper species into three distinct groups. In the cluster analysis, UPGMA dendrogram indicated the segregation of the three species into two distinct clades, and P. gracilis and P. variabilis were included in the sister group, whereas P. argentilineatus was in a separate clade. The development of the key pictorial of mudskippers showed that 10 species from five genera were successfully recognized and distinguished by comparing their body parts as key indications. This study will be helpful to researchers acquiring information for identifying mudskippers especially from the genus Periophthalmus.

Mystacoleucus marginatus and M. padangenesis are freshwater fish species that found in Indonesia. Mystacoleucus marginatus is native to Indonesia and M. padangensis is an endemic species to West Sumatra, Indonesia. This study aimed to investigate the relationship between M. marginatus from the Berantas River, East Java, and M. padangensis from Singkarak Lake, West Sumatra based on the Cytochrome Oxidase subunit I (COI) gene. Based on the results, M. marginatus and M. padangenesis have a close genetic distance, with similarity of 99.81%, having difference of 3 nucleotide bases; then they can be identical or synonym. The nucleotide composition in M. marginatus and M. padangensis are almost similar where the percentage of nucleotide composition in M. marginatus is T (28.1%), C (29.2%), A (27.0%) and G (15.8%) and that of M. padangensis is T (28.3%), C (28.8%), A (26.8%) and G (16.2%). Based on phylogenetic tree, both species are closely related in the same cluster. Therefore, it is suggested they are a same species based on the COI gene, but suggesting further research using mitochondrial DNA complex and in-depth morphological analysis.

Length-weight relationship (LWR) and relative condition factor are significant in fishery science as it provides information on fish wellbeing and biological data. The present study describes the LWR and condition factor of five small indigenous fish species of Sareswar Beel, Kokrajhar, Assam of Northeast India for the first time. A total of 443 specimens of five species viz. Nandus nandus, Glossogobius giuris, Puntius sophore, Pethia conchonius and Trichogaster fasciata were sampled from May 2021 to April 2022. All samples were collected using gill nets, bamboo traps, net traps and lift net. The total length and body weight were measured to determine the LWR and Fulton’s condition factor (K). The statistical parameters a, b, and Kn (Relative Condition factor) were also analysed. All species recorded K>1 except Glossogobius giuris (0.909±0.178), and the highest value was recorded in T. fasciata (2.023±0.687). The values of ‘b’ for all five species ranged from 1.643 to 2.961, indicating negative allometric growth pattern. This study is a first report on the LWR and condition factor of these species from Sareswar Beel, Assam. These results may be useful for sustainable management and comparison with future studies.

Despite remarkable recent increase of research in mesophotic coral ecosystems (30-150m depth), exploration at these depths is still resulting high rates of new species discovery, and new records worldwide, especially among taxa with low population size such as liopropomatid fishes. In the present study, a new record and significant range extension of a rare species, Randall’s Basslet Liopropoma randalli, into the Sea of Oman is reported, and its morphological characteristics are provided. This species is distinguished by the several characters: Dorsal-fin rays VIII, 11 (the last ray divided at its base); anal-fin rays III, 8; pectoral rays 14; pelvic rays I, 5; weak and specific ctenoid scales on the body, and a complete lateral line (highly arched over the pectoral fin) with 47 pored scales on the body plus 3 pored scales beyond the end of hypurals. This study also presents an annotated checklist of the species of the family Liopropomatidae, including 41 species in two subfamilies, the Liopropomatinae with three genera and 36 species, and the Diploprioninae, with 3 genera and 5 species.

The population dynamics and reproduction of the streaked gurnard, Chelidonichthys lastoviza (Bonnaterre 1788), has been studied based on collected data between January 2020 and December 2021 from the Egyptian Mediterranean waters. In this study, age, growth, mortality, critical lengths, sex, gonadal maturation and spawning season were determined. A total of 1215 specimens ranged between 7.9 and 26.6cm TL and 5 to 220g total weight were sampled. Total lengths of males ranged from 11.5 to 24.4cm (n= 474), and of females from 11.0 to 26.6cm (n= 553). The maximum observed age based on otolith readings was 4 and 5 years for males and females respectively. The length-weight relationship was estimated as W= 0.0093L3.0487 for males and W= 0.0089L3.0673 for females indicating an isometric growth. The von Bertalanffy growth equation was Lt= 27.56(1-e-0.433(t+0.62)) for males and Lt= 30.92(1-e-0.299(t+0.92)) for females. The growth performance index was computed as 2.52 (males) and 2.46 (females). Males mature at smaller lengths and younger ages (Lm= 15.2 cm, Tm= 0.61 years) than females (Lm= 15.8cm, Tm= 0.71 years). The male: female ratio was 1:1.17. The gonado-somatic index (GSI) values defined a protracted spawning season starting in November till February with a peak in January and December for males and females respectively.

Length-weight correlations and condition measures are important in fish biology to determine individual health and potential variations among stocks of the same species. Length-length, length-weight relationships, morpho-meristic characteristics and condition factor were documented for three small indigenous species (Chanda nama, Parambassis lala and Parambassis ranga) equally totaling 600 individuals collected in ‘Chalan Beel’ using a seine net (mesh size 0.5-1cm) from July 2020 to December 2020. Body weight was determined with an accuracy of 0.01g, and length was calculated to the nearest 0.1cm. The mean body weights of C. nama, P. lala and P. ranga were calculated as 1.75±0.61g, 0.55±0.16g and 0.88±0.31g and their average total lengths were 5.50±0.68cm, 3.18±0.28cm and 3.71±0.42cm, respectively. Standard morphometric and meristic traits were found throughout all three studies species and a strong relationship between length and weight (P<0.05) was observed. The final ‘b’ values for TL and BW were recorded at 2.52, 3.03 and 3.14 for C. nama, P. lala and P. ranga, respectively, indicating negative allometric growth for C. nama, isometric growth for P. lala and positive allometric growth for P. ranga. Furthermore, condition factors (>1) demonstrated that these species were in excellent condition in their natural habitats. The present observations would be an effective tool to help identify these fish species in varied aquatic environments across Bangladesh and nearby regions, enabling their optimal management and conservation.