Nike is a terminology used by Gorontalo local community to name schooling of minuscule amphidromous goby fish that has a limited appearance in Gorontalo waters. Understanding the biological performance of Nike fish is vital for implementing management and conservation strategy. This study aims to analyze daily recruitment and to determine growth patterns of Nike fish population in nature. Sampling was conducted in the Gorontalo waters during March, April, and May 2018 using a fish net with a mesh size of 0.5 inches. The duration of the appearance of Nike schooling in waters varies every month. The number of fish samples collected each month in this study ranged from 150 to 300 individuals. This study reveals that body color diversity and morphology of Nike fish strongly alleged to depend on where and how long they appear in the waters. Based on the daily recruitment pattern, Nike fish population distributed in Gorontalo waters is predicted to consist of individuals from multi-generation with an average length range of 1.848–2.805 cm. During the sampling time, a positive allometric growth pattern indicated by the population.

Investigating goby fish is vital to perform an integrated and comprehensive study in order to maintain the roles of the fish, thus providing balanced ecosystem functions and services, as well as contributing to fish biodiversity. Local societies simply recognize fish species by their local names, which are not common. This condition, in turn, causes hitches in conducting further studies. Nike, the name of a local fish, refers to the schools of goby fish larvae whose adult phase has not been fully confirmed. This study aimed to reveal the species that categorizes as nike fish through tracing adult goby inhabiting freshwater. Two fish samples, i.e., Unknown 01 and Unknown 02, were taken from two sites in Bone River, Gorontalo, Indonesia. These samples were captured purposively using a hand net by considering the morphological similarity between the two target samples and the general characteristic of goby. Furthermore, the samples were analyzed genetically through the PCR sequencing method using the Mitochondrial Cytochrome Oxidase Subunit 1 (CO1) gene. Based on the NCBI database, Unknown 01 had the highest similarity to Belobranchus belobranchus (99.54%), while Unknown 02 was identical with Awaous ocellaris (100%). Unknown 01 and Unknown 02, compared to the BOLD database, the similarity level, had the highest percentage of similarity with B. belobranchus (99.85%) and A. ocellaris (100%), respectively. Therefore, A. ocellaris and B. belobranchus were strongly alleged as two species making up the goby schools in the adult stadia that reach freshwater during their migration.

Abstract. Sahami FM, Kepel RC, Olii AH, Pratasik SB, Lasabuda R, Wantasen A, Habibie SA. 2020. Morphometric and genetic variations of species composers of nike fish assemblages in Gorontalo Bay Waters, Indonesia. Biodiversitas 21: 4571-4581.  Nike is Gobioidei fish at the post-larval and juvenile stages whose habitat is still in seawater before they migrate to the freshwater, grow up, and spawn to fulfill their life cycle as an amphidromous species. This study aims to identify the species composers of Nike fish in Gorontalo Bay waters based on their morphometric and molecular characters. 2,523 samples were collected from the catches of fishermen during three periods of their appearance in Gorontalo Bay waters from January to March 2019. The samples were grouped based on their similarity of melanophore patterns, and morphometric characters of 10 units were then measured. This study found 20 different groups of melanophore patterns; 15 of them were new melanophore patterns. DNA samples from each group of new melanophore patterns were then isolated for molecular analysis. The morphometric analysis grouped the 20 melanophore patterns into three separate clusters that were confirmed through molecular analysis. The results of Gen Cytochrome Oxidase I (COI) sequences indicate that the new melanophore patterns of Nike fish assemblages consisting of six species; five species in the Gobiidae family (i.e. Sicyopterus parvei, S. cynocephalus, S. longifilis, S. lagocephalus, and Stiphodon semoni) and a species in the Eleotridae family (Belobranchus belobranchus).

Abstract. Sahami FM, Habibie SA. 2021. Diversity of species in making up Nike fish schools and a new record of Eleotris melanosoma in Tomini Paguyaman Bay, Gorontalo, Indonesia. Biodiversitas 22: 5459-5467. Several estuaries in the waters of Tomini Bay are reported as the primary location for Nike fishing in Gorontalo; one of which is Paguyaman Bay. However, scientific information on Nike fish in the Tomini Bay waters is currently limited in Gorontalo Bay. The present study aims to determine the diversity of species in making up the Nike fish schools in Paguyaman Bay and show the types of constituent species whose distribution in Gorontalo waters has never been reported. A total of 1773 samples of Nike fish were collected from the sea to the estuary of Paguyaman Bay in one period of their emergence on April 8-10, 2021. The species were grouped based on the melanophore pattern’s similarity and then analyzed morphometrically. The molecular identification of COI mitochondrial DNA was performed on species with different morphological appearances from those found in Gorontalo Bay. The Discriminant Function Analysis (DFA) indicated that the main distinguishing character of morphometrics is body depth. The morphological results suggested that the Nike fish schools in Paguyaman Bay consisted of seven species, four genera, and two families, i.e., Sicyopterus longifilis, S. parvei, S. cynocephalus, Stiphodon semoni, Belobranchus segura, B. belobranchus, and Eleotris melanosoma. The first finding of E. melanosoma as a species making up the Nike fish schools in Paguyaman Bay was a new variant of the distribution of this species in Gorontalo waters and confirmed using morphology and molecular analysis. Further, based on the species composition, Nike fish schools in the waters of Paguyaman Bay show a typical species dominance trend during the recruitment process returning to freshwater, i.e., S. longifilis (52%) on the first day, Belobranchus segura (63.27%) on the second day, and Stiphodon semoni (83.43%) on the third day.

Red devil has been extensively researched due to extremely high morphometric and chromatophore variations, including the phenomena of polychromatic and trophic polymorphism. The purpose of this study was to identify and observe the phenomenon of sex dimorphism that occurs in polychromatic red devil species which caught in Sermo Reservoir. Fish sample as much as 240 individual was collected from fishermen catch during November 2016-September 2017 by using gill nets, cest nets, and fishing rods. Subsequently, the fish sample was grouped based on color and sex, the namely group of red devil red, red devil black, and red devil reddish black. The morphometric character data of 21 units were measured in each fish sample, whereas the DNA samples were taken from the gill tissue on each species of two individuals. The morphometric character data was analyzed for discriminant distance, while DNA was analyzed by BLAST (Basic Local Allignment Search Tools) from NCBI. The result of the principal component analysis and discriminant function showed the three group of fish can be distinguished by the characters around the head. The T-test of male and female morphometric characters in each fish group showed the phenomenon of sex dimorphism. Canonical and dendrogram diagrams consistently classify the three group of fish as the same species but are segregated by sex so that significantly dimorphism occurs. The mitochondrial sequencing results of the DNA control region show that among the red devil fish group found in the Sermo Reservoir is a species of A. amarillo.AbstrakRed devil telah banyak diteliti karena variasi morfometrik dan kromatofora yang sangat tinggi, termasuk di dalamnya fenomena polikromatisme dan trofik polimorfisme. Penelitian ini bertujuan untuk mengamati polikromatik dan dimor-fisme seksual serta mengidentifikasi spesies red devil di perairan Waduk Sermo Yogyakarta. Contoh ikan sebanyak 240 ekor diambil dari hasil tangkapan nelayan selama bulan November 2016-September 2017 dengan menggunakan jaring insang, jala dan pancing. Selanjutnya contoh ikan dikelompokkan berdasarkan warna dan jenis kelamin, yaitu kelompok red devil merah, red devil hitam, dan red devil merah kehitaman. Data karakter morfometrik sebanyak 21 unit diukur pada setiap contoh ikan, sedangkan contoh DNA diambil dari jaringan insang pada masing-masing kelompok ikan seba-nyak dua ekor. Data karakter morfometrik dianalisis pembedanya, sedangkan DNA dianalisis dengan BLAST (Basic Local Allignment Search Tools) dari NCBI. Hasil analisis komponen utama dan fungsi diskriminan menunjukkan ketiga kelompok ikan dapat dibedakan berdasarkan karakter yang berada di sekitar kepala. Uji t terhadap karakter morfome-trik jantan dan betina pada masing-masing kelompok ikan menunjukkan fenomena dimorfisme seksual. Diagram kanonikal dan dendrogram konsisten mengelompokkan ketiga kelompok ikan tersebut sebagai spesies yang sama, namun terpisah berdasarkan jenis kelamin sehingga sangat nyata terjadi dimorfisme. Hasil sekuensing mitokondria DNA control region menunjukkan seluruh kelompok ikan red devil yang ditemukan di Waduk Sermo merupakan spesies Amphilophus amarillo.