Fish Species Diversity Research Articles

Genetic Variations of Malaysian And Golden Thai Strains of Climbing Perch and Their Hybrids Based On The Partial Mitochondrial Cytochrome Oxidase Subunit 1 Gene

Rapid genetic improvements from selective breeding are anticipated in many aquaculture species and mitogenome is used to complement the morphological taxonomy of hybrids to evaluate its genetic structures. A study of the genetic variations within the two strains (Malaysian strain and Golden Thai strain) of Anabas testudineus (Bloch, 1792) and their hybrids, phylogenetic trees based on cytochrome oxidase subunit 1 (CO1) of the partial mitochondrial DNA gene were constructed using Maximum Likelihood and Neighbor Joining approaches. The findings support the monophyletic status of the genus with only one haplogroup from which other haplotypes were descended and of a single common ancestor. The individual fishes’ phylogenetic relationships revealed two major clades and Saurida undosquamis as an outgroup. All the groups had high haplotype diversity, except for the hybrid Malaysian strain × golden Thai strain (0.1540±0.126). This suggests that different fish species in each of these studies had different nucleotide compositions in their mitochondrial genomes. The highest number of haplotypes and the presence of distinct haplotypes in the Golden Thai strain × Malaysian strain hybrid point to the absence of recent or regular gene flow as well as high genetic diversity within the hybrids. This study demonstrated that the mtDNA diversity of Anabas testudineus from Malaysia and Thailand had been preserved. Studies on the population genetic diversity and molecular evolution of anabas fish species can benefit from the data provided by this work.

The Composition and Diversity of Fresh Water Fish in The Upstream of the Bedadung River, Jember District

The river is an irrational body of water from upstream to downstream. The upstream part of the river generally has a narrow width of the river flow, heavy air currents, the right and left banks of the river have vegetation trees, sandy rocky substrate types, and are located in the highlands or mountains. This character is also found in the Upper Bedadung River in the Argopuro Mountains. Characteristics in the upper reaches of the river are thought to affect the existence of creatures that live in it, such as fish. The purpose of this study was to determine the composition, dominance, and types of freshwater fish in the upper reaches of the Bedadung River, Jember Regency. The research method used is roaming method. The exploration was carried out at four research stations. The results showed that in the Upper S. Bedadung five species of fish were found including Channa gachua, Poecilia reticulata, Barbodes binotatus, Glyptothorax platypogon, and Nemacheilus fasciatus. The diversity of freshwater fish species in the upper reaches of the Bedadung River is moderate.

Nutritional composition of small indigenous species of fishes of Northeast India: A systematic review

Northeast India has various water bodies including the tributaries of the Brahmaputra and Barak river systems, wetlands, lakesand beels. These water bodies support the diversity of many fish species. Seasonal changes in the number of fish species inthe SIS category were also observed and they are most abundant during the winter and least abundant during the monsoonseason. Many researchers collected fish data from Assam's rivers and wetlands, particularly small indigenous species (SIS).Small Indigenous Species (SIS) of fish are a vital and conveniently accessible source of rare protein, vitamins, and minerals intraditional diets. The present study aimed to review Assam's small indigenous fish species and their nutritional worth. Thesources of the review article were Google Scholar, Web of Science, ScienceDirect, and PubMed for SIS nutrition composition,fish nutritional profile, and fish proximate composition. Northeast India’s rural inhabitants get their sustenance from fish SIS. TheSIS of Northeast India fish species contain proteins, lipids, vitamins, minerals, and vital macro- and micronutrients. The proteincontent of SIS range from 12.49% to 18.30% (12.49–18.30g/100 g), lipid content from 0.7% to 19.63% (0.7–19.63g/100 g),moisture content from 65.88% to 82.8% (65.88–82.8g/100 g), and ash level from 2% to 6.8% (2–6.8g/100 g). This review suggests SIS has adequate nutritional benefits because it is an excellent source of proteins, lipids, vitamins, minerals, and omega-3 fatty acids necessary for optimal health. Northeast India’s impoverished region might achieve their nutritional demands by eating more SIS of fish.

Hierarchical Interaction between Food Diversity and Competition in Brackish Fish Species in South Korea

Information about the food sources for fish is important not only for predation and food competition, but also for the direct impact on organism interactions, relationships, and biodiversity within aquatic ecosystems. We analyzed the food sources of 21 fish species in 9 families of 6 orders based on the literature data from brackish ecosystems in South Korea to improve the understanding of the estuarine ecosystem. The food sources of the 21 fish species contained 173 families, 86 orders, 39 classes, and 22 phyla. The 21 fish species were classified into 4 groups using hierarchical analysis based on their food sources: Group 1 fishes mainly consumed Amphipoda; Group 2 fishes were zooplanktivores; Group 3 were omnivorous; and Group 4 consumed small food sources, such as Nematoda, Corophiidae, and Harpacticidae. The feeding competition index was relatively high within each group, but the competition index for Group 3, the omnivorous fishes, was low. Network analysis and hub scores represented the importance of food sources consumed by each fish species by showing the connections between the fish and their prey. Polychaeta, Actinopterygii, and Decapoda were the most commonly consumed food sources. Food source diversity was high for zooplanktivores (group 2). Additionally, the food contents of each fish species were classified into freshwater and marine sources for identifying the habitats of the food sources. Trophic level measuring values using the data were similar to the reported literature data. This study can be utilized for understanding estuarine ecosystems and identifying food relationships.

Species Diversity and Abundance of Corals and Fishes in A Marine Protected Area

This quantitative-descriptive study’s purpose was to gather information about the current state of fish and coral distribution in the Barangay Tamisan Marine Protected Area. Specifically, it aimed to determine the level of physicochemical parameters, reef health status, coral composition and abundance, reef fish abundance, and biomass in the study site. The study used line transect and fish visual methods. Results of the study revealed that the physicochemical parameters in the said area fall within the normal range which is favorable for the survival of fishes and corals in the study site. The Tamisan Marine Protected Area’s average cover of hard coral is 38.5% which falls under the category of “fair”. Corals with the greatest abundance are from the massive porites genera which compromises 70% of the hard coral cover. Nineteen species from different families of fishes in the study area and 1 class was identified, Actinopterygii. Among the species, it is Pomacentridae that has the greatest number of counts, that is 34. Other species identified were the Labridae, Siganidae, Ephinephilenae, Acanthurida, Balistidae. Apogonida, Scarida, Chaetodontidae, Caesionidae. Monacantidae, Tetraodontidae, Fistularidae, Synodontidae, Synanciinae and, Pomacantidae. The fishes in the study area have a diversity index of 0,820, representing a high index of diversity, but have very low fish biomass. The results implied that although the coral cover is fair and fishes are diverse, it still needs further studies on human activities to find the reason behind very low fish biomass. Keywords: fishes, reef health status, quantitative-descriptive study, Marine Protected Area, Mati City

Diversity, distribution, and conservation status of fish species in Kallar Stream, Achankovil River, Western Ghats of Kerala, India

The current study presents the findings of fish species inventories conducted at 12 locations in ‘Kallar’, the perennial tributary of the undammed Achankovil River that flows through the Achankovil Reserve Forest in Kerala State. A new checklist of ichthyofauna is prepared, by adding the updated scientific names, which comprises 35 species from 27 genera, 13 families, and eight orders. In order of abundance, Opsarius bakeri, Salmostoma boopis, and Garra surendranathanii were the most prevalent species in the Kallar tributary. Eight of the total species documented are listed as threatened on IUCN Red List. The study reports the presence of a poorly known smiliogastrin cyprinid, Dawkinsia lepida for the first time in the Achankovil River as well as the range expansion of the threatened catfish, Batasio travancoria, and the Malabar Spiny Eel Macrognathus guentheri to the Kallar tributary. The study also reports a species of Balitora from Kallar, distinct from its congeners in several morphometric and meristic characteristics. The absence of any non-native fish species in the study area revealed the pristine nature of the stream habitat. A comparison of diversity indices with the available pre-flood study revealed that the fish species composition in Kallar stream has not altered as a result of the 2018 catastrophic flood. The main existing threat is the practice of destructive fishing at high levels by local communities adjacent to but outside the forest area during the dry season by damming the streamlets and then applying plant-based piscicides. It is recommended that fishing be banned during dry season because this is the time of year when the majority of the upstream fishes breed. The existing environment and fisheries acts should also be strictly enforced. For the sake of future conservation, the competent authorities should see to it that the last remaining natural forest cover in the Kanayar and Kallar ranges are safeguarded from being converted to forest plantations.

The effects of host quantitative genetic architecture on the gut microbiota composition of Chinook salmon (Oncorhynchus tshawytscha).

The microbiota consists of microbes living in or on an organism and has been implicated in host health and function. Environmental and host-related factors were shown to shape host microbiota composition and diversity in many fish species, but the role of host quantitative architecture across populations and among families within a population is not fully characterized. Here, Chinook salmon were used to determine if inter-population differences and additive genetic variation within populations influenced the gut microbiota diversity and composition. Specifically, hybrid stocks of Chinook salmon were created by crossing males from eight populations with eggs from an inbred line created from self-fertilized hermaphrodite salmon. Based on high-throughput sequencing of the 16S rRNA gene, significant gut microbial community diversity and composition differences were found among the hybrid stocks. Furthermore, additive genetic variance components varied among hybrid stocks, indicative of population-specific heritability patterns, suggesting the potential to select for specific gut microbiota composition for aquaculture purposes. Determining the role of host genetics in shaping their gut microbiota has important implications for predicting population responses to environmental changes and will thus impact conservation efforts for declining populations of Chinook salmon.

Fish biodiversity and their conservation measures in the Mathabhanga river, Chuadanga, Bangladesh

The study was concerned to determine the present status of the fish biodiversity in the Mathabhanga river, Chuadanga and its conversation measures based on the questionnaire interview with 40 fishers, focus group discussion with river bank community members and cross check interview with key informants. A field study was conducted for a period of four months from December, 2021 to March, 2022 to assess the fish biodiversity in the Mathabhanga river, investigate the existing fishing practices and also to identify proper management strategies for the conservation of fish biodiversity in the river. The results revealed that three categories of fishers were engaged in the Mathabhanga river namely, professional fishers (45.0%), seasonal fishers (37.5%) and subsistence fishers (17.5%). Shannon-Weaver diversity (H) and Margalef’s richness (D) values revealed that diversity and richness of fish species were the highest in March (H = 2.99, D = 4.45), followed by February (H = 2.96, D = 3.69) and January (H = 2.63, D = 3.15), while the lowest values were obtained in December (H = 2.60, D = 2.80). The Pielou’s evenness (e) values were found to be slightly varied with the variations of total number of species, being the highest in December (e = 0.94) and the lowest in January (e = 0.91). Different types of fishing gears like seine net, gill net, cast net, hook and line, and traps were found to be operated to catch fish by the fishers during this survey. A total of 26 fish species were identified in the catches of the Mathabhanga river. According to the survey, indiscriminate and overexploitation were found to be responsible for almost 40% loss, and pollution and siltation caused about 25% loss of ecosystem. Around 20% and 15% loss of ecosystem were caused by habitat destruction and changes of river course, respectively. As a result, the water quality was deteriorating day by day, and the availability of fish species and other aquatic biodiversity were decreasing gradually. During the survey, almost 16 fish species was found at a risk to be endangered. The specific conservation measures including community based fisheries management, establishment of sanctuary, control of pollution, maintenance of fishing gears and the implementation of fisheries act should need to be made for the sustainable utilization and conversation of fish biodiversity in the Mathabhanga river.

Fish diversity of the Bengawan Solo River estuary, East Java, Indonesia

Abstract. Hasan V, Andraini NE, Isroni W, Sari LA, Nafisyah AL, Dewi NN, Putri DNA, Prasasti TAB, Ramadhani AA, Daniel K, South J, Vieira LO, Ottoni FP, Maftuch, Faqih AR, Wirabuana PYAP, Tamam MB, Valen FS. 2023. Fish diversity of the Bengawan Solo River estuary, East Java, Indonesia. Biodiversitas 24: 2207-2216. Bengawan Solo River is the longest river in Java which flows from Mount Lawu and empties into the North Coast of Java. The watershed is a hot spot for fish species diversity, especially in the estuary area. The purpose of this study was to initiate an inventory of fish species, their abundance, and biodiversity assessment based on the Shannon diversity index (H'), evenness index (E), and dominance index (C) in the Bengawan Solo River estuary. The research was conducted from September to November 2022 at three stations with different ecological types and environmental conditions. Fish sampling was carried out using a gill net attached to a boat. In this study, 44 fish species from 22 families were identified. The highest abundance of fish was obtained from the Ariidae family, namely the Spotted sea catfish Arius maculatus (Thunberg, 1792) and Sagor catfish Hexanematichthys sagor (Hamilton, 1822). The fish diversity index obtained was 1.2-3.01, the uniformity index obtained was 0.7-0.92, and the dominance index obtained was 0.07-0.33. The H', E, and C at Station 2 have higher values ??than the other stations. The diversity expressed in H' values ??at the three research stations indicates that the mangrove in the Bengawan Solo River estuary area has a high diversity of fish species.

The Portuguese industrial pelagic longline fishery in the Northeast Atlantic: Catch composition, spatio-temporal dynamics of fishing effort, and target species catch rates

The multispecific and highly dynamic nature of pelagic longline fisheries demands a holistic view that will likely benefit the development of effective management strategies. This study aims to provide an integrated perspective of the Portuguese longline fishery targeting swordfish Xiphias gladius and blue shark Prionace glauca in the Northeast Atlantic, regarding fishing dynamics, target species catches and associated bycatch. Data from 896 observed fishing sets (887,641 hooks) collected between 2015 and 2020 were used in a cluster analysis to group sets according to the target species. These sets were investigated for spatio-temporal patterns, and the relationship between target species catches and environmental and operational characteristics were examined using generalized additive mixed models (GAMM). A total of 46,306 individuals from 54 species (30 fish, 11 sharks, 2 manta rays, 6 cetaceans, 2 sea turtles and 2 seabirds) were recorded. Swordfish and blue shark comprised over 88.3% of the total catch in numbers (33.6% and 54.7%, respectively). Overall, most of the fishing effort occurred west off mainland Portugal, congregated during autumn when vessels targeted mostly swordfish, and dispersed over the region during spring and summer, when vessels targeted mostly blue shark. The bycatch of sea turtles and a relatively higher diversity of bony fish species, yet low catch in terms of abundance, appeared more associated with sets identified as targeting swordfish. Recorded catch of tunas Thunnus spp. and pelagic sharks, such as the shortfin mako Isurus oxyrinchus and the porbeagle Lamna nasus, were more associated with blue shark sets. Bigeye thresher Alopias superciliosus, thresher Alopias vulpinus, pelagic stingray Pteroplatytrygon violacea and lancetfish Alepisauros ferox were found equally associated with both targeted species. Management strategies for the region are discussed in light of these new findings.

Seasonal and interannual variability of fish species composition in catches of bottom nets in the Russian waters of the Kunashir Strait

Seasonal and interannual variability of the demersal fish species composition is considered for the depths of 70–315 m in the eastern Kunashir Strait on the data obtained in 1998–2014. The fish community includes the species belonged to nine zoogeographical complexes and eighth ecological groups. Among them, species diversity is higher for the arctic-boreal, wide-boreal Pacific, wide-boreal Asian, and low-boreal Asian complexes and for the sublittoral, elittoral, and mesobental groups. The species diversity of fish in the surveyed area depends on seasonal migrations of demersal and pelagic fishes, including pacific salmon and some subtropical and tropical species. Interannual variations in the species composition are determined mainly by changes in the depth of netting and water temperature, but do not depend on the timing of samples collection during a season.

Diversity, abundance and dominance of fish species in the Churute River, Ecuador

En esta investigación se evaluó la diversidad de especies nativas e introducidas en el río Churute, el cual atraviesa la Reserva Ecológica Manglares Churute, en Ecuador, utilizando para ello un enfoque empírico-inductivo, con diseño no experimental de corte transversal-explicativo. Las capturas se realizaron con atarraya, arte de pesca tradicional en época de sequía, a lo largo del río Churute. Se muestrearon 25 sitios, considerando 33 lances como esfuerzo de pesca por cada sitio, y los peces capturados fueron clasificados taxonómicamente, contados y pesados para estimar los índices ecológicos de riqueza, abundancia, diversidad y dominancia en el área de estudio. Se identificaron 20 especies ícticas (19 nativas y 1 introducida) distribuidas en 18 géneros de 13 familias y 5 órdenes; las familias con mayor número de especies fue CICHLIDAE con cuatro especies, BRYCONIDAE, CHARACIDAE, ELEOTRIDAE y HEPTAPTERIDAE con dos especies cada una. De las especies identificadas, siete calificaron como importantes, sobresaliendo la tilapia, pez introducido con un Índice de Importancia Relativa (IRI) de 40.075,58, dominando en los sitios de muestreo en un 61,13 %. Se concluye que la tilapia es una especie dominante, con tasas de reproducción superiores al de las especies nativas presentes en el río Churute, por lo que su presencia constituye una seria amenaza a la biodiversidad de este ecosistema.

An approach to assess data-less small-scale fisheries: examples from Congo rivers

Small-scale fisheries (SSF) account for much of the global fish catch, but data to assess them often do not exist, impeding assessments of their historical dynamics and status. Here, we propose an approach to assess 'data-less' SSF using local knowledge to produce data, life history theory to describe their historical multispecies dynamics, and length-based reference points to evaluate stock status. We demonstrate use of this approach in three data-less SSFs of the Congo Basin. Fishers' recalls of past fishing events indicated fish catch declined by 65–80% over the last half-century. Declines in and depletion of many historically important species reduced the diversity of exploited species, making the species composition of the catch more homogenous in recent years. Length-at-catch of 11 of the 12 most important species were below their respective lengths-at-maturity and optimal lengths (obtained from Fishbase) in recent years, indicating overfishing. The most overfished species were large-bodied and found in the Congo mainstem. These results show the approach can suitably assess data-less SSF. Fishers' knowledge produced data at a fraction of the cost and effort of collecting fisheries landings data. Historical and current data on fish catch, length-at-catch, and species diversity can inform management and restoration efforts to curb shifting baselines of these fisheries. Classification of stock status allows prioritizing management efforts. The approach is easy to apply and generates intuitive results, having potential to complement the toolkits of researchers and managers working in SSF and engage stakeholders in decision-making processes.

Circadian rhythm of preferred temperature in fish: Behavioural thermoregulation linked to daily photocycles in zebrafish and Nile tilapia

Ectothermic vertebrates, e.g. fish, maintain their body temperature within a specific physiological range mainly through behavioural thermoregulation. Here, we characterise the presence of daily rhythms of thermal preference in two phylogenetically distant and well-studied fish species: the zebrafish (Danio rerio), an experimental model, and the Nile tilapia (Oreochromis niloticus), an aquaculture species. We created a non-continuous temperature gradient using multichambered tanks according to the natural environmental range for each species. Each species was allowed to freely choose their preferred temperature during the 24h cycle over a long-term period. Both species displayed strikingly consistent temporal daily rhythms of thermal preference with higher temperatures being selected during the second half of the light phase and lower temperatures at the end of the dark phase, with mean acrophases at Zeitgeber Time (ZT) 5.37 h (zebrafish) and ZT 12.5 h (tilapia). Interestingly, when moved to the experimental tank, only tilapia displayed consistent preference for higher temperatures and took longer time to establish the thermal rhythms. Our findings highlight the importance of integrating both light-driven daily rhythm and thermal choice to refine our understanding of fish biology and improve the management and welfare of the diversity of fish species used in research and food production.

Fish diversity and fish community analysis in ponds of Saran district in Bihar

The fish diversity of the ponds has been decreasing during the last few years due to some extrinsic and intrinsic factors. The total number of fish species recorded so far during the present study is 47 at Pond 1 and 37 at Pond 2 belonging to 5 families. Cyprinidae is the most dominant family represented by major group species (12), intermediate group species (7) and minor group species (3) of high commercial value. Among these three groups, the diversity of fish species is higher in the minor group fish.

Field studies in small streams of the Atlantic Forest of southern subtropical Brazil reveal two new interstitial microcambevine catfishes of the genus Listrura (Siluriformes: Trichomycteridae)

ABSTRACT A great diversity of small fish species inhabiting shallow aquatic biotopes of the South American Atlantic Forest have been reported in recent years, but records of interstitial catfishes of the genus Listrura for the southern subtropical Brazilian region are still rare. During field inventories in this region, two new species were collected, which are herein described. The new species are distinguished from congeners by a combination of morphological characters, including caudal peduncle morphology, number of vertebrae, relative position of fins, and bone morphology. The findings here described indicate that the scarcity of records of Listrura for the subtropical Atlantic Forest is probably due to the absence of collecting efforts in specialised biotopes, since species of Listrura are leaf litter dwellers. Both new species are probably more closely related to L. depinnai than to other congeners as all three uniquely possess an expanded skin fold supporting the procurrent caudal-fin rays, making the caudal peduncle deeper than the body region anterior to the dorsal and anal fins. However, only one of the new species shares with L. depinnai the presence of a process on the dorsal surface of the autopalatine articular facet for the mesethmoid, a condition not occurring in any other congener. The two new species are easily distinguished from L. depinnai by the absence of a dorsal fin in the latter species. http://www.zoobank.org/urn:lsid:zoobank.org:pub:F68F2A3E-B5F7-418E-BFA6-EA6752BAB543 http://www.zoobank.org/urn:lsid:zoobank.org:pub:F703D95A-0F7E-4261-8B97-5EAAAD9BD698

Sebaran Jenis Ikan Pelagis yang Ditangkap Menggunakan Pancing Ulur pada Rumpon di Laut Pemangkat Kabupaten Sambas

FAD technology has an indirect impact on the development of fishery stocks, thereby increasing the diversity of fish species in the FAD area. This study aimed to determine the types of pelagic fish caught using handlines around FADs. The target of this study was traditional fishermen. This research was conducted using survey methods and was directly involved in the fishing process. Fishing was carried out using handlines with specifications consisting of the main line, weight, swivel, fishing line, and hook. Fish catch samples were measured every week starting on the fourth week after the FADs were installed, with consideration of the regularity of the sample observation interval, the weather, and the fishermen's readiness. Data analysis was performed using tabulation, and the composition of the number and percentage of each type of catch was analyzed descriptively, which is presented in the form of a picture. The results showed that the types of fish caught were large trevally (Selaroides leptolepis) with an average catch of 10.1 kg/trip, mackerel (Rastrelliger sp.) with an average catch of 4.2 kg/trip, Kuwe (Caranx ignobillis) with an average catch of the average catch is 0.9 kg/trip and lastly the Tetengkek snakehead (Megalaspis cordyla).

Biodiversity and Abundance of Fish Species in Ekpene Ukpa River, A Tributary of Qua Iboe River Estuary, Niger Delta, Nigeria

The diversity and abundance of fish species in Ekpene Ukpa River were studied from July - October, 2020. Sampling was by direct observation of the fish species at the sampling sites following landing by fishermen. Frequency, counts, and percentages were employed to determine fish species composition and abundance, while a Microsoft Excel 2003 based program was used to determine the ecological indices. A total of 14 species belonging to seven (7) families were recorded. The family, Clarotidae had the highest relative abundance (38.1%) with the least value (2.38%) observed in the family Alestidae. The index of preponderance ranged from 0.0004 in Pellonula leonensis and Trachinotus teraria to 0.100 in Chrysichthys nigrodigitatus. The most abundant grouping of fish species was Chrysichthys igrodigitatus with 25.0% and the least in abundance were Pellonula leonensis and Trachinotus teraia with 1.19% each. The index of preponderance (IP) value of 0.10 was recorded for Chrysichthys nigrodigitatus which marked this species very significant in the study site. The study revealed that species richness and diversity were high in the month of October. Inference from the results clearly indicated that fish species were much diversified in all sampling months, and this is of great significance to the biodiversity of the study area. However, an inclusive management approach is recommended, such as educational awareness, involving of the local contents, and comprehensive rational planning on the management and development of the study site.

The Effect of Anthropogenic Activities on the Fish Fauna of the Devrez Stream (Turkiye)

In this study, fish species diversity and protection criteria, habitat evaluation, and threat elements of the ichthyofauna of the Devrez Stream were examined monthly between April 2020 and March 2021. Eight fish taxa (7 natives, 1 non-native) belonging to four families (Cyprinidae, Gobionidae, Leuciscidae, Gobiidae) were identified. Chondrostoma angorense Elvira, 1987 (endemic) from the mentioned species was reported for the first time in the Devrez Stream. Squalius sp. (32.5%), Chondrostoma angorense (24.4%), Capoeta tinca (23.9%), and Alburnoides freyhofi (11.1%) were the most common and abundant species while Pseudorasbora parva (0.5%), Barbus anatolicus (1.2%), Alburnus goekhani (2.4%) and Neogobius fluviatilis (4%) were the most rarely encountered species in the stream. According to our observations, drought, agricultural irrigation, and Devrez Kızlaryolu Dam, which is under construction, were considered major threats to the fish fauna.

Diversity and characteristics of commercial Red Sea fish species based on fish market survey: informing management to reduce the risk of overfishing.

In small-scale fisheries (SSFs), where the sampling of many small boats and landing sites sometimes is not practical, fish market surveys represent an alternative way to obtain key fisheries data. This study analyses the diversity and characteristics of commercial Red Sea fish species landed in the Egyptian coast, including family, species-specific abundance, biomass, size and price by surveying the largest local fish market on the Egyptian Red Sea coast, over the course of a year (July 2021-June 2022) to also reflect any seasonality of these variables. Based on 53 survey visits, a total of 131,795 fish individuals, belonging to 111 species, and 22 families, were identified, recorded and measured. The analysis focused on the 60 most abundant species (104,420 individuals, 15 families). The surveys revealed that the most abundant families were Serranidae, Lethrinidae and Scaridae. Carangidae also was one of the most important families in terms of biomass. The most abundant species were Lethrinus mahsena, Sargocentron spiniferum and Lethrinus nebulosus. About 60% of revenue comes from the four families Serranidae, Lethrinidae, Scaridae and Lutjanidae. In terms of prices, the most expensive categories were species belonging to Serranidae, Lethrinidae and Lutjanidae families, such as Plectropomus pessuliferus marisrubri, Argyrops spinifer, L. nebulosus and Variola louti. The overall mean prices were higher in spring and summer months likely due to tourism flows. The mean size of many species, including the most valuable and abundant ones, is below the length of maturity. These results provide important benchmarks for monitoring future changes and shed important insights for fisheries management. Co-organised Dutch auctions would provide reliable data when combined with a strict monitoring effort to avoid any sale of the catch outside these official auctions. Other monitoring tools and methods are also recommended in the discussion.