National park Plitvice Lakes is the oldest, the largest and the most visited national park in Croatia, well known for its stunning karstic watersheds that supply Plitvice Lakes and exceptionally valuable biodiversity. Lack of knowledge on the taxonomic status, population structure and viability of trout in the Plitvice Lakes National park, as well as the possibility of existence of cryptic diversity

Yellowfin tuna are the mainstay of the traditional tuna fisheries in St Helena waters, but there is limited knowledge of their ecology and feeding behaviour in the area. In this study yellowfin tuna stomach contents were used to assess spatio‐temporal changes in feeding strategy and consider the role of tuna in the local ecosystem. Comparisons of the feeding spectra of yellowfin tuna between inshore

Spotted sand bass (Paralabrax maculatofasciatus) is one of the most common inshore reef fishes in the northern Gulf of California (GOC), Mexico, but has rarely been studied. Objectives of this study were to estimate age and growth parameters of this species from two areas in the northern GOC and use an age‐structured model to assess fishery yield and Spawning Potential Ratio (SPR) over a wide range

The length–weight relationships (LWRs) of four fish species were determined from Vembanad‐Kole Wetland, Kerala, India between June 2015 and May 2016. Fish samples were collected monthly from various fishing gears such as gill nets (50 m long and 1.5 m height, mesh sizes 30–100 mm, soaking time 8 hr) and seine nets (mesh sizes 8–16 mm). Values of the parameter b ranged from 2.896 to 3.165 and such values

The length–weight relationships (LWRs) for six species were estimated. Fish were captured in the mangroves of Qinzhou Harbour, China, but also some specimens were purchased from fishermen. The sampling was undertaken monthly between May 2011 and April 2012 using seines (mesh size 5–10 mm; height 4 m; length 400 m) and traps (mesh size 8.5 mm; 35 cm2 × 10 m for one unit) at seven sampling sites. Standard

The length‐weight relationships (LWR) were estimated for five fish species from the Golfão Maranhense, Brazilian Amazon littoral region. Samplings were performed in August 2016, during the dry season, using trawl net with 6.0 m length by 3.0 m width (trawl mouth opening of 6.0 m2) and 1.0 cm mesh size between opposite knots. This study registers LWR for Anchoviella elongata and Gobioides broussonnetii

Calcium is a prerequisite factor for triggering the sperm activation in salmonids. The aim of this study was to test different concentrations of Ca2+ on sperm motility activation and fertility of rainbow trout (Oncorhynchus mykiss). Semen samples activated with calcium free activator (0.0 mM) and increasing concentrations of CaCl2 (6.3, 7.9, 9.5 and 11 Mm) were evaluated by computer‐assisted sperm

Monitoring trends in a long‐lived species such as lake sturgeon (Acipenser fulvescens) has it challenges. Targeting the correct life stage to monitor can provide different and contrasting results. Early life stages experience high variable mortality and are often not a good predictor of population trend. Juvenile lake sturgeon (i.e., 5–10 years) experience high survival and could be a good life stage

Environmental conditions during early life can have a profound impact on developmental trajectory and ultimately ecological fitness of individuals. Therefore, from a conservation perspective it is vital to understand the longer‐term implications of early phenotypic development on survival. In this study, we examined the effects of temperature (maintained at 16°C or ambient river temperature), prey

The ontogenetic structure and longitudinal variability of ichthyoplankton in a confluence zone of two river systems in the Eastern Amazon were evaluated between December 2018 and April 2019, at the time 137 eggs and 7,687 larvae of fish were captured. Ichthyoplankton proved to be heterogeneous between sections of rivers with differences in the number of taxa and abundance. The assemblages were distinguished

This study aimed to estimate the parameters of length‐weight relationship for 16 freshwater fish species that inhabit the Aracá and Demeni Rivers, which are two tributaries of the Negro River (Amazonas state, Brazil). The fishes were sampled using gillnets (15 × 2 m, mesh size 30–120 mm between opposite knots), during 6 days each year, in April 2016, November 2018 and April 2019. The gillnets were

The swimming performance of juvenile rock carp (Procypris rabaudi, Tchang) subjected to repeated fatigue exercise was studied using a flume‐type respirometer at 20°C. The critical swimming speed (Ucrit) and oxygen consumption rate (MO2) of juvenile rock carp were measured during two successive stepped velocity tests, following a 60 min rest interval. Ucrit of rock carp was giving a recovery ratio (Rr)

This work analysis the length‐weight relationships for fish species captured by artisanal fishery along the continental coast of Ecuador. Fishermen used the following fishing gear: beach seine nets (5.1–31.8 mm), shrimp trawl nets (21.8–31.8 mm) and bottom gill nets (54.1–203.2 mm). Sampling took place during the years 2012 and 2014. Frequency of sampling was monthly, and it was completed systematically

The present work provides length‐weight relationships (LWRs) for fish species captured around artificial offshore reef deployed 5 km from Guaxindiba Port, northern Rio de Janeiro, Brazil. The fish were captured during two sampling periods each year between 1996 and 2017 using bottom gill nets (25 mlength × 3 mdepth; 30 mm mesh). The fish were kept on ice and the biometric data, including total length

Length‐to‐weight and length‐to‐length ratios were estimated for six cavefishes including Yunnanilus longibarbatus, Yunnanilus bailianensis, Yunnanilus jinxiensis, Oreonectes polystigmus, Paranemachilus pingguoensis, and Paranemachilus genilepis from the upper reaches of the Pearl River, Guangxi Province, China (between 106.26E, 23.14N and 111.42E, 24.85N). The fish were captured between May and October

The length–weight relationships (LWRs) for six native fish species from the Chapala Lake, Mexico, are described in this paper. The fish were caught monthly with the support of local fishermen from different landing sites. The daily catch is obtained using the nasa charalera (pot) and the gill net. Each fisherman can operate 20 pots daily at each fishing site for approximately six or seven months; this

Aquarium and ornamental fish trade is currently recognized as a major source of invasive species in aquatic ecosystems around the world. The swordtail Xyphophorus hellerii is a popular ornamental freshwater fish that occurs as an introduced species in the aquatic habitats of at least thirty‐one countries. We report the first finding of an established population of the swordtail in Morocco. Twelve individuals

This study deals with the length‐weight relationships (LWRs) of three commercially important marine fishes belonging to the family Clupeidae from the major landing centers in Tuticorin, Mandapam, Thondi, Nagapattinam and Chennai in southeast coast of India. Monthly sampling were done at the respected landing centers from June, 2018 to April, 2019 from the commercial trawlers (with cod‐end mesh size

Ten microsatellite loci were developed and described for Pimelodus microstoma, identified in eggs collected from the lower Das Cinzas river. Nine loci were polymorphic, with 02–19 alleles per locus. The observed heterozygosity values were up to 0.898. Five species of the Pimelodidae family were also tested for amplification of loci, among which Pimelodus maculatus was the most successful in the transferability

Length‐weight relationship parameter was estimated for eight coral reef‐associated finfish species from the Gulf of Mannar and Palk Bay, Eastern Indian Ocean. Fish samples were collected from the landings of trawlers with a cod‐end mesh size of 25–35 mm, operated at a depth ranging from 50–70 m off Tuticorin, Rameswaram and Thondi coasts on monthly basis between June‐2018 and July‐2019. Fish specimens

Length‐weight relationship parameters were calculated for twelve mesopelagic fish species from the western Tropical Atlantic: Diretmus argenteus, Melamphaes polylepis, Bolinichthys distofax, Diaphus lucidus, Diaphus splendidus, Electrona risso, Hygophum taaningi, Taaningichthys bathyphilus, Melanolagus bericoides, Winteria telescopa, Diplophos taenia, Astronesthes similus. Data was collected off northeastern

Length weight relationships (LWRs) were estimated for four species of low value fishes that belongs to four families from the southwest coast of India. The specimens of, Callionymus margaretae, Dactyloptena peterseni, Rogadius serratus and Minous inermis were collected for a period of 1 year from the fishing trawlers of Cochin Fisheries Harbour (Lat. 09° 56′ 327″ N, Long. 76° 15′ 764″ E). The estimated

The Perccottus glenii is one of the most invasive of European fish species. During August‐September 2019, we examined Chinese sleeper from six waterbodies in Latvia and Ukraine for parasites. Seventeen parasite species were registered, including two ciliate species, one coccidia, one monogenean, one cestode, six trematodes, three nematodes, one acanthocephalan, one parasitic copepod, and one bivalve

The state of natural spawning of sturgeons in the Lower Volga River was investigated through genetic monitoring of juveniles (larvae, fingerlings, subadults) captured at seven traditionally used monitoring locations. Sampling was performed during the period 2017–2019. In total, 460 individuals were caught and genotyped using a set of six microsatellite loci (Afug41, Afug51, Afug135, An20, AoxD161,

Reproductive migration of a Telestes species is reported for the first time for the Balkan endemic Telestes pleurobipunctatus (Stephanidis, 1939) from Louros River (Northwestern Greece), while the embryonic and larval development is also described for the first time for this species and genus. Adult fish migrate in late winter upstream and spawn in a peak of 2–3 nights in the outflow of springs. Embryos

Long‐term environmental monitoring studies includes morphometric data (length and weight) of aggregating fish species around this artificial structure and adjacent soft‐bottom habitats. We used these data, obtained biannually (summer and spring) between 2012 and 2018, to estimate population parameters such as length‐weight relationships (LWRs) for 28 species. Gender and ontogeny‐based differences in

This study reports the Length‐Weight Relationships (LWR) for 10 freshwater fish species sampled in the Atlantic Rainforest, Southern Brazil. Sampling was conducted between 2016 and 2017, in nine streams, using electrofishing. Collected fishes were fixed in formalin, and thus some shrinking was unavoidable. The values of parameter b of the LWR (W  = aLb ) ranged between 2.5 and 3.5. We report for the

This paper reports the results of pioneer study carried on the length‐weight relationships (LWRs) of six deep‐sea fishes of the Southeastern Arabian Sea. We have collected samples from the survey cruise of FORV Sagar Sampada during January and December 2014. A high‐speed demersal trawler was used to collect the fishes from the depth ranging from 200 to 1000 m. The values for the parameter b of the

Length‐weight relationships for seven fish species caught from tidepools in an intertidal rocky shore in the Gulf of Cadiz are presented. Fish were sampled monthly (April 2008–January 2012), using hand nets (mesh size 1.5 mm). The values of b parameter remained within the expected range of 2.5–3.5 for all fish species. An ANCOVA test was used to evaluate differences in the b growth parameter between

An endangered tetraploid spined loach species, Cobitis takenoi (Cypriniformes: Cobitidae; hereafter called Tango loach) is known to inhabit only a single river in Kyoto Prefecture, Japan. Since Tango loach was discovered recently, in 2010, and only described in 2016, its morphology, ecology, and genetics are not well studied. Another tetraploid spined loach species Cobitis sp. BIWAE type A (hereafter

The pond loach Misgurnus dabryanus is a freshwater fish with a distribution range spanning the eastern part of the Asian continent, the Korean Peninsula, and Taiwan. The pond loach was transplanted to the Japanese archipelago through the co‐inclusion with dojo loach (Misgurnus anguillicaudatus species complex) populations, which were imported live from China for food materials, and it is currently

This work provides new length‐weight information for seven species of freshwater fishes. The analyzed specimens were collected monthly during a year (April 2018–March 2019) in a coastal lagoon system and its associated streams in southern Uruguay. During each sampling campaign, fishes were captured using gillnets in the lagoon and electrofishing in the streams. This study reports a new maximum size

Length‐weight relationship (LWR) for 39 freshwater fish species captured in the Catalão Lake, a floodplain area at the confluence of the Amazonas and Negro rivers is presented. LWRs were calculated based on fish sampled over 18 years (1999–2017) using a set of ten gill nets with different mesh sizes, monthly immersed in water for 24‐hr with 6‐hr interval catches. Measurements were done for standard

Length–weight relationships (LWR) were estimated for six fish species from the Cujubim lake on the Madeira River. The specimens were sampled between in the months of March and November, 2019 and February, 2020 using gillnets (10 × 5 m, mesh size 40, 60, 80 and 100 mm) which were checked every 6 hr during a 24‐hr period and casting nets (1.25 × 2.7 m, mesh size 40 mm) performed three times in this interval

The length–weight relationships (LWRs) were estimated for 12 fish species. The species were collected monthly from the commercial catch of small‐scale fisheries using gillnets (mesh size 7.6–15.2 cm, length 200–1,000 m, 6–48 hr of operation during the day) and longlines (surface and bottom, 300 hooks, sardine bait, operation during the day) in the period October 2017 to July 2018 along the Pacific

Aphaniops dispar, widespread around the Arabian Peninsula, was recently separated in four species (A. dispar, A. hormuzensis, A. kruppi, A. stoliczkanus) by molecular results and colour patterns, but the morphological differences are small and call for more studies. Here we report differences in skeleton and median fin osteology of these species. In addition, we introduce the term 'modified caudal

Present study report the Mud‐dwelling moray, Diaphenchelys dalmatian Hibino, Satapoomin & Kimura (Ichthyological Research, 64, 458) for the first time from the Indian coast. The species was only known by its first description from the Andaman Sea, marginal sea of the northeastern Indian Ocean and the Gulf of Thailand and this report extends its range of distribution to the Bay of Bengal along the Indian

Length‐weight relationships (LWRs) were estimated for 11 fish species from the Min River Estuary and its adjacent waters, Fujian Province, China. All samples were collected using gillnets (mesh size 45 mm) and bottom trawls (mesh sizes 45 mm at the main webbing and 25 mm at the cod end) seasonally in 2017 and 2018. The parameters for the LWRs were estimated, along with the basic Statistical analyses

Recent advancements in telemetry have allowed managers and researchers to conduct comprehensive studies on the movement ecology of lake sturgeon (Acipenser fulvescens), a species of conservation concern in most of the Laurentian Great Lakes basin. In Michigan waters of Lake Michigan, drowned river mouth systems (a protected lake‐like habitat that connects a river to lake) support 4 of 11 remaining

The fish rotan, Perccottus glenii Dybowski, 1877 (Odontobutidae) is one of the most successful fish invaders during 20th and beginning of 21st century in European and Asian fresh waters. The diversity of its parasites within its invaded range was first reviewed by Sokolov, Reshetnikov, et al. (2014). The current paper analyzes new data from 2013 to 2019 on protistan and metazoan parasites of the non‐native

Length‐weight relationships (LWR) and length‐length relationships (LLR) were provided for eight species inhabiting Northeastern Brazilian coast. Nine transects (5, 15, 30 m deep) between Sergipe and Vaza‐Barris rivers mouths were sampled monthly from September 2013 to August 2014. Each sampling was carried out using a shrimp boat equipped with double ring nets (4 m mouth wide, 10 m long and 20 mm mesh

Embryos of oviparous chondrichthyans develop within a structurally complex tertiary egg envelope known as the egg‐case, which is provisioned with a secondary egg coat known as the egg‐jelly. Whereas the former has been studied in detail, relatively little attention has been paid to the latter. This study examined the production and composition of egg‐jelly in the small‐spotted catshark Scyliorhinus

Innovative tools that benefit conservation are critical as freshwater fishes are lost at unprecedented rates. Mark‐recapture methods can characterize population demographics and life‐history traits of diverse fishes, but suitable techniques for tagging for individual recognition of small‐bodied fishes are rare. Passive integrated transponder (PIT) tag technology may facilitate the tagging of small

The length‐weight relationship is important for the study of populational dynamics. This study aimed to describe the length‐weight relationships (LWR) of 11 fish species sampled on 18 streams of the Capim river basin on eastern Amazon. Specimens were captured in 2014, 2015 and 2017, using sieve nets with 2 mm of mesh size. Fixed specimens were fixed in 10% formalin and conserved in alcohol 70%, measured

Length‐weight relationships (LWRs) and length‐length relationships (LLRs) were evaluated for three endemic fish species sampled from the lower Yalong River and its biggest tributary (the Anning River), in China. Specimens were captured using set gillnet (mesh size 4 cm) and backpack electro‐fishing (power output 400 W, depth fished 1 m, area covered 3 m2) from June to July 2018. LWRs and LLRs are presented

Analysis of the contemporary geographic distributions of mtDNA haplotypic diversity of sockeye salmon (Oncorhynchus nerka Walbaum) on the Asian part of its range and consideration of possible scenarios for microevolution of the species were performed. In total, 172 specimens of sockeye salmon from different rivers of Kamchatka, Chukotka, north coast of the Sea of Okhotsk, and from the Kuril Islands

Mudskippers are amphibious gobies (Teleostei: Gobioidei, Oxudercinae) that have served as models for the specialised physiology and behaviour of fishes out of water. In this study, a comparative analysis of the posterior vertebral column and the caudal skeleton of ten mudskipper species was conducted on the basis of X‐ray imaging. The species considered were Apocryptes bato, Apocryptodon madurensis

The identification of interspecific links (trophic niche) is important to characterize resource use of a predator, and to know its trophic role (for example, mesopredator or top predator) in the food web. In this study, we examined: a) the trophic ecology of Scomberomorus sierra as a predator (niche breadth, trophic overlap, and trophic position) and b) its presence as a prey in the diets of the region´s

Excessive fishing pressure can induce population declines or complete collapse of fisheries. Unless commercial and recreational fisheries for K‐selected fishes, or those with slow growth and late maturation, are carefully managed, declines in abundance or fishery collapse is probable. Paddlefish Polyodon spathula,are a K‐selected species that experienced historical declines in abundance as a result

In Italian freshwaters the introgressive hybridization with the alien Atlantic trout represents the principal threat to the native endangered Mediterranean trout. The aim of the research was to test the effectiveness of alien trout removal activities carried out by electrofishing in four streams in Central Italy. The four sites were chosen on the basis of the severe genetic introgression level of the

Common carp (Cyprinus carpio, [Linnaeus, 1758]) have long been established in the United States and in some cases their populations can be very dense, leading biologists to expend significant effort towards reducing numbers of common carp in some populations. Estimating abundance of common carp prior to removal efforts would be useful in evaluating success of these removal efforts, but marking large

We provide the first record of the Mayan Cichlid, Mayaheros urophthalmus from South Asia, based on specimens collected from the River Chalakudy in Kerala, India. Genetic analysis of the Indian sample showed close affinity with those from Philippines suggesting their potential South East Asian origin, and introduction through the unmanaged aquarium trade. Ecological plasticity, opportunistic predatory

The present study aimed to characterize the embryogenesis and larval development of matrinchã (Brycon orthotaenia), through the analysis of egg and larval morphology. Fertilized eggs had a mean diameter of 1.17 mm, with yolk occupying most of the egg (1.06 mm). Embryogenesis lasted for 15 hr at an average temperature of 27°C. At hatching, yolk‐sac larvae measured 3.67 mm in mean standard length (SL)

The study provides new information on the reproductive biology of Hypselobarbus thomassi (Day, 1874) an endemic cyprinid fish in the Western Ghats–a biodiversity hotspot of India. A total of 384 specimens (males = 244 and females = 140) were collected monthly from April 2009 to March 2011 from Kallada River of Southern part of Western Ghats, India. Monthly sex ratio indicated that males predominated

A specimen of the Chameleon sand tilefish Hoplolatilus chlupatyi was collected off Mozambique during a 2014 FAO Marine Ecosystem Survey by the R/V Dr. Fridtjof Nansen. Three additional larval specimens of H. chlupatyi were collected in the Mozambique Channel in 2008. These four specimens represent the first records of H. chlupatyi from the Western Indian Ocean, previously known to occur exclusively

The length–weight relationships (LWRs) were estimated of seven fish species from 22 localities in the Pantanal wetland between Mach 2006 and April 2011. Fish were sampled using seven gill nets (20 × 1.5 m; mesh size: 12, 15, 18, 20, 25, 30 and 50 mm between opposing knots) and throw traps (made of 1 m3 metal cubes, covered by a 1.5 mm nylon mesh). Standard length and weight were measured and used to

We present a critical checklist of freshwater fish species found so far in the countries of Armenia, Azerbaijan and Georgia. In total 119 freshwater fishes are recorded. There are 40, 86 and 96 species currently known for Armenia, Azerbaijan and Georgia respectively. From these 119 species, seven are endemic and seven species are alien. From the alien species, only three (Carassius gibelio, Gambusia

The length to weight ratio (LWR) was used to estimate populations of four fish species sampled on the Amazon coast of the state of Maranhão, Brazil. The fishes were sampled in 2018 and 2019 by artisanal coastal fishing, using gillnets (0.20–0.60 mm). The parameters a and b of the equation WT = a LTb were estimated. The obtained LWRs were WT = 0.06LT2.93, (r2) = .989 for Oligoplites saliens; WT = 0

Parameters of the length‐weight relationship (LWR) were estimated for four fish species [Beaufortia szechuanensis (Fang, 1930), Claea dabryi (Sauvage, 1874), Percocypris pingi (Tchang, 1930), and Yunnanilus sichuanensis Ding, 1995] from the Yalong River. Samples were collected seasonally from June 2018 to July 2019, using various fishing gears [set nets (mesh: 1.5 × 2.0 cm), hook, drift gill nets (three

A single‐species environmental DNA (eDNA) method was developed to sample for a small, benthic rare species, Eastern Sand Darter (Ammocrypta pellucida Putnam, 1863) in two large Lake Ontario embayments. Summer water sampling allowed for: (a) surveys of habitats (Wellers Bay) where traditional fish sampling gear could not be used; and, (b) a comparison between eDNA and seining‐based detection probabilities