Fish Research Articles

Dr. Trika Gerard

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

Dr. Beck Wehrle

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

Bayard Holmes Brattstrom

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

EDITORIAL NOTES AND NEWS

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

David B. Wake (1936–2021)

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

Miller and Lea's Guide to the Coastal Marine Fishes of California.

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

Information on forage fish ages from otoliths collected in avian stomach contents

Otolith analysis allows studying multiple aspects of fish biology, including age estimation; however, otoliths collected from avian stomach content have not been used to estimate the age of ingested fish. We evaluated the potential ability to estimate the age of Pacific sardine (Sardinops sagax) from otoliths collected from blue-footed booby (Sula nebouxii) stomach contents sampled in the Galapagos Islands. Blue-footed boobies were selected because they mostly forage close to their colony (&lt;100 m) and were, therefore, more likely to have almost intact otoliths. To estimate age, we employed three previously developed methods for otoliths. We then related these estimates to the fish's standard length and compared these relations statistically using the Akaike Information Criterion (AIC) to determine which method was most parsimonious. We collected 32 otoliths in relatively good condition, of which we aged 31 with the surface-reading method, 26 with the otolith weight method, and 29 with the posterior otolith length method. Average ages obtained with the otolith methods were 5.6 ± 1.7 yr (± standard deviation), 5.7 ± 2.0 yr, and 3.9 ± 1.5 yr, respectively. Estimates obtained with the otolith weight method had the highest correlation with standard length and the lowest AIC values of the three suggesting it was the best method for aging. Our results indicate that aging otoliths extracted from bird stomachs are possible; however, their use depends on the availability of previously developed methods and how digested the fish are when the birds return to the colony.

The complete mitochondrial genome of Pseudopleuronectes herzensteini

Pseudopleuronectes herzensteini belonging to Pleuronectiformes (family Pleuronectidae) is important in the fishery industry. However, the molecular biology of this valuable fish has hardly been reported. Thus, here we report the complete mitochondrial genome of P. herzensteini. The mitochondrial DNA (mtDNA) of P. herzensteini is 16,719 bp long and contains 13 mitochondrial protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a putative control region between tRNA-P and tRNA-F distinguished by a single short noncoding region. Phylogenetic analysis using PCGs confirmed that this mtDNA sequence belongs to the family Pleuronectidae. This is the first study reporting the complete mitochondrial genome sequence of P. herzensteini.

Aspects of the growth and reproductive biology of Oreochromis niloticus (Linnaeus, 1758) in a tropical Soda Lake, Lake Shala, Ethiopia

Morphometric relationships, condition factor (CF) and reproductive biology are significant tools in fish stock management, fish biology, physiology, conservation and ecology. Growth and reproductive strategy of Oreochromis niloticus were studied from 343 fish specimens collected from Lake Shala between January and December 2018. Fish samples ranged from 7.7 cm to 33.0 cm in total length (TL) and from 7.80 g to 708.21 g in total weight (TW) were collected using gillnets of 4, 6, 8, 10, and 12 mm mesh sizes. The length-weight relationship of O. niloticus was TW = 0.0104TL3.19, indicating positive allometric growth of the fish. The sex ratio (0.93:1) was insignificant from the ideal fish distribution of 1:1 (χ2 = 0.47, p &gt; 0.05). Mean CF for males, females and combined sexes was 1.04, 1.06 and 1.05, respectively and statistically insignificant (p &gt; 0.05). The spawning peak occurred in July (rainy) and February (dry) periods, as defined by ripe females and the breeding season. Absolute mean fecundity was 806 eggs and correlated positively with TL and TW of the fish (p &lt; 0.05) (F = 0.56TL2.29, R2 = 0.93, p &lt; 0.05; F = 18.83TW0.67, R2 = 0.90, p &lt; 0.05). The study provides the first detailed account of the morphometric relationships and reproductive biology of O. niloticus in Lake Shala, which can be used as baseline information for successive biological-based studies in Soda Lakes of Ethiopia.

Fishery and biology of cutlass fishes from Indian seas with special reference to the largehead hairtail Trichiurus lepturus Linnaeus, 1758 - A review

Cutlass fishes of the family Trichiuridae form an important group in the commercial fishery in India, contributing &gt;7% to the pelagic marine fish landings of the country during 2018-19. The largehead hairtail Trichiurus lepturus Linnaeus, 1758 forms a significant component of marine fish landings in India and several studies have reported its length-weight relationship, growth patterns, sex ratio, population parameters and stock status. Age and growth of T. lepturus were reported by the authors mostly using inverse interpolation of von Bertalanffy growth equation and ageing using hard parts is desirable to validate these observations. The present review highlights the importance of applying uniform methodologies for creating fisheries biology databases and timely publication of stock assessment results. Focussed utilisation of fisheries biology databases of commercially important fishery resources, including cutlass fishes using meta-analyses to validate and base fisheries management decisions should be considered. Keywords: Age and growth, Condition factor, Length-weight relationship, Population parameters, Ribbonfishes, Stock assessment, Trichiuridae

Reproductive biology of the Amazonian amphibian fish the splash tetra Copella arnoldi with emphasis to histological characterization

AbstractThis study describes important components of the reproductive biology of the Amazonian amphibian fish Copella arnoldi. The species sex ratio biased to female 1.8 to 1 male and the length‐weight relationship also shown differences between sexes (b value = 1.854 for females and 2.235 for males), although both presented allometric growth (b &lt; 3), “being lighter for its length”. The results also show the importance of the histological analysis to describe the gametogenesis and, consequently, define the reproductive cycle of a fish species. It showed both, males and females, spawning capable during a whole year, whereas the gonadosomatic index pointed spawning capable females during the winter and summer, and spawning capable males only in the autumn. The species presents the rare type of semicystic spermatogenesis and the spermatids complete their differentiation into the tubular lumen, forming a Type I spermatozoa. Both the characteristics are described for the first time for the Lebiasinidae family. Such data can contribute to the discussions about the position of the Lebiasinidae family within the Characiform order, which still does not have a conclusion. Moreover, understand the reproductive biology of a fish species helps its preservation in its habitat and may be applied in restoration programs.

A Comparative Study on Total Muscle Protein Content of Different Fish Species in Fresh and Smoked - Dried Condition and to Analyze their Banding Pattern through SDS- PAGE

Fish plays an important role in human nutrition. They are known to be a very healthy food item. They are excellent protein sources that also deliver various minerals and vitamins necessary for good health. Due to the high content of polyunsaturated fatty a cid, fish flesh and fish oil are beneficial in reducing the serum cholesterol. In addition to that, the special type of fatty acid, omega -3 polyunsaturated fatty acid, is recognized as an important component to prevent a number of coronary heart diseases. Fish proteins contain all the essential amino acids in the required proportion and hence have a high nutritional value, which contribute to their high biological value. In fresh fi sh muscles, the water content is strongly bound to the proteins and cannot be easily removed even under higher pressure. For the present study, three different fish species, Clarias batrachus (E1), Mystus tengara (E2) and Puntius ticto (E3) were taken to study their protein content and analyze the electrophoretic protein banding pattern for both fresh and smoked dried conditions. Pr otein extract was made from the muscle tissue of the fishes taken. The protein content was measured by Lowry’s method using BSA protein as standard. The optical density was measu red at 660nm. The electrophoretic protein banding patterns were determined using SDS-PAGE gel electrophoresis. The results showed that the total protein concentration of samples for fresh condition E1F, E2F and E3F was found to be 7.15±0.247 mg/ml, 7.20±0.224 mg/ml and 4.98±0.283 mg/ml respectively and for smoked dried condition E1D, E2D and E3D was 8.48±0.273 mg/ml, 8.31±0.222 mg/ml and 5.81±0.335 mg/ml respectively. The SDS-PAGE electrophoresis showed significant increase in the protein bands of three types of smoked dried fish samples when compared to fresh ones. Therefore, the percentage of protein content in selected smoked dried fishes was found more.&#x0D;

Leafy and weedy seadragon genomes connect genic and repetitive DNA features to the extravagant biology of syngnathid fishes

Seadragons are a remarkable lineage of teleost fishes in the family Syngnathidae, renowned for having evolved male pregnancy. Comprising three known species, seadragons are widely recognized and admired for their fantastical body forms and coloration, and their specific habitat requirements have made them flagship representatives for marine conservation and natural history interests. Until recently, a gap has been the lack of significant genomic resources for seadragons. We have produced gene-annotated, chromosome-scale genome models for the leafy and weedy seadragon to advance investigations of evolutionary innovation and elaboration of morphological traits in seadragons as well as their pipefish and seahorse relatives. We identified several interesting features specific to seadragon genomes, including divergent noncoding regions near a developmental gene important for integumentary outgrowth, a high genome-wide density of repetitive DNA, and recent expansions of transposable elements and a vesicular trafficking gene family. Surprisingly, comparative analyses leveraging the seadragon genomes and additional syngnathid and outgroup genomes revealed striking, syngnathid-specific losses in the family of fibroblast growth factors (FGFs), which likely involve reorganization of highly conserved gene regulatory networks in ways that have not previously been documented in natural populations. The resources presented here serve as important tools for future evolutionary studies of developmental processes in syngnathids and hold value for conservation of the extravagant seadragons and their relatives.

Liver-derived cell lines from cavefish Astyanax mexicanus as an in vitro model for studying metabolic adaptation

Cell lines have become an integral resource and tool for conducting biological experiments ever since the Hela cell line was first developed (Scherer et al. in J Exp Med 97:695–710, 1953). They not only allow detailed investigation of molecular pathways but are faster and more cost-effective than most in vivo approaches. The last decade saw many emerging model systems strengthening basic science research. However, lack of genetic and molecular tools in these newer systems pose many obstacles. Astyanax mexicanus is proving to be an interesting new model system for understanding metabolic adaptation. To further enhance the utility of this system, we developed liver-derived cell lines from both surface-dwelling and cave-dwelling morphotypes. In this study, we provide detailed methodology of the derivation process along with comprehensive biochemical and molecular characterization of the cell lines, which reflect key metabolic traits of cavefish adaptation. We anticipate these cell lines to become a useful resource for the Astyanax community as well as researchers investigating fish biology, comparative physiology, and metabolism.

Growth analysis and sex ratio of fish species from the Ovia River, Edo State, Nigeria

This study investigated the length-weight relationships, the condition factor, and the sex ratio of Hemichromis fasciatus, Synodontis nigrita, and Tilapia zillii in the Ovia River, Edo State, Nigeria. Fish specimens were collected with the assistance of artisanal fishermen using fishing traps, cast and gill nets of various mesh sizes from February to April 2021. Taxonomical identification, morphometric measurements, and macroscopic examination of the fresh gonads were carried out. The linear regression equation was used to determine the relationship between fish length and body weight, while the condition factor and the sex ratio were analysed using standard techniques. Length-weight relationship (LWR) showed a significant (p &lt; 0.05) correlation and the growth exponent b = 2.973, 2.340, and 2.565 for H. fasciatus, S. nigrita and T. zillii, respectively, indicated a negative allometric growth pattern. Mean condition factor values ranged from 2.34 to 5.68 and was indicative of good health condition for the fishes. Sex ratios did not differ significantly (p &gt; 0.05) from the one male to one female distribution in H. fasciatus (1:1.11), S. nigrita (1:0.89), and T. zillii (1:0.93). The study has provided information on some aspects of the fish biology of Hemichromis fasciatus, Synodontis nigrita, and Tilapia zillii in the Ovia River, and these data are helpful tools for fisheries management and conservation of freshwater fishes.

The reproductive biology of small fishes and the clutch concept: Combining macroscopic and histological approaches

AbstractAccurate estimates of reproductive parameters important in understanding life history evolution and conservation of small fishes are dependent upon careful assignment of ovarian phases. Proper assignment is based upon the stages of propagule (oocyte) development, oocyte maturation and the location of any clutch or portion thereof within the ovaries. Macroscopic inspection and assignment of ovarian developmental phases have often been used for small freshwater fishes. By contrast, histological methods for assignment of reproductive phases have been developed and are widely used for marine fishes, but they have rarely been used for small freshwater fishes. We review oocyte development, ovum maturation, and the ovarian cycling process using both macroscopic and histological approaches which incorporate the clutch concept. New terminology, including three actively spawning phases based on macroscopic appearance of the clutch (actively spawning‐maturation, actively spawning‐hydration, actively spawning‐ovulation), is proposed. We assert that combining histological and macroscopic methodologies, shown to be complementary, will allow a more accurate and precise understanding of the reproductive biology of small fishes—especially freshwater fishes experiencing effects of habitat change and loss of habitat.

Nutritional programming by maternal diet alters offspring lipid metabolism in a marine teleost

Nutritional programming - the association between the early nutritional environment and long-term consequences for an animal - is an emerging area of research in fish biology. Previous studies reported correlations between maternal provisioning of essential fatty acids to eggs and the whole-body fatty acid composition of larvae reared under uniform conditions for red drum, Sciaenops ocellatus. This study aimed to further investigate the nutritional stimulus and the consequences of nutritional programming by feeding adult red drum several distinct diets and rearing larvae under uniform conditions until 21days post-hatching when larval lipid and fatty acid compositions were assessed. Different maternal diets produced eggs with distinctive lipid and fatty acid compositions, and despite receiving the same larval diet for almost 3weeks, larvae showed differences in total fatty acid accumulation and in retention of highly unsaturated fatty acids (HUFA). Specifically, larvae reared from a maternal diet of shrimp generally showed elevated levels of fatty acids in the initial steps of the n-3 and n-6 HUFA biosynthetic pathways and reduced levels of fatty acid products of the same pathways, especially in triglyceride. Furthermore, the variations in larval fatty acid accumulation induced by maternal diet varied among females. Lipid metabolism altered by parental diet may have consequences for larval physiological processes and behavioral performance, which may ultimately influence larval survival.

INSTRUCTIONS TO AUTHORS

<i>Ichthyology & Herpetology</i> (formerly <i>Copeia</i>) publishes work on the biology of fishes, amphibians, and reptiles, or work using those organisms as models for testing hypotheses of broad significance.

A chromosome-scale genome assembly of the false clownfish, Amphiprion ocellaris.

The false clownfish Amphiprion ocellaris is a popular fish species and an emerging model organism for studying the ecology, evolution, adaptation, and developmental biology of reef fishes. Despite this, high-quality genomic resources for this species are scarce, hindering advanced genomic analyses. Leveraging the power of PacBio long-read sequencing and Hi-C chromosome conformation capture techniques, we constructed a high-quality chromosome-scale genome assembly for the clownfish A. ocellaris. The initial genome assembly comprised of 1,551 contigs of 861.42 Mb, with an N50 of 863.85 kb. Hi-C scaffolding of the genome resulted in 24 chromosomes containing 856.61 Mb. The genome was annotated with 26,797 protein-coding genes and had 96.62% completeness of conserved actinopterygian genes, making this genome the most complete and high quality among published anemonefish genomes. Transcriptomic analysis identified tissue-specific gene expression patterns, with the brain and optic lobe having the largest number of expressed genes. Further, comparative genomic analysis revealed 91 genome elements conserved only in A. ocellaris and its sister species Amphiprion percula, and not in other anemonefish species. These elements are close to genes that are involved in various nervous system functions and exhibited distinct expression patterns in brain tissue, potentially highlighting the genetic toolkits involved in lineage-specific divergence and behaviors of the clownfish branch. Overall, our study provides the highest quality A. ocellaris genome assembly and annotation to date, whilst also providing a valuable resource for understanding the ecology and evolution of reef fishes.

An updated review of cold shock and cold stress in fish.

Temperature is critical in regulating virtually all biological functions in fish. Low temperature stress (cold shock/stress) is an often-overlooked challenge that many fish face as a result of both natural events and anthropogenic activities. In this study, we present an updated review of the cold shock literature based on a comprehensive literature search, following an initial review on the subject by M.R. Donaldson and colleagues, published in a 2008 volume of this journal. We focus on how knowledge on cold shock and fish has evolved over the past decade, describing advances in the understanding of the generalized stress response in fish under cold stress, what metrics may be used to quantify cold stress and what knowledge gaps remain to be addressed in future research. We also describe the relevance of cold shock as it pertains to environmental managers, policymakers and industry professionals, including practical applications of cold shock. Although substantial progress has been made in addressing some of the knowledge gaps identified a decade ago, other topics (e.g., population-level effects and interactions between primary, secondary and tertiary stress responses) have received little or no attention despite their significance to fish biology and thermal stress. Approaches using combinations of primary, secondary and tertiary stress responses are crucial as a research priority to better understand the mechanisms underlying cold shock responses, from short-term physiological changes to individual- and population-level effects, thereby providing researchers with better means of quantifying cold shock in laboratory and field settings.