Population genetic structure and demographic history of small yellow croaker, Larimichthys polyactis (Bleeker, 1877), from coastal waters of China

Small yellow croaker, Larimichthys polyactis (Bleeker, 1877), a commercially important benthopelagic fish, is widely distributed in the Bohai, Yellow and East China Seas. To evaluate the population genetic structure and demographic history of L. polyactis, we sequenced the complete mitochondrial deoxyribonucleic acid (mtDNA) control region (798 to 801 bp) in 127 individuals sampled from seven localities throughout its distribution region in China. A total of 136 polymorphic sites were detected, which defined 125 haplotypes. High haplotype diversity (1.000 ± 0.013 to 1.000 ± 0.034) and moderate nucleotide diversity (0.0112 ± 0.0061 to 0.0141 ± 0.0075) were detected in the species. The neighbor-joining tree of haplotypes was assigned into two closely related clades, but did not appear to have any geographic genealogic structure. Hierarchical molecular variance analysis (AMOVA), pair wise FST comparisons and the nearest-neighbor statistic (Snn) showed no significant genetic differences among populations in the Bohai, Yellow and East China Seas. The demographic history of L. polyactis was examined by using neutrality tests and mismatch distribution analysis, which revealed that the species had undergone a Pleistocene population expansion. The results based on the complete mtDNA control region sequences analysis indicate that within its distribution range, L. polyactis constituted a panmictic mtDNA gene pool. Factors such as dispersal capacity, ocean currents and insufficient evolution time could be responsible for the lack of population genetic differentiation in L. polyactis.Keywords: Larimichthys polyactis, mitochondrial control region, population genetic structure, demographi

Study on Vibrio Disease of Pseudosciaena crocea and Recognition of the Disease Resistant Group Based on Automatic Detection System for Hemogram

Chemical medicines and antibiotics can kill pathogenic microorganisms in aquiculture animals, but they will lead to environmental pollution and serious food safety problems. Therefore, study on the selection for the disease resistant group of animals is necessary to solve the problem and promote the development of aquaculture. From the view of the relationship between fishes and pathogenic microorganisms, the present paper studies hemogram changes of Pseudosciaena crocea with different disease resistant abilities after artificial infected with the Vibrio harveyi. The results showed that the changes of hemograms of Pseudosciaena crocea after infected with Vibrio harveyi had close relationship with its disease resistant abilities. The hemogram indicators of the high disease resistant group (HDRG) did not change remarkably after infection compared with the control (P >0.05). But in the low disease resistant group (LDRG) or sensitive group, the concentrations of the red blood cells, white blood cells, lymphocytes, monocytes and neutrophil cells, as well as hematocrit and hemoglobin content per litre blood, decreased remarkably compared with the control (p < 0.05). And the white blood cells, monocytes and neutrophil cells of the LDRG also decreased remarkably compared with that of the HDRG (P < 0.05). These indicators of hemogram provide better referrences for the study on the anti-disease ability of Pseudosciaena crocea, and also provide selection basis for the group with high disease resistant abilities. Application of automatic detection system greatly improved the analytical efficiency and would be a better choice for a large number of samples

Rates of oxygen consumption and tolerance of hypoxia and desiccation in Chinese black sleeper (Bostrichthys sinensis) and mudskipper (Boleophthalmus pectinirostris) embryos

The rates of oxygen consumption, tolerance of hypoxia and desiccation of the Chinese black sleeper (Bostrichthys sinensis) and mudskipper (Boleophthalmus pectinirostris) embryos were investigated. The pattern of oxygen consumption of the Chinese black sleeper embryos was similar to that of the mudskipper ones. The lowest rates of oxygen consumption [(1.65 +/- 0.66) nmol/(ind. center dot h)] of the Chinese black sleeper embryos 16 h after fertilization and the lowest rates of oxygen consumption [(0.79 +/- 0.08) nmol/(ind. center dot h)] of the mudskipper embryos 6 h after fertilization were recorded, respectively. Then the rates of oxygen consumption of these two species embryos increased gradually until hatching [8.26 +/- 1.70) nmol/(ind. center dot h) in the Chinese black sleeper, (2.69 +/- 0.23) nmol/(ind. center dot h) in mudskipper]. After exposure to hypoxia water (0.16 mg/dm(3)), bradycardia of the embryos occurred in both the Chinese black sleeper and the mudskipper. However, the Chinese black sleeper embryos survived approximately 45 min longer than the mudskipper ones. After exposure to desiccation at a relative humidity of 58%, bradycardia of the embryos was observed in both the Chinese black sleeper and the mudskipper, and the Chinese black sleeper embryos lived approximately 9 min longer than the mudskipper ones

Validity of Pampus liuorum Liu &amp; Li, 2013, Revealed by the DNA Barcoding of Pampus Fishes (Perciformes, Stromateidae)

The genus Pampus contains seven valid species, which are commercially important fishery species in the Indo-Pacific area. Due to their highly similar external morphologies, Pampus&nbsp;liuorum has been proposed as a synonym of Pampus cinereus. In this study, partial sequences of COI (582 bp) and Cytb (1077 bp) were presented as potential DNA barcodes of six valid Pampus species and the controversial species P. liuorum. A species delimitation of the seven Pampus species was performed to verify their validities. Explicit COI barcoding gaps were found in all assessed species, except for P. liuorum and P. cinereus, which resulted from their smaller interspecific K2P distance (0.0034&ndash;0.0069). A Cytb barcoding gap (0.0200) of the two species was revealed, with a K2P distance ranging from 0.0237 to 0.0277. The longer Cytb fragment is thus a more suitable DNA barcode for the genus Pampus. In the genetic tree, using concatenated Cytb and COI sequences, the seven species reciprocally formed well-supported clades. Species delimitations with ABGD, GMYC, and bPTP models identified seven operational taxonomic units, which were congruent with the seven morphological species. Therefore, all of the seven analyzed species, including P. liuorum, should be kept as valid species

Validity of <i>Pampus liuorum</i> Liu & Li, 2013, Revealed by the DNA Barcoding of <i>Pampus</i> Fishes (Perciformes, Stromateidae)

The genus Pampus contains seven valid species, which are commercially important fishery species in the Indo-Pacific area. Due to their highly similar external morphologies, Pampus liuorum has been proposed as a synonym of Pampus cinereus. In this study, partial sequences of COI (582 bp) and Cytb (1077 bp) were presented as potential DNA barcodes of six valid Pampus species and the controversial species P. liuorum. A species delimitation of the seven Pampus species was performed to verify their validities. Explicit COI barcoding gaps were found in all assessed species, except for P. liuorum and P. cinereus, which resulted from their smaller interspecific K2P distance (0.0034–0.0069). A Cytb barcoding gap (0.0200) of the two species was revealed, with a K2P distance ranging from 0.0237 to 0.0277. The longer Cytb fragment is thus a more suitable DNA barcode for the genus Pampus. In the genetic tree, using concatenated Cytb and COI sequences, the seven species reciprocally formed well-supported clades. Species delimitations with ABGD, GMYC, and bPTP models identified seven operational taxonomic units, which were congruent with the seven morphological species. Therefore, all of the seven analyzed species, including P. liuorum, should be kept as valid species

Species diversity and distribution of genus Pampus (Pelagiaria: Stromateidae) based on global mitochondrial data

Due to the highly similar external morphology of the Pampus species, misidentifications frequently occur and hinder the understanding of the taxonomy and species distributions of the genus. In this study, we generated 271 mitochondrial sequences and obtained 1,226 sequences from the public databases to understand the species diversity and distributions of the genus Pampus. Most phylogenetic analyses and species delimitations congruently concluded seven valid species within the genus Pampus (i.e., P. argenteus, P. candidus, P. chinensis, P. cinereus, P. liuorum, P. minor, and P. punctatissimus). Sequences of P. argenteus are reported through the northern South China Sea to the Japan Archipelago, which covered the type locality of P. echinogaster. Sequences of P. echinogaster in the public databases are all identified as P. argenteus, suggesting that the species should be synonymized with P. argenteus. Furthermore, sequences of P. griseus were identical to our P. cinereus data and, therefore, should be treated as a synonym of the latter. Inference on divergence time and ancestral distribution implied that the genus Pampus originated in the central Indo-Pacific region around 8.35–11.33 million years ago (the late Miocene), associated with the rise of the Indonesian– Australian Archipelago biodiversity hotspot. The divergence between P. cinereus and P. liuorum dated back to 1.20–1.72 million years ago, which might be related to glacial isolation during the Mid-Pleistocene transition.Debido a la morfología externa muy similar de la especie Pampus, Con frecuencia se producen identificaciones erróneas que dificultan la comprensión del taxonomía y distribución de especies del género. En este estudio generamos 271 secuencias mitocondriales y obtuvo 1.226 secuencias del público bases de datos para comprender la diversidad de especies y distribuciones del género Pampus. La mayoría de los análisis filogenéticos y delimitaciones de especies son congruentes. concluyó siete especies válidas dentro del género Pampus (es decir, P. argenteus, P. candidus, P. chinensis, P. cinereus, P. liuorum, P. minor y P. punctatissimus). Se informan secuencias de P. argenteus en el norte del Mar de China Meridional al archipiélago de Japón, que cubría la localidad tipo de P. echinogaster. Todas las secuencias de P. echinogaster en las bases de datos públicas están identificadas como P. argenteus, lo que sugiere que la especie debería ser sinonimizada con P. argenteo. Además, las secuencias de P. griseus eran idénticas a las de nuestro P. cinereus data y, por lo tanto, debe ser tratado como sinónimo de este último. La inferencia sobre el tiempo de divergencia y la distribución ancestral implicó que el género Pampus se originó en la región central del Indo-Pacífico alrededor de 8,35 a 11,33 millones. hace años (el Mioceno tardío), asociado con el surgimiento de los indonesios– Punto crítico de biodiversidad del archipiélago australiano. La divergencia entre P. cinereus y P. liuorum se remontan a hace 1,20-1,72 millones de años, lo que podría estar relacionado con el aislamiento glacial durante la transición del Pleistoceno medio.Universidad Nacional, Costa RicaEscuela de Ciencias Biológica

Digestive enzyme activities in mudskipper Boleophthalmus pectinirostris and Chinese black sleeper Bostrichthys sinensis

The mudskipper Boleophthalmus pectinirostris and Chinese black sleeper Bostrichthys sinensis occupy the intertidal zone. However, both species have their own unique diet. The former is an herbivore and the latter is a carnivore. In order to reveal the relationship between digestive enzyme activities and diets in the two species, the activities of protease (P), non-specific bile salt-activated lipase (BAL) and alpha-amylase (A) were determined in the stomach and intestine of adult mudskipper B. pectinirostris and Chinese black sleeper B. sinensis. The results showed that the activities of protease, BAL and alpha-amylase in the intestine of B. pectinirostris were significantly (P 0.05), while BAL and alpha-amylase activities of the intestine were significantly (P 0.05). BAL activities of the stomach and intestine in B. sinensis were significantly (P < 0.05) higher than those in B. pectinirostris, while alpha-amylase activities of the stomach and intestine in B. pectinirostris were significantly (P < 0.05) higher than those in B. sinensis. The ratios of P/BAL, A/P and A/BAL of the digestive tract in B. pectinirostris were 1.5, 107.3 and 158.6, respectively; and those in B. sinensis were 0.2, 1.6 and 0.2, respectively. It can be concluded that food digestion in the adult B. pectinirostris is mainly carried out in the intestine, whereas in the adult B. sinensis it is initiated in the stomach and finishes in the intestine. The activities of BAL and alpha-amylase in B. pectinirostris and B. sinensis are well correlated with their diets. However, a clear-cut correlation between protease activity and diets is not found in these two species.Natural Science Foundation of China [40476056]; Key Projects of Science and Technology of Fujian Province [2003, 26, 2004SZ01-02