Distribution of mercury species in different tissues and trophic levels of commonly consumed fish species from the south Bay of Biscay (France)

The low biomagnification of total mercury (THg) and methylmercury (MeHg) in commercially important marine fish from the south coast of China has been demonstrated through the analysis of stable carbon and nitrogen isotopes. In this study, levels of THg, MeHg and stable carbon and nitrogen isotope ratios were determined. Stable isotope signatures of carbon and nitrogen (13C/12C, 15N/14N) were used to trace the carbon flow and reconstruct trophic interactions. Levels of THg and MeHg in fish muscle samples were <220ngg–1. The trophic levels of sampled fish ranged from 2.31 to 5.03. The trophic magnification slopes were ~0.1 for both THg and MeHg, whereas the trophic magnification factor showed that the average biomagnification of THg and MeHg per trophic level was 3.02 and 2.87ngHgg–1 respectively along fish food chains, indicating low biomagnification potential of these mercury species. The low concentrations of MeHg and low biomagnification of mercury in marine fish may result from the trophic levels and habitats of these fish.

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Purpleback Flying Squid Sthenoteuthis oualaniensis in the South China Sea: Growth, Resources and Association with the Environment

Water ◽

10.3390/w13010065 ◽

2020 ◽

Vol 13 (1) ◽

pp. 65

Author(s):

Chunxu Zhao ◽

Chunyan Shen ◽

Andrew Bakun ◽

Yunrong Yan ◽

Bin Kang

Keyword(s):

South China Sea ◽

South China ◽

The South China Sea ◽

Biological Characteristics ◽

Trophic Levels ◽

Sea Surface ◽

Height Anomaly ◽

The South ◽

China Sea ◽

Sthenoteuthis Oualaniensis

The purpleback flying squid (Ommastrephidae: Sthenoteuthis oualaniensis) is an important species at higher trophic levels of the regional marine ecosystem in the South China Sea (SCS), where it is considered to show the potential for fishery development. Accordingly, under increasing climatic and environmental changes, understanding the nature and importance of various factors that determine the spatial and temporal distribution and abundance of S. oualaniensis in the SCS is of great scientific and socio-economic interest. Using generalized additive model (GAM) methods, we analyzed the relationship between available environmental factors and catch per unit effort (CPUE) data of S. oualaniensis. The body size of S. oualaniensis in the SCS was relatively small (<19.4 cm), with a shorter lifespan than individuals in other seas. The biological characteristics indicate that S. oualaniensis in the SCS showed a positive allometric growth, and could be suitably described by the logistic growth equation. In our study, the sea areas with higher CPUE were mainly distributed at 10°–11° N, with a 27–28 °C sea surface temperature (SST) range, a sea surface height anomaly (SSHA) of −0.05–0.05 m, and chlorophyll-a concentration (Chl-a) higher than 0.18 μg/L. The SST was the most important factor in the GAM analysis and the best fitting GAM model explained 67.9% of the variance. Understanding the biological characteristics and habitat status of S. oualaniensis in the SCS will benefit the management of this resource.

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Optimization of Acetylcholinesterase and Metabolic Enzyme Activity in Multiple Fish Species

Water Quality Research Journal ◽

10.2166/wqrj.2007.013 ◽

2007 ◽

Vol 42 (2) ◽

pp. 101-110 ◽

Cited By ~ 3

Author(s):

Eugene T. Georgiades ◽

Douglas A. Holdway

Keyword(s):

Fish Species ◽

Cholinesterase Inhibitors ◽

Citrate Synthase ◽

Trophic Levels ◽

Metabolic Enzyme ◽

Ache Inhibition ◽

Metabolic Enzyme Activity ◽

Laboratory Investigations ◽

The Brain ◽

Critical Aspects

Abstract An examination of acetylcholinesterase (AChE), citrate synthase (CS) and lactate dehydrogenase (LDH) activities in the brains of a range of fish species, occupying different trophic levels, is useful to investigate the full extent of the effects of sublethal or pulse exposures to pesticides. This investigation explores the optimization of microplate procedures for AChE, CS and LDH measurements in the brain tissue of species commonly used in laboratory investigations and those common to Canadian watersheds. A microplate assay was optimized for the measurement of AChE in the brain homogenates of seven fish species. The critical aspects of this assay requiring optimization were pH, substrate concentration and tissue dilution. Incubation with specific cholinesterase inhibitors indicated that enzymatic activity in the brain homogenates of each species was attributed to AChE only. Microplate assays were also optimized for the measurement of the metabolic enzymes, CS and LDH, in the brain homogenates of six fish species. For these assays, low interspecies variability was exhibited between optimized factors including pH, substrate, chromogen and cofactor concentrations. For each assay optimized, enzyme activities in the brain homogenates were stable for 2 to 3 hours post-thaw. Results from the present study will aid future ecotoxicological investigations of the potential impacts of AChE inhibition on neuronal glucose metabolism.

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The first unified inventory of non-native fishes of the South Caucasian countries, Armenia, Azerbaijan, and Georgia

Knowledge and Management of Aquatic Ecosystems ◽

10.1051/kmae/2021028 ◽

2021 ◽

pp. 32

Author(s):

Tatia Kuljanishvili ◽

Levan Mumladze ◽

Bella Japoshvili ◽

Namig Mustafayev ◽

Shaig Ibrahimov ◽

...

Keyword(s):

Black Sea ◽

Fish Species ◽

Caspian Sea ◽

Native Species ◽

Biological Diversity ◽

Native Fish ◽

The Black Sea ◽

The South ◽

In The Wild ◽

Native Fishes

The South Caucasus (SC) region is recognized for its high biological diversity and various endemic animal taxa. The area has experienced many fish introductions over the years, but the overall information about non-native fishes in the three SC countries, Armenia, Azerbaijan, and Georgia did not exist. Although these three countries belong to the Kura River drainage, Caspian Sea basin (only the western half of Georgia drains into the Black Sea), the legislative framework for each country regarding introduction of non-native fish species and their treatment is different and poorly developed. The goal of the present study was to make an initial inventory of non-native fish species in the three SC countries, and summarize the existing knowledge as a basis for future risk assessment models and formulation of regional management policies. Here, we present a unified list of 27 non-native species recorded in the wild in Armenia, Azerbaijan, and Georgia. Among these 27 species, eight were translocated from the Black Sea basin to the Caspian Sea basin. Out of these 27 non-native fishes, 15 species have become established (three of them being considered invasive) and six fish species could not survive in the wild.

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‘Taking Fishers’ Knowledge to the Lab’: An Interdisciplinary Approach to Understand Fish Trophic Relationships in the Brazilian Amazon

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.723026 ◽

2021 ◽

Vol 9 ◽

Author(s):

Paula Evelyn Rubira Pereyra ◽

Gustavo Hallwass ◽

Mark Poesch ◽

Renato Azevedo Matias Silvano

Keyword(s):

Stable Isotopes ◽

Food Webs ◽

Fish Species ◽

Trophic Interactions ◽

Brazilian Amazon ◽

Trophic Levels ◽

Trophic Relationships ◽

Ecological Knowledge ◽

Data Limitations ◽

Combining Data

Trophic levels can be applied to describe the ecological role of organisms in food webs and assess changes in ecosystems. Stable isotopes analysis can assist in the understanding of trophic interactions and use of food resources by aquatic organisms. The local ecological knowledge (LEK) of fishers can be an alternative to advance understanding about fish trophic interactions and to construct aquatic food webs, especially in regions lacking research capacity. The objectives of this study are: to calculate the trophic levels of six fish species important to fishing by combining data from stable isotopes analysis and fishers’ LEK in two clear water rivers (Tapajós and Tocantins) in the Brazilian Amazon; to compare the trophic levels of these fish between the two methods (stable isotopes analysis and LEK) and the two rivers; and to develop diagrams representing the trophic webs of the main fish prey and predators based on fisher’s LEK. The fish species studied were Pescada (Plagioscion squamosissimus), Tucunaré (Cichla pinima), Piranha (Serrasalmus rhombeus), Aracu (Leporinus fasciatus), Charuto (Hemiodus unimaculatus), and Jaraqui (Semaprochilodus spp.). A total of 98 interviews and 63 samples for stable isotopes analysis were carried out in both rivers. The average fish trophic levels did not differ between the stable isotopes analysis and the LEK in the Tapajós, nor in the Tocantins Rivers. The overall trophic level of the studied fish species obtained through the LEK did not differ from data obtained through the stable isotopes analysis in both rivers, except for the Aracu in the Tapajós River. The main food items consumed by the fish according to fishers’ LEK did agree with fish diets as described in the biological literature. Fishers provided useful information on fish predators and feeding habits of endangered species, such as river dolphin and river otter. Collaboration with fishers through LEK studies can be a viable approach to produce reliable data on fish trophic ecology to improve fisheries management and species conservation in tropical freshwater environments and other regions with data limitations.

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Variability in the air–sea interaction patterns and timescales within the south-eastern Bay of Biscay, as observed by HF radar data

Ocean Science ◽

10.5194/os-9-399-2013 ◽

2013 ◽

Vol 9 (2) ◽

pp. 399-410 ◽

Cited By ~ 6

Author(s):

A. Fontán ◽

G. Esnaola ◽

J. Sáenz ◽

M. González

Keyword(s):

Radar Data ◽

Hf Radar ◽

Bay Of Biscay ◽

Interaction Patterns ◽

The South ◽

South Eastern ◽

Continental Shelves ◽

Surface Circulation ◽

Spatial Coverage ◽

Current Interaction

Abstract. Two high-frequency (HF) radar stations were installed on the coast of the south-eastern Bay of Biscay in 2009, providing high spatial and temporal resolution and large spatial coverage of currents in the area for the first time. This has made it possible to quantitatively assess the air–sea interaction patterns and timescales for the period 2009–2010. The analysis was conducted using the Barnett–Preisendorfer approach to canonical correlation analysis (CCA) of reanalysis surface winds and HF radar-derived surface currents. The CCA yields two canonical patterns: the first wind–current interaction pattern corresponds to the classical Ekman drift at the sea surface, whilst the second describes an anticyclonic/cyclonic surface circulation. The results obtained demonstrate that local winds play an important role in driving the upper water circulation. The wind–current interaction timescales are mainly related to diurnal breezes and synoptic variability. In particular, the breezes force diurnal currents in waters of the continental shelf and slope of the south-eastern Bay. It is concluded that the breezes may force diurnal currents over considerably wider areas than that covered by the HF radar, considering that the northern and southern continental shelves of the Bay exhibit stronger diurnal than annual wind amplitudes.

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Evidence of cryptic species in the blenniid Cirripectes alboapicalis species complex, with zoogeographic implications for the South Pacific

ZooKeys ◽

10.3897/zookeys.810.28887 ◽

2018 ◽

Vol 810 ◽

pp. 127-138 ◽

Cited By ~ 4

Author(s):

Erwan Delrieu-Trottin ◽

Libby Liggins ◽

Thomas Trnski ◽

Jeffrey T. Williams ◽

Valentina Neglia ◽

...

Keyword(s):

Cryptic Species ◽

Geographic Distribution ◽

Fish Species ◽

Species Complex ◽

Genetic Relationships ◽

South Pacific ◽

The South ◽

Rapa Nui ◽

Distribution Ranges ◽

Geographic Distributions

Rapa Nui, commonly known as Easter Island (Chile), is one of the most isolated tropical islands of the Pacific Ocean. The island location of Rapa Nui makes it the easternmost point of the geographic ranges for many western Pacific fish species that are restricted to the subtropical islands south of 20°S latitude. The blenniid fish speciesCirripectesalboapicalishas been thought to have one of the most extensive geographic distribution ranges among these southern subtropical fish species, extending from the southern Great Barrier Reef to Rapa Nui. A phylogenetic analysis was conducted to determine the taxonomic status of the species. The results provide genetic evidence that suggests that this formerly South Pacific-wide species comprises at least three cryptic species with allopatric geographic distributions. The analyses reveal the geographic distributions of these clades and their genetic relationships with each other, and with other species within the genusCirripectes. The processes that culminated in the current geographic distribution of this species complex and the zoogeographic implications of this finding for the South Pacific region are discussed.

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DNA barcoding reveals a high incidence of fish species misrepresentation and substitution on the South African market

Food Research International ◽

10.1016/j.foodres.2011.11.011 ◽

2012 ◽

Vol 46 (1) ◽

pp. 30-40 ◽

Cited By ~ 88

Author(s):

Donna-Mareè Cawthorn ◽

Harris Andrew Steinman ◽

R. Corli Witthuhn

Keyword(s):

Dna Barcoding ◽

South African ◽

Fish Species ◽

The South ◽

High Incidence

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The sighting of pygmy killer whales (Feresa attenuata) in the southern Bay of Biscay and their association with cetacean calves

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315402005799 ◽

2002 ◽

Vol 82 (3) ◽

pp. 509-511 ◽

Cited By ~ 5

Author(s):

A.D. Williams ◽

R. Williams ◽

T. Brereton

Keyword(s):

Killer Whale ◽

South Atlantic ◽

First Year ◽

Bay Of Biscay ◽

Killer Whales ◽

The South ◽

Tropical Waters ◽

New Born ◽

Close Proximity

The pygmy killer whale Feresa attenuata is a poorly understood species that occurs in tropical and warm sub-tropical waters worldwide. The true range of these animals is not well established and there have been reports of them in temperate waters of the South Atlantic and Pacific Oceans. At 1746 h on 24 April 1997 at 45°15′76″N 30°56′54″W the first of two groups of small robust cetaceans were observed by experienced cetacean observers during a survey carried out aboard the P&O Portsmouth cruise ferry ‘Pride of Bilbao’. At 1820 at position 45°25′96″N 40°00′94″W on the same day a second group of animals of this species was encountered. In both cases the cetaceans were in close proximity to cetaceans with new born or first year calves. Identification information was recorded by the observers and the animals were identified as pygmy killer whales. These records represent the first in the Bay of Biscay and the most northerly records for this species.

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