Research

17 pages, 2735 KiB

Open AccessArticle

Changes in Fish Taxonomy Affect Freshwater Biogeographical Regionalisations: Insights from Greece

by Theocharis Vavalidis, Stamatis Zogaris, Alcibiades N. Economou, Athanasios S. Kallimanis and Dimitra C. Bobori

Water 2019, 11(9), 1743; https://0-doi-org.brum.beds.ac.uk/10.3390/w11091743 - 21 Aug 2019

Cited by 11 | Viewed by 4007

Abstract

Freshwater fishes are key indicators for delineating biogeographical maps worldwide. However, controversy in regional-scale ichthyogeographic boundaries still persists, especially in areas of high species endemicity, such as in Greece. One problem concerns the taxonomy of the fishes because there have been extensive changes, [...] Read more.

Freshwater fishes are key indicators for delineating biogeographical maps worldwide. However, controversy in regional-scale ichthyogeographic boundaries still persists, especially in areas of high species endemicity, such as in Greece. One problem concerns the taxonomy of the fishes because there have been extensive changes, mainly due to an increased splitting of species in recent years in Europe. Here, we explore why ichthyogeographic boundary disagreements and uncertainties in region-scale biogeographical units persist. We compare cluster analyses of river basin fish fauna in Greece using two taxonomic datasets: the older fish taxonomy (from 1991) and the current taxonomy that now follows the phylogenetic species concept (PSC), which has become widely established in Europe after 2007. Cluster analyses using the older fish taxonomy depicts only two major biogeographical regional divisions, while the current taxonomy defines four major regional divisions in mainland Greece. Interestingly, some older maps from the pre-PSC taxonomy era also similarly show four ichthyogeographic divisions in Greece and we can assume that the older biogeographical work did not solely use numerical taxonomy but followed an expert-guided synthesis; the older regional definitions have persisted quite well despite radical changes in Europe’s fish taxonomy. Through the prism of biodiversity conservation planning, we hope this review may help identify ways to help standardize policy-relevant biogeographical mapping. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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10 pages, 1665 KiB

Open AccessArticle

Mortality and Effect on Growth of Artemia franciscana Exposed to Two Common Organic Pollutants

by George Ekonomou, Alexios Lolas, Jeanne Castritsi-Catharios, Christos Neofitou, George D. Zouganelis, Nikolaos Tsiropoulos and Athanasios Exadactylos

Water 2019, 11(8), 1614; https://0-doi-org.brum.beds.ac.uk/10.3390/w11081614 - 04 Aug 2019

Cited by 14 | Viewed by 5831

Abstract

Acute toxicity and inhibition on growth of Artemia franciscana nauplii (Instar I-II) after exposure to the reference toxicants bisphenol a (BPA) and sodium dodecyl sulfate (SDS) were studied. LC₅₀ values were calculated and differences in body growth were recorded after 24, 48, [...] Read more.

Acute toxicity and inhibition on growth of Artemia franciscana nauplii (Instar I-II) after exposure to the reference toxicants bisphenol a (BPA) and sodium dodecyl sulfate (SDS) were studied. LC₅₀ values were calculated and differences in body growth were recorded after 24, 48, and 72 h of exposure to the toxicants. The results indicated that BPA had lower toxicity than SDS. Development of the nauplii was clearly influenced by duration of exposure. Growth inhibition was detected for both toxicants. Abnormal growth of the central eye of several Artemia nauplii after 72 h of exposure to BPA was also detected. Our results indicate that growth inhibition could be used as a valid endpoint for toxicity studies. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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17 pages, 1776 KiB

Open AccessArticle

Net Fisheries’ Métiers in the Eastern Mediterranean: Insights for Small-Scale Fishery Management on Kalymnos Island

by Kyriakoula Roditi and Dimitris Vafidis

Water 2019, 11(7), 1509; https://0-doi-org.brum.beds.ac.uk/10.3390/w11071509 - 21 Jul 2019

Cited by 9 | Viewed by 3676

Abstract

Small-scale fisheries constitute an important component of coastal human societies. The present study describes the small-scale net fisheries on Kalymnos Island (south-east Aegean Sea) that harbors the largest small-scale fleet in the eastern Mediterranean Sea. In addition, this study aims to evaluate their [...] Read more.

Small-scale fisheries constitute an important component of coastal human societies. The present study describes the small-scale net fisheries on Kalymnos Island (south-east Aegean Sea) that harbors the largest small-scale fleet in the eastern Mediterranean Sea. In addition, this study aims to evaluate their characteristics and economics. Relevant métiers were identified through a multivariate analysis by inputting the main resources and fishing gear data that were recorded during landings. Four main practices were observed being used as fishing gears, gillnets and trammel nets, targeting the species Mullus barbatus, Boops boops, Mullus surmuletus, Scorpaena porcus, and Sepia officinalis. Further analysis, which incorporated data concerning the type of the gear used, revealed 11 distinct métiers. Most of these métiers are practiced by other Mediterranean small-scale fisheries as well, in terms of target species, gear and seasonality. However, the métier that had its target species as B.boops is not practiced in other Mediterranean small-scale fisheries. The seasonal rotation of métiers was determined by the availability of different species rather than their market price. The results revealed the difference in fishing practice used by the fishermen in the study area compared to other fishing practices in the Mediterranean Sea. In particular, the fishermen of this study area targeted more species (B.boops) with a very low market price. They also provided essential information for the development and implementation of management plans aiming at the sustainability of small-scale fisheries. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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19 pages, 1777 KiB

Open AccessArticle

Grazing Potential—A Functional Plankton Food Web Metric for Ecological Water Quality Assessment in Mediterranean Lakes

by Georgia Stamou, Matina Katsiapi, Maria Moustaka-Gouni and Evangelia Michaloudi

Water 2019, 11(6), 1274; https://0-doi-org.brum.beds.ac.uk/10.3390/w11061274 - 18 Jun 2019

Cited by 12 | Viewed by 3184

Abstract

Grazing potential (GP, in % day⁻¹) was estimated for the plankton communities of 13 Greek lakes covering the trophic spectrum, in order to examine its sensitiveness in discriminating different classes of ecological water quality. Lakes with high GP values exhibited high [...] Read more.

Grazing potential (GP, in % day⁻¹) was estimated for the plankton communities of 13 Greek lakes covering the trophic spectrum, in order to examine its sensitiveness in discriminating different classes of ecological water quality. Lakes with high GP values exhibited high zooplankton biomass dominated by large cladocerans or/and calanoids while lakes with low GP values had increased phytoplankton biomass and/or domination of small-bodied zooplankton indicating intensive fish predation. GP successfully distinguished among ecological water quality classes (estimated using the phytoplankton water quality index PhyCoI) indicating its potential use as a metric for ecological water quality assessment. As a next step, PhyCoI index was modified to include GP as a metric in order to enhance the phytoplankton-based ecological status classification of lakes incorporating zooplankton as a supporting factor. The PhyCoI_GP successfully assessed the ecological water quality in accordance with PhyCoI classification whereas it was significantly correlated with the eutrophication proxy TSI_SD based on Secchi Depth. Thus, we propose to use the modified phytoplankton index PhyCoI_GP for monitoring the ecological water quality of lakes. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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11 pages, 1119 KiB

Open AccessArticle

Bio-Ecological Traits of Western Tubenose Goby Proterorhinus semilunaris (Heckel, 1837): A Key to Understand Its Invasion Success

by Gülşah Saç

Water 2019, 11(6), 1247; https://0-doi-org.brum.beds.ac.uk/10.3390/w11061247 - 14 Jun 2019

Cited by 2 | Viewed by 2458

Abstract

This study aims to contribute to the limited knowledge on the bio-ecological traits of the native Western tubenose goby, Proterorhinus semilunaris, which is considered to invade many inland waters in Europe and North America. During monthly sampling surveys from March 2012 to [...] Read more.

This study aims to contribute to the limited knowledge on the bio-ecological traits of the native Western tubenose goby, Proterorhinus semilunaris, which is considered to invade many inland waters in Europe and North America. During monthly sampling surveys from March 2012 to June 2013, the species was collected from the four stations in the Istranca River (Turkey) by electrofishing. The standard length and body weight of 310 samples varied between 1.4–6.1 cm and 0.08–7.09 g, respectively. The sex ratio of female to male was found to be 1.7:1.0, with a significant difference. The values of the exponent b in the length–weight relationship were approximately 3 for females, males, and all individuals, indicating an isometric growth. The size at first sexual maturity was 2.44 cm standard length (SL) for females and 2.29 cm SL for males. Absolute fecundity ranged from 56 to 344 eggs with a mean of 164 eggs. The food composition of the species comprised of 8 major groups: Insecta (Diptera, Ephemeroptera, Plecoptera, Odonata, Trichoptera, Coleoptera), Arachnida, Annelida, Gastropoda, Crustacea, Pisces, plant, and detritus. According to the results of modified index of relative importance (MI) and index of relative importance (IRI), insect and Diptera were the most prevalent prey for this fish. The present study has provided baseline information on the basic biological traits of the fish in its natural habitat for further understanding of this species success of invasion. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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11 pages, 3647 KiB

Open AccessArticle

Reproductive Cycle of the Edible Sea Urchin Paracentrotus lividus (Echinodermata: Echinoidae) in the Aegean Sea

by Dimitris Vafidis, Chryssanthi Antoniadou and Kyratso Kyriakouli

Water 2019, 11(5), 1029; https://0-doi-org.brum.beds.ac.uk/10.3390/w11051029 - 16 May 2019

Cited by 11 | Viewed by 4321

Abstract

The sustainable management of fisheries resources requires extensive knowledge of their reproductive biology, which is scarcely the case for marine invertebrates. Sea urchins are among the most intensively harvested invertebrates, since their gonads, or “roe”, constitute a highly appreciated gastronomic delicacy, causing a [...] Read more.

The sustainable management of fisheries resources requires extensive knowledge of their reproductive biology, which is scarcely the case for marine invertebrates. Sea urchins are among the most intensively harvested invertebrates, since their gonads, or “roe”, constitute a highly appreciated gastronomic delicacy, causing a severe decline in natural populations worldwide. In the Mediterranean, the typical commercial echinoid species is Paracentrotus lividus; its biology, however, has not been adequately studied in the Aegean Sea. Within this context, the present study examined the reproductive biology of the edible sea urchin, P. lividus, in the Aegean Sea (Pagasitikos Gulf) over a two-year period. Adult specimens were randomly collected by SCUBA diving (3–5 m) at monthly intervals to determine the gonad-somatic index, fecundity, and gametogenesis through the morphological and histological examination of the gonads. An annual reproductive cycle was defined in both years with a clear spawning peak in early spring, conforming to previous reports from other Mediterranean populations. A discrete secondary spawning period was also detected in early winter, as the species undergoes a second gametogenic event. These results are indicative for the increased reproductive potential of P. lividus in its south distributional range, suggesting a relevant revision of the official fishing season of the species. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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15 pages, 1612 KiB

Open AccessArticle

Diversity of Bacteria in Lakes with Different Chlorophyll Content and Investigation of Their Respiratory Activity through a Long-Term Microcosm Experiment

by Hera Karayanni, Sofia C. Macingo, Vasilis Tolis and Dimitrios Alivertis

Water 2019, 11(3), 467; https://0-doi-org.brum.beds.ac.uk/10.3390/w11030467 - 05 Mar 2019

Cited by 7 | Viewed by 3711

Abstract

Bacterial community structure and metabolism are critical factors for ecosystem functioning since they affect remineralization of nutrients and carbon flow. We used Illumina sequencing of 16SrRNA V3-V4 regions to investigate whether bacterial assemblage composition differs between four samples from two lakes in the [...] Read more.

Bacterial community structure and metabolism are critical factors for ecosystem functioning since they affect remineralization of nutrients and carbon flow. We used Illumina sequencing of 16SrRNA V3-V4 regions to investigate whether bacterial assemblage composition differs between four samples from two lakes in the geographic region of Epirus (Greece) characterized by distinct oligotrophic to eutrophic/hypereutrophic conditions as revealed by chlorophyll-a values. We found high similarity (>60%) for bacterial assemblages recovered from the two lakes when eutrophic/hypereutrophic conditions prevailed. Distinct bacterial communities appeared in oligotrophic and mesotrophic waters. Low temperature was occasionally an important factor in shaping the bacterial community. In parallel, microcosm experiments were performed to estimate respiration rates of bacterioplankton at in situ temperature and under a 2 °C temperature increase scenario. Differently assembled communities were found to display similar rates except under hypereutrophic conditions when respiration increased significantly, leading to hypoxic conditions. Temperature increase did not affect respiration rates. Overall this study indicated a clear differentiation of bacterial communities between sites of different trophic state. However, different communities responded similarly under a specific range of chlorophyll-a values and resisted small scale temperature perturbations. Different results were found for hypereutrophic conditions and this has implications for ecosystems functioning, given the increasing occurrence of eutrophication events. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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13 pages, 6266 KiB

Open AccessArticle

Skeletal Deformity of Scoliosis in Gilthead Seabreams (Sparus aurata): Association with Changes to Calcium-Phosphor Hydroxyapatite Salts and Collagen Fibers

by Vaia Boursiaki, Charitini Theochari, Stefanos P. Zaoutsos, Eleni Mente, Dimitris Vafidis, Chrisoula Apostologamvrou and Panagiotis Berillis

Water 2019, 11(2), 257; https://0-doi-org.brum.beds.ac.uk/10.3390/w11020257 - 01 Feb 2019

Cited by 11 | Viewed by 4789

Abstract

The development of skeletal deformities in seabream farming affects fish growth, survival, and production costs. Collagen distribution in different fish tissues might be correlated with swimming behavior. This study investigates whether scoliosis in seabreams is associated with changes to calcium-phosphor hydroxyapatite salts and [...] Read more.

The development of skeletal deformities in seabream farming affects fish growth, survival, and production costs. Collagen distribution in different fish tissues might be correlated with swimming behavior. This study investigates whether scoliosis in seabreams is associated with changes to calcium-phosphor hydroxyapatite salts and collagen fibril morphology. Samples of decalcified vertebrae of scoliotic and non-scoliotic seabreams were examined with transmission electron microscopy and collagen micrographs were taken and analyzed. The mineral content, modulus of elasticity, and morphology of the vertebrae were also determined. The results indicated that fish with scoliosis had significant smaller mean vertebral collagen fibril diameters than the controls. Vertebrae in abdominal and caudal regions of the scoliotic seabreams appeared to be smaller than the respective vertebrae of the non-deformed seabreams. The calcium (Ca) and phosphorus (P) amounts of vertebrae of both scoliotic and non-scoliotic seabreams were not affected by the scoliosis deformity. The modulus of elasticity showed that the vertebrae from seabreams with scoliosis were more flexible than the vertebrae from seabreams without any skeletal deformity. The mechanical properties of bone are crucially dependent on collagen structure. Hence, how the vertebral column collagen of juvenile fish is related to the mechanism of deformities requires further investigation in order to provide a risk-reducing strategy to increase fish performance in aquaculture. Full article

(This article belongs to the Special Issue Selected Papers from HydroMediT 2018)

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