Inter-annual fluctuation in the population structure of an estuarine fish: Influence of environmental drivers

The unusual and prolonged occurrence of rare and poorly known dinoflagellate Prorocentrum arcuatum in the phytoplankton of the shallow aquaculture site in Medulin Bay was recorded from July 2013 to October 2014. This enabled us to investigate changes in abundance and environmental drivers of P. arcuatum population dynamics in natural conditions, and to provide first detailed description of P. arcuatum from field samples based on SEM images. During 15 months of observations we also recorded seasonal variability in P. arcuatum cell size. The optimum physical conditions for P. arcuatum proliferation were reached in autumn 2013, during the narrow temperature range between 19.6 oC – 20.4 oC, and salinity between 36.7 - 37.7. Despite the general similarity in physical conditions in autumn 2014, this increase in the abundance of P. arcuatum was not repeated, which might be connected to higher competition due to observed interannual changes in phytoplankton population structure.

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Stable genetic structure and connectivity in pollution-adapted and nearby pollution-sensitive populations of Fundulus heteroclitus

Royal Society Open Science ◽

10.1098/rsos.171532 ◽

2018 ◽

Vol 5 (5) ◽

pp. 171532 ◽

Cited By ~ 1

Author(s):

Joaquin C. B. Nunez ◽

Leann M. Biancani ◽

Patrick A. Flight ◽

Diane E. Nacci ◽

David M. Rand ◽

...

Keyword(s):

Population Structure ◽

Genetic Variation ◽

Fundulus Heteroclitus ◽

Isolation By Distance ◽

Spatial Scales ◽

Purifying Selection ◽

Spatial Distance ◽

Estuarine Fish ◽

Synonymous Mutations ◽

Microsatellite Analyses

Populations of the non-migratory estuarine fish Fundulus heteroclitus inhabiting the heavily polluted New Bedford Harbour (NBH) estuary have shown inherited tolerance to local pollutants introduced to their habitats in the past 100 years. Here we examine two questions: (i) Is there pollution-driven selection on the mitochondrial genome across a fine geographical scale? and (ii) What is the pattern of migration among sites spanning a strong pollution gradient? Whole mitochondrial genomes were analysed for 133 F. heteroclitus from seven nearby collection sites: four sites along the NBH pollution cline (approx. 5 km distance), which had pollution-adapted fish, as well as one site adjacent to the pollution cline and two relatively unpolluted sites about 30 km away, which had pollution-sensitive fish. Additionally, we used microsatellite analyses to quantify genetic variation over three F. heteroclitus generations in both pollution-adapted and sensitive individuals collected from two sites at two different time points (1999/2000 and 2007/2008). Our results show no evidence for a selective sweep of mtDNA in the polluted sites. Moreover, mtDNA analyses revealed that both pollution-adapted and sensitive populations harbour similar levels of genetic diversity. We observed a high level of non-synonymous mutations in the most polluted site. This is probably associated with a reduction in N e and concomitant weakening of purifying selection, a demographic expansion following a pollution-related bottleneck or increased mutation rates. Our demographic analyses suggest that isolation by distance influences the distribution of mtDNA genetic variation between the pollution cline and the clean populations at broad spatial scales. At finer scales, population structure is patchy, and neither spatial distance, pollution concentration or pollution tolerance is a good predictor of mtDNA variation. Lastly, microsatellite analyses revealed stable population structure over the last decade.

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ENVIRONMENTAL DRIVERS OF FISH ASSEMBLAGES FROM THE SHALLOW INFRALITTORAL AREAS OF THE PARANAGUÁ BAY, SOUTHERN BRAZIL

Oecologia Australis ◽

10.4257/oeco.2020.2404.14 ◽

2020 ◽

Vol 24 (04) ◽

pp. 917-927

Author(s):

Paula Nakayama ◽

◽

Alberto Carvalho Peret ◽

Johnatas Adelir-Alves ◽

Olímpio Rafael Cardoso ◽

...

Keyword(s):

Fish Assemblages ◽

Diversity Index ◽

Abiotic Factors ◽

Sampling Site ◽

Fish Fauna ◽

Environmental Drivers ◽

Estuarine Fish ◽

Otter Trawl ◽

Paranaguá Bay ◽

Wiener Diversity Index

The composition of estuarine fish fauna is dynamic and complex. Despite the variation in fish fauna in estuaries, it is possible to observe some species associated with microhabitats. The assemblage composition of these communities is apparently derived from habitat selection. The aim of this study was to assess the structure of the demersal fish fauna of the Paranaguá Bay and its relationship with biotic and abiotic factors. To this end, monthly collections were conducted using an otter trawl, from October 1999 to September 2000, at five sites in the shallow infralittoral. Biotic (organic matter, and invertebrates) and abiotic factors (salinity, temperature, pH, dissolved oxygen, seston, and nutrients) were recorded during sampling. A total of 6,623 individuals were captured, belonging to 2 species of Chondrichthyes and 53 species of Actinopterygii (26 families). Sciaenidae was the most representative in terms of richness, with 11 species, and Ariidae was the most representative in terms of abundance. The catfish Cathorops spixii was the most abundant species, representing 21 % of the entire catch. There were significant differences in the composition and abundance of the fish fauna among the studied areas, as evidenced by the Shannon-Wiener diversity index. Such differences seem to be related to the complexity of habitats, which occur due to different types of bottom cover found at each sampling site. The abiotic variables indicated little influence on the structure of the fish assembly. These results contribute to a better understanding of the fish fauna from the shallow infralittoral areas of the Paranaguá Bay, and provide data to decision makers for better implementation of management and conservation measures.

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Molecular ecology meets remote sensing: environmental drivers to population structure of humpback dolphins in the Western Indian Ocean

Heredity ◽

10.1038/hdy.2011.21 ◽

2011 ◽

Vol 107 (4) ◽

pp. 349-361 ◽

Cited By ~ 28

Author(s):

M Mendez ◽

A Subramaniam ◽

T Collins ◽

G Minton ◽

R Baldwin ◽

...

Keyword(s):

Remote Sensing ◽

Population Structure ◽

Indian Ocean ◽

Molecular Ecology ◽

Western Indian Ocean ◽

Environmental Drivers

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Lingering Chukchi Sea sea ice and Chukchi Sea mean winds influence population age structure of euphausiids (krill) found in the bowhead whale feeding hotspot near Pt. Barrow, Alaska

PLoS ONE ◽

10.1371/journal.pone.0254418 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254418

Author(s):

Carin J. Ashjian ◽

Stephen R. Okkonen ◽

Robert G. Campbell ◽

Philip Alatalo

Keyword(s):

Population Structure ◽

Sea Ice ◽

Interannual Variability ◽

Chukchi Sea ◽

Late Spring ◽

Bowhead Whale ◽

Environmental Drivers ◽

Sea Ice Extent ◽

Krill Abundance ◽

Spring Sea Ice

Interannual variability in euphausiid (krill) abundance and population structure and associations of those measures with environmental drivers were investigated in an 11-year study conducted in late August–early September 2005–2015 in offshelf waters (bottom depth > 40 m) in Barrow Canyon and the Beaufort Sea just downstream of Distributed Biological Observatory site 5 (DBO5) near Pt. Barrow, Alaska. Statistically-significant positive correlations were observed among krill population structure (proportion of juveniles and adults), the volume of Late Season Melt Water (LMW), and late-spring Chukchi Sea sea ice extent. High proportions of juvenile and adult krill were seen in years with larger volumes of LMW and greater spring sea ice extents (2006, 2009, 2012–2014) while the converse, high proportions of furcilia, were seen in years with smaller volumes of LMW and lower spring sea ice extent (2005, 2007, 2010, 2011, 2015). These different life stage, sea ice and water mass regimes represent integrated advective responses to mean fall and/or spring Chukchi Sea winds, driven by prevailing atmospheric pressure distributions in the two sets of years. In years with high proportions of juveniles and adults, late-spring and preceding-fall winds were weak and variable while in years with high proportions of furcilia, late-spring and preceding-fall winds were strong, easterly and consistent. The interaction of krill life history with yearly differences in the northward transports of krill and water masses along with sea ice retreat determines the population structure of late-summer krill populations in the DBO5 region near Pt. Barrow. Years with higher proportions of mature krill may provide larger prey to the Pt. Barrow area bowhead whale prey hotspot. The characteristics of prey near Pt. Barrow is dependent on krill abundance and size, large-scale environmental forcing, and interannual variability in recruitment success of krill in the Bering Sea.

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