Predicting mercury levels in yellow perch: use of water chemistry, trophic ecology, and spatial traits

2001 ◽  
Vol 58 (7) ◽  
pp. 1419-1429 ◽  
Author(s):  
Ben K Greenfield ◽  
Thomas R Hrabik ◽  
Chris J Harvey ◽  
Stephen R Carpenter

Recent research suggests that wetland abundance surrounding lakes, fish trophic position, and fish community composition may influence the bioavailability of mercury (Hg) to fish. To compare the importance of these spatial and biological factors to chemical factors known to influence bioavailability, we determined the relationship between 24 lake traits and Hg concentrations in yellow perch (Perca flavescens; whole fish samples) for 43 northern Wisconsin lakes. Independent variables included biological traits such as fish trophic position and body condition, spatial traits such as lake hydrologic position and surrounding wetland abundance, and chemical traits such as pH and water color. The strongest predictor of fish Hg levels was pH (R2 = 0.42; p < 0.002). Of the biological traits measured, yellow perch body condition explained significant additional variation (final R2 = 0.54; p = 0.024). Trophic position explained limited variability and population abundance of planktivores and piscivores were not correlated to perch Hg levels. Regression tree models indicated that small lakes with greater than 6% wetland in their watershed have moderately elevated fish Hg levels. Our results indicate that within-lake chemistry and fish growth patterns are stronger correlates of Hg levels in yellow perch than spatial traits, trophic position, or fish community attributes.

2021 ◽  
Author(s):  
Vanessa De Santis ◽  
Silvia Quadroni ◽  
Robert J. Britton ◽  
Antonella Carosi ◽  
Catherine Gutmann Roberts ◽  
...  

Abstract Genetic introgression with native species is recognized as a detrimental impact resulting from biological invasions involving taxonomically similar invaders. Whilst the underlying genetic mechanisms are increasingly understood, the ecological consequences of introgression are relatively less studied, despite their utility for increasing knowledge on how invasion impacts can manifest. Here, the ecological consequences of genetic introgression from an invasive congener were tested using the endemic barbel populations of central Italy, where the invader was the European barbel Barbus barbus. Four populations of native Barbus species (B. plebejus and B. tyberinus) were studied: two purebred and two completely introgressed with alien B. barbus. Across the four populations, differences in their biological traits (growth, body condition and population demographic structure) and trophic ecology (gut content analysis and stable isotope analysis) were tested. While all populations had similar body condition and were dominated by fish up to 2 years of age, the introgressed fish had substantially greater lengths at the same age, with maximum lengths 410–460 mm in hybrids versus 340–360 mm in native purebred barbel. The population characterized by the highest number of introgressed B. barbus alleles (81%) had the largest trophic niche and a substantially lower trophic position than the other populations through their exploitation of a wider range of resources (e.g. small fishes and plants). These results attest that the genetic introgression of an invasive congener with native species can results in substantial ecological consequences, including potential cascading effects.


Author(s):  
Vanessa De Santis ◽  
Silvia Quadroni ◽  
Robert J. Britton ◽  
Antonella Carosi ◽  
Catherine Gutmann Roberts ◽  
...  

AbstractGenetic introgression with native species is recognized as a detrimental impact resulting from biological invasions involving taxonomically similar invaders. Whilst the underlying genetic mechanisms are increasingly understood, the ecological consequences of introgression are relatively less studied, despite their utility for increasing knowledge on how invasion impacts can manifest. Here, the ecological consequences of genetic introgression from an invasive congener were tested using the endemic barbel populations of central Italy, where the invader was the European barbel Barbus barbus. Four populations of native Barbus species (B. plebejus and B. tyberinus) were studied: two purebred and two completely introgressed with alien B. barbus. Across the four populations, differences in their biological traits (growth, body condition and population demographic structure) and trophic ecology (gut content analysis and stable isotope analysis) were tested. While all populations had similar body condition and were dominated by fish up to 2 years of age, the introgressed fish had substantially greater lengths at the same age, with maximum lengths 410–460 mm in hybrids versus 340–360 mm in native purebred barbel. The population characterized by the highest number of introgressed B. barbus alleles (81 %) had the largest trophic niche and a substantially lower trophic position than the other populations through its exploitation of a wider range of resources (e.g. small fishes and plants). These results attest that the genetic introgression of an invasive congener with native species can result in substantial ecological consequences, including the potential for cascading effects.


1984 ◽  
Vol 41 (1) ◽  
pp. 20-29 ◽  
Author(s):  
Keith M. Somers ◽  
Harold H. Harvey

Based on chemical criteria such as excess sulfate and low bicarbonate relative to cation, 50 lakes in the Wawa area show some degree of acidification. We conclude that the observed perturbations of lake chemistry and fish populations were primarily the result of smelting operations in the Wawa area. Six lakes have acidified to pH 3.1–4.1 and had high concentrations of metals such as Al, Mn, and Fe. Most of the lakes were in contact with felsic and mafic metavolcanic rocks containing minerals such as siderite, and only a few lakes had granitic basins. The six most acidic lakes contained no fishes and some lakes in the fume-kill area had known losses of brook trout (Salvelinus fontinalis) and lake trout (Salvelinus namaycush) populations. Based on a regression of number of species on lake area for 34 lakes, it was estimated that 83 fish populations have been lost from 16 lakes. Fish community changes were difficult to assess due to the distributions of species in the four watersheds. The northern pike (Esox lucius)–walleye (Stizostedion vitreum vitreum)–yellow perch (Perca flavescens) community was found now to be present only in lakes distant from the source of emissions. The fish community with brook and/or lake trout as the top predator was the most affected.


Author(s):  
Osei O. Antobre ◽  
Nat Owusu-Prempeh ◽  
Michael J. Twumasi-Ankrah

The study evaluated the fish community assemblage in the sections of the Subri river, the Ankobra river, and the “galamsey” pond within the Prestea community as impacted by alluvial mining activities. Gill nets of length 10 m and mesh size 1.27 cm were used to trap fish of average length 25.25 cm whilst cane baskets were used to trap fish of average width 10.40 cm using the catch and recapture method. All the 46 fish samples identified belong to 10 genera and 5 families. The Chichlidae was the dominant family, accounting for 60% of the total families observed. With an H’ index of 1.57 the Subri river had the most fish diversity in comparison with the Ankobra river and the “galamsey” pond, which had 1.21 and 0.71, respectively. Similarly, the Subri river had a more complex fish community structure than the Ankobra and “galamsey” pond. The dominant species, Oreochromis niloticus, has not yet been evaluated by the IUCN, but the least dominated Brienomyrus brachyistus could be regarded as “least concern”. Notwithstanding, these fish are essential for food by the local communities. There is a possibility that the alluvial mining might have influenced the complexities of fish species communities. Thus conservation efforts must be promoted to sustain fish communities and overall freshwater ecosystem health.


2017 ◽  
Vol 284 (1857) ◽  
pp. 20170923 ◽  
Author(s):  
José M. Riascos ◽  
Marco A. Solís ◽  
Aldo S. Pacheco ◽  
Manuel Ballesteros

The trophic flow of a species is considered a characteristic trait reflecting its trophic position and function in the ecosystem and its interaction with the environment. However, climate patterns are changing and we ignore how patterns of trophic flow are being affected. In the Humboldt Current ecosystem, arguably one of the most productive marine systems, El Niño-Southern Oscillation is the main source of interannual and longer-term variability. To assess the effect of this variability on trophic flow we built a 16-year series of mass-specific somatic production rate (P/B) of the Peruvian scallop ( Argopecten purpuratus ), a species belonging to a former tropical fauna that thrived in this cold ecosystem. A strong increase of the P/B ratio of this species was observed during nutrient-poor, warmer water conditions typical of El Niño, owing to the massive recruitment of fast-growing juvenile scallops. Trophic ecology theory predicts that when primary production is nutrient limited, the trophic flow of organisms occupying low trophic levels should be constrained (bottom-up control). For former tropical fauna thriving in cold, productive upwelling coastal zones, a short time of low food conditions but warm waters during El Niño could be sufficient to waken their ancestral biological features and display massive proliferations.


2005 ◽  
Vol 62 (12) ◽  
pp. 2727-2739 ◽  
Author(s):  
Marcus Sundbom ◽  
Markus Meili

One decade after the Chernobyl fallout, the variability of 137Cs activity concentrations among fish within a Swedish lake was >20-fold based on 1361 individuals from seven species collected continually during 1996–1999. Of the total variability, 64% was due to differences between species but only 7% due to temporal variation, which was 1.3-fold for the whole community and 1.3- to 2-fold for population means. Contamination increased with body size (0.6- to 6-fold) and decreased with body condition in most species (1.3-fold). Body size and time together accounted for about half of the total variation within populations. Fish 137Cs was related to differences in feeding ecology, both between and within populations. Biomagnification factors ranged from 2.4 to 5.8. Contamination was highest in piscivorous populations and individuals, intermediate in herbivores and zooplanktivores, and lowest in fish specialized in benthic invertebrates despite their association with contaminated sediments. The 137Cs variance within populations was not correlated with their niche width but moderately positively correlated with fish trophic position and strongly positively correlated with functional omnivory (diversity in prey 137Cs). We conclude that individual resource specialization is an important source of variation in 137Cs concentrations within fish populations.


Author(s):  
Víctor M. Muro-Torres ◽  
Felipe Amezcua ◽  
Raul E. Lara-Mendoza ◽  
John T. Buszkiewicz ◽  
Felipe Amezcua-Linares

The trophic ecology of the chihuil sea catfish Bagre panamensis was studied through high-resolution variations in its feeding habits and trophic position (TP) in the SE Gulf of California, relevant to sex, size and season. The combined use of stomach content (SCA) and stable isotope analysis (SIA) allowed us to perform these analyses and also estimate the TP of its preys. Results of this study show that the chihuil sea catfish is a generalist and opportunistic omnivore predator that consumes primarily demersal fish and peneid shrimps. Its diet did not vary with climatic season (rainy or dry), size or sex. Results from the SIA indicated high plasticity in habitat use and prey species. The estimated TP value was 4.19, which indicates a tertiary consumer from the soft bottom demersal community in the SE Gulf of California, preying on lower trophic levels, which aids in understanding the species' trophic role in the food web. Because this species and its prey are important to artisanal and industrial fisheries in the Gulf of California, diet assimilation information is useful for the potential establishment of an ecosystem-based fisheries management in the area.


2015 ◽  
Vol 20 (3) ◽  
pp. 170 ◽  
Author(s):  
Ahmad Zahid ◽  
M.F. Rahardjo ◽  
Lenny S Syafei ◽  
Rini Susilowati

Pengetahuan mengenai ekologi trofik merupakan dasar dalam memahami ekosistem secara keseluruhan yang dapat dijelaskan melalui pola hubungan trofik interspesies ataupun interserikat. Penelitian bertujuan untuk menjelaskan ekologi trofik meliputi indeks trofik dan jenis makanan dominan, serikat dan tingkat trofik, dan variasi spasial dan temporal komunitas ikan di estuari Segara Menyan. Pengambilan ikan contoh dilakukan setiap bulan pada zona berbeda. Ikan contoh dipisahkan berdasarkan waktu dan lokasi pengamatan, dianalisis isi saluran pencernaannya. Analisa data meliputi indeks vakuitas, jumlah total organisme makanan, jenis makanan dominan, luas relung makanan, dan tingkat trofik.  Pada pengamatan 106 spesies ikan, sebanyak 1-380 saluran pencernaan ikan diamati. Sebanyak lima dari 106 spesies memiliki nilai indeks vakuitas “0” dan jumlah makanan yang dikonsumsi bervariasi mulai dari empat hingga 27 jenis makanan. Secara umum, luas relung ikan adalah rendah berkisar 0,20-0,78 dan kebanyakan berada pada kisaran 0,20-0,48. Zooplankton merupakan jenis makanan paling dominan dikonsumsi oleh ikan. Komunitas ikan dikelompokkan dalam tujuh serikat trofik, yaitu detritivora, fitoplanktivora, zooplanktivora, zoobentivora, moluskivora, krustasivora, dan pisivora. Tingkat trofik komunitas ikan berkisar 2,05-4,73. Faktor perubahan ontogenetik, persediaan makanan, karakteristik habitat, dan ruaya beberapa spesies ikan memengaruhi variasi spasio-temporal jejaring makanan di Segara Menyan. Kata kunci: interaksi trofik, laguna, ikan, variasi spasio-temporal, serikat trofik Knowledge of trophic ecology is one way to understanding the whole ecosystem which explained by trophic relationship pattern (interspecies or interguild). The objective research was described of the trophic ecology, i.e. trophic index and dominant prey, trophic guild and trophic level, and spatio-temporal variation of fish community in Segara Menyan coastal lagoon. Fish were collected monthly for one year at three zones. Fish samples were placed in separate labelled plastic bags according to the time scale and location sampling, then gut contents were analyzed. The data of vacuity index, number of prey, prey dominant, diet breadth, and trophic level were analyzed. For each of 106 fish species, between 1 and 380 stomachs, were examined. The vacuity index was also different among species. Five of 106 species had a vacuity index of “0” and total number of food items consumed varied between fish species, ranging from three items to 27 items. The overall diet breadth (Bi) was relatively low among species, ranging from 0.20 to 0.78, with most of them between 0.20 and 0.48. Calanoid copepods comprised the most common food item consumed by all the fishes examined. Fishes occurring can be broadly categorized into seven different trophic guilds. The trophic level of fish communities ranged from 2.05 to 4.73. Spatio-temporal variation of food web was influenced of ontogenetic shift, food availability, habitat characteristic, and migration of some species in Segara Menyan coastal lagoon. Keywords: trophic interaction, lagoon, fishes, spatio-temporal variation, trophic guild


1991 ◽  
Vol 48 (S1) ◽  
pp. 8-12 ◽  
Author(s):  
Richard Ogutu-Ohwayo ◽  
R. E. Hecky

Fish introductions in Africa have been made at various spatial scales from small fish ponds to the largest lakes, primarily to sustain or increase production, though some were to develop sport fisheries and to control unwanted organisms. Some introductions have fulfilled their objective in the short term, but several "successful" introductions have created uncertainties about their long-term sustainability. Lates niloticus, Oreochromis niloticus, O. leucostictus, Tilapia melanopleura and T. zilli were introduced into Lakes Victoria and Kyoga in 1950's and early 1960's; by the 1980's L. niloticus and O. niloticus dominated the fisheries, having virtually eliminated a number of endemic species. In Lake Victoria, the loss of genetic diversity has been accompanied by a loss of trophic diversity; the transformation of the fish community coincided with profound eutrophication (algal blooms, fish kills, hypolimnetic anoxia) which might be related to alterations of the lake's food-web structure. By contrast, the introduction of a planktivore, Limnothrissa miodon into Lake Kivu and the Kariba reservoir has established highly successful fisheries with little effect on the pre-existing fish community or trophic ecology. The endemic species-rich African Great Lakes may be particularly sensitive to introductions. Species extinctions, introgressive hybridization and ecosystem alterations may occur following introductions.


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