Trophic level scales positively with body size in fishes

Romanuk, Tamara N.; Hayward, April; Hutchings, Jeffrey A.

doi:10.1111/j.1466-8238.2010.00579.x

Cited by 202 publications

(184 citation statements)

References 32 publications

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“…It is consistent with the tendency for fisheries to first exploit species at higher trophic levels and subsequently move down the food web (10), as animals at higher trophic levels are typically larger than their counterparts at lower trophic levels (11). Size-biased vulnerabilities operate within species as well (12,13), reflecting a unique human propensity to cull the largest members of a population (14).…”

mentioning

confidence: 55%

“…The preferential threat to large-bodied marine animals poses a danger to ecosystems disproportionate to the percentage of threatened species. Large-bodied animals are critical to ecosystem function because of their preferential position at the top of food webs (11,23) and importance to nutrient cycling (24) and bioturbation of sediments (25). Removal of large-bodied predators can also trigger trophic cascades affecting many other species [e.g., (26)].…”

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confidence: 99%

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Ecological selectivity of the emerging mass extinction in the oceans

Payne

Bush

Heim

et al. 2016

Science

170

124

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To better predict the ecological and evolutionary effects of the emerging biodiversity crisis in the modern oceans, we compared the association between extinction threat and ecological traits in modern marine animals to associations observed during past extinction events using a database of 2497 marine vertebrate and mollusc genera. We find that extinction threat in the modern oceans is strongly associated with large body size, whereas past extinction events were either nonselective or preferentially removed smaller-bodied taxa. Pelagic animals were victimized more than benthic animals during previous mass extinctions but are not preferentially threatened in the modern ocean. The differential importance of large-bodied animals to ecosystem function portends greater future ecological disruption than that caused by similar levels of taxonomic loss in past mass extinction events.

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mentioning

confidence: 55%

mentioning

confidence: 99%

Ecological selectivity of the emerging mass extinction in the oceans

Payne

Bush

Heim

et al. 2016

Science

170

124

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show abstract

“…5). Salmonids tend to swallow their prey whole (Hart 1997) and thus can show a strong positive relationship between body size and trophic position (Romanuk et al 2011). Thus, if δ 15 N values were driven by trophic position alone, we should expect a positive relationship between fish size and δ 15 N. That we saw a negative relationship suggested that variation in nitrogen isotopes may have been related to foraging location and driven by nitrogen sources at the base of the food web, rather than reflecting a trophic difference.…”

Section: Stable Isotopes and Fish Sizementioning

confidence: 99%

Four decades of foraging history: stock-specific variation in the carbon and nitrogen stable isotope signatures of Alaskan sockeye salmon

Johnson

Schindler²

2012

Mar. Ecol. Prog. Ser.

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Broad-scale shifts in climate during the 20th century had large effects on the ecology of the North Pacific Ocean, including a substantial change in the composition of the dominant food web. Salmon production in Alaskan stocks increased with a concurrent shift of the Pacific Decadal Oscillation in 1977. Salmon production has since been persistently high through 2010, yet the biological mechanisms for this increase in production remain unclear. Carbon and nitrogen stable isotopes of sockeye salmon scales collected from 8 rivers in Bristol Bay between 1964 and 2003 were analyzed to assess whether the trophic ecology of these fish changed systematically over this period, during which there were substantial changes in oceanographic conditions. Isotope values were remarkably stable over the study despite substantial changes in salmon production and oceanographic conditions in this region. Our results also suggest river-specific patterns in the variation of stable isotopes through time; stable isotope changes were related to stock identity and showed some geographic organization. Larger salmon tended to have depleted δ 15 N and δ 13 C. Isotopic characteristics among rivers became more variable during the period of high ocean productivity (after the 1977 regime shift and before the 1989 regime shift). Some of the dominant signals of variation in stable isotope variation were related to important environmental physical processes, but they appear to have unique effects on the isotopic characteristics of stocks from different rivers, suggesting important connections between the ecology of sockeye salmon in freshwater and in the ocean. 460: 155-167, 2012 Changes in the climate regime during the mid1970s were also associated with large-scale changes in Pacific salmon (Oncorhynchus spp.) production (Mantua et al. 1997). Climate forcing, as captured by PDO dynamics, is correlated with salmon production such that small changes in the physical environment, such as nearshore warming and offshore cooling in the ocean, translated into substantial changes in fisheries production (Mantua et al. 1997). In addition, there was geographic organization in the responses of salmon production to climate change. Pacific salmon production in Alaska increased sharply after the late 1970s but declined substantially in Canada and the Pacific Northwest (Mantua et al. 1997, Hare et al. 1999. Although several studies have modeled variation in marine food webs in response to climate change that affects salmon survival (e.g. Francis et al. 1998, Beamish et al. 1999, Aydin et al. 2005, there has been little assessment of the patterns of marine salmon foraging in relation to climatic variation over the periods encompassing the major food web reorganization associated with shifts in the PDO. Thus, the linkages between changes in climate forcing variables, oceanographic conditions and the trophic ecology of Pacific salmon remain poorly understood. OPEN PEN ACCESS CCESSMar Ecol Prog SerThe term biocomplexity has been used to describe the div...

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“…top predators and prey) are limited by energetic constraints, whereas low trophic levels (i.e. primary and secondary consumers) are limited by morphological constraints as mouth opening capacity (Romanuk et al 2010). We did not use the common ratio between mouth opening length and head length as a proxy of trophic level (Clifton & Motta 1998, Upeniece 2011) because none of the studied species were capable of jaw protrusion (Schaeffer & Rosen 1961, Alexander 1967, Motta 1984, Westneat 2004.…”

Section: Interpretative Palaeoecological Synthesismentioning

confidence: 99%

“…Eusthenopteron kurshi estimated from Eusthenopteron foordi; electronic supplementary appendix -Annex II). The variable eTL is used as a proxy of body size (Cohen et al 1993, Jennings et al 2001, Emmerson & Raffaelli 2004, Romanuk et al 2010. Mouth position, size, shape, dentition, protrusion degree and eye size are indicators of diet (Clifton & Motta 1998).…”

mentioning

confidence: 99%

Early establishment of vertebrate trophic interactions: Food web structure in Middle to Late Devonian fish assemblages with exceptional fossilization

Chevrinais¹,

Jacquet²,

Cloutier³

2017

Bull. Geosci.

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In past and present ecosystems, trophic interactions determine material and energy transfers among species, regulating population dynamics and community stability. Food web studies in past ecosystems are helpful to assess the persistence of ecosystem structure throughout geological times and to explore the existence of general principles of food web assembly. We determined and compared the trophic structure of two Devonian fish assemblages [(1) the Escuminac assemblage (ca. 380 Ma), Miguasha, eastern Canada and (2) the Lode assemblage (ca. 390 Ma), Straupe, Latvia] with a closer look at the Escuminac assemblage. Both localities are representative of Middle to Late Devonian aquatic vertebrate assemblages in terms of taxonomic richness (ca. 20 species), phylogenetic diversity (all major groups of lower vertebrates) and palaeoenvironment (palaeoestuaries). Fossil food web structures were assessed using different kinds of direct (i.e. digestive contents and bite marks in fossils) and indirect (e.g. ecomorphological measurements, stratigraphic species co-occurrences) indicators. First, the relationships between predator and prey body size established for the Escuminac fishes are comparable to those of recent aquatic ecosystems, highlighting a consistency of aquatic food web structure across geological time. Second, non-metric dimensional scaling on ecomorphological variables and cluster analysis showed a common pattern of functional groups for both fish assemblages; top predators, predators, primary and secondary consumers were identified. We conclude that Devonian communities were organized in multiple trophic levels and that size-based feeding interactions were established early in vertebrate history. • Key words: digestive contents, fossil fish, Devonian, ecomorphology, palaeoecology, bottom-up control, top-down control. Ursulines, Rimouski, Québec, G5L 3A1, Canada; richard_cloutier@uqar.ca The trophic structure of recent ecosystems has long been described as controlled either by lower trophic levels (bottom-up control) or by higher trophic levels (top-down control) depending on species interactions. In extant aquatic ecosystems, both bottom-up and top-down controls are recognized (McQueen et al. 1989, Menge 2000, Arreguín-Sánchez 2011. Large species are represented in the upper trophic level, but in relatively low abundance, whereas smaller and more abundant species represent lower trophic levels (Cohen et al. 1993) implying that relationships between predator and prey total lengths can be estimated.Trophic interactions in taxonomically, environmentally and temporally diverse ecosystems of the past have been reconstructed based on direct (e.g. digestive contents) and indirect (e.g. species co-occurrences) indicators such as for e.g. the Cambrian (Vannier & Chen 2005, Dunne et al. 2008, Vannier 2012, Devonian (Lebedev 1992, Lukševičs 1992, Novitskaya 1992, Mark-Kurik 1995, Habgood et al. 2003 (Maisey 1994, Wang et al. 2005) and the Quaternary (Nenzén et al. 2014). Most of these studies rely on qualitative d...

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Trophic level scales positively with body size in fishes

Cited by 202 publications

References 32 publications

Ecological selectivity of the emerging mass extinction in the oceans

Ecological selectivity of the emerging mass extinction in the oceans

Four decades of foraging history: stock-specific variation in the carbon and nitrogen stable isotope signatures of Alaskan sockeye salmon

Early establishment of vertebrate trophic interactions: Food web structure in Middle to Late Devonian fish assemblages with exceptional fossilization

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