Size-based approaches to aquatic ecosystems and fisheries science: a symposium in honour of Rob Peters

2016 ◽  
Vol 73 (4) ◽  
pp. 471-476 ◽  
Author(s):  
Henrique C. Giacomini ◽  
Brian J. Shuter ◽  
Julia K. Baum
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Empirical Studies ◽  
Ecosystem Dynamics ◽  
Future Research ◽  
Size Spectrum ◽  
Ecological Change ◽  
Size Spectra ◽  
Predator Prey ◽  
Fisheries Science

This special issue honours Rob Peters’ outstanding contributions to the field of aquatic ecology. It focuses on the size spectrum approach — in which individual organisms, rather than species, are the most basic biological unit — and highlights applications of this approach to fisheries management. The 21 papers in this issue cover three subject areas: (i) the use of size spectra to characterize variation in community structure, (ii) the development of size-based models of ecosystem dynamics to address fisheries questions, and (iii) applications of size-based theory to examine the consequences of variation in predator–prey size relationships, body size – trophic level relationships, and body size – life history relationships. The empirical studies herein demonstrate the utility of size spectra as indicators of population or community structure and for detecting impacts associated with environmental change. Future research focused on refining size-based sampling methods, standardizing metrics and analytical methods, understanding model sensitivity to the underlying assumptions, and comparative studies across ecosystems will enhance our ability to reliably interpret changes in size spectrum characteristics, thus facilitating their use as indicators of ecological change.

Structure of the Body-Size Spectrum of the Biomass in Aquatic Ecosystems: A Consequence of Allometry in Predator–Prey Interactions

1993 ◽  
Vol 50 (6) ◽  
pp. 1308-1317 ◽  
Author(s):  
M. L. Thiebaux ◽  
L. M. Dickie
Keyword(s):  
Body Size ◽  
Aquatic Ecosystems ◽  
The Body ◽  
Ecosystem Dynamics ◽  
Size Spectrum ◽  
Quadratic Term ◽  
Predator Prey ◽  
Basic Model ◽  
Energy Transfers ◽  
Allometric Functions

An equation describing predator–prey trophic energy transfers and production within the body-size spectrum of the biomass of aquatic ecosystems is formulated using allometric functions of body size. Its solution is the sum of two parts. One is a quadratic term that gives parabolic domes of biomass, in accordance with observations in nature. A second part, which seems not to have been recognized earlier, is a periodic function of log body size having significant potential for interpreting sample data reflecting ecosystem dynamics. The formulation is fitted to fish data from a small lake to demonstrate the applicability of the basic model to observations and to examine the scales of interaction of the measures of ecosystem dynamics that may be derived from them.

Using an individual-based model of fish assemblages to study the response of size spectra to changes in fishing

2004 ◽  
Vol 61 (3) ◽  
pp. 414-431 ◽  
Author(s):  
Yunne-Jai Shin ◽  
Philippe Cury
Keyword(s):  
Fish Assemblages ◽  
Prey Availability ◽  
Empirical Studies ◽  
Marine Ecosystem ◽  
Predatory Fish ◽  
Size Spectrum ◽  
Individual Based Model ◽  
Size Spectra ◽  
Predation Mortality ◽  
Body Shapes

For most fish species, strong environmental constraints imposed by living in an aquatic medium have produced converging streamlined body forms without prehensile appendices. This similarity in body shapes highlights a common predation constraint: a predatory fish must have a jaw large enough to swallow its prey. Fish diets may then reflect local prey availability and predator–prey size ratios. Based on this size-based opportunistic predation process, the multispecies individual-based model OSMOSE (Object-oriented Simulator of Marine ecOSystem Exploitation) is used to investigate to what extent the size distribution of fish communities can contribute to better our understanding of the functioning of marine food webs and the ecosystem effects of fishing. Strong similarity in shape is found between simulated size spectra and those described in empirical studies. The existence of a curvature towards small size classes is discussed in the light of the size-based predation hypothesis, which implies that smaller fish may undergo higher predation mortality. Applying linear and quadratic regressions to the simulated size spectra allows the detection of variations in fishing pressure and the proposal of different ways to quantify them. In particular, it is shown that the slope of the size spectrum decreases quasilinearly with fishing mortality and that the curvature could help to detect ecosystem overexploitation.

scholarly journals Examining predator–prey body size, trophic level and body mass across marine and terrestrial mammals

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142103 ◽  
Author(s):  
Marlee A. Tucker ◽  
Tracey L. Rogers
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Body Mass ◽  
Marine Environment ◽  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Position ◽  
Trophic Levels ◽  
Predator Prey ◽  
Terrestrial Mammals

Predator–prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator–prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator–prey ratio across terrestrial ( n = 51) and marine ( n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator–prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.

Species body size distribution patterns of marine benthic macrofauna assemblages from contrasting sediment types

1999 ◽  
Vol 79 (5) ◽  
pp. 793-801 ◽  
Author(s):  
David M. Parry ◽  
Michael A. Kendall ◽  
Ashley A. Rowden ◽  
Stephen Widdicombe
Keyword(s):  
Body Size ◽  
Size Distribution ◽  
Species Turnover ◽  
Distribution Patterns ◽  
Benthic Macrofauna ◽  
Size Spectrum ◽  
Size Spectra ◽  
Β Diversity ◽  
Sediment Types ◽  
Geometric Size

Species body size spectra have been constructed for macrofauna assemblages from four sites with contrasting sediment granulometry and heterogeneity in and around Plymouth Sound. The number of species and species turnover (β diversity) were higher on coarse sediment. While the fauna were distinct between sites, the median geometric size-class was conservative (class 14; 0.153–0.305 mg dry blotted weight). Only one site had significantly lower heterogeneity within the species size spectrum, yet this was the most heterogeneous sediment. As such, we were unable to reject the null hypothesis that species body size distribution patterns are conservative despite differences in sediment granulometry and heterogeneity.

Comparison and utility of different size-based metrics of fish communities for detecting fishery impacts

2006 ◽  
Vol 63 (4) ◽  
pp. 810-820 ◽  
Author(s):  
Daniel E Duplisea ◽  
Martin Castonguay
Keyword(s):  
Standing Stock ◽  
Fish Communities ◽  
Ecosystem Approach ◽  
Size Spectrum ◽  
Size Spectra ◽  
Predator Prey ◽  
Similar Information ◽  
Chance Events ◽  
Length Frequency Analysis ◽  
Scientific Survey

The use of fish community indicators based on size spectra has become popular in the development of an ecosystem approach to fisheries. Size spectrum theory arose from basic ecological work on energy flow, predator–prey interactions, and biomass standing stock and was later applied to fish communities as length–frequency analysis. A multitude of size spectrum indicators have resulted, but it is not clear if they all present similar information. Here we develop a simple framework describing what four size spectra indicators suggest about fish communities, their likely response to fisheries exploitation, their ecological interpretation, and some of their biases. We examined indicators for scientific survey data from six exploited North Atlantic fish communities for the information that they reveal about each community. Each indicator revealed different information and had different biases. Combining indicators for the most impacted system (owing to fisheries and environmental change), the eastern Scotian Shelf, revealed a pattern analogous to Holling's ecological cycle of exploitation, conservation, release, and reorganisation. If this analogy is generally valid, then it suggests that collapsed fish communities are more susceptible to chance events, and recovery is not directly reversible and may not be recoverable (to previous known state) at all if the system moves to an alternative cycle.

scholarly journals Running the gauntlet: the predation environment of small fish in the northern Gulf of St Lawrence, Canada

2005 ◽  
Vol 62 (3) ◽  
pp. 412-416 ◽  
Author(s):  
Daniel E. Duplisea
Keyword(s):  
Body Size ◽  
North Sea ◽  
Prey Size ◽  
Small Fish ◽  
Size Spectra ◽  
Predator Prey ◽  
The North ◽  
Prefer Prey ◽  
Seal Population ◽  
The North Sea

Abstract Predation size spectra were constructed for the northern Gulf of St Lawrence, covering prey size ranges that include pre-recruit cod. Predation by fish and harp seals was modelled with a log-normally distributed predator–prey size ratio along with a relationship between predator body size and the energy required. Fish concentrate predation on prey of weight 0.5–2 g, whereas harp seals prefer prey of 60–125 g. It is speculated that predation caused by harp seals on pre-recruits could be a major factor limiting cod recruitment in the system. The northern Gulf of St Lawrence is a cold boreal system with a large predatory seal population, and cod recruit older than elsewhere. Therefore, cod recruitment may be more strongly affected by predation in the northern Gulf of St Lawrence than in warmer systems such as the North Sea, where recruitment is strongly influenced by temperature.

scholarly journals Will Love Tear Them Apart? Identifying the Eco-Evolutionary Feedbacks of Sexual Traits

2018 ◽  
Author(s):  
Joao Alpedrinha ◽  
Leonor Rodrigues ◽  
Sara Magalhães ◽  
Jessica Abbott
Keyword(s):  
Sexual Selection ◽  
Future Research ◽  
Ecological Change ◽  
Ecological Context ◽  
Contemporary Evolution ◽  
Ample Evidence ◽  
Predator Prey ◽  
Host Parasite Interactions ◽  
Sexual Traits ◽  
Host Parasite

The study of eco-evolutionary feedbacks is in clear recent expansion. However, most studies concern predator-prey and host-parasite interactions, while the analysis of eco-evolutionary feedbacks involving sexual interactions is lagging behind. This is at odds with the potential of these interactions to engage in such processes. Indeed, there is now ample evidence that sexual selection is affected by ecological change. There is also evidence that sexual selection traits evolve rapidly, which may modify the ecological context of species, and thus the selection pressures they will be exposed to. Here, we first set a clear distinction between processes in which ecology drives evolution and those in which the contemporary evolution of populations may change their ecology, depending on which traits act as drivers and objects of change. We then review evidence for these processes and discuss examples of closed eco-evolutionary feedbacks in an attempt to understand how we can tear this loop apart. We suggest that a better understanding of eco-evolutionary feedbacks of sexual selection may help us understand the effects of sexual selection on the rate of adaptation, speciation, and extinction, and thus foster future research in this area.

Size Spectrum Theory

2019 ◽  
pp. 15-37
Author(s):  
Ken H. Andersen
Keyword(s):  
Body Size ◽  
Power Law ◽  
Clearance Rate ◽  
Size Structure ◽  
Prey Size ◽  
Marine Ecosystem ◽  
Size Spectrum ◽  
Predator Prey ◽  
Predation Mortality ◽  
Size Preference

This chapter follows the size-structure of the entire marine ecosystem. It shows how the Sheldon spectrum emerges from predator–prey interactions and the limitations that physics and physiology place on individual organisms. How predator–prey interactions and physiological limitations scale with body size are the central assumptions in size spectrum theory. To that end, this chapter first defines body size and size spectrum. Next, it shows how central aspects of individual physiology scale with size: metabolism, clearance rate, and prey size preference. On that basis, it is possible to derive a power-law representation of the size spectrum by considering a balance between the needs of an organism (its metabolism) and the encountered prey, which is determined by the spectrum, the clearance rate, and the size preference. Lastly, the chapter uses the solution of the size spectrum to derive the expected size scaling of predation mortality.

Ecological change in Great Lakes communities — a matter of perspective

2008 ◽  
Vol 65 (1) ◽  
pp. 1-9 ◽  
Author(s):  
W Gary Sprules
Keyword(s):  
Great Lakes ◽  
Food Webs ◽  
Emergent Properties ◽  
Size Spectrum ◽  
Species Structure ◽  
Ecological Change ◽  
Size Spectra ◽  
Rate Processes ◽  
African Rift ◽  
Specific Species

Enormous change in food webs of the Laurentian Great Lakes has been documented from the early 1970s to the 1990s. Variation in abundances of species at all levels in these food webs has been attributed to a variety of causes, including nutrient abatement, invasive species, fishing practices, and climate change. However, this impression of great change is not obvious if food webs are examined from the different perspective of the biomass size spectrum. Despite large shifts in the species structure of zooplankton communities in Lakes Erie and Ontario from 1991 to 1997, zooplankton size spectra have not changed. Furthermore, size spectra for complete food webs of Lake Ontario (Laurentian Great Lake) and Lake Malawi (African Rift Valley Lake) are statistically indistinguishable despite enormous contrast in the geological age and fauna of the two lakes. I conclude that constraints on bioenergetic rate processes and physiological and ecological similarities of like-sized organisms at various hierarchical levels of organization lead to regular and repeatedly observed emergent properties of aquatic ecosystems that are independent of specific species.

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