Interlake variation in growth and size structure of bluegill (Lepomis macrochirus): inverse analysis of an individual-based model

1998 ◽  
Vol 55 (2) ◽  
pp. 387-396 ◽  
Author(s):  
Nathan P Nibbelink ◽  
Stephen R Carpenter

Habitat structure alters food availability and predation risk, thereby directly affecting growth, mortality, and size structure of fish populations. Size structure has often been used to infer patterns of resource abundance and predation. However, food availability and predation risk in contrasting habitats have proven difficult to measure in the field. We use an inverse modeling approach to estimate food availability and habitat choice parameters from changes in length distributions of bluegill (Lepomis macrochirus). The model suggests that dynamics of bluegill length distributions primarily reflect food availability and habitat choice. Bluegill behavior minimized effects of size-selective predation on size structure. Parameters for food availability and habitat choice were correlated. It was therefore not possible to attain unique estimates of food availability and habitat selection when both were free parameters. However, when one parameter was estimated independently, the other could be identified. In five Wisconsin lakes, seining studies were used to estimate the size at which bluegill switched from littoral to pelagic habitats. Using this measure of switch size in the model, we estimated food availability for bluegill in each lake. These estimates were positively correlated with observed growth (r2 = 0.91), demonstrating the model's ability to estimate food availability.

2013 ◽  
Vol 71 (4) ◽  
pp. 909-917 ◽  
Author(s):  
Christian Jørgensen ◽  
Anders Frugård Opdal ◽  
Øyvind Fiksen

Abstract Since the classical works by Hjort linked the survival of early life stages of fish to year-class strength and recruitment, fisheries science has struggled to understand the fate of fish eggs and larvae. Here we discuss how food availability will influence growth and survival of larvae when foraging behaviour is flexible and involves predation risk. We use theory to show that small larval fish with a high risk of predation should nevertheless forage intensely and maintain high growth rates. The implication of this is that food availability is more important to recruitment success than is often assumed from studies of growth rate, since the main effect of low food availability appears as increased predation rates. As larvae develop and grow bigger, they are expected to tailor their behaviour to balance food intake and predation risk, which makes it more probable that environmental fluctuations will cause growth differences. A theoretical framework including larval behaviour thus illustrates how several existing hypotheses, i.e. “bigger is better”, “stage duration”, and “growth-selective predation”, emphasize different aspects of larval success but can be understood more generally and coherently when interpreted in the light of behavioural trade-offs. This may lead to more consistent consideration of larval behaviour in biophysical models of fish recruitment.


2010 ◽  
Vol 76 (4) ◽  
pp. 348-353 ◽  
Author(s):  
A. A. Robson ◽  
C. Garcia De Leaniz ◽  
R. P. Wilson ◽  
L. G. Halsey

2005 ◽  
Vol 83 (8) ◽  
pp. 1128-1133 ◽  
Author(s):  
S J McCauley

The relationship between habitat distribution, growth rate, and plasticity was examined in the larvae of three species of dragonfly in the genus Libellula L., 1758. Growth rates were compared under three conditions: in the absence of predation risk, in the presence of sunfish (Lepomis macrochirus Rafinesque, 1819; Pisciformes: Centrachidae), and in the presence of invertebrate predators. I assessed how the habitat distributions of the three species of dragonfly, specifically how commonly they occur with fish, were related to growth rates and to the level of growth plasticity under different levels of perceived predation risk. There was a negative relationship between growth rate and the frequency with which species coexist with sunfish. Growth-rate plasticity was limited and does not appear to be important in determining the ability of species to coexist with alternative top predator types. Only one species exhibited growth-rate plasticity, decreasing growth in response to the predator with which it most commonly coexists but not to the species which poses the greatest predation risk. A comparison of growth rates and activity levels in the presence and absence of these predators suggests that growth and activity level parallel each other in these species.


<em>Abstract</em>.—Although stunting is a fairly common phenomenon in fishes, confusion remains about underlying mechanisms and appropriate management strategies. Herein, I summarize current literature to provide a synthetic look at factors that can cause stunting and consider associated management strategies. First, I provide historical context by reviewing early literature, much of which is focused on density-dependent slow growth as the cause of stunting. A brief summary of more recent literature, however, suggests that stunting is often more complex than early investigations might indicate, and mechanisms such as early maturation and overexploitation of adults are considered. Because the bluegill <em>Lepomis macrochirus </em>is an extremely common reservoir species, a large body of literature related to its population size structure and associated management strategies is available. Therefore, I use bluegill as a model system to describe how various mechanisms might lead to stunting and indicate important considerations from a management standpoint. In the final section, I review management strategies and argue, among other things, that consistent language, clear identification of underlying mechanisms, and multifaceted management approaches are necessary for robust results when dealing with stunted populations.


2019 ◽  
Vol 116 (52) ◽  
pp. 26682-26689 ◽  
Author(s):  
Jan Ohlberger ◽  
Daniel E. Schindler ◽  
Eric J. Ward ◽  
Timothy E. Walsworth ◽  
Timothy E. Essington

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North American range. This raises the question of whether size-selective predation by marine mammals is generating these trends in life-history characteristics. Here we show that increased predation since the 1970s, but not fishery selection alone, can explain the changes in age and size structure observed for Chinook salmon populations along the west coast of North America. Simulations suggest that the decline in mean size results from the selective removal of large fish and an evolutionary shift toward faster growth and earlier maturation caused by selection. Our conclusion that intensifying predation by fish-eating killer whales contributes to the continuing decline in Chinook salmon body size points to conflicting management and conservation objectives for these two iconic species.


Mammalia ◽  
2015 ◽  
Vol 79 (4) ◽  
Author(s):  
Roberta Chirichella ◽  
Andrea Mustoni ◽  
Marco Apollonio

AbstractIn large mammalian herbivores, an increase in herd size not only reduces predation risk but also energy intake. As a consequence, the size of the groups made up by herbivores is often assumed to be the outcome of a trade-off depending on local predation risk and food availability. We studied Alpine chamois (


2011 ◽  
Vol 80 (6) ◽  
pp. 1278-1287 ◽  
Author(s):  
Osamu Kishida ◽  
Geoffrey C. Trussell ◽  
Ayaka Ohno ◽  
Shinya Kuwano ◽  
Takuya Ikawa ◽  
...  

2010 ◽  
Vol 81 (4) ◽  
pp. 420-429 ◽  
Author(s):  
Bruce A. Robertson ◽  
Richard L. Hutto ◽  
Joseph J. Fontaine

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