scholarly journals Evaluation of the Shepherd and Cushing (1980) model of density-dependent survival: a case study using striped bass (Morone saxatilis) larvae in the Potomac River, Maryland, USA

2003 ◽  
Vol 60 (6) ◽  
pp. 1275-1287 ◽  
Author(s):  
Edward S Rutherford ◽  
Kenneth A Rose ◽  
James H Cowan
Keyword(s):  
Regression Model ◽  
Striped Bass ◽  
Carrying Capacity ◽  
Field Data ◽  
Larval Growth ◽  
Fish Population ◽  
Potomac River ◽  
Average Growth ◽  
Density Dependent ◽  
Dependent Growth

Abstract Quantifying the degree of density-dependence in stock–recruit relationships is critical to understanding fish population dynamics. The Shepherd and Cushing (1980) model couples a simple model of density-dependent larval growth with a constant rate of mortality to predict numbers surviving to recruitment. The model has not been evaluated using field data, nor have its predictions been compared with those from other models. Here, the S&C model, an individual-based model (IBM), and a regression model are applied to 8 years of field data for striped bass larvae in the Potomac River, Maryland, USA, to predict larval carrying capacity (K) and percentage of recruitment lost as a consequence of density-dependent growth. The IBM and the regression model were corroborated by comparing their predictions of average growth rates of larvae and relative recruitment strengths to observed values for the 8 years of field data. Although the IBM and the regression model differed in their predictions of several important intermediate variables, both models predicted higher values of K and lower values of density-dependent growth than did the S&C model. Over the 8 years, the IBM and the regression model predicted an average of 0.3 and 1.8% recruitment lost as a result of density-dependent growth, respectively. In contrast, the S&C model predicted much higher recruitment lost (average of 27%). Slight differences in the assumed rate of mortality used in the S&C model resulted in values of carrying capacity similar to those predicted by the IBM and the regression model. Difficulties in estimating parameters of the S&C model from field data are discussed.

Density-dependent regulation of year-class strength in age-0 juvenile striped bass (Morone saxatilis)

2012 ◽  
Vol 69 (3) ◽  
pp. 430-446 ◽  
Author(s):  
E.J. Martino ◽  
E.D. Houde
Keyword(s):  
Chesapeake Bay ◽  
Striped Bass ◽  
Morone Saxatilis ◽  
Winter Temperature ◽  
Density Dependent ◽  
Early Juvenile Stage ◽  
Class Strength ◽  
Dependent Growth ◽  
Overwinter Mortality ◽  
Density Dependent Regulation

Abundance of age-0 striped bass ( Morone saxatilis ) exhibits 50-fold variability in Chesapeake Bay. Processes that act to reduce and thus regulate this variability were investigated. The potential for density-dependent regulation of growth and mortality in the early juvenile stage and its causes were investigated. Data from multiple seine and trawl surveys in upper Chesapeake Bay and tributaries were analyzed to construct growth and mortality indices having a high degree of spatial and temporal resolution. Age-0 mean lengths in September were inversely related to density, ranging from 67.8 mm in 1994, when mean density was 0.036·m–2, to 104.5 mm in 1992, when mean density was 0.003·m–2. Except for the Potomac River, evidence for density-dependent growth was consistent across subpopulations. Bioenergetics modeling indicated that prey consumption was limiting except in low-abundance years. Mortality increased with respect to abundance and also was density-dependent. The significant interaction between age-0 juvenile length in September and subsequent winter temperature on mortality indicated that density-dependent growth leads to size-selective overwinter mortality. A statistical model including age-0 abundances, age-0 lengths, and winter temperature explained a substantial fraction of variability and the mechanisms for regulation of striped bass recruitment.

scholarly journals Stronger density-dependent growth of Japanese sardine with lower food availability: Comparison of growth and zooplankton biomass between a historical and current stock-increase period in the western North Pacific

2021 ◽  
Author(s):  
Yasuhiro Kamimura ◽  
Kazuaki Tadokoro ◽  
Sho Furuichi ◽  
Ryuji Yukami
Keyword(s):  
Density Dependence ◽  
Food Availability ◽  
North Pacific ◽  
Western North Pacific ◽  
Fish Population ◽  
Japanese Sardine ◽  
Density Dependent ◽  
Mesozooplankton Biomass ◽  
Current Period ◽  
Dependent Growth

Density dependence is a fundamental concept for fish population dynamics. Although density-dependent growth and maturity among older juveniles and adults is important for regulating fish population size and for fisheries management, the mechanism of density dependence for marine fishes remains unclear. Here, we examined changes in Japanese sardine growth with increasing abundance beginning in the 2010s and how the current pattern of density-dependent growth differs from that of a previous stock-increase period from the 1970s to early 1980s. During the current period of increasing abundance, mean standard length has already dropped to the lowest level yet observed and growth has declined more sharply with increased abundance than in the 1970s and 1980s. Mesozooplankton biomass in July in the summer feeding grounds was also lower during the current period. Therefore, our results suggest that summer food availability in the western North Pacific controls the strength of density-dependent growth. A lower carrying capacity for Japanese sardine could account for the stronger density dependence of growth observed in the 2010s; this indicates that future Japanese sardine abundance might not increase as much as in the 1980s unless food availability improves.

Analysis of an estuarine striped bass (Morone saxatilis) population: influence of density-dependent mortality between metamorphosis and recruitment

2000 ◽  
Vol 57 (2) ◽  
pp. 478-486 ◽  
Author(s):  
W J Kimmerer ◽  
J H Cowan, Jr. ◽  
L W Miller ◽  
K A Rose
Keyword(s):  
San Francisco ◽  
Striped Bass ◽  
Carrying Capacity ◽  
Food Limitation ◽  
Morone Saxatilis ◽  
Fish Stock ◽  
Compensatory Mechanism ◽  
Density Dependent ◽  
Density Dependent Mortality ◽  
Dependent Mortality

Compensation due to density-dependent mechanisms is essential for the maintenance of an exploited fish stock. Understanding compensation is important for understanding population regulation and responses to added mortality. We examined possible density-dependent effects on striped bass (Morone saxatilis) in the San Francisco Estuary. Three sets of data from sampling programs for young striped bass showed density-dependent mortality between 1 month of age and 8-12 months. The relationships between two indices of young striped bass abundance and recruitment at age 3 fit a Beverton-Holt function, also indicating density dependence. The carrying capacity, as determined by the asymptote of the Beverton-Holt curves, has declined over the last two to three decades. These results are consistent with a compensatory mechanism based on food limitation occurring after metamorphosis and with the decline in food resources observed in the estuary over the same period. The decline in striped bass over the last two to three decades may be partly due to this declining carrying capacity.

Density-dependent growth of double-crested cormorant colonies on Lake Huron

2006 ◽  
Vol 84 (10) ◽  
pp. 1409-1420 ◽  
Author(s):  
Mark S. Ridgway ◽  
J. Bruce Pollard ◽  
D.V. Chip Weseloh
Keyword(s):  
Time Series ◽  
Population Growth ◽  
Carrying Capacity ◽  
Colony Size ◽  
Lake Huron ◽  
Population Increase ◽  
Density Dependent ◽  
Georgian Bay ◽  
The North ◽  
Dependent Growth

By analyzing 20+ years of data, we found that the nesting colonies of double-crested cormorants ( Phalacrocorax auritus (Lesson, 1831)) in the North Channel and Georgian Bay of Lake Huron exhibit density-dependent population regulation. This conclusion is based on four lines of evidence. First, a time series of nest counts at specific colonies (1979–2001) showed density-dependent growth based on randomization tests of the time series. Second, the per capita rate of change in colony size declined with increasing colony size over a 10-year period. Third, a Ricker model of aggregate nest counts showed that population growth of nesting double-crested cormorants stabilized in recent years (through 2003), with K, the carrying capacity parameter, being 11 445 nests in the North Channel and 10 815 nests in Georgian Bay. Fourth, a colony area index showed near complete coverage of coastal areas by adult nesters coinciding with overall declines in population growth. High rates of population increase of double-crested cormorants on Lake Huron have largely come to an end, but changes in fish abundance may result in changes in carrying capacity.

Demographic Consequences of Age-Specific Dispersal in Marine Fish Populations

1992 ◽  
Vol 49 (11) ◽  
pp. 2222-2231 ◽  
Author(s):  
Kenneth T. Frank
Keyword(s):  
Marine Fish ◽  
Management Practices ◽  
Fish Population ◽  
Alternative View ◽  
Stock Management ◽  
Density Dependent ◽  
Home Area ◽  
Low Probability ◽  
Dependent Growth ◽  
Census Area

The fundamental model of marine fish population dynamics assumes that major events occur within the census area and that immigrants and emigrants can be safely ignored in the evaluation of stock dynamics. Dispersal is generally assumed to be associated with the movement of immature individuals away from their home area. Such a process may produce vagrants that have a low probability of surviving or successfully reproducing elsewhere. An alternative view, developed here, proposes that dispersal can have profound demographic consequences not only for the resident stock but for neighbouring stocks. A review of the fisheries literature and an analysis of data for two Scotian Shelf haddock stocks provided support for the hypothesis that the spatial magnitude of postlarval dispersal is generally density dependent, that vagrants flourish as juveniles outside the home area in neighbouring stocks, that they subsequently return home when mature, and that the recruitment dynamics of the neighbouring stocks are seriously misinterpreted when such movements are ignored. Additional implications of these findings, including synchronous recruitment patterns commonly observed between stocks, density-dependent growth, and groundfish stock management practices, are discussed.

The box-balance model: a new tool to assess fish larval survival, applied to field data on two small pelagic fish

2020 ◽  
Vol 650 ◽  
pp. 289-308 ◽  
Author(s):  
V Raya ◽  
J Salat ◽  
A Sabatés
Keyword(s):  
Field Data ◽  
Fish Larvae ◽  
Larval Growth ◽  
Warming Trend ◽  
Mortality Rates ◽  
Larval Survival ◽  
Pelagic Fish ◽  
Balance Model ◽  
Small Pelagic Fish ◽  
Mesoscale Structures

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.

scholarly journals The spatial scale of density-dependent growth and implications for dispersal from nests in juvenile Atlantic salmon

Oecologia ◽  
2010 ◽  
Vol 165 (4) ◽  
pp. 959-969 ◽  
Author(s):  
Sigurd Einum ◽  
Grethe Robertsen ◽  
Keith H. Nislow ◽  
Simon McKelvey ◽  
John D. Armstrong
Keyword(s):  
Atlantic Salmon ◽  
Spatial Scale ◽  
Density Dependent ◽  
Juvenile Atlantic Salmon ◽  
Dependent Growth

Lack of relationship between simulated fish population responses and their life history traits: inadequate models, incorrect analysis, or site-specific factors?

2005 ◽  
Vol 62 (4) ◽  
pp. 886-902 ◽  
Author(s):  
Kenneth A Rose
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Lake Trout ◽  
Fish Population ◽  
Population Models ◽  
Site Specific ◽  
Density Dependent ◽  
Population Responses ◽  
Adult Growth ◽  
Specific Factors

Relationships between fish population responses to changes in their vital rates and commonly available life history traits would be a powerful screening tool to guide management about species vulnerability, to focus future data collection on species and life stages of concern, and to aid in designing effective habitat enhancements. As an extension of previous analyses by others, I analyzed the responses to changes in fecundity and yearling survival of age-structured matrix and individual-based population models of 17 populations comprising 10 species. Simulations of the matrix models showed that the magnitude of population responses, but not the relative order of species sensitivity, depended on the state (sustainable or undergoing excessive removals) of the population. Matrix and individual-based models predicted population responses that appeared to be unrelated to their species-level life history traits when responses were plotted on a three-end-point life history surface. Density-dependent adult growth was added to the lake trout (Salvelinus namaycush) matrix model, and simulations demonstrated the potential importance to predicted responses of density-dependent processes outside the usual spawner–recruit relationship. Four reasons for the lack of relationship between population responses and life history traits related to inadequate population models, incorrect analysis, inappropriate life history model, and important site-specific factors are discussed.

Sign in / Sign up

Export Citation Format

Share Document