scholarly journals Modeling the Ecological Dynamics of a Three-Species Fish Population in the Chesapeake Bay

2021 ◽  
Vol 14 (1) ◽  
pp. 1-31
Author(s):  
Iordanka Panayotova ◽  
Maila Hallare
Keyword(s):  
Chesapeake Bay ◽  
Striped Bass ◽  
Fish Population ◽  
Atlantic Menhaden ◽  
Biological Interactions ◽  
Blue Catfish ◽  
Predator Species ◽  
Theoretical Concepts ◽  
Long Time ◽  
Simplifying Assumptions

We present an inquiry-based project that is designed for a mathematical modeling class of undergraduate junior or senior students. It discusses a three-species mathematical model that simulates the biological interactions among three important fish species in the Chesapeake Bay: the prey Atlantic menhaden and its two competing predators, the striped bass and the non-native blue catfish. The model also considers the following ecological issues related to these three species: the overfishing of menhaden, the invasiveness of the blue catfish, and the harvesting of blue catfish as a method to control the population. A series of modeling scenarios are considered based on some simplifying assumptions to demonstrate the application of theoretical concepts to actual fisheries in the Chesapeake Bay. Analysis involves elementary skills such as finding the roots of polynomial equations, computing eigenvalues and eigenvectors, and some advanced topics such as Routh-Hurwitz criteria and the Hartman-Grobman Theorem. Numerical simulations via MATLAB are utilized to produce graphical simulations and analyze long-time behaviors. Our model predicts that if no serious measures are taken to prevent the spread of the invasive blue catfish, the native predator species will be seriously affected and may even become extinct. The model also shows that linear harvesting is sufficient to limit the growth of the invasive catfish population; however, it is not sufficient to save the striped bass from becoming extinct. The results of this study illustrate the fundamental ecological principle of competitive exclusion, according to which two competing species that attempt to occupy the same niche in an ecosystem cannot co-exist indefinitely and one of the two populations will either go extinct or will adapt to fill a different niche.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Chesapeake Bay ◽  
Fork Length ◽  
Atlantic Menhaden ◽  
Tidal River ◽  
Human Consumption ◽  
Apex Predators ◽  
Blue Catfish ◽  
Brevoortia Tyrannus ◽  
Conflicting Demands ◽  
Peak Abundance

<em>Abstract</em>.—Rapid increase in abundance and expanded distribution of introduced blue catfish <em>Ictalurus furcatus</em> populations in the Chesapeake Bay watershed have raised regional management concerns. This study uses information from multiple surveys to examine expansion of blue catfish populations and document their role in tidal river communities. Originally stocked in the James, York, and Rappahannock River systems for development of commercial and recreational fisheries, blue catfish have now been documented in adjacent rivers and have expanded their within-river distribution to oligo- and mesohaline environments. Range expansions coincided with periods of peak abundance in 1996 and 2003 and with the concurrent decline in abundance of native white catfish <em>I. catus</em>. Blue catfish in these systems use a diverse prey base; various amphipod species typically dominate the diet of smaller individuals (<300 mm fork length [FL]), and fishes are common prey for larger blue catfish (>300 mm FL). Recent studies based on stable isotope analyses suggest that adult blue catfish in these systems are apex predators that feed extensively on important fishery resources, including anadromous shads and herrings Alosa spp. and juvenile Atlantic menhaden <em>Brevoortia tyrannus</em>. Minimizing effects on Chesapeake Bay communities by controlling high densities of blue catfish populations is a primary goal of management, but conflicting demands of the commercial and recreational sectors must be resolved. Further, low market demand and human consumption concerns associated with purported accumulation of contaminants in blue catfish pose additional complications for regulating these fisheries.

Predatory demand and impact of striped bass, bluefish, and weakfish in the Chesapeake Bay: applications of bioenergetics models

1995 ◽  
Vol 52 (8) ◽  
pp. 1667-1687 ◽  
Author(s):  
Kyle J. Harfmart ◽  
Stephen B. Brandt
Keyword(s):  
Chesapeake Bay ◽  
Striped Bass ◽  
Atlantic Menhaden ◽  
Pomatomus Saltatrix ◽  
Brevoortia Tyrannus ◽  
Annual Biomass ◽  
Production Area ◽  
Relationship Of ◽  
Trophic Linkages ◽  
Bioenergetics Models

We applied bioenergetics models for dominant Chesapeake Bay piscivores, striped bass (Morone saxatilis), bluefish (Pomatomus saltatrix), and weakfish (Cynoscion regalis), along with site-specific data on diets, growth, and energy density, to examine trophic linkages and the relationship of predatory demand to prey supply. Atlantic menhaden (Brevoortia tyrannus), bay anchovy (Anchoa mitchilli), and spot (Leiostomus xanthurus) accounted for 65–99% of the annual biomass of piscivore diets (excluding age-0 striped bass that ate mostly invertebrates). The diets of young piscivores were dominated by anchovy, but menhaden and spot became increasingly important to older fish. Young (age < 2) striped bass ate mostly benthic prey. Older striped bass fed increasingly on pelagic sources, primarily menhaden, but bluefish and weakfish increased benthic resource use from 10% at age 0 to 50% by age 2. Comparison of consumption (supply) to demand (potential consumption) measured the suitability of Chesapeake Bay for predator production. Bluefish came closest to achieving their demand for prey, suggesting that they are more successful predators than either striped bass or weakfish. Results suggest that Chesapeake Bay may be a better nursery than production area for older fish, and prey supply (not temperature) may account for the movements and use of the estuary by older piscivores.

scholarly journals Quantitative PCR Assay for Mycobacterium pseudoshottsii and Mycobacterium shottsii and Application to Environmental Samples and Fishes from the Chesapeake Bay

2010 ◽  
Vol 76 (18) ◽  
pp. 6171-6179 ◽  
Author(s):  
D. T. Gauthier ◽  
K. S. Reece ◽  
J. Xiao ◽  
M. W. Rhodes ◽  
H. I. Kator ◽  
...  
Keyword(s):  
Chesapeake Bay ◽  
Striped Bass ◽  
Atlantic Menhaden ◽  
Pcr Assay ◽  
Brevoortia Tyrannus ◽  
High Prevalence ◽  
Obligate Pathogen ◽  
Bay Anchovy ◽  
Very High ◽  
Quantitative Pcr Assay

ABSTRACT Striped bass (Morone saxatilis) in the Chesapeake Bay are currently experiencing a very high prevalence of mycobacteriosis associated with newly described Mycobacterium species, Mycobacterium pseudoshottsii and M. shottsii. The ecology of these mycobacteria outside the striped bass host is currently unknown. In this work, we developed quantitative real-time PCR assays for M. pseudoshottsii and M. shottsii and applied these assays to DNA extracts from Chesapeake Bay water and sediment samples, as well as to tissues from two dominant prey of striped bass, Atlantic menhaden (Brevoortia tyrannus) and bay anchovy (Anchoa mitchilli). Mycobacterium pseudoshottsii was found to be ubiquitous in water samples from the main stem of the Chesapeake Bay and was also present in water and sediments from the Rappahannock River, Virginia. M. pseudoshottsii was also detected in menhaden and anchovy tissues. In contrast, M. shottsii was not detected in water, sediment, or prey fish tissues. In conjunction with its nonpigmented phenotype, which is frequently found in obligately pathogenic mycobacteria of humans, this pattern of occurrence suggests that M. shottsii may be an obligate pathogen of striped bass.

Dose-Related Toxicity of Copper and Cadmium in Striped Bass Larvae from the Chesapeake Bay: Field Considerations

1988 ◽  
Vol 20 (6-7) ◽  
pp. 39-48 ◽  
Author(s):  
David A. Wright
Keyword(s):  
Chesapeake Bay ◽  
Striped Bass ◽  
Toxic Metal ◽  
Published Data ◽  
Metal Concentrations ◽  
Frequency Distributions ◽  
Order Of Magnitude ◽  
Toxic Concentrations ◽  
And Control ◽  
Spawning Tributaries

Copper and cadmium monitoring in Chesapeake Bay sediments indicates that metal contamination exists in nursery areas for striped bass (Moronesaxatilis), which has been in serious decline over the last 17 years. Whole water metal concentrations in one spawning river were within an order of magnitude of published acutely toxic concentrations. Larval striped bass were exposed in the laboratory to copper and cadmium concentrations which were acutely toxic over a 96h period (24 and 19 µg L−1, respectively), and to sub-lethal concentrations of these metals over a three week period. Larvae from acutely toxic metal treatments, sub-lethal metal concentrations and control tanks were analyzed for cadmium and copper and the frequency distribution of metal body burdens was compared with field data. The distribution of copper concentrations in laboratory-exposed larvae was completely within the range of field specimens, and there was considerable overlap in cadmium frequency distributions from laboratory and field larvae. These results together with other published data suggest that environmental metal concentrations in some spawning tributaries of the Chesapeake Bay may pose a threat to striped bass, and the suggestion is made that greater efforts should be made to link laboratory and field toxicological data.

Survival of striped bass larvae and yearlings in relation to contaminants and water quality in the upper chesapeake bay

1987 ◽  
Vol 16 (4) ◽  
pp. 391-400 ◽  
Author(s):  
Lenwood W. Hall ◽  
Alfred E. Pinkney ◽  
L. Herman ◽  
Susan E. Finger
Keyword(s):  
Water Quality ◽  
Chesapeake Bay ◽  
Striped Bass

Non-Gaussian probability distributions of solar wind fluctuations

1994 ◽  
Vol 12 (12) ◽  
pp. 1127-1138 ◽  
Author(s):  
E. Marsch ◽  
C. Y. Tu
Keyword(s):  
Solar Wind ◽  
Probability Distributions ◽  
Time Lag ◽  
Small Scale ◽  
Time Lags ◽  
Mhd Turbulence ◽  
Theoretical Concepts ◽  
Fluid Turbulence ◽  
Long Time ◽  
Non Gaussian

Abstract. The probability distributions of field differences ∆x(τ)=x(t+τ)-x(t), where the variable x(t) may denote any solar wind scalar field or vector field component at time t, have been calculated from time series of Helios data obtained in 1976 at heliocentric distances near 0.3 AU. It is found that for comparatively long time lag τ, ranging from a few hours to 1 day, the differences are normally distributed according to a Gaussian. For shorter time lags, of less than ten minutes, significant changes in shape are observed. The distributions are often spikier and narrower than the equivalent Gaussian distribution with the same standard deviation, and they are enhanced for large, reduced for intermediate and enhanced for very small values of ∆x. This result is in accordance with fluid observations and numerical simulations. Hence statistical properties are dominated at small scale τ by large fluctuation amplitudes that are sparsely distributed, which is direct evidence for spatial intermittency of the fluctuations. This is in agreement with results from earlier analyses of the structure functions of ∆x. The non-Gaussian features are differently developed for the various types of fluctuations. The relevance of these observations to the interpretation and understanding of the nature of solar wind magnetohydrodynamic (MHD) turbulence is pointed out, and contact is made with existing theoretical concepts of intermittency in fluid turbulence.

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