Ecology and Evolutionary Biology Commons^™

Seasonal Reproductive Allocation In Landlocked Alewife Alosa Pseudoharengus, In The Context Of Niche Construction And Eco-Evolutionary Feedbacks, Foivos Mouchlianitis, Eric T. Schultz, Kostas Ganias

EEB Articles

The bidirectional dynamics between species and their biotic and abiotic environments, known as eco-evolutionary feedbacks, may shift the direction of evolution and alter the ecological role of species. Alewife, Alosa pseudoharengus, is an exemplary species to study reciprocal feedbacks between ecology and evolution, owing to repeated independent derivations of a landlocked life history from an ancestral anadromous form. In this study we analysed the reproductive allocation during the spawning season in a landlocked Alewife population in the context of eco-evolutionary feedbacks. We also compared our findings with previous results from a neighbouring anadromous population of the species. Similarities were found …

Stomach Contents And Stable Isotope Analysis Reveal Ontogenetic Shifts And Spatial Variability In Brama Australis Diet, Sebastian A. Klarian, Eric T. Schultz, María Francisca Hernández, Juan Antonio Valdes, Francisco Fernandoy, Mónica Barros, Sergio Neira, Hugo Arancibia

EEB Articles

Many marine fisheries rely on production and energy flow in the pelagic zone, thus sustainable management of exploited pelagic fishes benefits from insight into temporal, spatial and ontogenetic variability in the trophic ecology of these species. Here we analyze stomach contents and stable isotopes to reveal spatial variability (focusing on two fishing grounds, north and south of an oceanographic barrier in the Pacific Ocean) and ontogenetic changes (contrasting immature and mature) in Southern Ray’s Bream (Brama australis) diet composition in Chilean waters. Stomach contents analysis indicated that euphausiids were predominant components of the diet in both fishing grounds and ontogenetic …

Seasonal Plumage Condition Variation And The Thermal Value Of The Feather Coats Of House Sparrows (Passer Domesticus), Jordana Mf Graveley, Margaret Rubega, Kevin R. Burgio

Honors Scholar Theses

Feathers are critical to how birds thermoregulate, and thus their total energy balance. The feather coat insulates birds by trapping air next to the skin and acting as a physical barrier to heat loss. Despite previous work studying thermal balance in birds, relatively few studies have focused on the thermal contribution of the feather coat alone; most studies have focused on physiological and behavioral responses. Moreover, to our knowledge, no studies have directly measured the effect of feather wear through the annual cycle on the thermal performance of the feather coat. To address this, we used a thermal camera to …

Temperature Variability And Multiple Environmental Stressors: How Will Tadpole Performance Change With Our Climate?, Diana C. Macklem, Tracy A. G. Rittenhouse, Ashley M. Helton, Jason H. O'Connor, Jaron T. Kolek

University Scholar Projects

This project seeks to analyze how predicted changes in climate and its interactions with other environmental factors will influence tadpole growth and development. Our first study examined how the frequency and magnitude of temperature variability affect wood frog and gray tree frog tadpole performance. We found that performance responses to repeatedly fluctuating treatments did not differ significantly from constant temperatures held at the same mean for wood frog tadpoles. However, elevated mean temperatures of 26 degrees Celsius caused tadpoles to metamorphose early, suggesting a potential developmental threshold. We found that gray tree frog performance was affected by fluctuating temperature treatments, …

Zebra Mussel (Dreissena Polymorpha) Affects The Feeding Ecology Of Early Stage Striped Bass (Morone Saxatilis) In The Hudson River Estuary, Michael G. Smircich, David L. Strayer, Eric T. Schultz

EEB Articles

Variability in the feeding ecology of young fishes over short and long time scales in estuaries is likely to affect population dynamics. We studied 14 years of early stage Striped Bass feeding ecology in the Hudson River Estuary over a 25-year time span, including years in which invasive zebra mussels markedly altered energy flow within the estuary. We predicted that feeding success would be low and that diet composition would be altered during years of high zebra mussel impact, particularly in upriver locations where mussels occur. Feeding success in the short term was indicated by volume of gut contents and …

For The Birds, Milan Bull

Wrack Lines

A new column about shore birds, starting with piping plovers.

An Approach For Use Of Dual Frequency Identification Sonar (Didson) To Quantify Behavioral Aspects Of Piscivory At Ecologically Relevant Time And Space Scales, Victoria E. Price

Master's Theses

Predator-prey interactions of large vagile fishes are difficult to study in the ocean due to limitations in the space and time requirements for observations. Small-scale direct underwater observations by divers (<10m >radius) and large-scale hydroacoustic surveys (10s - 100s km2) are traditional approaches. However, large piscivorous predators identify and attack prey at the scale of meters to tens of meters. Dual- Frequency Identification Sonar, or DIDSON, is a high-resolution acoustic camera operating in the MHz range that provides detailed continuous video-like imaging of objects out to 30 m range. This technology can be used to observe predator-prey interactions at ecologically …

Who's Afraid Of The Big Bad Cormorant?, Richard Jay King

Wrack Lines

How much do you really know about the cormorant? It's an amazing coastal bird, though not a very pretty one. Lately it has a bad rap as a destroyer of island ecosystems. This article talks about these avian creatures and their habits.

Salinity Preference Of Alaskan Threespine Stickleback: Test For Divergence In Halotaxis Between Ancestral And Landlocked Populations, David Fryxell, Eric T. Schultz

EEB Articles

Glacial retreat during the Pleistocene caused landlocking of anadromous Alaskan threespine stickleback, Gasterosteus aculeatus, furnishing a natural ‘experiment’ in osmoregulatory divergence. The objective of this study was to assess the effects of individual acclimation and population divergence on salinity preference. Full-sibling families of marine, anadromous, and freshwater-landlocked populations of stickleback were reared in common environments until 3 weeks post-hatch, then were split and acclimated to low or high salinity. At 6 to 8 weeks of age the six experimental groups were tested for salinity preference in a tank that offers fish a choice of compartments with different salinities arranged …

Environmental And Endogenous Factors Influencing Emigration In Juvenile Anadromous Alewives, Benjamin I. Gahagan, Eric T. Schultz, Katie E. Gherard

EEB Articles

We analyzed juvenile anadromous alewife migration at Bride Lake, a coastal lake in Connecticut, during summer 2006 and found that migration on 24-hour and seasonal timescales was influenced by conditions of the environment and characteristics of the individual. To identify environmental cues of juvenile migration, we continuously video recorded fish at the lake outflow and employed information-theoretic model selection to identify the best predictors of daily migration rate. More than 80% of the approximately 320,000 juveniles that migrated from mid-June to mid-August departed in three pulses lasting one or two days. Pulses of migration were associated with precipitation events, transient …

Temporal Shifts In Demography And Life History Of An Anadromous Alewife Population In Connecticut, Justin P. Davis, Eric T. Schultz

EEB Articles

Populations of anadromous alewives (Alosa pseudoharengus) are declining throughout much of their range, particularly in southern New England where fishery moratoriums have recently been instituted in three states. The alewife run at Bride Brook, a coastal stream in East Lyme, Connecticut, was studied from 2003-06 to assess shifts in demography and life history. Annual censuses of abundance, along with sampling for size, age, and spawning history structure were conducted. These data were compared to similar data in 1966-67 at this site. Recent alewife runs at Bride Brook featured lower abundance and younger, smaller fish that were less likely to be …

Time Series Observations Of Species Composition And Behavioral Interactions Of Fish At An Ocean Observatory Off The Coast Of Georgia, Amy E. Paquette

Honors Scholar Theses

The use of ocean observatories is expanding with the potential for collecting serial data with high temporal resolution at multiple sites within an ecosystem. Integration of underwater video cameras in observatory systems allow observation of vagile species and are useful tools for observing variations in behavior over time. In order to assess the utility of using video records for time series behavioral data I analyzed video records from an observatory site in the South Atlantic Bight (SAB) off the Coast of Georgia collected during the month of November in 2000, 2002 and 2004. Data were used to quantify annual variation …

Estimating Predation On Declining River Herring: Tag-Recapture Study Of Striped Bass In The Connecticut River, Eric T. Schultz, Justin P. Davis, Jason Vokoun

EEB Articles

Populations of anadromous alewife Alosa pseudoharengus and blueback herring Alosa aestivalis, collectively referred to as river herring, have declined in the Connecticut River. A hypothesis for why river herring have declined is that predation pressures have increased associated with recent increases in abundance of striped bass Morone saxatilis. Information on striped bass abundance, size structure, and consumption rates are required to test this hypothesis. This study was designed to provide estimates of striped bass population size in the Connecticut River during the spring migration season, via an intensive mark-recapture exercise and either an open or robust mark-recapture model. …

Assessment Of River Herring And Striped Bass In The Connecticut River: Abundance, Population Structure, And Predator/Prey Interactions, Justin P. Davis, Eric T. Schultz, Jason Vokoun

EEB Articles

Populations of anadromous alewife Alosa pseudoharengus and blueback herring A. aestivalis, collectively referred to as river herring, have declined in the Connecticut River. An explanatory hypothesis for these declines is that predation pressures have increased as a result of recent increases in abundance of sympatric striped bass Morone saxatilis. We sampled river herring and striped bass from the stretch of the Connecticut River between Wethersfield, CT and Holyoke, MA during the vernal migration seasons of 2005-2008. The objectives of the sampling program were to assess abundance, temporal/spatial distribution, and population structure of both river herring and striped bass, …

Integrating Fluvial Geomorphology And Stream Ecology: Processes Shaping The Distribution Of Freshwater Mussels In Connecticut, Piyumi T. Obeysekara, Eric T. Schultz, Melinda Daniels, Jason Vokoun

EEB Articles

No abstract provided.

Mating Systems, Copulatory Organ Size, And Scaling Relationship In Mollies (Poecilia Spp.), Martha Divver, Eric T. Schultz

EEB Articles

Copulatory organs rapidly evolve and are subject to complex selective pressures affecting mating success. One feature of copulatory organs that is subject to such selective pressures is size. Benefits of longer organs may include greater signal effectiveness in courtship and longer ‘reach’ when attempting copulations with evasive females. Costs of longer organs may include impaired locomotion, increased energetic cost or reduced mechanical compatibility with female genitalia. The optimal size for a copulatory organ may vary with mating behavior. The objective of this study is to examine among-species variability in copulatory organ size, body size and the relationship between copulatory organ …

Determining Winter Flounder Spawning Sites In Two Connecticut Estuaries, Eric T. Schultz, Jose J. Pereira, Peter J. Auster

EEB Articles

Winter flounder (Pseudopleuronectes americanus) come inshore during the late winter and early spring to lay their eggs in shallow bays and estuaries along the coast. Unlike most fish eggs, which are buoyant, these eggs are demersal and sink to the seafloor. This makes them vulnerable to burial from various types of natural and human caused disturbances (e.g., storms, mobile fishing gear, maintenance dredging). Our objective was to map spawning areas in two harbors and search for generalities among these sites that would allow us to predict where winter flounder might spawn in other areas. This would allow managers to avoid …

Anadromous Rainbow Smelt And Tomcod In Connecticut: Assessment Of Populations, Conservation Status, And Need For Restoration Plan, Heather A. Fried, Eric T. Schultz

EEB Articles

(beginning of rainbow smelt executive summary)

Evidence indicates that anadromous rainbow smelt (Osmerus mordax) populations in Connecticut and elsewhere in the northeast United States have severely declined. Several sampling programs have documented declines in Connecticut’s smelt populations over the last three decades (Marcy 1976a, Marcy 1976b, Millstone Environmental Laboratory 2005). Similar declines have also been documented in the Hudson River (ASA Analysis & Communication 2005) and in Massachusetts (personal communication, Brad Chase, MA Division of Marine Fisheries 2004). Recreational and commercial fisheries in the region for this species have virtually ceased (Blake and Smith 1984). The Connecticut Fish Advisory Committee …

Assessment Of Anadromous Alewife And Blueback Herring Populations In Connecticut Coastal Streams And Connecticut River Tributaries, Justin P. Davis, Eric T. Schultz

EEB Articles

Alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) occur in anadromous populations that have a largely overlapping distribution from Florida to Newfoundland (Loesch 1987). Anadromous populations of these species are commonly collectively referred to as “river herring”. Adults inhabit coastal shelf waters until sexual maturity is reached at age 3-5 (Neves 1981). Sexually mature individuals make spawning migrations, commonly referred to as “runs”, into freshwater systems during spring months (Loesch 1987). Spawners can survive and return to spawn in subsequent years (Mullen et al. 1986). Juveniles reside in freshwater for 3-7 months, at which time they undertake a gradual migration …

The Dynamics Of Bay Anchovy In The Hudson River Estuary: Process-Oriented Studies And Long-Term Changes, Eric T. Schultz, Kamazima M. M. Lwiza, John R. Young, Kyle J. Hartman, R. C. Tipton

EEB Articles

We review three areas of recent research on Hudson River bay anchovy. One focus has been the along-estuary movement of early life stages. A cohort analysis of samples collected in a spatiotemporally extensive monitoring program has confirmed that early-stage anchovy migrate up-estuary, at an estimated rate of 0.6 km/d. Complementary fine-scale field sampling was designed to clarify behaviors that effect the migration. This work found that early-stage anchovy can show preferences for depth and can conduct periodic vertical migration. To determine whether these behaviors were sufficient to produce up-estuary migration, larval flux and velocity were estimated. These estimates were consistent …

The Essentials On Estuarine Fish Habitat, Its Evaluation And Protection By Federal Fisheries Law, Eric T. Schultz, Michael Ludwig

EEB Articles

No abstract provided.

Distribution, Habitat Use, Growth, And Condition Of A Native And An Introduced Catfish Species In The Hudson River Estuary, Stephen M. Jordan, Robert M. Neumann, Eric T. Schultz

EEB Articles

White catfish (Ameiurus catus) is native to the Hudson River and is now coexisting with the recently established channel catfish (Ictalurus punctatus). These species were sampled from four freshwater reaches and four habitat types of the Hudson River estuary to assess whether the two species overlapped in their habitat use, and whether any impact on the native species was evident. Catfishes were sampled in 1998 and 1999 using baited hoop nets (N = 708 net nights). Catch-per-unit-effort (CPUE, number of fish per net night; total catch = 368) of white catfish was significantly different among reaches …

Do Naked Goby (Gobiosoma Bosci) Larvae Exhibit Periodic Vertical Movements In Order To Facilitate Upriver Migration In The Hudson River Estuary?, Megan C. Fencil, Eric T. Schultz

EEB Articles

Estuaries provide high quality nursery habitat for larval fishes due to high productivity, predator protection, and warm temperatures. Previous studies suggest that larval naked gobies (Gobiosoma bosci) are capable of upriver migration and estuarine retention despite net seaward flow. Gobiosoma bosci larvae were collected at a fixed site in the Hudson River estuary in late July of 1998 from 4 discrete depths to provide a time-series of depth-stratified abundance during both a spring and a neap tide. Larvae were concentrated at depth, indicating that depth preference behavior is present and will likely contribute to up-river transport. Harmonic regression …