Aquaculture and Fisheries Commons^™

Nile Tilapia And Blue Tilapia Fry Production In A Subtropical Climate Based On Degree Days, Bartholomew W. Green, Esam H. Rizkalla

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The relationship between production in subtropical earthen ponds of fry suitable for hormonal sex inversion and degree days was quantified for Nile tilapia (Oreochromis niloticus; Egypt strain) and blue tilapia (O. aureus). Degree days were calculated for each trial as the sum of mean daily water column temperature minus the reference temperature, 15◦C. No fry from either species were harvested at fewer than 124–126 degree days. Total fry production for each increased linearly as cumulative degree days increased from 129 to 281 degree days. Production of fry suitable for hormonal sex inversion was positively related to …

Reservoir Area Of Influence And Implications For Fisheries Management, Dustin R. Martin, Christopher J. Chizinski, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Understanding the spatial area that a reservoir draws anglers from, defined as the reservoir’s area of influence, and the potential overlap of that area of influence between reservoirs is important for fishery managers. Our objective was to define the area of influence for reservoirs of the Salt Valley regional fishery in southeastern Nebraska using kernel density estimation. We used angler survey data obtained from in-person interviews at 17 reservoirs during 2009–2012. The area of influence, defined by the 95% kernel density, for reservoirs within the Salt Valley regional fishery varied, indicating that anglers use reservoirs differently across the regional fishery. …

Reservoir Rehabilitations: Seeking The Fountain Of Youth, Mark A. Pegg, Kevin L. Pope, Larkin A. Powell, Kelly C. Turek, Jonathan J. Spurgeon, Nathaniel T. Stewart, Nick P. Hogberg, Mark T. Porath

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Aging of reservoirs alters the functions, and associated services, of these systems through time. The goal of habitat rehabilitation is often to alter the trajectory of the aging process such that the duration of the desired state is prolonged. There are two important characteristics in alteration of the trajectory—the amplitude relative to current state and the subsequent rate of change, or aging—that ultimately determine the duration of extension for the desired state. Rehabilitation processes largely fall into three main categories: fish community manipulation, water quality manipulation, and physical habitat manipulation. We can slow aging of reservoirs through carefully implemented management …

The Global Status Of Freshwater Fish Age Validation Studies And A Prioritization Framework For Further Research, Jonathan J. Spurgeon, Martin J. Hamel, Kevin L. Pope, Mark A. Pegg

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Age information derived from calcified structures is commonly used to estimate recruitment, growth, and mortality for fish populations. Validation of daily or annual marks on age structures is often assumed, presumably due to a lack of general knowledge concerning the status of age validation studies. Therefore, the current status of freshwater fish age validation studies was summarized to show where additional effort is needed, and increase the accessibility of validation studies to researchers. In total, 1351 original peer-reviewed articles were reviewed from freshwater systems that studied age in fish. Periodicity and age validation studies were found for 88 freshwater species …

Experimental Evaluation Of Rainbow Trout Oncorhynchus Mykiss Predation On Longnose Dace Rhinichthys Cataractae, Kelly C. Turek, Mark A. Pegg, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Laboratory and in-stream enclosure experiments were used to determine whether rainbow trout Oncorhynchus mykiss influence survival of longnose dace Rhinichthys cataractae. In the laboratory, adult rainbow trout preyed on longnose dace in 42% of trials and juvenile rainbow trout did not prey on longnose dace during the first 6 h after rainbow trout introduction. Survival of longnose dace did not differ in the presence of adult rainbow trout previously exposed to active prey and those not previously exposed to active prey (x²₁ = 0.28, P = 0.60). In field enclosures, the number of longnose dace decreased at …

Barriers And Bridges To The Integration Of Social–Ecological Resilience And Law, Olivia Odom Green, Ahjond S. Garmestani, Craig R. Allen, Lance H. Gunderson, J.B. Ruhl, Craig A. Arnold, Nicholas A.J. Graham, Barbara Cosens, David G. Angeler, Brian C. Chaffin, C.S. Holling

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

There is a fundamental difference between the ways in which ecologists and lawyers view uncertainty: in the study of ecology, uncertainty provides a catalyst for exploration, whereas uncertainty is antithetical to the rule of law. This issue is particularly troubling in environmental management, where the tensions between law and ecology become apparent. Rather than acknowledge uncertainties in management actions, legal frameworks often force a false sense of certainty in linking cause and effect. While adaptive management has been developed to deal with uncertainty, laws and legal wrangling can be obstacles to implementation. In this article, we recommend resilience-based governance – …

Quantifying The Adaptive Cycle, David G. Angeler, Craig R. Allen, Ahjond S. Garmestani, Lance H. Gunderson

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term …

Across-Ecoregion Analysis Suggests A Hierarchy Of Ecological Filters That Regulate Recruitment Of A Globally Invasive Fish, Przemek G. Bajer, Timothy K. Cross, Joseph D. Lechelt, Christopher J. Chizinski, Michael J. Weber, Peter W. Sorensen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Aim -- Even successful invaders are abundant only in a fraction of locales they inhabit. One of the main challenges in invasion ecology is explaining processes that drive these patterns. We investigated recruitment of a globally invasive fish, common carp (Cyprinus carpio), across three ecoregions to determine the role of environmental characteristics, predatory communities and propagule pressure on the invasion process at coarse and fine spatial scales.

Location -- Lakes across Northern Forest, Temperate Forest and Great Plains ecoregions of North America.

Methods -- We used data from 567 lakes to model presence or absence of carp recruitment …

The Value Of Captains’ Behavioral Choices In The Success Of The Surfclam (Spisula Solidissima) Fishery On The U.S. Mid-Atlantic Coast: A Model Evaluation, Eric N. Powell, John M. Klinck, Daphne M. Munroe, Eileen E. Hofmann, Paula Moreno, Roger Mann

CCPO Publications

The response of the surfclam Spisula solidissima to warming of the Mid-Atlantic Bight is manifested by recession of the southern and inshore boundary of the clam’s range. This phenomenon has impacted the fishery through the closure of southern ports and the movement of processing capacity north, impacts that may require responsive actions on the part of fishery captains to mitigate a decline in fishery performance otherwise ineluctably accompanying this shift in range. The purpose of this study was to evaluate options in the behavioral repertoire of captains that might provide mitigation. A model capable of simulating a spatially and temporally …

The Effect Of Parental Size On Spermatophore Production, Egg Quality, Fertilization Success, And Larval Characteristics In The Caribbean Spiny Lobster, Panulirus Argus, Mark J. Butler Iv, Alison Macdiarmid, Gaya Gnanalingam

Biological Sciences Faculty Publications

The average size of spiny lobsters (Decapoda; Palinuridae) has decreased worldwide over the past few decades. Market forces coupled with minimum size limits compel fishers to target the largest individuals. Males are targeted disproportionately as a consequence of sexual dimorphism in spiny lobster size (i.e. males grow larger than females) and because of protections for ovigerous females. Therefore, overexploitation of males has led to sperm limitation in several decapod populations with serious repercussions for reproductive success. In the Caribbean spiny lobster, Panulirus argus, little is known about the effect of reduced male size on fertilization success or the role …

Effects Of The Algal Toxin Microcystin On Fishes In The James River, Virginia, Maxwell D. Haase

Theses and Dissertations

With the global rise in frequency of harmful algal blooms in estuarine environments comes an increase in prevalence of toxic metabolites, such as microcystin (MC), that some of the cyanobacteria involved will produce. At high concentrations, MC may accumulate in consumer tissues and have deleterious effects on organisms; however impacts of the toxin on aquatic living resources at ecologically relevant concentrations have not been widely documented. We analyzed the effects of MC on juveniles of five fish species from the James River, Virginia to determine if MC has the potential to impede growth. Using three separate experimental approaches, it was …

Density Dependent Effects On Cutthroat And Brook Trout Behavioral Competition And Energy Expenditure, Ethan Daniel Green

All Master's Theses

Cutthroat Trout (Oncorhynchus clarki) are being displaced rangewide by invasive Brook Trout (Salvelinusfontinalis). There are many potential causes of displacement but the underlying mechanisms of the invasion and displacement are not well understood. Increased population densities in streams in which Cutthroat Trout and Brook Trout occur in sympatry appears to have detrimental effects on Cutthroat Trout. In this study, I compared the competitive behaviors and activity allocation patterns of Brook Trout and Cutthroat Trout at varying population densities in a simulated stream aquarium. I concluded that Brook Trout likely have a behavioral advantage over Cutthroat Trout …

River Report. State Of The Lower St. Johns River Basin, Florida: Water Quality, Fisheries, Aquatic Life, Contaminants, 2015, Environmental Protection Board, City Of Jacksonville, University Of North Florida, Jacksonville University, Lucy Sonnenberg, Gerry Pinto, Nisse Goldberg, Anthony Ouellette, Gretchen Bielmyer-Fraser, Stuart J. Chalk, Peter Bacopoulos, Brian P. Zoellner

State of the River Report

No abstract provided.

Assessing The Contributions Of Two Stocked Strains On A Minnesota-Wisconsin Border Water, Douglas Zentner

Journal of Earth and Life Science

Stocking has long been used as a management tool in the United States even though many of its effects remain cryptic. Past comparisons between stocked strains were generally based on the survival and growth rates of physically marked individuals. More recently the use of genetic markers to assess contributions of stocked individuals has been employed by fisheries managers. Using 13 microsatellite markers we assessed the contributions of two muskellunge (Esox masquinongy) strains (Wisconsin and Leech) stocked into the St. Louis River Estuary. Ancestry in the adult samples remained relatively constant with differences only observed between the 2008 and …

Using Wild I.D. As A Reliable Source For Mark And Recapture Studies On Northern Pike (Esox Lucius), Martin Evans

Journal of Earth and Life Science

Mark and recapture studies are a very popular method fisheries biologists use to assess certain fish populations in lakes. This process can be very labor intensive and expensive. Wild I.D. is free software developed by Dartmouth College that uses SIFT program to find unique features in photographs. Initially developed for identification of African land mammals the program gives each photo a score and percent match to other photos. Northern pike were used in this study to determine if the program can recognize simulated recapture events. Photos of sample fish were taken at two separate locations, the photos were then copied …

Juvenile Chinook Salmon Diet In Comparison To Invertebrate Drift In The Merced River, California, Tyler Orgon

Journal of Earth and Life Science

Diets and habitat types of salmonids have been widely studied in disturbed streams and rivers. The Merced River in California has a long history of flooding, damming, levee failures, and channel reconstruction events that has disrupted the aquatic ecosystem. This 30 day study was conducted in the Robinson Reach of the Merced River using juvenile Chinook salmon (Oncorhynchus tshawtscha). The objectives were to try and understand if juvenile Chinook salmon were selecting certain invertebrate species, determine if there were any differences in diets between habitat types, and determine whether diets and drift samples were different. Diets consisted of …

Effects Of Cooler Northern Waters On Growth Rates In Bluegill And Pumpkinseed Sunfish, Alec Spurbeck

Journal of Earth and Life Science

The Centrarchidae family range spans all across the United States making them a favorite target for many recreational anglers. In northern Minnesota, most water bodies do not reach optimal growth temperatures for the sunfishes, putting them right on the edge of their suitable range and potentially slowing overall growth. Therefore, the main objectives of this study were to 1) determine if sunfish growth rates respond to the severity of winter and 2) investigate growth differences between two sunfish species. Growth rates of bluegill (Lepomis macrochirus) and pumpkinseed (Lepomis gibbosus) were estimated from Big Sugar Bush Lake, …

Spatial And Temporal Factors Influencing Northern Pike Fry Density Estimates, Nate Stott

Journal of Earth and Life Science

The Tamarac River in northern Minnesota is an important spawning site for northern pike (Esox lucius) in the Red Lake system. However, little is known about fry production in the river. This study investigates migration densities and spatial and temporal factors influencing northern pike fry density estimates. Northern pike fry were collected with drift nets between 28 May and 4 June 2014. Thirty northern pike fry were randomly selected to have total length measured from each sample. Northern pike fry were observed in the first sample day. Northern pike fry density maxima occurred on 29 May at midnight …

A Genetic Based Approach To Management And Stocking Of Muskellunge, Douglas Zentner

Journal of Earth and Life Science

Fish stocking has long been used as a management tool among fisheries biologists and continues to be met with popular public opinion. Despite perceived simplicity, the full effects of stocking remain cryptic for many fish populations. Stocking has frequently been used to maintain or establish successful muskellunge (Esox masquinongy) populations. Coupled with other management practices the Minnesota Department of Natural Resources (MNDNR) has established Minnesota as a premier muskellunge fishery. From 1958 to 2012 the MNDNR stocked three strains of muskellunge in Big Mantrap Lake, MN. The first from Shoepack Lake, MN (hereafter Shoepack-strain) was used until the …

Saffron Cod (Eleginus Gracilis) In North Pacific Archaeology, Megan A. Partlow, Eric Munk

All Faculty Scholarship for the College of the Sciences

Saffron cod (Eleginus gracilis) is a marine species often found in shallow, brackish water in the Bering Sea, although it can occur as far southeast as Sitka, Alaska. Recently, we identified saffron cod remains in two ca. 500-year-old Afognak Island midden assemblages from the Kodiak Archipelago. We developed regression formulae to relate bone measurements to total length using thirty-five modern saffron cod specimens. The archaeological saffron cod remains appear to be from mature adults, measuring 22–45 cm in total length, and likely caught from shore during spawning. Saffron cod may have been an important winter resource for Alutiiq people living …