bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Ecosystem Perspective on Re-establishing Native Deepwater Fishes in the Laurentian Great Lakes
Authors: Zimmerman Mara S. , Krueger Charles C. 
Published: October 2009

Abstract
Herein we examine scientific questions related to successful re-establishment of native deepwater fish communities in the Laurentian Great Lakes, and we (1) propose a conceptual model for native deepwater fish communities; (2) review current research and identify research hypotheses for lake trout Salvelinus namaycush, pelagic ciscoes Coregonus spp., and sculpins (Cottus spp. and Myoxocephalus spp.); (3) pose research questions emerging at community and ecosystem levels; and (4) identify high-priority research topics related to population re-establishment. The conceptual model is based on a generalized life cycle nested within processes at the population, metapopulation, community, and ecosystem levels. The conceptual model assumes that variation in population abundance is a natural phenomenon and that biodiversity contributes to ecosystem stability. Key research topics related to lake trout re-establishment include understanding recruitment variation over space and time, identifying sources of early life history mortality, determining the level of genetic differentiation among morphotypes and populations, and comparing the life history and ecology of lean lake trout with those of other lake trout morphotypes. Key research topics related to re-establishing deepwater species of cisco include resolving uncertainties in species identifications, understanding processes maintaining distinctiveness among species, understanding processes leading to cyclic and erratic recruitment, and developing effective propagation methods. Key research topics related to re-establishment of sculpin species include comparing spawning ecology and early life history of each species, determining population structure, and evaluating the feasibility of live-transfer methods. Key research topics related to community- and ecosystem-level interactions include understanding large-scale directional influences on community function, expanding current views on ecological succession in large lakes, and determining the evolutionary role of diel vertical migration in phenotypic diversification of deepwater fishes. Finally, we propose that research in four topical areas are most pertinent to re-establishing native deepwater fishes: life history bottlenecks, population and metapopulation dynamics, matching fish phenotypes to stocking sites, and propagation and stocking methods.
Detection and Longevity of Uncured and Cured Visible Implant Elastomer Tags in Larval Pacific Lampreys
Authors: Silver Gregory S. , Luzier Christina W. , Whitesel Timothy A. 
Published: October 2009

Abstract
Studies of the biology, ecology, and status of the Pacific lamprey Lampetra tridentata may require effective means of tagging larval Pacific lampreys. However, few assessments of the methods suitable for tagging larval Pacific lampreys have been conducted. We evaluated the performance of visible implant elastomer (VIE) tags in larval Pacific lampreys, specifically testing the effects of elastomer treatment (uncured versus cured VIE) and inspection light source (ambient light versus blue light-emitting diode [LED] flashlight) on tag detection in 40 larvae. Through day 251 after tagging, tag detection was 100% for both uncured and cured VIE tags observed under ambient light and blue LED light. Longevity of uncured VIE tags was assessed in a second cohort of 32 VIE-tagged larval Pacific lampreys over a 2-year captive rearing period. Percent VIE tag detection was 91% for red tags, 90% for orange tags, and 64% for green tags through day 699 after tagging. This study affirms that both uncured and cured VIE tags can be effectively used to tag larval Pacific lampreys. Tagging with uncured VIE is a convenient and economical alternative to cured VIE tagging, particularly when tagging over protracted periods or small sample sizes.
Genetic Evaluation of a Conservation Hatchery Program for Reintroduction of Sicklefin Redhorse Moxostoma sp. in the Tuckasegee River, North Carolina
Authors: Moyer Gregory R. , Rousey J. D. , Cantrell M. A. 
Published: October 2009

Abstract
Restoration and reintroduction efforts for the sicklefin redhorse Moxostoma sp. have been initiated by state, tribal, and federal agencies owing to the limited geographic distribution of this species and threats associated with the physical alteration of its habitat. A critical component of a successful reintroduction is that the source and recipient populations have similar genetic resources and life history patterns. We used 10 microsatellite loci to estimate and compare indices of genetic diversity between the Little Tennessee River population of wild adults and the hatchery broodstock being used for initial reintroduction efforts. We also compared relatedness values for the broodstock used for restoration efforts. There were no significant differences between hatchery broodstock and wild adults with respect to average gene diversity, but the average number of alleles for each brood year was significantly less than that for wild adults. While this trend persisted when the 2007 and 2008 brood years (combined) were compared with wild adults, the reduction was not significant. Finally, all hatchery crosses were among unrelated individuals. Our results highlight the importance of using genetic information to assist restoration and reintroduction efforts.
Utility of a Probabilistic Sampling Design to Determine Bull Trout Population Status Using Redd Counts in Basins of the Columbia River Plateau
Authors: Jacobs Steven E. , Gaeuman William , Weeber Matt A. , Gunckel Stephanie L. , Starcevich Steven J. 
Published: October 2009

Abstract
Redd counts are commonly used to monitor the current population status, trends in abundance, and distribution of bull trout Salvelinus confluentus. In many cases redd counts are conducted at subjectively selected sites, and there has been limited evaluation of statistical sampling designs. We evaluated the utility of the generalized random tessellation stratified (GRTS) sampling design to determine bull trout population status through redd counts. We tested a sampling effort that would be economically practical to implement on a continuous basis in multiple drainages within the southeastern Washington and Oregon portions of the Columbia River plateau. We evaluated the logistics of a pilot application of the GRTS design, compared GRTS-based estimates of redd abundance with those from census surveys, determined the precision of the GRTS estimates and the associated power for abundance comparisons, and compared the performance of the GRTS design with that of other probability sampling designs through simulation. A target of 50 sites per basin can be sampled by a two-person survey crew multiple times over the spawning season. At that level of effort, the precision of redd abundance estimates ranges from 15% to 35%, depending on the patchiness of the redd distribution and the extent of the target population. These levels of precision are suitable for detecting a 30–70% change in redd abundance. Direct comparisons of GRTS-based estimates with those obtained from a census showed mixed results. However, in a simulation study with three other probability sampling designs, GRTS consistently outperformed all but systematic sampling, which provided slightly better precision at intermediate sample sizes. Depending on the scale of inference, GRTS is useful in monitoring bull trout conservation units through redd counts, though a census may provide a more practical design for monitoring core areas as defined by the U.S. Fish and Wildlife Service.
Poststocking Harvest of Catchable-Sized Rainbow Trout Enhanced by Dietary Supplementation with a Fully Fermented Commercial Yeast Culture during Hatchery Rearing
Authors: Barnes Michael E. , Simpson Greg , Durben Dan J. 
Published: October 2009

Abstract
Catchable-sized salmonids are often stocked without regard to their hatchery rearing history, including the diets used. To evaluate the possible effects of a proprietary, fully fermented yeast Saccharomyces cerevisiae dietary supplement (DVAqua; Diamond V Mills, Cedar Rapids, Iowa) on poststocking harvest, Shasta-strain rainbow trout Oncorhynchus mykiss (280 mm) were fed either a hatchery diet containing 0.125% yeast product or a control diet prior to four stockings over the course of 3 months in two small put-and-take fishing lakes (Upper Mirror and Lower Mirror lakes, South Dakota). An angler census indicated that for each lake on each of four stocking dates, rainbow trout receiving yeast supplementation were harvested at higher rates than fish fed the control diet; each lake had one stocking for which the percent harvest of fish fed the yeast-supplemented diet was more than 30% higher than that of control fish. Overall, returns to the creel in Upper Mirror and Lower Mirror lakes were 17% and 13% higher, respectively, for fish fed the yeast-supplemented diet than for control fish. Most of the rainbow trout were harvested within 2 weeks after stocking, with no difference in timing of harvest observed between the two diet groups. In addition to experiencing greater harvest by anglers during the census, more fish fed the yeast-supplemented diet were recovered from each lake after the census through a combination of gillnetting and voluntary tag reporting by fishermen. The results suggest that rainbow trout fed the yeast-supplemented diet during hatchery rearing consistently returned to the creel in significantly greater numbers than fish receiving the control diet. Fisheries managers may want to consider these results when requesting hatchery-produced catchable rainbow trout for put-and-take waters.
Accounting Explicitly for Predation Mortality in Surplus Production Models: An Application to Longfin Inshore Squid
Authors: Moustahfid Hassan , Tyrrell Megan C. , Link Jason S. 
Published: October 2009

Abstract
One approach to better account for ecosystem considerations in fisheries science is to incorporate ecological interactions into conventional stock assessment models. The longfin inshore squid Loligo pealeii is one of two squid species of ecological and commercial significance in the northwest Atlantic Ocean. A surplus production model with quarterly time steps was fitted to longfin inshore squid total removal (fishing and predation removal) and tuned with fishery-dependent, fishery-independent, and predation-dependent indices to examine the effect of incorporating predation into a single-species model. Total consumption of squid by all predatory fish exceeded the landings in most years of this analysis. The model output indicated that biological reference points for longfin inshore squid differ considerably when predation removals are included. It appears that by not including predation, the model underestimates stock biomass and overestimates fishery surplus production. Short-term stochastic projections of such estimates demonstrate that increasing predation mortality and fishing mortality will decrease the biomass of longfin inshore squid. Failing to account for predation when performing stock assessments for longfin inshore squid and other similar forage species may misrepresent reference point estimates and result in management advice that could lead to biomass declines. We envision that the approach presented here will provide requisite information and a useful example towards improving the current modeling practices for longfin inshore squid and similar forage species.
Effects of Striped Bass Stocking on Largemouth Bass and Spotted Bass in Lewis Smith Lake, Alabama
Authors: Shepherd Michael D. , Maceina Michael J. 
Published: October 2009

Abstract
Introductions of striped bass Morone saxatilis into U.S. reservoirs have caused concern among anglers that target other species owing to the perception that this predator reduces the number of other sport fish and can limit available prey supplies. Recently, this controversy arose in Lewis Smith Lake (8,583 ha), Alabama, prompting this study to examine the effects of stocking striped bass on the resident population of black bass Micropterus spp. From October 2006 to August 2007, the diets of striped bass, largemouth bass M. salmoides, and spotted bass M. punctulatus were examined in this reservoir. The density and biomass of striped bass and black bass were computed from estimates of age-0 black bass abundance, striped bass stocking rates, growth, and survival. Bioenergetics models were used to estimate striped bass and black bass consumptive food demands. Striped bass diets (by weight) were dominated by shad Dorosoma spp. (64%), followed by crayfish Oronectes spp. (12%), while black bass and sunfish Lepomis and crappies Pomoxis spp. comprised 5% and 6% of the diet, respectively. Numerically, sunfish–crappies and black bass only comprised 0.28% and 0.16% of the diets of striped bass. The diets of largemouth bass and spotted bass (by weight) were dominated by crayfish (72% and 75%, respectively) and sunfish–crappies (21% and 9%, respectively), while shad comprised 6% and 14% of the diets, respectively. Diet overlap values between striped bass and black bass were generally low but varied seasonally among species. The highest overlap between the diets of striped bass and black bass was observed in April and June. However, the relative weights of black bass did not decline or the frequency of empty stomachs among these species did not increase during or after this time. Overall, consumptive prey demand was similar between striped bass and black bass. Bioenergetics modeling estimated striped bass consumption of shad, bass–sunfish–crappies, and crayfish averaging 14, 3, and 5 kg/ha, respectively, compared with 3, 6, and 16 kg/ha, respectively, for black bass. Shad consumption by striped bass and black bass (relative to the total annual supply) was within acceptable levels. Striped bass consumption of black bass was low, striped bass and black bass partitioned prey resources, and the temporal differences in maximum consumptive demand varied between black bass and striped bass. Thus, we found that the impact of striped bass stocking on the black bass population was minimal.
Estimates of Predator Consumption of the Northern Shrimp Pandalus borealis with Implications for Estimates of Population Biomass in the Gulf of Maine
Authors: Link Jason S. , Idoine Josef S. 
Published: October 2009

Abstract
Globally, shrimp stocks are important both economically and ecologically, and this is true for the northern shrimp Pandalus borealis in the Gulf of Maine. Understanding and modeling of shrimp stock dynamics have often posed challenges, leading to the suggestion that inclusion of more multidisciplinary data may help to better elucidate shrimp stock dynamics. Thus, we explored the potential implications of including additional information for northern shrimp biomass estimates by examining fish food habits from the Gulf of Maine. We estimated the consumptive removals by 18 predators of northern shrimp. Summed across all predators, the consumptive removals for northern shrimp in recent years were on the order of 20,000–30,000 metric tons. These estimates are generally conservative based upon consumption model assumptions. Compared with survey indices, the trends in consumptive removals were out of phase in the 1990s but both trended upwards in the early 2000s. Compared with the base assessment model, consumptive removals were of the same order of magnitude, trended similarly, and were two to four times higher than estimates of northern shrimp biomass. Changing the natural mortality (M) parameter in the assessment model to higher levels (M from 0.25 to 0.50 or 0.60) reconciled the difference in estimates of biomass. Our objective was neither to fit a new assessment model nor to provide precise estimates of northern shrimp biomass; rather, we demonstrate that including food habits data as contextual information in such assessments is feasible and should lead to enhanced estimates of M. Improvements in obtaining relative estimates of biomass could then result from these enhanced estimates of M, particularly as it would allow for evaluating the tradeoffs between fishing and predation as sources of northern shrimp removals.
The Differential Response to Decompression in Three Species of Nearshore Pacific Rockfish
Authors: Pribyl Alena L. , Schreck Carl B. , Kent Michael L. , Parker Steven J. 
Published: October 2009

Abstract
The genus Sebastes (rockfishes) is an ecologically diverse group of fish, more than 60 species occurring off the Oregon, Washington, and California coasts. As of 2004, seven species of rockfish were classified as overfished by the Pacific Fishery Management Council. Because rockfishes often experience barotrauma to varying degrees when forced up from depth, the management of discard mortality has been difficult. In this study, the macroscopic, morphological, and physiological responses to decompression of black rockfish S. melanops, blue rockfish S. mystinus, and yellowtail rockfish S. flavidus, all nearshore species, were investigated. The rockfish were adjusted to 4.5 atmospheres absolute (ATA; 35 m) over a period of 7–10 d in hyperbaric pressure chambers and when neutrally buoyant were rapidly brought to surface pressure in a simulated ascent. They were then examined for barotrauma injury, and the heart ventricle, head kidney, liver, gill, and pseudobranch were collected for histological analysis. We observed more macroscopic barotrauma indicators in black rockfish and blue rockfish than in yellowtail rockfish. Histological analysis showed emphysema was present in the heart ventricle of more than one-half of the black rockfish, 11% of the blue rockfish, and none of the yellowtail rockfish. No other tissue had observable injury at the histological level that was attributable to barotrauma. The lack of injury at the tissue level for black, blue, and yellowtail rockfishes decompressed from 4.5 ATA is remarkable.
Effects of Body Size and River Environment on the Upstream Migration of Adult Pacific Lampreys
Authors: Keefer Matthew L. , Moser Mary L. , Boggs Charles T. , Daigle William R. , Peery Christopher A. 
Published: October 2009

Abstract
Dams in the Columbia River basin present significant obstacles to declining populations of anadromous Pacific lampreys Lampetra tridentata. Mitigation efforts have focused on fine-scale improvements in passage at individual dams, but there is an increasing need for basinwide estimates of survival and escapement. We developed a half-duplex passive integrated transponder (PIT) tag monitoring array at five Columbia and Snake River dams to evaluate adult lamprey migrations. We tagged 3,598 lampreys over 3 years and calculated the rates of main-stem escapement through 15 river reaches. From these data, we assessed the relative effects of lamprey size, river discharge, water temperature, and migration timing on upstream passage. The results indicated high attrition as lampreys progressed upstream. In each year, about one-half of the fish passed one dam, 28–33% passed two dams, 17–19% passed three dams, 4–5% passed four dams, and about 1% passed the first dam on the Snake River (five dams and &gt;300 km upstream from their release sites). In most reaches, upstream passage was strongly size dependent, the largest lampreys being two to four times more likely to pass than the smallest fish. Lamprey size was more predictive of passage than were the river discharge, temperature, or migration timing variables. These findings suggest that adult Pacific lamprey migration is affected by physiological constraints and that effective mitigation for the difficult passage conditions at dams should include size-related considerations.
Morphological Models for Identifying Largemouth Bass, Spotted Bass, and Largemouth Bass × Spotted Bass Hybrids
Authors: Godbout Jason D. , Aday D. Derek , Rice James A. , Bangs Max R. , Quattro Joseph M. 
Published: October 2009

Abstract
Hybridization is common among many closely related fishes, such as the largemouth bass Micropterus salmoides and spotted bass M. punctulatus. Although these species are common members of the sport fish community in midwestern and southeastern U.S. reservoirs, fairly little is known about their ecological interactions or the potential for the introduction of one species to influence the other species. To address these ecological questions and develop appropriate management strategies, reliable field and laboratory identification of each parental species and their hybrid is required. To that end, we collected juvenile (n = 60) and adult (n = 78) largemouth bass, spotted bass, and largemouth bass × spotted bass hybrids from Lake Norman, North Carolina, a system with a historically strong largemouth bass fishery that recently experienced a spotted bass introduction. We recorded a suite of morphological traits on each individual and correlated those observations with DNA sequences from one mitochondrial marker and three nuclear DNA markers in an attempt to develop morphological field and laboratory methods for identifying individuals of the parental species and their hybrid. After confirming that largemouth bass and spotted bass were hybridizing in Lake Norman, we used classification tree analyses to form dichotomous keys for field and laboratory identification of parental individuals and hybrids at juvenile (50–100 mm total length) and adult (300–500 mm) life stages. These keys should provide fishery biologists and managers with a tool to identify these two species, which commonly interact and closely resemble one another. In addition, these keys should be useful in providing evidence that largemouth bass and spotted bass are hybridizing before more expensive techniques like DNA sequencing are pursued.
Age and Growth Variability between Sexes of Three Catfish Species in Lake Wilson, Alabama
Authors: Marshall Matthew D. , Maceina Michael J. , Holley Michael P. 
Published: October 2009

Abstract
Blue catfish Ictalurus furcatus, channel catfish I. punctatus, and flathead catfish Pylodictus olivaris were collected from Lake Wilson (Tennessee River), Alabama. Fish were aged with otoliths to determine sex-specific differences in growth, age structure, and longevity. Male blue catfish grew faster, lived longer, and attained larger sizes than females. Growth of flathead catfish did not differ statistically between sexes; however, male flathead catfish tended to be longer and to attain older ages than females. Sex-specific differences in age-related population demographics were not evident for channel catfish. Reproductive strategies of catfishes may cause sexual selection toward larger male blue catfish and flathead catfish. Recently imposed harvest regulations in Alabama that permit only one catfish greater than 864 mm to be harvested daily will protect older and slower-growing female blue catfish and could allow disproportionate protection of larger male blue catfish and flathead catfish.