Wedding LM, CA Lepczyk, SJ Pittman, AM Friedlander, S Jorgensen. 2011. Quantifying seascape structure: extending terrestrial spatial pattern metrics to the marine realm. Mar. Ecol. Prog. Ser. 427:219-232.
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April 2011
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Suarez B & TB Grabowski. 2021. Estimating detection and occupancy coefficients for the Pacific Islands coral reef fish species. Hawaii Cooperative Fishery Research Unit Technical Report Series HCFRU-001. University of Hawaii at Hilo. Available online at: hdl.handle.net/10790/5553
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Abstract
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Publisher Website
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January 2021
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The data-limited stock assessment models used to monitor the status of coral reef fish species in the Western Pacific region are dependent upon accurate estimates of standing stock biomass generated from underwater visual surveys of reefs. However, the imperfect detection of and variable occupancy of habitat by reef fishes are not currently accounted for in these estimates. Therefore, the objective of this project was to estimate detection and occupancy coefficients for the species listed in the Western Pacific Regional Fishery Management Council’s Fishery Ecosystem Plans by analyzing the Pacific Island Fishery Science Center-Coral Reef Ecosystem Program Reef Fish Dataset. These detection and occupancy coefficients would then be applied to refine standing stock biomass estimates. In general, species with higher detection probabilities and/or lower occupancy rates tended to exhibit the greatest differences in the estimates of standing stock biomass calculated with and without accounting for detection and occupancy. The standing stock biomass of most reef fish species seem to be underestimated when detection and occupancy are not accounted for. However, the standing stock biomass of larger-bodied targeted species, such as jacks, snappers, and groupers, seem to be over-estimated relative to the estimates generated when accounting for occupancy and detection. Based on the re-estimated standing stock biomass. While there are still issues to resolve regarding how well the current data collection methods meet the underlying assumptions of the detection and occupancy modeling approach, the inclusion of detection and occupancy coefficients seems likely to improve estimates of standing stock biomass of coral reef fish species.
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Smith, L.W., D. Barshis, and C. Birkeland. 2007. Phenotypic plasticity for skeletal growth, density and calcification of Porites lobata in response to habitat type. Coral Reefs 26: 559-667.
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April 2007
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Smith, L.W, and C. Birkeland. 2007. .Effects of intermittent flow and irradiance level on back reef Porites corals corals at elevated seawater temperatures. Journal of Experimental Marine Biology and Ecology 341: 282-294
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March 2007
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Smith, L., H. Wirshing, A. C. Baker, C. Birkeland. Environmental versus genetic influences on growth rates of the corals Pocillopora eydouxi and Porites lobata. Pacific Science 62: 57-69.
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January 2008
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Sala E, Ballesteros E, Dendrinos P, Di Franco A, Ferretti F, Foley D, Fraschetti S, Friedlander A, and 19 others. 2012. The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications. PLoS ONE 7(2): e32742. doi:10.1371/journal.pone.0032742
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March 2012
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Ruttenberg BI, Hamilton SL, Walsh SM, Donovan MK, Friedlander A, E DeMartini, E Sala, SA Sandin. 2011 Predator-induced demographic shifts in coral reef fish assemblages. PLoS ONE 6(6): e21062. doi:10.1371/journal.pone.0021062
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June 2011
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Roesler EL, & TB Grabowski. 2018. Estimating factors influencing the detection probability of semi-aquatic freshwater snails using quadrat survey methods. Hydrobiologia 808:153-161. doi: 10.1007/s10750-017-3415-9
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Abstract
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February 2018
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Developing effective monitoring methods for elusive, rare, or patchily distributed species requires extra considerations, such as imperfect detection. Although detection is frequently modeled, the opportunity to assess it empirically is rare, particularly for imperiled species. We used Pecos assiminea (Assiminea pecos), an endangered semi-aquatic snail, as a case study to test detection and accuracy issues surrounding quadrat searches. Quadrats (9 x 20 cm; n = 12) were placed in suitable Pecos assiminea habitat and randomly assigned a treatment, defined as the number of empty snail shells (0, 3, 6, or 9). Ten observers rotated through each quadrat, conducting 5-minute visual searches for shells. The probability of detecting a shell when present was 67.4% ± 3.0, but decreased with increasing litter depth and fewer shells present. The mean (± SE) observer accuracy was 25.5% ± 4.3%. Accuracy was positively correlated to number of shells in the quadrat and negatively correlated to number of times a quadrat was searched. The results indicate quadrat surveys likely underrepresent true abundance, but accurately determine presence or absence. Understanding detection and accuracy of elusive, rare, or imperiled species improves density estimates and aids in monitoring and conservation efforts.
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Raffaelli, D.G., Friedlander, A.M. 2012. Biodiversity and ecosystem functioning: an ecosystem-level approach. In Marine Biodiversity Futures and Ecosystem Functioning: frameworks, methodologies and integration (Paterson, D.M., Aspden, R.J., Solan, M., editors). Oxford Univ. Press. Pp 149-163.
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July 2012
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Pease JE, TB Grabowski, AP Pease, & PT Bean. 2018. Changing environmental gradients over forty years alter ecomorphological variation in Guadalupe Bass Micropterus treculii throughout a river basin. Ecology and Evolution 8:8508-8522. doi: 10.1002/ece3.4349.
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Abstract
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Publisher Website
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July 2018
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Understanding the degree of intraspecific variation within and among populations is a key aspect of predicting the capacity of a species to respond to anthropogenic disturbances. However, intraspecific variation is usually assessed at either limited temporal, but broad spatial scales or vice versa, which can make assessing changes in response to long-term disturbances challenging. We evaluated the relationship between the longitudinal gradient of changing flow regimes and land use/land cover patterns since 1980 and morphological variation of Guadalupe Bass Micropterus treculii throughout the Colorado River Basin of central Texas. The Colorado River Basin in Texas has experienced major alterations to the hydrologic regime due to changing land and water-use patterns. Historical collections of Guadalupe Bass prior to rapid human-induced change present the unique opportunity to study the response of populations to varying environmental conditions through space and time. Morphological differentiation of Guadalupe Bass associated with temporal changes in flow regimes and land use/land cover patterns suggests that they are exhibiting intraspecific trait variability, with contemporary individuals showing increased body depth, in response to environmental alteration through time (specifically related to an increase in herbaceous land cover, maximum flows, and the number of low pulses and high pulses). Additionally, individuals from tributaries with increased hydrologic alteration associated with urbanization or agricultural withdrawals tended to have a greater distance between the anal and caudal fin. These results reveal trait variation that may help to buffer populations under conditions of increased urbanization and sprawl, human population growth, and climate risk, all of which impose novel selective pressures, especially on endemic species like Guadalupe Bass. Our results contribute an understanding of the adaptability and capacity of an endemic population to respond to future changes expected based on demographic or climatic projection.
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Pease JE, TB Grabowski, & AA Pease. 2017. Variation and plasticity and their interaction with urbanization in Guadalupe Bass populations on and off the Edwards Plateau. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/CSS-125-2017, Washington, D.C.
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Abstract
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August 2017
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The Colorado River Basin in Texas has experienced major alterations to its hydrologic regime due to changing land and water use patterns. These anthropogenic influences on hydrologic variability have had major implications for riparian and aquatic ecosystems and the species dependent upon them. However, impacts are often assessed at a limited temporal and spatial scale, tending to focus on relatively short and discrete periods or portions of a river basin. It is not clear how basin-wide alterations occurring over decades affect species. Guadalupe Bass Micropterus treculii are endemic to central Texas and are typically associated with shallow runs and riffles in small streams. However, Guadalupe Bass are found throughout the Colorado River Basin, including the mainstem portion of the lower river downstream of the city of Austin where they support a popular fishery. Because Guadalupe Bass exist across a wide range of stream orders within the basin, it is unclear whether populations respond similarly to anthropogenic disturbances or to conservation and restoration activities. Therefore, our objectives were to:
1. Assess the effects of urbanization and hydrology on the population structure and dynamics of Guadalupe Bass.
2. Evaluate the effects of environmental gradients on ecomorphological variation in Guadalupe Bass populations across multiple spatial scales.
3. Describe the life history, habitat use, and behavior of the Guadalupe Bass population in the lower Colorado River and compare it to populations in more “typical” habitats.
Results contribute to an understanding of the response of Guadalupe Bass to anthropogenic disturbances, including increased urbanization in central Texas and further assist in the conservation of the species. The ability of the population to not only persist, but flourish downstream of a heavily populated urban area presented a unique opportunity to investigate a native species response to anthropogenic disturbance. This research revealed differences in Guadalupe Bass habitat associations and movements, contrasts in age and growth, and morphological variation across a gradient of disturbance throughout the Colorado River Basin. Results of this work provide information on the potential effects of human population growth and increased water withdrawals on Guadalupe Bass populations. Additionally, this work adds to an understanding of the unique Guadalupe Bass population found in the lower Colorado River and how it differs from upstream tributary populations. Gathering additional population-level information facilitates conservation actions critical to preserving preferred habitat and promoting growth rates for Guadalupe Bass in streams of different sizes and flow conditions while highlighting interpopulation differences that may warrant consideration for stocking programs and other management strategies. Key findings of this study were:
• The similarity in response of growth rates to streamflow throughout the Colorado Basin suggests phenotypic plasticity in this trait rather than population-specific adaptations.
• Reductions in streamflows in the Colorado River Basin, whether due to increased frequency of drought or increased anthropogenic water withdrawal, will likely result in lower Guadalupe Bass growth rates with the potential to impact the structure of populations.
• Growth and recruitment showed a positive correlation with increased baseflows and mean monthly flows; however, continued assessment is necessary to determine a true relationship.
• We documented morphological divergence among Guadalupe Bass populations in response to spatial and temporal environmental variation. These ecomorphological differences among populations provide insight into the ability of Guadalupe Bass to respond to the differing in-stream habitat and flow conditions between small ‘typical’ tributary systems and the mainstem Colorado River.
• Morphological variation may be a population-level adaptation that potentially needs to be taken into consideration when choosing broodstock to maximize stocking success within a system. Understanding the morphological differences between Guadalupe Bass populations in response to local conditions could improve the success of restoration and supplemental stocking programs, especially in the ever-changing landscape of central Texas.
• We established a baseline for understanding the morphological response of Guadalupe Bass to increased population growth and the threats posed by increased water withdrawals and impervious surface.
• The mainstem population of Guadalupe Bass was generally more mobile, and more responsive to changes in streamflow, than tributary populations. The observed differences could influence the response of Guadalupe Bass populations to conservation and management actions, such as habitat restoration efforts.
• Continued monitoring of recruitment and angler exploitation may be beneficial to identify any changes that could negatively impact the population. Conservation initiatives solely focused on physical instream or riparian habitat are unlikely to be as beneficial to Guadalupe Bass as those focused on restoring or maintaining adequate streamflow.
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Pease AA, JE Pease, PT Bean, & TB Grabowski. 2022. Endemic Guadalupe Bass (Micropterus treculii) are supported by isotopically distinct resources in tributary versus mainstem river food webs. River Research and Applications. doi: 10.1002/rra.4015
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Abstract
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June 2022
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We used stable isotope analysis to investigate differences in Guadalupe bass<i> Micropterus treculii</i> resource use that might be associated with population-level variation in main-stem river versus tributary stream habitats. <i>Micropterus treculii</i> from main-stem sites had more enriched δ<sup>13</sup>C and δ<sup>15</sup>N signatures compared to those collected in tributaries, likely reflecting greater importance of algae as a basal resource and influences of urban wastewater in main-stem habitats. Documenting ecological variation across ecosystem types is important to inform fish conservation efforts, especially for species that occupy a range of stream sizes.
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Papastamatiou, Y.P., Caselle, J.E., Lowe, C.G., AM Friedlander. 2009. Scale dependent effects of habitat on movements and foraging strategies of blacktip reef sharks, Carcharhinus melanopterus, at Palmyra atoll: a predator dominated ecosystem. Ecology 90:996-1008
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April 2009
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Papastamatiou YP, JE Caselle, AM Friedlander, CG Lowe. 2009. Distribution, size frequency, and sex ratios of blacktip reef sharks, Carcharhinus melanopterus, at Palmyra Atoll: a predator-dominated ecosystem. J. Fish Biology 75:647-654.
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February 2009
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Papastamatiou YP, AM Friedlander, JE Caselle, CG Lowe. 2010. Longterm movement patterns and trophic ecology of blacktip reef sharks (Carcharhinus melanopterus) at Palmyra Atoll. Journal of Experimental Marine Biology and Ecology 386:94-102
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February 2009
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Paddack, MJ, J D Reynolds, C Aguilar, R S Appeldoorn, J Beets, E W Burkett, P M Chittaro, K Clarke, R Esteves, A C Fonseca, G E Forrester, A M Friedlander, and 23 others. 2009. Recent region-wide declines in Caribbean reef fish abundance. Current Biology 19:590-595
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April 2009
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Nalley, EM, LJ Tuttle, AL Barkman, EE Conklin, DM Wulstein, M Schmidbauer, and MJ Donahue. 2023. A systematic review and meta-analysis of the direct effects of nutrients on corals. Science of the Total Environment. 856(1): 159093. https://doi.org/10.1016/j.scitotenv.2022.159093
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January 2023
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Mueller JS, TB Grabowski, SK Brewer, & TA Worthington. 2017. Effects of temperature, dissolved solids, and suspended solids on the survival and development of larval Arkansas River Shiner. Journal of Fish and Wildlife Management 8:79-88.
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Abstract
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June 2017
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Decreases in the abundance and diversity of stream fishes in the North American Great Plains have been attributed to habitat fragmentation, altered hydrological and temperature regimes, and elevated levels of total dissolved solids and total suspended solids. Pelagic-broadcast spawning cyprinids, such as the Arkansas River Shiner Notropis girardi, may be particularly vulnerable to these changing conditions due to their reproductive strategy. Our objectives were to assess the effects of temperature, total dissolved solids, and total suspended solids on the developmental and survival rates of Arkansas River Shiner larvae. Results suggest temperature had the greatest influence on the developmental rate of Arkansas River Shiner larvae. However, embryos exposed to the higher levels of total dissolved solids and total suspended solids reached developmental stages earlier than counterparts at equivalent temperatures. Although this rapid development may be beneficial in fragmented waters, our data suggest it may be associated with lower survival rates. Furthermore, those embryos incubating at high temperatures, or in high levels of total dissolved solids and total suspended solids resulted in less viable embryos and larvae than those incubating in all other temperature, total dissolved solid, and total suspended solid treatment groups. As the Great Plains ecoregion continues to change, these results may assist in understanding reasons for past extirpations and future extirpation threats as well as predict stream reaches capable of sustaining Arkansas River Shiners and other species with similar early life-history strategies.
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Mora C, OAburto-Oropeza, A Ayala Bocos, PM Ayotte, S Banks, AG Bauman, M Beger, S Bessudo, DJ Booth, E Brokovich, A Brooks, P Chabanet, J Cinner, J Cortés, JJ Cruz-Motta, A Cupul Magaña, E DeMartini, GJ Edgar, DA Feary, SCA. Ferse, A Friedlander, and 34 others. 2011. Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes. PLoS Biol 9(4): e1000606. doi:10.1371/journal.pbio.1000606
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April 2011
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Monaco, ME, AM Friedlander, C Caldow, SD Hile, C Menza, RH Boulon. 2009. Long-term monitoring of habitats and reef fish found inside and outside the US Virgin Islands Coral Reef. Carib. J. Sci. 45:338-347.
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July 2009
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Monaco ME, AM Friedlander, SD Hile, SJ Pittman, RH Boulon. 2009. The coupling of St. John, US Virgin Islands marine protected areas based on reef fish habitat affinities and movements across management boundaries. Proceedings of the 11th International Coral Reef Symposium: 1022-1025.
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July 2009
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Miyazono S, AA Pease, TB Grabowski, & SR Fritts. 2019. Recruitment dynamics and reproductive ecology of Blue Sucker in Texas, with a focus on the Big Bend region of the Rio Grande. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series XXX-XXX. Washington, D.C.
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Abstract
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June 2019
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Blue Sucker (Cycleptus elongatus) is a state-listed threatened species in Texas and is considered vulnerable throughout its range. Once considered a single, wide-ranging species, blue suckers are now recognized as a complex of closely related, but genetically and morphologically distinct species within the genus Cycleptus, including an undescribed species within the Rio Grande Basin. Numerous factors likely are driving the decline of blue suckers in Texas, including flow alteration, water quality, habitat fragmentation, and changing land-use patterns, but it is not clear how these factors interact to influence the abundance and distribution of the species. Our research integrates a variety of methodologies to provide information critical to the conservation and management of Blue Sucker in the Sabine River (Texas and Louisiana) and Colorado River (Texas) and Rio Grande Blue Sucker (Cycleptus sp. cf. elongatus) in the Rio Grande.
The objectives of this report are to 1) determine the habitat associations of the young-of-the-year (YOY) Rio Grande Blue Sucker; 2) assess the effects of flow regime on growth and recruitment of Blue Sucker in the lower Sabine River; and 3) examine differences in life-history traits of Blue Suckers and flow regime across river basins in Texas. This study is the first to quantitatively address the sequence of YOY blue sucker mesohabitat use and increases our understanding of early life history of blue suckers, and the results of this work will help to develop conservation and management strategies (e.g., prioritizing conservation areas, developing flow recommendation, etc.) for blue suckers throughout their geographic distribution.
Key findings of this study were:
1) The body size of YOY Rio Grande Blue Sucker in pool habitats were significantly lower than that in other mesohabitats, suggesting that YOY Rio Grande Blue Sucker undergo onotogenetic habitat shifts into higher current velocity habitats as they grow.
2) Slow current areas, such as pools, could be important nursery habitats for small YOY Rio Grande Blue Sucker (total length ≤ 45 mm).
3) YOY Rio Grande Blue Sucker move into riffles and runs as they grow from April to June, suggesting that extreme low flow conditions during early summer may negatively affect the habitat quality or availability for YOY Rio Grande Blue Sucker.
4) The growth and recruitment of Blue Sucker in the lower Sabine River increased with increasing the river discharge from early summer to fall in our study areas.
5) The life-history traits of Blue Sucker differed between the lower Sabine River and the lower Colorado River: the total length and age of Blue Sucker in the lower Colorado River were larger than those of Blue Sucker in the lower Sabine River, and the growth and mortality rates of Blue Sucker of the lower Sabine River tended to be higher than those of the lower Colorado River.
6) Our results suggest that mesohabitat area and flow regime could be important factors determining the growth and recruitment of blue suckers, and the importance of these environmental factors could change according to the life-history stage (larval stage, juvenile stage, and adult stage).
7) Important areas for future research efforts include a) quantifying the differences in the mesohabitat area/quality/density among the three river basins; b) examining interactions between the spatial distributions of potential spawning habitat relative to suitable YOY mesohabitat and how variations in river flow influence their quality and connectivity to each other; and c) continuing to monitor the effects of flow regime on blue suckers for longer time periods.
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Miyazono S, AA Pease, S Fritts, & TB Grabowski. 2020. Ontogenetic shifts in mesohabitat use of young-of-year Rio Grande Blue Sucker in the Big Bend region of the Rio Grande. Environmental Biology of Fishes 103:1471-1480. doi: 10.1007/s10641-020-01038-8
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Abstract
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Publisher Website
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December 2020
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Changes in flow regime by anthropogenic activities is one of the primary environmental problems in riverine systems. It is important to understand how hydrologic conditions can affect ontogenetic habitat shifts of imperiled fishes in order to develop conservation and management strategies for each life-history stage. To better understand the factors affecting ontogenetic habitat shifts of an imperiled aridland river fish, we examined relationships between the abundance of young-of-the-year (YOY) Rio Grande Blue Sucker and various abiotic variables in the Trans-Pecos region of the Rio Grande in Texas, USA using open <i>N</i>-mixture modeling. In addition, we examined differences in Rio Grande Blue Sucker total length among three mesohabitat types (pool, riffle, and run). The results of open <i>N</i>-mixture modeling suggested that as pool area increased, the recruitment of Rio Grande Blue Sucker increased. Total length of YOY Rio Grande Blue Sucker also significantly differed among the three mesohabitat types. The total lengths of YOY Rio Grande Blue Sucker in pool habitats were lower than in other mesohabitats, suggesting that YOY Rio Grande Blue Sucker undergo ontogenetic habitat shifts into greater current velocity habitats as they grow. The habitat associations we documented support the growing body of research emphasizing the importance of maintaining sufficient and appropriately timed flows to avoid prolonged low flows that limit habitat availability for native fish species during sensitive life stages in the Rio Grande and other aridland rivers.
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Long, J.M. and T.B. Grabowski. 2017. Otoliths. Pages 189-219 in M.C. Quist and D. Isermann, editors. Age and growth of fishes: principles and techniques. American Fisheries Society, Bethesda, Maryland.
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November 2017
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Kelly LW, Barott KL, Dinsdale E, Friedlander AM, Nosrat B, Obura D, Sala E, Sandin SA, Smith JE, Vermeij MJA, Williams GJ, Willner D, Rohwer F. 2011. Black reefs: iron-induced phase shifts on coral reefs. International Society for Microbial Ecology Journal.
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October 2011
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Keller, BD, Gleason DF, McLeod E, Woodley CM, Airame S, Causey BD, Friedlander AM, Grober-Dunsmore R, Johnson JE, Miller SL, Steneck R. 2009 Climate change, coral reef ecosystems, and management options for marine protected areas. Environmental Management. 44:1069-1088
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July 2009
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Jayewardene, D., and C. Birkeland. 2006. Fish predation on Hawaiian corals. Coral Reef 25: 328
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March 2006
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Jayewardene, D., M.J. Donahue, C. Birkeland. 2009. Effects of frequent fish predation on corals in Hawaii. 28(2) 499-506.
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February 2009
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Groeschel JR, S Miyazono, TB Grabowski, BD Cheek, & GP Garrett. 2020. Growth and habitat Use of Guadalupe Bass in the South Llano River, Texas. Journal of Fish and Wildlife Management 11:33-45. doi: 10.3996/022018-JFWM-015
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Abstract
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Publisher Website
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January 2020
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Predicting how stream fishes may respond to habitat restoration efforts is difficult due, in part, to an incomplete understanding of how basic biological parameters such as growth and ontogenetic habitat shifts interact with flow regime and riverscape ecology. We assessed age-specific Guadalupe bass habitat associations at three different spatial scales in the South Llano River, a spring-fed stream on the Edwards Plateau of central Texas, and the influence of habitat and flow regime on growth. Substrates were classified using a low-cost side-scan sonar system. Scale microstructure was used to determine age and back-calculated size at age. Over 65% of captured Guadalupe bass were age-2 or age-3, but individuals ranged from 0-7 years of age. There was considerable overlap in habitat associations among age classes 1-3+, but age-0 Guadalupe bass tended to associate with greater proportions of pool and run mesohabitats with submerged aquatic substrates. While habitat metrics across multiple scales did not have a large effect on growth, discharge was negatively correlated with growth rates. Understanding age-specific Guadalupe bass habitat associations at multiple scales will increase the effectiveness of restoration efforts directed at the species and the use of low-cost side scan sonar seemed to provide an effective means of generating these data that can be adapted for other stream fishes.
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Grabowski TB, SP Young, & P Cott. 2019. Looking for love under the ice: Using passive acoustics to detect burbot (Lota lota: Gadidae) spawning activity. Freshwater Biology. 65:37-44. doi: 10.1111/fwb.13314
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Abstract
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Publisher Website
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April 2019
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The objective of this study was to assess the feasibility of collecting and using acoustic data to characterize the spawning activity and locations of Burbot under field conditions. Audio and video recordings of Burbot spawning aggregations were made through holes drilled into the ice at known spawning grounds at Moyie Lake in British Columbia, Canada. Acoustic behavior was related to video data to determine how acoustic activity correlated to any observed spawning behavior. Burbot vocalizations were difficult to identify with only about 6% of the recordings containing calls being successfully identified as such in the field. Burbot vocalized more often between sundown and sunrise than during daylight hours. Calls recorded at night tended to be lower frequency, longer duration and have lower bandwidth than those made during the day. Further, Burbot vocalizations were not recorded in conjunction with video recordings of spawning activity. These results suggest that while it may be feasible to use passive acoustic monitoring to locate Burbot spawning grounds and identify periods of activity, it does not seem to hold much promise for monitoring activity in real time.
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Grabowski TB, JE Pease, & JR Groeschel-Taylor. 2018. Intraspecific differences in morphology correspond to differential spawning habitat use in two riverine catostomid species. Environmental Biology of Fishes 101:1249-1260. DOI: 10.1007/s10641-018-0772-9
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Abstract
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Publisher Website
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July 2018
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Maintaining intraspecific diversity is an important goal for fisheries conservation and recovery actions. While ecomorphological studies have demonstrated intraspecific diversity related to feeding or flow regime, there has been little assessment of such variation in regards to spawning. We evaluated the relationship between individual morphology of Robust Redhorse and Notchlip Redhorse and variables describing the spawning habitat from which they were captured, such as current velocity, slope, and substrate particle size.. Robust Redhorse (n = 58) and Notchlip Redhorse (n = 43) were captured from the lower Savannah River, South Carolina-Georgia using prepositioned grid electrofishers, they were then measured, and photographed before being released. We constructed a truss network using digitized landmarks on each of the photographs. Relationships between the morphological and environmental datasets were assessed using canonical correlation analysis. In both species, these morphological predictors were correlated primarily to depth, though current velocity also contributed to the environmental canonical variable for Robust Redhorse. Robust Redhorse captured from the deeper locations with higher current velocities had lower aspect ratio heads than those of individuals captured from shallower areas. Notchlip Redhorse from shallower areas were deeper-bodied and had shorter trunks than counterparts from deeper areas. These differences suggest that ensuring spawning habitat heterogeneity may be an important component to conserving intraspecific diversity, particularly in systems where such habitat is limiting.
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Grabowski TB, HM Williams, R Verble, A Pease, & JE Pease. 2019. Guadalupe Bass flow-ecology relationships; with emphasis on the impact of flow on recruitment. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series XXX-XXX. Washington, D.C.
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Abstract
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December 2019
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Guadalupe Bass Micropterus treculii is an economically and ecologically important black bass species endemic to the Edwards Plateau ecoregion and the lower portions of the Colorado River in central Texas. It is considered a fluvial specialist and as such, there are concerns that the increasing demands being placed upon the water resources of central Texas by growing human populations have the potential to negatively impact Guadalupe Bass populations. As such, this study assessed the relationship between Guadalupe Bass growth, feeding ecology, and streamflow. Sagittal otoliths were removed from Guadalupe Bass collected from throughout their range during 2015-2017 and used to estimate the age and back-calculate the growth trajectory of each individual. Additionally, young-of-year (YOY) Guadalupe Bass were collected every 10-14 days from two second-order streams, the North Llano River and South Llano River, in the Colorado Basin on the Edwards Plateau. Stomach contents of these individuals were identified and the effect of streamflow on the occurrence of the taxa comprising the stomach contents assessed. <br>Guadalupe Bass growth was greater in the Colorado and Guadalupe River basins, independent of stream order, and tended increase with increasing stream order within a basin. Growth was higher in streams and during years with lower spring and summer monthly median flows, lower minimum and maximum flows, slower rise and fall rates, and higher baseflows. Growth was not influenced by years with higher monthly median flows in winter. These results would seem to contradict previous research, but seem to be influenced by the fact that previous studies were conducted during a period of extensive drought, while the current study was conducted during relatively wet conditions. Taken together with previous studies, the current study suggests that Guadalupe Bass growth is sensitive to flow conditions and is lower in years with flow conditions that fall outside a basin- and stream order-specific optimal range for the species.<br>A total of 21 unique taxonomic groups were recovered from the stomachs of YOY Guadalupe Bass collected from the North Llano River and South Llano River. Aquatic insects, especially larval mayflies (Ephemeroptera), damselflies (Odanata: Zygoptera), and caddisflies (Trichoptera), were the most frequently encountered taxa. While there was no difference between the two rivers in stomach content composition, there was a strong longitudinal gradient in both systems with aquatic insects predominating at upstream sample sites and fishes being more common at downstream sites. Stream discharge during the 24 hours prior to collection did not have any influence on the probability of a taxa being found in Guadalupe Bass stomachs. <br>The results of this study support efforts to manage Guadalupe Bass populations at a sub-watershed basis and suggests that populations occupying the same stream order within a basin are likely to have similar responses to annual flow conditions. In addition, these results indicate that the lower Colorado River population may inhabit a unique set of conditions that has supported the development of a trophy Guadalupe Bass fishery. Further, this study highlights the need to incorporate a sufficient range of annual flow conditions to ensure that the influence of stream flow on fish growth is adequately assessed. While interannual variation in growth rates are seem to be capable of serving as a proxy for recruitment and year-class strength, long-term monitoring of recruitment paired with assessment of growth is necessary to further clarify the relationship between population density, flow regime, recruitment and growth and allow the construction of predictive models.
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Grabowski TB, Benedum ME, Curley A, Dill De-Sa C, & Shuey ML. 2023. Pandemic-driven changes in the Hawaiian nearshore noncommercial fishery: analysis of catch photos posted to social media captures changing fisher behavior in response to disruptive events. PeerJ 11:e14994. https://doi.org/10.7717/peerj.14994 .
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Abstract
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Download
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Publisher Website
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December 2023
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How does a global pandemic alter fishing behaviors in Hawaiian nearshore fisheries? Using social media, we collect evidence for how nearshore fisheries are impacted by the global pandemic in Hawai’i. We later confirm our social media findings and obtain a more complete understanding of the changes in nearshore non-commercial fisheries in Hawaiʻi through a more conventional approach - speaking directly with fishers. We find that resource users posted nearly three times as often during the pandemic with nearly double the number of fishes pictured per post. We also find that individuals who fished for subsistence were more likely to increase the amount of time spent fishing and relied more on their catch for food security. Furthermore, we find that individuals fishing exclusively for subsistence were more likely to fish for different species during the pandemic than individuals fishing recreationally. Traditional data collection methods are resource-intensive and this study shows that social media data can be used to rapidly collect data and predict changes in nearshore fisheries due to large scale disturbances. As climate change threatens additional disturbances, it will be necessary for resource managers to collect reliable data efficiently to prevent species collapse and to better target monitoring and management efforts.
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Grabowski TB and EC Franklin. 2017. What can volunteer angler tagging data tell us about the status of the Giant Trevally (ulua akuea) Caranx ignobilis fishery in Hawaii: revisiting data collected during Hawaiʻi’s Ulua and Papio Tagging Project 2000-2016. Report provided by the Cooperative Fish and Wildlife Research Unit Program under agreement with the U.S. Fish and Wildlife Service. U.S. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/CSS-126-2017, National Conservation Training Center.
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Abstract
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Publisher Website
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September 2017
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Giant Trevally (ulua aukea) Caranx ignobilis is one of the most highly prized and frequently targeted nearshore species. However, there is very little information on its current status in Hawaiian waters. This study uses mark-recapture data collected as part of recreational angler tagging program conducted by the Hawaii Department of Land and Natural Resources-Division of Aquatic Resources during 2000-2012. Mark-recapture data were used to estimate von Bertalanffy growth curve parameters and survivorship. Growth curves generated from the mark-recapture data suggested that Giant Trevally from the main Hawaiian Islands may be growing faster and reach a smaller maximum size than individuals in the Northwest Hawaiian Islands, but there are a number of issues rendering this conclusion uncertain. The survivorship of Giant Trevally was positively associated with age, in part due to ontogenetic habitat shifts that result in older fish moving to offshore habitats where they are less vulnerable to anglers. When compared to stock assessments performed using commercial landings data and fisheries-independent visual surveys, the mark-recapture data produced similar estimates for the average length of exploited fish, a metric highly negatively correlated to fishing mortality. These results emphasize the need for additional information on the biology of Giant Trevally in Hawaiian waters and suggest that the data collected from this recreational angler tagging program may be useful to generate reliable estimates of mortality for stock assessment purposes.
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Grabowski TB & JH Grabowski. 2019. Early life history. Pages 133-168 in GA Rose (ed.). Atlantic Cod: the bio-ecology of the fish. John Wiley and Sons, New York.
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Abstract
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January 2019
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Like all marine fishes that undergo a planktonic life history stage, Atlantic cod must overcome a daunting set of challenges as part of their early life history. Atlantic cod must develop the morphological and physiological characteristics that will enable them to transition to a demersal, predatory existence as juveniles and adults, while retaining the ability to deal with the immediate and pressing challenges of a planktonic existence, e.g., avoiding predators while finding and subduing prey. At fertilization, an individual Atlantic cod embryo is cast adrift simultaneously with potentially millions of its siblings and half-siblings. Each embryo will take with it all of the parental investment it will ever receive in the form of energy reserves in its yolk sac provided by its mother and genetic material with a proven record of success from both parents. The parents of each embryo have themselves successfully completed the journey that this new generation of cod is about to undertake. The parents may have traveled hundreds of kilometers to release their offspring at the time and place where the most favorable conditions possible exist for success. Even so, the odds of any individual possessing the “winning” combination of pure luck and genetic fitness to overcome the specific hazards faced are infinitesimally small. Only the sheer number of embryos set adrift guarantees that there will be individuals capable of running the gauntlet. The truly amazing thing about cod is not the tremendous amount of mortality that occurs during this stage, but the fact that so many individuals survive. From a management perspective, understanding the factors influencing the high levels of mortality that occur during the early life history of cod is a critical component of predicting the future population size of cod stocks. This chapter details the early life history of the Atlantic cod starting at fertilization through larval development and continues with the descent of a juvenile cod from the plankton to suitable nursery habitat on the seafloor. This chapter also covers the early years, from habitat use to growth, diet, mortality and behavior, and ends as the juvenile cod begins to shift to adult habitats and behaviors.
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Golbuu Y, A Friedlander. 2010. Spatial and temporal characteristics of grouper aggregations in marine protected areas in Palau, western Micronesia. Estuarine, Coastal, and Shelf Science. 92:223-231.
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February 2011
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Friedlander, A.M., L.M. Wedding, J. E. Caselle, B. M. Costa. 2011. Integration of remote sensing and in situ ecology for the design and evaluation of marine protected areas: examples from tropical and temperate ecosystems. Pages 245-279 In: Remote sensing of protected lands (Y.Q. Wang, ed.). CRC Press, Boca Raton, Florida.
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November 2011
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Friedlander, A.M. 2009. Marine protected areas. In: Encyclopedia of Islands (R. Gillespie and D.A. Clague, eds.). University of California Press. Pages 607-610.
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August 2009
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Friedlander AM, SA Sandin, EE DeMartini, E Sala. 2010. Habitat-specific characterization of the fish assemblage at a piscivore-dominated, pristine atoll in the central Pacific. Marine Ecology Progress Series 410: 219–231.
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July 2010
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Fagre, D.B., C.W. Charles, C.D. Allen, C. Birkeland, F.S. Chapin III, P.M. Groffman, G.R. Gunternspergen, A.K. Knapp, A.D. McGuire, P.J. Mulholland, D.P.C. Peters, D.D. Roby, and G. Sugihara. 2009. Thresholds of climate change in ecosystems. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. U.S. Geological Survey, Reston VA, USA. 170 pages.
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January 2009
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DeMartini EE, Zgliczynski BJ, Boland RC, Friedlander AM. 2009. Influences of wind-wave exposure on the distribution and density of recruit reef fishes at Kure and Pearl & Hermes atolls, Northwestern Hawaiian Islands. Environmental Biology of Fishes 85:319-332
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July 2009
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DeMartini EE, TW Anderson, JC Kenyon, JP Beets, AM Friedlander. 2010. Management implications of juvenile reef fish habitat preferences and coral susceptibility to stressors. Marine and Freshwater Research. 61:532-540.
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April 2010
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DeMartini EE, TW Anderson, AM Friedlander, JP Beets. 2011. Predator biomass, prey density, and species composition effects on group size in recruit coral reef fishes. Marine Biology. 158: 2437-2447.
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July 2011
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Craig, P., C. Birkeland and S. A. Belliveau. 2001. High temperatures tolerated by a diverse assemblage of shallow water corals. Coral Reefs 20:185-189.
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October 2001
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Coastal salwater econsystems. Pages 133-151. D. Mueller-Dombois, K. W. Bridges, C. C. Daehler (eds. ). Biodiversity assessment of tropical ecosystems. PABITRA manual for interactive ecology and management. Bishop Museum Press. 255 p.
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October 2008
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Boulon RH, ME Monaco, AM Friedlander, C Caldow, J Christensen, C Rogers, J Beets, W Miller, SD Hile. 2009. An Ecological Correction to Marine Reserve Boundaries in the US Virgin Islands. Proceedings of the 11th International Coral Reef Symposium: 1074-1077.
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July 2009
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Birkeland, C., and P. K. Dayton. 2005. The importance in fishery management of leaving the big ones. Trends in Ecology and Evolution 20: 356-358
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April 2005
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Birkeland, C., A. Edward, Y. Golbuu, J. Guiterrez, N. Idechong, J. Maragos, G. paulay, R. Richmond, A. Tafileichig, and N. V. Valde. 2002. Freely Associated States. Pages 205-223 In D. D. Turgeon and R. G. Asch (eds. ), The state of coral reef ecosystems of the united States and Pacific Freely Associated States. 265 p.
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July 2002
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Birkeland, C., P. Craig, D. Fenner, L. Smith, W.E. Kleine, and B. Riegl. Geologic setting and ecological functioning of coral reefs in American Samora. Pp. 737-761. In B. Riegl and R. E. Dodge (eds. ) Coral Reefs of the U. S. A.
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January 2008
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Birkeland, C. 2004. Ratcheting down the coral reefs. BioScience 54: 1021-1027
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October 2004
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Birkeland, C. 2001. Implications for coral reef management and policy: relevant findings from the 9th International Coral Reef Symposium, Bali. Pages 55-56 In B. A. Best, R. S. Pomeroy, and C. M. Balboa (eds. ). U. S. Agency for International Development, the World resources Institute, Conservation international, and the International Society for Reef Studies. 113 p.
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October 2001
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Birkeland, C. 2001. Can ecosystem management of coral reefs be achieved? pp. 21-25 In: Best, B. A., and A. H. Bornbusch (Eds. ) Global trade and consumer choices: coral reefs in crisis. AAAS Publications, Washinton, D. C. 39 pp.
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October 2001
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Birkeland, C. 2000. The future of coral reefs. Galaxea (Japanese Coral Reef Society) 2:13-16.
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October 2000
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Barott KL, JE Caselle, EA Dinsdale, AM Friedlander, JE Maragos, D Obura, FL Rohwer, SA Sandin, JE Smith, B Zgliczynski. 2010. Natural History of the Lagoon at Caroline/Millennium Atoll, Republic of Kiribati. PLoS ONE 5(6):e10950
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June 2010
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Acre MR, TB Grabowski, DJ Leavitt, NG Smith, AA Pease, & JE Pease. 2021. Blue Sucker movement and habitat use in a regulated Texas River: implications for conservation and restoration. Environmental Biology of Fishes 104:501-516. doi: 10.1007/s10641-021-01093-9
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Abstract
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April 2021
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Species conservation requires a clear understanding of the availability of suitable habitat and the subsequent use of those habitats. In cases where species declines have occurred and gone undetected to conservation managers, habitat alteration, fragmentation and loss are often the largest contributors. River fragmentation often results in altered flow regimes, which is considered the primary variable determining riverine habitat availability. Blue Suckers <i>Cycleptus elongatus</i> are associated with riffle and run habitat, a habitat type that is especially impacted when river flows are altered. The objective of this research was to identify the extent of suitable habitat and mobility for Blue Sucker in the Colorado River, Texas. To understand habitat selection and use, Blue Suckers (N = 49) were surgically implanted with combined acoustic radio transmitter tags. During 2015-2017, thirty-eight attempts were completed to relocate individuals using mobile tracking. Optimized hotspot analysis identified three river reaches critical for Blue Sucker that accounted for 20% of the study area. Blue Sucker used these locations year-round including during spawning. Habitats used by Blue Sucker were composed of gravel, cobble, boulder, and bedrock typically in riffle and run habitat. Additionally, mobility, as measured by home range size, increased as riffle density decreased. The larger home ranges were presumably to find suitable habitat to complete aspects of their life history. The results of this study suggest that suitable habitats are limited throughout the fragmented riverscape. Conservation action in the form of habitat construction or increased stream connectivity through barrier mitigation could have positive impacts on the future of Blue Sucker in the lower Colorado River, Texas.
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Acre MR, C Alejandrez, J East, WA Massure, S Miyazono, JE Pease, EL Roesler, HM Williams, & TB Grabowski. 2017. Comparison of the precision of age estimates generated from fin rays, scales, and otoliths of Blue Sucker. Southeastern Naturalist 16:215-224.
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Abstract
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July 2017
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Evaluating the precision of age estimates generated by different readers and different calcified structures is an important part of generating reliable estimations of growth, recruitment, and mortality for fish populations. Understanding the potential loss of precision associated with using structures harvested without sacrificing individuals, such as scales or fin rays, is particularly important when working with imperiled species, such as Blue Sucker Cycleptus elongatus. We collected otoliths (lapilli), scales, and the first fin rays of the dorsal, anal, pelvic, and pectoral fins of nine Blue Sucker. Age estimates were generated from each structure by both experienced (n=5) and novice (n=4) readers. We found that independent of the structure used to generate the age estimates, the mean coefficient of variation (CV) of experienced readers was approximately 29% lower than that of novice readers. Further, the mean CV of age estimates generated from pectoral fin rays, pelvic fin rays, and scales were statistically indistinguishable and less than those of dorsal fin rays, anal fin rays, and otoliths. Anal, dorsal, and pelvic fin rays and scales underestimated age compared to otoliths, but age estimates from pectoral fin rays were comparable to those from otoliths. Skill level, structure, and fish total length were factors influencing reader precision between subsequent reads of the same aging structure from a particular fish. Using structures that can be harvested non-lethally to estimate the age of Blue Sucker can provide reliable and reproducible results, similar to those that would be expected from using of otoliths. Therefore, we recommend the use of pectoral fin rays as a non-lethal method to obtain age estimates for Blue Suckers.
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