Regional Economic Implications of Water Allocation and Reliability

The understanding of how allocation decisions can maximise the economic returns to the community from water for irrigation has received little attention, but is a significant issue for regional councils, those interested in water allocation policy development, and for irrigated farmers. There is a tradeoff between the amount of irrigated area and the reliability with which it can be undertaken. Overseas studies have generated a curve with optimum levels of allocation which maximise the economic return to the community from the resource. The study on which this paper is based used a single case study to model the individual and regional economic outcomes for four scenarios of water allocation, using daily time step simulation models of the hydrological, irrigation, farm and financial systems over the 1973 – 2000 period. The results show that there is an increasing return to the region as the allocation from the resource increases, at the expense of lower returns to existing users.Irrigation, reliability, regional economic impacts, Agribusiness, Agricultural and Food Policy, Agricultural Finance, Community/Rural/Urban Development, Environmental Economics and Policy, Farm Management, Financial Economics, Institutional and Behavioral Economics, Land Economics/Use, Resource /Energy Economics and Policy,

A review of ecogeochemistry approaches to estimating movements of marine animals

Author Posting. © Association for the Sciences of Limnology and Oceanography, 2013. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 58 (2013): 697-714, doi:10.4319/lo.2013.58.2.0697.Ecogeochemistry—the application of geochemical techniques to fundamental questions in population and community ecology—has been used in animal migration studies in terrestrial environments for several decades; however, the approach has received far less attention in marine systems. This review includes comprehensive meta-analyses of organic zooplankton δ13C and δ15N values at the base of the food web, dissolved inorganic carbon δ13C values, and seawater δ18O values to create, for the first time, robust isoscapes for the Atlantic Ocean. These isoscapes present far greater geographic variability in multiple geochemical tracers than was previously thought, thus forming the foundation for reconstructions of habitat use and migration patterns of marine organisms. We review several additional tracers, including trace-element-to-calcium ratios and heavy element stable isotopes, to examine anadromous migrations. We highlight the value of the ecogeochemistry approach by examining case studies on three components of connectivity: dispersal and natal homing, functional connectivity, and migratory connectivity. We also discuss recent advances in compound-specific stable carbon and nitrogen isotope analyses for tracking animal movement. A better understanding of isotopic routing and fractionation factors, particularly of individual compound classes, is necessary to realize the full potential of ecogeochemistry.We were supported by funding from the National Science Foundation (Division of Ocean Sciences–0825148 to S.R.T.), Award USA 00002 and KSA 00011 from the King Abdullah University of Science and Technology (to S.R.T.), and a National Science Foundation Graduate Research Fellowship (to L.H.)

Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture

The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD ha⁻¹, with a total annual application of 33 kg ha⁻¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 ± 3 days (mean and standard deviation)

Movements of the white shark Carcharodon carcharias in the North Atlantic Ocean

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Ecology Progress Series 580 (2017): 1-16, doi:10.3354/meps12306.In the western North Atlantic, much of what is known about the movement ecology of the white shark Carcharodon carcharias is based on historical fisheries-dependent catch records, which portray a shelf-oriented species that moves north and south seasonally. In this study, we tagged 32 white sharks (16 females, 7 males, 9 unknown), ranging from 2.4 to 5.2 m total length, with satellite-based tags to investigate broad-scale movements in the North Atlantic. Based on 10427 days of tracking data, we found that white sharks are more broadly distributed, both horizontally and vertically, throughout the North Atlantic than previously understood, exhibiting an ontogenetic shift from near-coastal, shelf-oriented habitat to pelagic habitat with frequent excursions to mesopelagic depths. During the coastal phase, white sharks migrated seasonally from the northeast shelf in the summer to overwintering habitat off the southeastern US and the Gulf of Mexico, spending 95% of their time at <50 m depth. During the pelagic phase, subadult and adult white sharks exhibited wide-ranging movements during the fall, winter, and spring into the broader Atlantic over a 30° latitudinal range and as far east as the Azores. These sharks moved daily to depths of up to 1128 m, spending significant time at specific mesopelagic depth zones through a temperature range of 1.6 to 30.4°C. We believe these movements are associated with offshore foraging facilitated by the thermal physiology of the species. Our findings extend the known essential habitat for the white shark in the North Atlantic beyond existing protection, with implications for future conservation.This research was funded by Federal Aid in Sport Fish Restoration, the National Science Foundation (OCE-0825148), the John J. Sacco and Edith L. Sacco Charitable Foundation, the Atlantic White Shark Conservancy, the Massachusetts Environmental Trust, Discovery Communications, National Geographic, and the Woods Hole Oceanographic Institution

The Potential Cost to New Zealand Dairy Farmers from the Introduction of Nitrate-Based Stocking Rate Restrictions

Introducing a stocking rate restriction is one possible course of action for regulators to improve water quality where it is affected by nitrate pollution. To determine the impact of a stocking rate restriction on a range of New Zealand dairy farms, a whole-farm model was optimised with and without a maximum stocking rate of 2.5 cows per hectare. Three farm systems, which differ by their level of feed-related capital, were examined for the changes to the optimal stocking rate and optimal level of animal milk production genetics when utility was maximised. The whole-farm model was optimised through the use of an evolutionary algorithm called differential evolution. The introduction of a stocking rate restriction would have a very large impact on the optimally organised high feed-related capital farm systems, reducing their certainty equivalent by almost half. However, there was no impact on the certainty equivalent of low feed-related capital systems.environmental regulation, dairy farms, whole-farm model, evolutionary algorithm, Environmental Economics and Policy, Livestock Production/Industries, Q12, Q52, C61,

HMMoce : an R package for improved geolocation of archival-tagged fishes using a hidden Markov method

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Methods in Ecology and Evolution 9 (2018): 1212-1220, doi:10.1111/2041-210X.12959.Electronic tagging of marine fishes is commonly achieved with archival tags that rely on light levels and sea surface temperatures to retrospectively estimate movements. However, methodological issues associated with light-level geolocation have constrained meaningful inference to species where it is possible to accurately estimate time of sunrise and sunset. Most studies have largely ignored the oceanographic profiles collected by the tag as a potential way to refine light-level geolocation estimates. Open-source oceanographic measurements and outputs from high-resolution models are increasingly available and accessible. Temperature and depth profiles recorded by electronic tags can be integrated with these empirical data and model outputs to construct likelihoods and improve geolocation estimates. The R package HMMoce leverages available tag and oceanographic data to improve position estimates derived from electronic tags using a hidden Markov approach. We illustrate the use of the model and test its performance using example blue and mako shark archival tag data. Model results were validated using independent, known tracks and compared to results from other geolocation approaches. HMMoce exhibited as much as 6-fold improvement in pointwise error as compared to traditional light-level geolocation approaches. The results demonstrated the general applicability of HMMoce to marine animals, particularly those that do not frequent surface waters during crepuscular periods.This work was funded by awards to C. Braun from the Martin Family Society of Fellows for Sustainability Fellowship at the Massachusetts Institute of Technology, the Grassle Fellowship and Ocean Venture Fund at the Woods Hole Oceanographic Institution, and the NASA Earth and Space Science Fellowship

Movements of the reef manta ray (Manta alfredi) in the Red Sea using satellite and acoustic telemetry

Populations of mobulid rays are declining globally through a combination of directed fisheries and indirect anthropogenic threats. Understanding the movement ecology of these rays remains an important priority for devising appropriate conservation measures throughout the world’s oceans. We sought to determine manta movements across several temporal and spatial scales with a focus on quantifying site fidelity and seasonality in the northern Farasan Banks, Red Sea. We fitted manta rays with acoustic transmitters (n = 9) and pop-up satellite archival transmitting (PSAT) tags (n = 9), including four with GPS capability (Fastloc), during spring 2011 and 2012. We deployed an extensive array of acoustic receivers (n = 67) to record movements of tagged mantas in the study area. All acoustically tagged individuals traveled frequently among high-use receiver locations and reefs and demonstrated fidelity to specific sites within the array. Estimated and realized satellite tag data indicated regional movements <200 km from the tagging location, largely coastal residency, and high surface occupation. GPS-tagged individuals regularly moved within the coastal reef matrix up to ~70 km to the south but continued to return to the tagging area near the high-occupancy sites identified in the acoustic array. We also tested the accuracy of several geolocation models to determine the best approach to analyze our light-based satellite tag data. We documented significant errors in light-based movement estimates that should be considered when interpreting tracks derived from light-level geolocation, especially for animals with restricted movements through a homogenous temperature field. Despite some error in satellite tag positions, combining results from PSAT and acoustic tags in this study yielded a comprehensive representation of manta spatial ecology across several scales, and such approaches will, in the future, inform the design of appropriate management strategies for manta rays in the Red Sea and tropical regions worldwide

Movement patterns of juvenile whale sharks tagged at an aggregation site in the Red Sea

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 9 (2014): e103536, doi:10.1371/journal.pone.0103536.Conservation efforts aimed at the whale shark, Rhincodon typus, remain limited by a lack of basic information on most aspects of its ecology, including global population structure, population sizes and movement patterns. Here we report on the movements of 47 Red Sea whale sharks fitted with three types of satellite transmitting tags from 2009–2011. Most of these sharks were tagged at a single aggregation site near Al-Lith, on the central coast of the Saudi Arabian Red Sea. Individuals encountered at this site were all juveniles based on size estimates ranging from 2.5–7 m total length with a sex ratio of approximately 1:1. All other known aggregation sites for juvenile whale sharks are dominated by males. Results from tagging efforts showed that most individuals remained in the southern Red Sea and that some sharks returned to the same location in subsequent years. Diving data were recorded by 37 tags, revealing frequent deep dives to at least 500 m and as deep as 1360 m. The unique temperature-depth profiles of the Red Sea confirmed that several whale sharks moved out of the Red Sea while tagged. The wide-ranging horizontal movements of these individuals highlight the need for multinational, cooperative efforts to conserve R. typus populations in the Red Sea and Indian Ocean.Financial support was provided in part by KAUST baseline research funds (to MLB), KAUST award nos. USA00002 and KSA 00011 (to SRT), and the United States National Science Foundation (OCE 0825148 to SRT and GBS)

Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Oecologia 180 (2016): 809-821, doi:10.1007/s00442-015-3475-3.Coral reefs support spectacularly productive and diverse communities in tropical and sub26 tropical waters throughout the world’s oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon. We coupled compound-specific δ13C analyses with Bayesian mixing models to quantify carbon flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ13C values of essential amino acids from all baseline carbon sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single source end-member often dominated dietary carbon assimilation of a given species, even for highly mobile, generalist top predators. Microbially-reworked detritus was an important secondary carbon source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, L. ehrenbergii, showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13% of dietary carbon) to a phytoplankton-based food web (72 ± 11%) on oceanic reefs. Our work provides insights into the roles that diverse carbon sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.This research was based on work supported by Awards USA 00002 and KSA 00011 from King Abdullah University of Science and Technology (KAUST); additional funding was provided by the Woods Hole Oceanographic Institution (WHOI), a KAUST-WHOI award (SPCF-7000000104), and KAUST baseline research funds.2016-11-2

Carbon and nitrogen isotope fractionation of amino acids in an avian marine predator, the gentoo penguin (Pygoscelis papua)

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecology and Evolution 5 (2015): 1278–1290, doi:10.1002/ece3.1437.Compound-specific stable isotope analysis (CSIA) of amino acids (AA) has rapidly become a powerful tool in studies of food web architecture, resource use, and biogeochemical cycling. However, applications to avian ecology have been limited because no controlled studies have examined the patterns in AA isotope fractionation in birds. We conducted a controlled CSIA feeding experiment on an avian species, the gentoo penguin (Pygoscelis papua), to examine patterns in individual AA carbon and nitrogen stable isotope fractionation between diet (D) and consumer (C) (Δ13CC-D and Δ15NC-D, respectively). We found that essential AA δ13C values and source AA δ15N values in feathers showed minimal trophic fractionation between diet and consumer, providing independent but complimentary archival proxies for primary producers and nitrogen sources respectively, at the base of food webs supporting penguins. Variations in nonessential AA Δ13CC-D values reflected differences in macromolecule sources used for biosynthesis (e.g., protein vs. lipids) and provided a metric to assess resource utilization. The avian-specific nitrogen trophic discrimination factor (TDFGlu-Phe = 3.5 ± 0.4‰) that we calculated from the difference in trophic fractionation (Δ15NC-D) of glutamic acid and phenylalanine was significantly lower than the conventional literature value of 7.6‰. Trophic positions of five species of wild penguins calculated using a multi-TDFGlu-Phe equation with the avian-specific TDFGlu-Phe value from our experiment provided estimates that were more ecologically realistic than estimates using a single TDFGlu-Phe of 7.6‰ from the previous literature. Our results provide a quantitative, mechanistic framework for the use of CSIA in nonlethal, archival feathers to study the movement and foraging ecology of avian consumers.This research was funded by National Science Foundation Office of Polar Programs [grants ANT-0125098, ANT-0739575] and the 2013 Antarctic Science Bursaries