Environmental impacts on grazing of different brine shrimp (Artemia franciscana) life stages (original) (raw)
Related papers
Impacts of harvesting on brine shrimp (Artemia franciscana) in Great Salt Lake, Utah, USA
Ecological Applications, 2016
Selective harvesting can cause evolutionary responses in populations via shifts in phenotypic characteristics, especially those affecting life history. Brine shrimp (Artemia franciscana) cysts in Great Salt Lake (GSL), Utah, USA are commercially harvested with techniques that select against floating cysts. This selective pressure could cause evolutionary changes over time. Our objectives are to (1) determine if there is a genetic basis to cyst buoyancy, (2) determine if cyst buoyancy and nauplii mortality have changed over time, and (3) to examine GSL environmental conditions over time to distinguish whether selective harvesting pressure or a trend in environmental conditions has caused changes in cyst buoyancy and nauplii mortality. Mating crosses between floating and sinking parental phenotypes with two food Accepted Article This article is protected by copyright. All rights reserved. concentrations (low and high) indicated there is a genetic basis to cyst buoyancy. Using cysts harvested from 1991-2011, we found cyst buoyancy decreased and nauplii mortality increased over time. Data on water temperature, salinity, and chlorophyll a concentration in GSL from 1994 to 2011 indicated that although water temperature has increased over time and chlorophyll a concentration has decreased over time, the selective harvesting pressure against floating cysts is a better predictor of changes in cyst buoyancy and nauplii mortality over time than trends in environmental conditions. Harvesting of GSL A. franciscana cysts is causing evolutionary changes, which has implications for the sustainable management and harvesting of these cysts. Monitoring phenotypic characteristics and life-history traits of the population should be implemented and appropriate responses taken to reduce the impacts of the selective harvesting.
Impacts of harvesting on brine shrimp (Artemia franciscana) in Great Salt Lake, UT
Ecological Applications, 2015
Selective harvesting can cause evolutionary responses in populations via shifts in phenotypic characteristics, especially those affecting life history. Brine shrimp (Artemia franciscana) cysts in Great Salt Lake (GSL), Utah, USA are commercially harvested with techniques that select against floating cysts. This selective pressure could cause evolutionary changes over time. Our objectives are to (1) determine if there is a genetic basis to cyst buoyancy, (2) determine if cyst buoyancy and nauplii mortality have changed over time, and (3) to examine GSL environmental conditions over time to distinguish whether selective harvesting pressure or a trend in environmental conditions caused changes in cyst buoyancy and nauplii mortality. Mating crosses between floating and sinking parental phenotypes with two food concentrations (low and high) indicated there is a genetic basis to cyst buoyancy. Using cysts harvested from 1991-2011, we found cyst buoyancy decreased and nauplii mortality increased over time. Data on water temperature, salinity, and chlorophyll a concentration in GSL from 1994 to 2011 indicated that although water temperature has increased over time and chlorophyll a concentration has decreased over time, the selective harvesting pressure against floating cysts is a better predictor of changes in cyst buoyancy and nauplii mortality over time than trends in environmental conditions. Harvesting of GSL A. franciscana cysts is causing evolutionary changes, which has implications for the sustainable management and harvesting of these cysts. Monitoring phenotypic characteristics and life-history traits of the population should be implemented and appropriate responses taken to reduce the impacts of the selective harvesting.
Hydrobiologia, 2017
Great Salt Lake (Utah) has a monimolimnion with high concentrations of salts, particulate matter, nutrients, and mercury. To test the importance of brine shrimp (Artemia franciscana) grazing on particulate matter flux, we created salinity gradients in 160-cm high columns, reflecting the lake's gradient. Two experiments were performed in replicated columns with or without Artemia. Sediment traps were positioned at the bottoms of the mixolimnion (95 cm), chemolimnion (105 cm), or monimolimnion (140 cm). We hypothesized that because of the high salt densities of the monimolimnia, greater accumulation of sediments would be in the lower chemocline, than in the monimolimnia. The presence of Artemia significantly decreased chlorophyll, total nitrogen, and total phosphorus in the mixolimnion and increased particulate matter collected in sediment traps by 28-90%. As hypothesized, the largest increase of sedimenting material was at the top of chemocline, but only in the absence of Artemia. When present, the largest increase of collected matter was in the bottom traps. Artemia significantly decreased the molar TN:TP ratio of collected material, suggesting nitrogen-deficient fecal material. The experiments demonstrated the importance of Artemia grazing for increasing material flux from the mixolimnion to the bottom, and determining the stoichiometry of accumulated material.
Changes in freshwater inflow and salinity patterns may affect the nursery value of estuarine systems for penaeid shrimp, but the relationship between salinity and shrimp abundance is complex and likely confounded by other environmental variables. Laboratory experiments can provide insights into salinity selection, and we designed an experimental gradient tank to examine salinity preferences of juvenile brown shrimp and white shrimp. Our design uses gently flowing water to eliminate various physical constraints often associated with selection experiments. We conducted experiments with juvenile brown shrimp (12 trials) and white shrimp (seven trials), to examine selection for salinities along a gradient from 1 to 42. Data were analyzed using contingency tables and log-linear modeling to examine relationships with salinity and possible interactions with temperature. Both brown shrimp and white shrimp were present in all salinities examined within the experimental range. In general, brown shrimp showed a preference for salinities from 17 to 35 and demonstrated avoidance for the extreme low salinities along the gradient. Results for white shrimp were not statistically significant, and this species did not appear to avoid low salinities. There was no effect of water temperature on the observed selection patterns for brown or white shrimp. Our results suggest that although salinity preferences likely exist for these species, strong distribution trends associated with salinity gradients in estuaries are likely caused by other environmental factors.
Estuaries, 1998
The influence of temperature, salinity, body size, and sex on the bioenergetics and life-history parameters of grass shrimp (Palaemonetespugio Holthuis) was determined under laboratory conditions. Sex and/or size show a highly significant effect only on energy allocation for metabolism. Temperature, salinity and their interaction are the main effects on most energetic parameters, with temperature showing the strongest influence on both life-history parameters and energetics. The adult grass shrimp's energy budget is different from that of larval or juvenile stages, in that most of the energy ingested by adults is allocated to reproduction. Under optimal conditions (25~ and 28~'~0), allocation of ingested energy in the adult grass shrimp is 51.7% for reproduction, 25.4% for respiration, 14.1% for somatic growth, 4.8% for exnskeletons, and 1.8% for excretion.
Aquaculture Research, 2009
Despite the recent success of Alabama shrimp farmers in culturing the Paci¢c white shrimp, Litopenaeus vannamei, in inland low-salinity waters there is large variability in growth and survival among ponds. Farmers suspect that high mortality occurs during the ¢rst weeks of culture following stocking of postlarvae (PL). In order to determine the e¡ect of pond ionic composition on PL growth and survival, three trials were carried out at a shrimp farm. Trials 1 and 2 evaluated PL growth and survival over 21-and 28day periods, respectively, using static water from different production ponds. Trial 3 evaluated growth and survival over 7, 14, 21 and 28 days using water from one production pond. Results suggest that initial mortality (8^10%) is attributed to the acclimation process and occurs immediately following stocking. Pond-to-pond variations in ionic pro¢les could be a contributing factor but are not likely the major reason for variable 'survival' . Mortalities after stocking appear to occur quickly as there were no di¡erences in survival from 7 to 28 days post stock. Variable survival is likely due to a combination of reasons including environmental factors, but is largely due to poor handling of PL and stocking errors that produce perceived reductions in survival.
2010
Hypersaline environments are essential, integral and dynamic part of the biosphere. Their management and protection depend on an understanding of the influence of salinity on biological productivity and community structure. The aim of this study was to review the relationships between the two basic biological components of hypersaline environments (micro-algae and Artemia) to provide a better understanding the dynamics of these unique ecosystems. Algal composition as the main food source of Artemia determines Artemia growth, reproduction rates, brood size, density, lipid index and cysts yields. Furthermore, the reproduction mode of Artemia depends on food levels, so that at the low food levels the main reproduction going into cysts. On the other hand, seasonal fluctu-ations of algal abundance influence Artemia population in temperate large hypersaline lakes such as the Great Salt Lake (USA), Urmia Lake (Iran) and Mono Lake (USA). However, Artemia grazing pressure has significant effects on microalgal density.
Ecological Indicators, 2017
The pink shrimp (Farfantepenaeus duorarum) has been selected as an ecological indicator to assess ecological effects on estuaries of implementation of the Comprehensive Everglades Restoration Plan that seeks to restore historical freshwater flows and nearshore salinity regimes in southern Florida. Concern over altered freshwater delivery impacts on pink shrimp productivity was expressed as early as the 1960s. The present review assessed pink shrimp scientific literature of the past 75+ years (> 500 publications) to glean information relevant to understanding potential influence of freshwater management on pink shrimp productivity. The review was organized around "Essential Fish Habitat" metrics concerning abundance, growth, survival, distribution, productivity, and behavior. It summarizes previous pink shrimp field, laboratory, and modeling studies. Where possible, statistical analyses and meta-analyses of previously published data were performed to investigate consistency among independent findings. Pink shrimp occur in a wide range of salinities (0.5-67 ppt). A majority of studies (53.3%) reported maximal abundance between ∼20 to 35 ppt salinities. One laboratory study reported maximal growth at 30 ppt. Meta-analysis of reported growth rates did not yield results due to non-convergence of regression models. Reported survival was maximal at ∼30 ppt and remained high (> 80% survival) across salinities of ∼15 to 40 ppt. A regression model that combined survival data across studies confirmed a previously reported parabolic relationship between salinity and survival; in this regression, 35 ppt maximized survival. Productivity, conditional upon survival and growth, was maximized at polyhaline (18-30 ppt) conditions. Inshore hypersalinity (> 40 ppt) may elicit young pink shrimp behavioral cues counterproductive to settlement in nearshore areas. Virtually no information exists regarding postlarval pink shrimp movement or preference relative to salinity gradients. Realization and preservation of nearshore polyhaline conditions and elimination of hypersalinity should maximize growth, survival, and density, thus improving pink shrimp productivity. New and updated statistical models predicting pink shrimp distribution, abundance, growth, survival, and productivity relative to salinity conditions are needed to better guide freshwater management decisions. 2005). The Comprehensive Everglades Restoration Plan (CERP) seeks to restore the quality, quantity, timing, and distribution of freshwater flows through terrestrial ecosystems and ultimately to downstream bays and nearshore areas that historically received these flows. It is expected that CERP implementation will restore nearshore salinity gradients extending perpendicular to the shoreline by expansion of nearshore