Acuna S.,University of California at Davis |
Deng D.-F.,Oceanic Institute |
Teh S.,University of California at Davis
Aquatic Toxicology | Year: 2012
The presence of the toxic cyanobacterium Microcystis in the upper San Francisco Estuary (SFE) since 1999 is a potential but to date an unquantified threat to the health and survival of aquatic organisms, such as fish and zooplankton. The microcystins (MCs) predominantly in the LR-form (MC-LR) contained in Microcystis is hepatotoxic and a potential threat to the fishery. This study was conducted to determine the effects of dietary exposure of the endemic Sacramento splittail, Pogonichthys macrolepidotus in SFE to Microcystis and its toxin, MC-LR. Juvenile splittail (12.59±0.7gfish -1) were exposed to five diets for 28d with MC-LR obtained from: (1) Microcystis harvested from the SFE and (2) a synthetic purified form of MC-LR. Three of the test diets contained 3.55 (D5), 9.14 (D10) and 17.13 (D20)mg MC-LRkg -1 from Microcystis. The other two diets contained either purified MC-LR at 3.89mg MC-LRkg -1 (D5R) or no MC-LR (D0). The RNA/DNA ratio of fish muscle was significantly lower for all treatments fed test diets containing MC-LR compared to the control diet D0, suggesting Microcystis adversely affected nutritional status. Protein phosphatase 2A expression in the fish from the D5, D10 and D20 treatments were inversely affected by increasing concentrations of MC-LR. Cytoplasmic inclusion bodies and single cell necrosis were more prevalent and greater in severity in the fish exposed to the diets D10 and D20 compared to fish from the D0 treatment and indicate severe liver toxicity in splittail exposed to MC-LR. The sublethal effects on splittail characterized by this study suggest cyanobacterial blooms have the potential to affect splittail nutritional status and health in SFE. © 2011 Elsevier B.V..
Huang S.S.Y.,University of California at Davis |
Strathe A.B.,University of California at Davis |
Wang W.-F.,Chinese Academy of Fishery Sciences |
Deng D.-F.,Oceanic Institute |
And 2 more authors.
Aquatic Toxicology | Year: 2012
Selenium (Se) is an essential micronutrient for all vertebrates, however, at environmental relevant levels, it is a potent toxin. In the San Francisco Bay-Delta, white sturgeon, an ancient Chondrostean fish of high ecological and economic value, is at risk to Se exposure. The present study is the first to examine the uptake, distribution, and excretion of various selenocompounds in white sturgeon. A combined technique of stomach intubation, dorsal aorta cannulation, and urinary catheterization was utilized, in this study, to characterize the short-term effects of Se in the forms of sodium-selenate (Selenate), sodium-selenite (Selenite), selenocystine (SeCys), l-selenomethionine (SeMet), Se-methylseleno-l-cysteine (MSeCys), and selenoyeast (SeYeast). An ecologically relevant dose of Se (~500μg/kg body weight) was intubated into groups of 5 juvenile white sturgeon. Blood and urine samples were repeatedly collected over the 48. h post intubation period and fish were sacrificed for Se tissue concentration and distribution at 48. h. The tissue concentration and distribution, blood concentrations, and urinary elimination of Se significantly differ (p≤0.05) among forms. In general, organic selenocompounds maintain higher blood concentrations, with SeMeCys maintaining the highest area under the curve (66.3 ± 8.7 and 9.3 ± 1.0μg. h/ml) and maximum Se concentration in blood (2.3 ± 0.2 and 0.4 ± 0.2μg/ml) in both the protein and non-protein bound fractions, respectively. Selenate, however, did not result in significant increase of Se concentration, compared with the control, in the protein-bound blood fraction. Regardless of source, Se is preferentially distributed into metabolically active tissues, with the SeMet treated fish achieving the highest concentration in most tissues. In contrast, Selenite has very similar blood concentrations and tissue distribution profile to SeCys and SeYeast. From blood and tissue Se concentrations, Selenate is not stored in blood, but taken up rapidly by the liver and white muscle. Urinary elimination of Se is form dependent and peaks between 3 and 12. h post intubation. A basic understanding of the overall Se absorption, distribution, and elimination is provided through monitoring tissue Se concentrations, however, conclusions regarding to the dynamics and the specific processes of Se metabolism can only be inferred, in the absence of kinetic information. © 2011 Elsevier B.V..
Deng D.-F.,Oceanic Institute |
Ju Z.Y.,Oceanic Institute |
Dominy W.,Oceanic Institute |
Murashige R.,Grove Farms Fish and Poi LLC |
Aquaculture | Year: 2011
This study was designed to estimate the optimal dietary protein level for juvenile Pacific threadfin fed two levels of dietary lipid. Ten semi-purified diets were formulated to contain five levels of dietary protein (25, 30, 35, 40 and 45%) at either 10 or 14% dietary lipid. A commercial diet containing 14% lipid and 50% protein was fed as a reference treatment. Juvenile threadfin (initial body weight, 3.4. g) were hand fed these diets at 7% body weight/day for 8. weeks with 3 replications per dietary treatment. Fish were cultured in an indoor flow-through system with 31‰ seawater at 26 °C. There were 20 fish per replicate. The dietary lipid levels did not cause significant changes in growth performance or body composition (P > 0.05). In contrast, the diet with 25% protein resulted in significantly (P < 0.05) lower weight gain and higher feed conversion ratios (FCR) than the diets with 30-45% protein. The lowest FCR occurred in fish fed diets containing 35% protein and 10% lipid or 30% protein and 14% lipid. Increased dietary protein level resulted in decreased protein efficiency ratio, hepatosomatic index, and lipid level in carcass or whole fish. Protein and energy retentions in carcass or whole fish were negatively correlated to dietary protein levels. Estimation using a polynomial model, 41% protein supported maximum growth of Pacific threadfin under these experimental conditions. Fish fed the test diets containing 35% protein, however, had similar growth performance but better protein utilization than fish fed either the commercial feed or the diet with 40% protein. These results demonstrate the possibility of reducing protein content in commercial feeds and thus lowing feed costs needed for Pacific threadfin culture. © 2011 Elsevier B.V.
Holl C.M.,Oceanic Institute |
Glazer C.T.,Oceanic Institute |
Moss S.M.,Oceanic Institute
Aquaculture | Year: 2011
To understand how filtration affected microbial community nitrogen (N) cycling, natural abundance stable isotope ratios of suspended particles and nitrate (NO3 -) were measured in recirculating aquaculture systems (RAS) for the super-intensive culture (425shrimpm-2) of Pacific white shrimp, Litopenaeus vannamei. Samples were collected throughout a trial during which triplicate RAS were equipped with either a foam fractionator (FF) or a propeller-washed bead filter (BF) to determine solids removal and inorganic N cycling efficacy of each filtration technique. Shrimp performance was unaffected by filtration technique. The time course of DIN concentration was consistent with rapid full nitrification (NH4 + to NO2 - to NO3 -) in the BF treatment. Persistent, elevated NO2 - suggested a slower onset of NO2 - oxidation in the FF treatment. However, NO3 - began to accumulate at approximately the same time in both treatments and NO3 - accumulated more rapidly in the FF treatment even though feed N input to the FF treatment was slightly lower than in the BF treatment. Consistently depleted -15N-NO3 - in the FF treatment illustrated isotopic fractionation of the NH4 + pool attributable to NH4 + oxidation. After an initial depletion, -15N-NO3 - in the BF treatment remained significantly enriched relative to the FF treatment, consistent with isotopic fractionation due to denitrification where the filtration mechanism promoted sub-oxic conditions. The latter is supported by significantly lower NO3 - and N budget analyses which indicate the potential for N loss. Together these results suggest that, despite identical inocula, the microbial community responded differently to the filtration technique and as a result natural abundance isotopes revealed distinct dominant N cycle pathways. © 2010 Elsevier B.V.
Bushnell M.E.,University of Hawaii at Manoa |
Claisse J.T.,Oceanic Institute |
Laidley C.W.,Oceanic Institute
Journal of Fish Biology | Year: 2010
Reproduction was investigated in relation to lunar and annual cycles in a population of yellow tang Zebrasoma flavescens, a popular aquarium species commercially harvested in Hawaii. Lunar periodicity was determined to be an inherent characteristic of reproduction; peaks in mean daily egg production, female gonado-somatic index (IG) and the fraction of females with eggs were observed at the full moon of each sampled month. An increase in the fraction of late-stage vitellogenic oocytes within the ovaries was also observed at the full moon. Reproductive effort peaked in the late spring and summer as indicated by high values of mean daily egg production, female IG and the recorded incidence of females spawning for at least two consecutive days. Mean daily egg production and IG of monthly samples were lowest in November to February, although some level of egg production continued throughout the year. Large individual variation in batch fecundity was observed, with a range from 44 to > 24 000 eggs per female produced on a single sampling date. Smaller females, 80-120 mm standard length (LS), produced limited numbers of eggs, while females ≥ 120 mm LS were capable of maximal egg production (> 20 000 eggs per batch). In contrast to trends observed in many fish species, no significant relationship between batch fecundity and adult LS > 120 mm was observed in female Z. flavescens. An estimate of annual fecundity (mean ± s.e. 1 055 628 ± 120 596 eggs) was also generated using a simple model of the lunar variability in egg production. This study illustrates the importance of accounting for potential variation in egg production over time, especially with respect to diel and lunar cycles, in the design of reproductive studies of multiple-spawning fishes. Greater insight into the environmental factors that regulate reproductive activity may be gained by determining the relative reproductive investment allocated at each spawning event. The ability to estimate annual fecundity for more multiple-spawning species will facilitate examination of the effects of fishing on the reproductive characteristics of these populations and permit examination of life-history evolution across a broader suite of fishes. © 2010 The Authors. Journal compilation © 2010 The Fisheries Society of the British Isles.
Kline M.D.,Oceanic Institute |
Laidley C.W.,Oceanic Institute
Aquaculture | Year: 2015
The use of copepod nauplii as live prey for first-feeding marine fish larvae is enabling the culture of many marine fish species with small, difficult to rear larvae. The small planktonic nauplii of the copepod Parvocalanus crassirostris is a particularly suitable first-feed due to its small size and ready acceptance by larvae of many species. This study details the relationship between stocking density and egg and nauplii production rates for P. crassirostris copepods, demonstrating a significant decline in culture production as system densities are increased. Fecundity decreased from 26eggsfemale-1day-1 at an adult density of 0.25mL-1 to less than 1eggfemale-1day-1 when operated at 8adultsmL-1. Effects of increasing adult densities on nauplii survival, feed availability, and water quality were sequentially investigated as potential mechanisms for the apparent inverse relationship between adult density and fecundity, with little success. In contrast, increasing egg and nauplii harvest frequency yielded large improvements in egg and nauplii production, with small (1L) scale cultures yielding over 40,000 eggs and nauplii per day when stocked at 4adultsmL-1. A 1500L pilot production system, designed to efficiently remove eggs and nauplii, generated a mean daily output of 18million eggs and nauplii per cubic meter of culture volume under continuous operating conditions for a period of over one month. © 2014 Elsevier B.V.
Ju Z.Y.,Oceanic Institute |
Deng D.-F.,Oceanic Institute |
Dominy W.,Oceanic Institute
Aquaculture | Year: 2012
This trial evaluated the effects of partial replacement of fishmeal protein by a defatted microalgae meal (DMM) in a shrimp diet. The DMM was a by-product of astaxanthin production from Haematococcus pluvialis and contained 40.3% crude protein (CP) and 0.9% crude lipid (CL). Test diets were prepared by using DMM (3, 6, 9 and 12% in a diet) to replace 12.5%, 25%, 37.5% or 50% of a fishmeal protein in a control diet (32.3% CP & 8.9% CL). All test diets had similar protein and lipid levels. Each diet was randomly assigned to four tanks (12 juvenile shrimp per tank) in an indoor flow through seawater laboratory. After an 8-week feeding trial, shrimp fed the diet with 12.5% of the fishmeal protein replaced showed a significantly higher growth rate and lower feed conversion ratio than the shrimp fed the control diet (P < 0.05). The other three DMM-added diets had a similar effect on the growth of shrimp as the control diet (P > 0.05). Shrimp fed the four DMM-added diets appeared redder and contained higher free and esterified astaxanthins than shrimp fed the control diet. The results indicated that DMM could be a valuable alternative protein and pigmentation ingredient in shrimp feed. © 2012 Elsevier B.V.
Moss S.M.,Oceanic Institute |
Moss D.R.,Oceanic Institute |
Arce S.M.,Oceanic Institute |
Lightner D.V.,University of Arizona |
Lotz J.M.,University of Southern Mississippi
Journal of Invertebrate Pathology | Year: 2012
About 3.5 million metric tons of farmed shrimp were produced globally in 2009 with an estimated value greater than USD$Boyle, M.L.14.6 billion. Despite the economic importance of farmed shrimp, the global shrimp farming industry continues to be plagued by disease. There are a number of strategies a shrimp farmer can employ to mitigate crop loss from disease, including the use of Specific Pathogen Free (SPF), selectively bred shrimp and the adoption of on-farm biosecurity practices. Selective breeding for disease resistance began in the mid 1990s in response to outbreaks of Taura syndrome, caused by Taura syndrome virus (TSV), which devastated populations of farmed shrimp (. Litopenaeus vannamei) throughout the Americas. Breeding programs designed to enhance TSV survival have generated valuable information about the quantitative genetics of disease resistance in shrimp and have produced shrimp families which exhibit high survival after TSV exposure. The commercial availability of these selected shrimp has benefitted the shrimp farming industry and TSV is no longer considered a major threat in many shrimp farming regions. Although selective breeding has been valuable in combating TSV, this approach has not been effective for other viral pathogens and selective breeding may not be the most effective strategy for the long-term viability of the industry. Cost-effective, on-farm biosecurity protocols can be more practical and less expensive than breeding programs designed to enhance disease resistance. Of particular importance is the use of SPF shrimp stocked in biosecure environments where physical barriers are in place to mitigate the introduction and spread of virulent pathogens. © 2012 Elsevier Inc.
Agency: NSF | Branch: Standard Grant | Program: | Phase: BIOLOGICAL OCEANOGRAPHY | Award Amount: 95.30K | Year: 2010
Evidence increasingly demonstrates that selective removal of marine life can induce restructuring of marine food webs. Trophic structure is the central component of mass balance models, widely used tools to evaluate fisheries in an ecosystem context. Food web structure is commonly determined by stomach contents or by bulk tissue stable isotope analyses, both of which are limited in terms of resolution and versatility. The investigators will refine a tool, Amino Acid Compound-Specific Isotopic Analyses (AA-CSIA), which can be broadly applicable for quantifying the time-integrated trophic position (TP) of consumers. Differences in source and trophic nitrogen isotopic composition for specific amino acids will provide an unambiguous and integrated measure of fractional trophic TP across multiple phyla, regardless of an animals physiological condition or of the biogeochemical cycling at the base of the food web. AA-CSIA will allow testing of the efficacy of trophic position estimates derived from ecosystem-based models and promote the evolution of these models into decision-support tools. This project has three goals: 1. To validate the application of AA-CSIA across multiple marine phyla under differing physiological conditions. 2. To compare the application of AA-CSIA across systems with contrasting biogeochemical cycling regimes. 3. To develop the use of AA-CSIA TP estimates for validating trophic models of exploited ecosystems. The investigators will test and refine the approach using a combination of laboratory feeding experiments and field studies across regions with differing biogeochemical cycling regimes. They will determine the applicability of the AA-CSIA approach in a variety of marine organisms assessed in controlled studies. Subsequently, ecosystem components will be sampled from the eastern tropical Pacific, coastal California and the subtropical Pacific gyre. They will also test the effects of sample preservation on the isotopic composition of individual AA to determine whether the approach can be used on archived samples. This tool will allow testing of the efficacy of ecosystem-based models currently used to gain insight into the ecological effects of fisheries removals and improve the reliability of future models required to manage marine resources. In addition to the goal of developing AA-CSIA for use as a TP indicator, the information obtained through this project will provide important species-specific biological data on the feeding behavior of marine organisms that could have implications for their resilience to anthropogenic pressures and climate change.
This project will have direct application to evaluating ecosystem effects of fisheries by providing an unbiased, integrated and independent approach to
estimating trophic structure, and a method by which to validate existing ecosystem-based model outputs and predictions. In addition, the project will have outreach benefits through the involvement of graduate and undergraduate students, and exposure of younger students through K-12 programs. This research will contribute to the greater understanding of the biology of locally important fish species as well as globally important shrimp and endangered marine turtles.
News Article | December 17, 2016
In this scene from the 2001 film 'Harry Potter and the Sorcerer's Stone,' Professor McGonagall (l.), played by Maggie Smith, places the sorting hat on Harry Potter, played by Daniel Radcliffe. —Harry Potter fans, rejoice! References to British author J.K. Rowling’s famous fantasy series about the boy wizard have once again crept into scientific language, after a team of Indian scientists named a new species of spider after the famous sorting hat. The spider’s discoverers say that the arachnid’s shape immediately put them in mind of the sorting hat. Potterheads will recognize the spider’s scientific name, Eriovixia gryffindori, as a reference to the sorting hat’s original owner and Hogwarts co-founder, Godric Gryffindor. "My colleagues and I are geeks and we all thought, 'Hey this curious little spider looks exactly like the sorting hat.' It was uncannily similar," said scientist Javed Ahmed, according to AFP. "So we made a pact that if this turns out to be a new species we will name it after the sorting hat.” Experts agreed that the tiny spider – only measuring about a quarter of an inch – was definitely a new species, which led to the publication of a new study in the Indian Journal of Arachnology this month. After the announcement of the finding, Potter author J.K. Rowling reached out in congratulations, tweeting: This little arachnid isn’t the first creature to be named after the bestselling series. In 2012, an ant-like wasp species was named Ampulex dementor after the spooky, happiness-draining monsters featured in several Harry Potter books. The name won a popular vote, apparent because the voters agreed that the wasp’s “life-sucking” habits were reminiscent of Rowling’s dementors. Another creature, a 66-million-year-old dinosaur named Dracorex hogwartsia, also took on a Harry Potter name recently. In 2015, The Christian Science Monitor’s Shontee Pant reported on the popularity of pop-culture references in scientific naming practices, part of the scientific community's attempts to appeal to a broader audience. She wrote: With its complex rules and Latin verbiage, the process of naming new species can easily alienate the public from the scientific community, which raises a new research question: How do you make an audience care about a new animal that lacks the charisma of, say, a giant panda? The results of the study – which constitute the only appearance of the term "soul-sucking" in the world's largest scientific journal – indicate that the voting public responded “very positively” to learning about the nomenclature process.... “Visitors were highly interested and during the event spent a significant amount of time asking for details and listening to explanations,” wrote the authors. Growing numbers of scientists, museums, and nonprofits are reaching out to the greater community for inspiration (and cash) as they name their discoveries. Early this year, for instance, scientists named another new variety of spider for singer Johnny Cash. Aphonopelma johnnycashi was discovered near California’s Folsom Prison, the subject of one of Mr. Cash’s most famous songs. Pop culture icons as diverse as Beyoncé, Spongebob Squarepants, and Stephen Colbert have all become the namesakes of newly discovered creatures. In the modern world, crowdsourcing isn’t limited to fundraising for natural disaster relief or college funds. For a small fee, many scientific institutions and nonprofits will allow you to name your own species. For example, the Scripps Oceanic Institute allows donors to name newly discovered maritime creatures for a donation of at least $5,000 per species. In 2008, the Monitor’s Randy Dotinga reported that members of the general public were given the chance to name rare hydrothermal vent worms for a donation of $50,000. Naming rights for other creatures, including a sea slug, went for the comparatively meager $15,000 per species. Proponents of selling naming rights say that it supports research and discovery. A German group called Biopat has raised approximately half a million dollars for scientific research through auctioning off the opportunity to name newly discovered creatures. Despite its growing popularity, some critics remain staunchly opposed to auctioning off naming rights. “There are concerns that profiteering is inappropriate,” says Joe Mendelson, curator of herpetology at Zoo Atlanta. “There are people out in the taxonomy community who say as soon as there’s money involved, 'This is flat-out wrong.' ”