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Grass Shrimp (grass + shrimp)
Selected AbstractsThe influence of reproductive state on cardiac parameters and hypoxia tolerance in the Grass Shrimp, Palaemonetes pugioFUNCTIONAL ECOLOGY, Issue 6 2005J. A. GUADAGNOLI Summary 1In many crustaceans, female reproduction represents a time of increased metabolic demand. Palaemonetes pugio are typically hypoxia tolerant; but the energetic demands of reproduction may compromise their ability to tolerate hypoxic conditions. Given the correlation between cardiac output and metabolic demand, we used cardiac output (CO) to measure differences in metabolic demand in the life-history stages of P. pugeo. 2We hypothesized that (1) the cost of egg production would result in an increased CO for gravid females compared with non-gravid females; (2) those females that were both ovigerous and gravid would have an additional metabolic demand due to brooding behaviour (pleopod fanning) and hence an even greater CO; and (3) hypoxia tolerance would decrease with increasing reproductive demand. To test these hypotheses, we compared cardiac output across three reproductive states and at decreasing water oxygen tensions. 3Ovigerous females had significantly greater pleopod fanning frequency than non-ovigerous females at all oxygen tensions. Additionally, ovigerous/gravid females had significantly higher cardiac output at all oxygen tensions than gravid only or non-gravid females. 4Changes in cardiac output indicate that females became more sensitive to environmental oxygen tension with increasing reproductive demand. Non-gravid females were able to maintain cardiac output down to 15 mm Hg O2, whereas gravid and ovigerous/gravid females maintained cardiac output down to 50 mm Hg and 75 mm Hg O2, respectively. 5These differences in CO suggest that metabolic demands of females change with reproductive state and, while gravid and ovigerous/gravid females appear more sensitive to low oxygen tensions, they are able to physiologically tolerate low environmental oxygen conditions. [source] Acute effects of the antibiotic oxytetracycline on the bacterial community of the grass shrimp, Palaemonetes pugio,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2009Miguel Uyaguari Abstract The toxicity of oxytetracycline (OTC) was evaluated in adult grass shrimp, Palaemonetes pugio. Initially, static acute (96 h) toxicity tests were conducted with shrimp exposed from 0 to 1,000 mg/L OTC. A calculated lethal concentration 50% value of 683.30 mg/L OTC (95% confidence interval 610.85,764.40 mg/L) was determined from these tests, along with a lowest-observable-effect concentration of 750 mg/L and no-observable-effect concentration of 500 mg/L. Moreover, chronic sublethal effects of OTC exposure on grass shrimp intestinal bacterial population were assessed using doses from 0 to 32 mg/L OTC. The total viable counts in digestive tract content had levels between 5.2 and 1 × 104 colony-forming units per gram of tissue at times 0 and 96 h, respectively. Aeromonas hydrophila were the most resistant isolates (27.78%) to OTC exposure. Vibrio alginolyticus showed significant positive growth following exposure to OTC, whereas other bacterial species abundance declined over time. A total of 268 bacterial isolates were screened using antibiotic resistance analysis from a library containing 459 isolates. Among the tested isolates from the OTC treatments, 15.4% were resistant to OTC and 84.6% were OTC sensitive. Oxytetracycline was generally not consistently quantifiable with liquid chromatography-mass spectroscopy technique in shrimp homogenates. The only peak detected was at the 32 mg/L dose of OTC at 96 h. Nevertheless, OTC had a significant biological effect on the bacterial population. Antibiotic resistance to five other antibiotics (penicillin G, sulfathiazole, trimethoprim, trimethoprim and sulfamethoxazole, and tetracycline) was strongly associated with OTC exposures. The present study indicates that OTC toxicity effects in P. pugio and changes in the shrimp microbial community would only be expected under special circumstances. [source] Predicting survival of grass shrimp (Palaemonetes pugio) exposed to naphthalene, fluorene, and dibenzothiophene,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2008Michael A. Unger Abstract The composition and persistence of dissolved polycyclic aromatic hydrocarbons (PAHs) released to the water column during oil spills are altered by weathering, tidal transport, and addition of dispersants. Conventional toxicity effect metrics, such as the median lethal concentration (LC50), are inaccurate predictors of mortality from all toxicant exposure duration/concentration combinations likely to occur during spills. In contrast, survival models can predict the proportions of animals dying as a consequence of exposures differing in duration and intensity. Extending previous work with ethylnaphthalene, dimethylnaphthalene, and phen-anthrene, survival time models were developed that include exposure duration and concentration to predict time to death for grass shrimp (Palaemonetes pugio). Two additional PAHs (naphthalene and fluorene) and a heterocyclic aromatic hydrocarbon (dibenzothiophene) were evaluated for the present study. Preliminary explorations of these models confirmed that quantitative structure-activity regression models were possible for predicting survival model parameters from compound characteristics. Conventional 48-h LC50s also were calculated for the compounds and combined with published LC50s to predict relative PAH toxicity to P. pugio based on octanol-water partitioning. [source] Influence of salinity on the bioaccumulation and photoinduced toxicity of fluoranthene to an estuarine shrimp and oligochaeteENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2003John E. Weinstein Abstract The effect of salinity on the photoinduced toxicity of waterborne fluoranthene to larvae of the grass shrimp (Palaemonetes pugto) and tubificid oligochaete worms (Monopylephorus rubrontveus) was studied in a laboratory system under simulated sunlight. In the grass shrimp toxicity tests, five concentrations of fluoranthene (0, 3.6, 7.3, 13.8, and 29.0 ,g/L) and four salinities (6.9, 14.5, 21.2, and 28.6,) were achieved. In the oligochaete toxicity tests, five concentrations of fluoranthene (0, 0.8, 1.4, 3.3, and 7.7 ,g/L) and four salinities (7.1, 13.3, 20.5, and 27.6,) were achieved. Salinity had no effect on either the photoinduced toxicity or the bioaccumulation of fluoranthene in the grass shrimp. However, the highest level of salinity decreased the median lethal time for the oligochaete. Bioaccumulation of fluoranthene was inversely related to salinity for the oligochaete. Additional experiments demonstrated an inverse relationship between salinity and short-term osmotic weight change in the oligochaete. Weight of the grass shrimp larvae was not affected by salinity. These findings show that salinity can influence the toxicity and bioaccumulation of fluoranthene in some estuarine organisms. The influence of salinity on these populations may be related to physiological responses associated with internal osmotic volume changes. Thus, salinity needs to be taken into account when assessing the risk of photoactivated polycyclic aromatic hydrocarbon (PAH) to at least some estuarine species. [source] The use of alternative diets to culture juvenile cuttlefish, Sepia officinalis: effects on growth and lipid compositionAQUACULTURE NUTRITION, Issue 3 2010A. FERREIRA Abstract The effects of feeding three natural frozen diets, grass shrimp (Palaemonetes sp.), crayfish (Procambarus clarkii) and fish (Sardina pilchardus) and two semi-humid artificial diets (based on fish or shrimp powder) to the cuttlefish, Sepia officinalis, were analysed. Growth rate and feeding rate [FR; % body weight (BW) day,1] and food conversions (FC, %) were determined. Cuttlefish fed shrimp grew larger (3.8% BW day,1) and had the highest FC, followed by those fed crayfish, and sardine. The highest FR was obtained for cuttlefish fed crayfish (10.5% BW day,1). Although both artificial diets were accepted, none produced growth. Digestive gland-to-body weight ratio (DG/BW ratio) was calculated for animals fed each diet. A positive correlation (r = 0.94) between cuttlefish ingestion FR and DG weight was obtained. Mortality occurred mainly during the last week, and some cannibalism occurred among cuttlefish fed artificial diets. Finally, lipid composition of diets, DG and mantle of each group were analysed. Sardine diet was characterized by high levels of triacylglycerol (TG), whereas the main difference between shrimp and crayfish was the higher n -3/n -6 ratio found in shrimp. Changes in the lipid composition of DG were related to diet, but did not correlate with growth data. A strong loss of TG in the DG of artificial diets groups was notable. No differences in mantle lipid composition among the natural diets were found, but artificial diet groups showed higher contents of neutral lipids in their mantle respect to natural diets. According to results obtained, crayfish (P. clarkii) could be used as an alternative prey for rearing S. officinalis compared with shrimp. Artificial diets showed the worst effects in growth and mortality as well as the stronger influence on DG and mantle lipid composition of cuttlefish. [source] | ||||||||||