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Stephen A. Watts - One of the best experts on this subject based on the ideXlab platform.
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effects of dietary carbohydrate on weight gain and gonad production in small sea urchins Lytechinus variegatus
Aquaculture Nutrition, 2017Co-Authors: Anna M Taylor, Laura E. Heflin, Addison L. Lawrence, Mickie L. Powell, Stephen A. WattsAbstract:In experiment 1, juvenile sea urchins (n = 80, 0.088 ± 0.001 g wet weight and 5.72 ± 0.04 mm diameter) were held individually and fed ad libitum one of three semi-purified formulated diets (n = 16 individuals treatment-1). In the diets, protein was held constant (310g kg-1 dry, as fed) and carbohydrate level varied (190, 260, or 380 g kg-1 dry, as fed). Wet weights were measured every 2 weeks. Total wet weight gain was inversely proportional to dietary carbohydrate level and energy content of the respective diet. In experiment 2, sea urchins (5.60 ± 0.48g wet weight, n= 40) fed 190 g kg-1 carbohydrate consumed significantly more dry feed than those fed 260 g kg-1, but not more than those fed 380 g kg-1 carbohydrate. Based on differential feed intake rates, sea urchins that consumed more feed also consumed higher levels of protein and had the highest weight gain. Consequently, protein content and/or protein: energy ratio may be important in determining feed utilization and growth among sea urchins in this study. The average digestible energy intake was approximately 70 kcal kg-1 body weight day-1, suggesting daily caloric intake of juvenile Lytechinus variegatus is lower than in shrimp and fish.
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Balancing macronutrient intake in cultured Lytechinus variegatus
Aquaculture, 2016Co-Authors: Laura E. Heflin, David Raubenheimer, Stephen J. Simpson, Stephen A. WattsAbstract:Abstract Among aquatic organisms, nutritional requirements are historically assessed by evaluating formulated diets with changes in a single nutrient profile. These studies provide organisms with the option of regulating the total feed intake but do not enable individuals to regulate intake of specific nutrient ratios. An alternate experimental approach, known as the geometric framework (GF) for nutrition, tests whether organisms held under specific conditions have optimal target intake levels for particular nutrients and whether, when provided with diet choices, they will self-regulate nutrient intake to reach these specific targets. In this study, we used the GF to assess intake levels of dietary protein and carbohydrate in cultured adults of the sea urchin Lytechinus variegatus provided choices between diets varying in both dry matter and specific macronutrient concentrations. Adult urchins (ca. 120 g) held previously on formulated diets were offered moist gel-based diets in pairwise combinations. Diets varied in levels of fish meal isolate (as a protein source) and wheat starch (as a carbohydrate source) and in nutrient concentration (5 or 10% dry matter). Regardless of diet combination, individuals maintained an average dietary protein intake of ca. 0.047–0.061 g day − 1 . Dietary carbohydrate intake was not regulated to a specific level and ranged from 0.042–.0136 g day − 1 . These data suggest that large adult L. variegatus held in culture have a tightly regulated intake target for dietary protein but not carbohydrate. Regardless of nutrient ratios or macronutrient concentration, individuals adjusted intake patterns to defend this target. We suggest that the GF will be an important tool in evaluating macronutrient requirements in cultured sea urchins and other aquatic species.
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Select light spectra affect gonad color in the sea urchin Lytechinus variegatus
Marine and Freshwater Behaviour and Physiology, 2014Co-Authors: J. Christopher Taylor, Addison L. Lawrence, Stephen A. WattsAbstract:It is suggested that gonad color in sea urchins depends upon the in vivo accumulation and metabolism of red and yellow carotenoid pigments. We hypothesized that differential light exposure could affect carotenoid deposition and, hence, gonad color in sea urchins. We therefore performed two experiments to determine whether light spectra affect the gonad color of Lytechinus variegatus. In the first experiment, urchins were fed a formulated feed supplemented with or without β-carotene and held beneath three lighting regimes designed to emit differing wavelengths of the visible spectrum. After 12 weeks, urchins were dissected and gonad color (CIE L*a*b*) was measured with a Pantone Capsure RM200. Actinic light significantly increased the value of a* (red) in gonad color. Color in the orange and yellow spectra in the gonads increased in individuals fed the β-carotene supplemented diet. In the second experiment, we cultured urchins for nine weeks under lamps specialized to emit UV radiation. All urchins in this...
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Effects of hypercapnia on aspects of feeding, nutrition, and growth in the edible sea urchin Lytechinus variegatus held in culture
Marine and Freshwater Behaviour and Physiology, 2014Co-Authors: Roberta C. Challener, Stephen A. Watts, James B McclintockAbstract:Land-based aquaculture facilities experience occasional hypercapnic conditions due to the accumulation of the metabolic waste product carbon dioxide. Pre-gonadal Lytechinus variegatus (horizontal diameter = 20 mm) were exposed to control (608 μatm pCO2, pH 8.1) or hypercapnic conditions (1738 μatm pCO2, pH 7.7) in synthetic seawater for 14 weeks. Sea urchins exposed to hypercapnic conditions exhibited significantly slower growth (reduced dry matter production), primarily due to reduced test production. Higher fecal production rates and lower ash absorption efficiency (%) in individuals exposed to hypercapnic conditions suggest the ability to process or retain dietary carbonates may have been affected. Significant increases in neutral lipid storage in the gut and increased soluble protein storage in the gonads of individuals exposed to hypercapnic conditions suggest alterations in nutrient metabolism and storage. Furthermore, organic production and energy allocation increased in the lantern of those indivi...
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Opportunistic Predation of the Sea Urchin, Lytechinus variegatus, by the Amphipod, Elasmopus levis, in an Intensive Inland Culture System
Journal of the World Aquaculture Society, 2011Co-Authors: Victoria K. Gibbs, Mickie L. Powell, Kelcie A. Brown, Stephen A. WattsAbstract:Invasive and/or opportunistic organisms can negatively influence the success of sea urchin culture operations. To our knowledge, pests associated with sea urchin aquaculture have not been reported. In this study, we report the predatory association of the amphipod, Elasmopus levis (Amphipoda: Melitidae), with the sea urchin, Lytechinus variegatus (Echinodermata: Echinoidea), within an intensive inland culture system. Wild-caught Ly. variegatus broodstock were placed in an intensive culture system, and within their canopy of spines or within transport seawater, populations of epifauna (including amphipods) and microfauna were most likely transferred into the culture system. A growing population of the amphipod developed over time. Associations of the amphipod with the sea urchin were observed to negatively affect the health of the sea urchin, and in some cases, epithelial tissue from the sea urchin test appeared to be consumed by the amphipod. An infestation of these amphipods in commercial sea urchin cultures could have the potential to be costly, and we recommend quarantine and/or water purification procedures be considered to prevent the introduction of pests to inland culture systems.
John M. Lawrence - One of the best experts on this subject based on the ideXlab platform.
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Dietary Copper Affects Survival, Growth, and Reproduction in the Sea Urchin Lytechinus variegatus
Journal of Shellfish Research, 2010Co-Authors: Mickie L. Powell, John M. Lawrence, Addison L. Lawrence, Victoria K. Gibbs, Hugh S. Hammer, Warren T. Jones, Joe M. Fox, Stephen A. WattsAbstract:ABSTRACT Copper is an essential micronutrient in the diets of animals. It is a component of many enzymes involved in energy production, participates in immune function, and protects cells from free radicals. However, excessive levels in the diet can be toxic. Small (∼13 g wet weight) Lytechinus variegatus were fed formulated feeds with 12, 36, or 114 mg Cu/kg for 12 wk (levels based on established dietary levels for other marine invertebrates, supplemented as CuSO4·5H2O). Under these experimental conditions, wet weights of individuals fed a 36-mg Cu/kg diet were slightly higher (43.2 ± 1.2 g (SEM); P = 0.069) than those fed a 12mg Cu/kg and 114-mg Cu/kg diet (39.9 ± 1.2 and 40.3 ± 1.7 g wet weight, respectively). Ovary and gut wet weights were significantly lower (P < 0.003) in the 114-mg Cu/kg diet than the 12-mg Cu/kg and 36-mg Cu/kg diets (7.24 ± 0.75 g, 8.11 ± 0.55 g, and 4.99 ± 0.32 g ovary wet weight and 0.97 ± 0.04 g, 1.07 ± 0.06 g, and 0.83 ± 0.04 g gut wet weight for the 12-, 36-, and 114-mg Cu/k...
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Dietary phospholipids affect growth and production of juvenile sea urchin Lytechinus variegatus
Aquaculture, 2009Co-Authors: Victoria K. Gibbs, Addison L. Lawrence, Stephen A. Watts, John M. LawrenceAbstract:Abstract To facilitate sea urchin aquaculture, nutritionally-complete feeds are being developed for a number of species. In this study, the effects of dietary phospholipids from soy lecithin on weight gain and production were investigated to ascertain a potential dietary requirement for small juvenile sea urchins, Lytechinus variegatus . Laboratory-produced juvenile L. variegatus ( n = 16 per treatment, average 0.091 g ± 0.01 SE wet weight and 5.80 mm ± 0.09 SE diameter) were fed semi-purified formulated diets supplemented with 1, 2.5, 4, 5.2, 6.4, 7.6, or 8.8% phospholipids (as fed) from soy lecithin for 12 weeks. Under the conditions of this study, a negative correlation between dietary phospholipid level and weight gain was observed. By 6 wk and continuing through 12 wk, sea urchins fed the 1 to 6.4% supplemented phospholipid diet (SPLD) had significantly higher total wet weight than sea urchins fed either the 7.6 or 8.8% SPLD (final wet weight ranged from 10.53 ± 0.41 g to 7.42 ± 0.65 g, for the 1 and 8.8% treatments, respectively, P P
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EFFECT OF FOOD CONCENTRATION ON PROTEIN AND CARBOHYDRATE PRODUCTION DURING LARVAL DEVELOPMENT OF THE SEA URCHIN Lytechinus variegatus
Journal of Shellfish Research, 2007Co-Authors: Patricia Miloslavich, John M. Lawrence, Daniela Schiopu, Eduardo KleinAbstract:Abstract Changes in protein and carbohydrate content during larval development of Lytechinus variegatus were measured under two diet conditions, low concentration (600 algal cells ml−1 day−1) and high concentration (6,000 algal cells ml−1 day−1) to determine the larval stage at which these proximate constituents showed significant changes under different conditions of food availability. In terms of morphology, larvae under the high concentration diet developed fully and metamorphosed after 30 days, whereas under the low concentration diet, some larvae developed up to the 4 arm stage, and some ceased to develop at the 8 arm stage. No significant differences were found in the percentage of larval survival up to day 24 with both treatments (high: 77 ± 18%, low: 66 ± 24%). With the high concentration diet, protein and carbohydrate content per larvae remained relatively constant through day 17 after fertilization, through the 8-arm stage, and then significantly increased by day 20 coinciding with the first app...
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interactive effects of temperature and nutritional condition on the energy budgets of the sea urchins arbacia punctulata and Lytechinus variegatus echinodermata echinoidea
Journal of the Marine Biological Association of the United Kingdom, 2006Co-Authors: Sophie K Hill, John M. LawrenceAbstract:Arbacia punctulata and Lytechinus variegatus are widely distributed echinoid species in shallow water in the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico that seem to have diierent life history strategies. We evaluated the eiect of two types of stress (high temperature and starvation) on gonad production and scope for growth. We hypothesized that A. punctulata has a stress tolerant life strategy and would be more tolerant to stress and L. variegatus has a competitive ^ ruderal strategy and would be less tolerant to stress. Gonad production by A. punctulata was not as greatly aiected by temperature as L. variegatus, suggesting the hypothesis was correct. Arbacia punctulata had a signi¢cantly higher excretion rate indicating greater energy allocation to maintenance than production. Lytechinus variegatus had a signi¢cantly greater consumption rate but did not absorb signi¢cantly more energy. Arbacia punctulata compensated for its lower food consumption by a higher absorption e⁄ciency. Measured energy expenditure and calculated scope for growth did not diier. However, the percentage change in energy absorbed and energy expenditure was greater for L. variegatus than for A. punctulata with a change in temperature. Feeding had a greater eiect on production than temperature suggesting that the biotic stress of low food availability is more important than an abiotic stress such as temperature on energy budgets.
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Complete larval development of the sea urchin Lytechinus variegatus fed an artificial feed
Aquaculture, 2004Co-Authors: Sophie B. George, John M. Lawrence, Addison L. LawrenceAbstract:Complete development of sea-urchin larvae fed an artificial feed has been carried out for the first time. Naturally spawned gametes were obtained from adult Lytechinus variegatus fed an artificial feed in the laboratory for 9 months. Larvae from these adults, cultured in artificial seawater and fed microencapsulated capsules, reached the rudiment stage between 9 and 12 days, the usual time required. Larvae produced by artificial spawning and cultured in natural seawater and fed microencapsulated capsules or phytoplankton (Dunaliella tertiolecta) had similar chronology of development and sizes of newly metamorphosed juveniles. The larvae fed capsules were significantly smaller than those fed D. tertiolecta. Larval survival was 72±6% for those fed capsules and 85±4% for those fed D. tertiolecta. Artificial feed for larvae eliminates the necessity of culturing phytoplankton and provides the potential of establishing nutritional requirements of larvae and of standardizing and manipulating the diet. This has application in mass aquaculture of sea urchins as well as using larvae as models in developmental studies.
Addison L. Lawrence - One of the best experts on this subject based on the ideXlab platform.
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effects of dietary carbohydrate on weight gain and gonad production in small sea urchins Lytechinus variegatus
Aquaculture Nutrition, 2017Co-Authors: Anna M Taylor, Laura E. Heflin, Addison L. Lawrence, Mickie L. Powell, Stephen A. WattsAbstract:In experiment 1, juvenile sea urchins (n = 80, 0.088 ± 0.001 g wet weight and 5.72 ± 0.04 mm diameter) were held individually and fed ad libitum one of three semi-purified formulated diets (n = 16 individuals treatment-1). In the diets, protein was held constant (310g kg-1 dry, as fed) and carbohydrate level varied (190, 260, or 380 g kg-1 dry, as fed). Wet weights were measured every 2 weeks. Total wet weight gain was inversely proportional to dietary carbohydrate level and energy content of the respective diet. In experiment 2, sea urchins (5.60 ± 0.48g wet weight, n= 40) fed 190 g kg-1 carbohydrate consumed significantly more dry feed than those fed 260 g kg-1, but not more than those fed 380 g kg-1 carbohydrate. Based on differential feed intake rates, sea urchins that consumed more feed also consumed higher levels of protein and had the highest weight gain. Consequently, protein content and/or protein: energy ratio may be important in determining feed utilization and growth among sea urchins in this study. The average digestible energy intake was approximately 70 kcal kg-1 body weight day-1, suggesting daily caloric intake of juvenile Lytechinus variegatus is lower than in shrimp and fish.
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Select light spectra affect gonad color in the sea urchin Lytechinus variegatus
Marine and Freshwater Behaviour and Physiology, 2014Co-Authors: J. Christopher Taylor, Addison L. Lawrence, Stephen A. WattsAbstract:It is suggested that gonad color in sea urchins depends upon the in vivo accumulation and metabolism of red and yellow carotenoid pigments. We hypothesized that differential light exposure could affect carotenoid deposition and, hence, gonad color in sea urchins. We therefore performed two experiments to determine whether light spectra affect the gonad color of Lytechinus variegatus. In the first experiment, urchins were fed a formulated feed supplemented with or without β-carotene and held beneath three lighting regimes designed to emit differing wavelengths of the visible spectrum. After 12 weeks, urchins were dissected and gonad color (CIE L*a*b*) was measured with a Pantone Capsure RM200. Actinic light significantly increased the value of a* (red) in gonad color. Color in the orange and yellow spectra in the gonads increased in individuals fed the β-carotene supplemented diet. In the second experiment, we cultured urchins for nine weeks under lamps specialized to emit UV radiation. All urchins in this...
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Molecular analysis of gut microflora in captive-raised sea urchins (Lytechinus variegatus).
Journal of the World Aquaculture Society, 2010Co-Authors: Lawrence Nelson, Stephen A. Watts, Benjie Blair, Chris Murdock, Mark E. Meade, Addison L. LawrenceAbstract:In the USA, sea urchin aquaculture is in its infancy. One concern with current captive culture involves maintaining roe, or “uni,” quality. Diet of cultured urchins has been shown to affect roe quality. Sea urchins have a unique digestive system and lack certain digestive enzymes, yet they are able to digest high percentages of food biomass consumed. It is hypothesized that their highly efficient digestion is because of the presence of bacteria in the gut. This study determined bacterial profiles in guts of captive-raised sea urchins, Lytechinus variegatus, by analyzing DNA extracted from the urchins. Using a bacteria-specific forward and universal reverse primer, 16s rDNA genes were amplified using L. variegatus gut DNA samples and subsequently cloned. Recombinant colonies containing putative 16S rDNA were randomly selected for sequencing. Sequences generated from these clones were analyzed and compared with published bacterial 16S rDNA sequences available through the National Center for Biotechnology Information database. Sequence data analysis suggested that the captive-raised sea urchins contained a limited number of representative genera. The genera most commonly identified included Pseudomonads, Vibrio, and various epsilon and gamma proteobacterium species.
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Dietary Copper Affects Survival, Growth, and Reproduction in the Sea Urchin Lytechinus variegatus
Journal of Shellfish Research, 2010Co-Authors: Mickie L. Powell, John M. Lawrence, Addison L. Lawrence, Victoria K. Gibbs, Hugh S. Hammer, Warren T. Jones, Joe M. Fox, Stephen A. WattsAbstract:ABSTRACT Copper is an essential micronutrient in the diets of animals. It is a component of many enzymes involved in energy production, participates in immune function, and protects cells from free radicals. However, excessive levels in the diet can be toxic. Small (∼13 g wet weight) Lytechinus variegatus were fed formulated feeds with 12, 36, or 114 mg Cu/kg for 12 wk (levels based on established dietary levels for other marine invertebrates, supplemented as CuSO4·5H2O). Under these experimental conditions, wet weights of individuals fed a 36-mg Cu/kg diet were slightly higher (43.2 ± 1.2 g (SEM); P = 0.069) than those fed a 12mg Cu/kg and 114-mg Cu/kg diet (39.9 ± 1.2 and 40.3 ± 1.7 g wet weight, respectively). Ovary and gut wet weights were significantly lower (P < 0.003) in the 114-mg Cu/kg diet than the 12-mg Cu/kg and 36-mg Cu/kg diets (7.24 ± 0.75 g, 8.11 ± 0.55 g, and 4.99 ± 0.32 g ovary wet weight and 0.97 ± 0.04 g, 1.07 ± 0.06 g, and 0.83 ± 0.04 g gut wet weight for the 12-, 36-, and 114-mg Cu/k...
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Dietary phospholipids affect growth and production of juvenile sea urchin Lytechinus variegatus
Aquaculture, 2009Co-Authors: Victoria K. Gibbs, Addison L. Lawrence, Stephen A. Watts, John M. LawrenceAbstract:Abstract To facilitate sea urchin aquaculture, nutritionally-complete feeds are being developed for a number of species. In this study, the effects of dietary phospholipids from soy lecithin on weight gain and production were investigated to ascertain a potential dietary requirement for small juvenile sea urchins, Lytechinus variegatus . Laboratory-produced juvenile L. variegatus ( n = 16 per treatment, average 0.091 g ± 0.01 SE wet weight and 5.80 mm ± 0.09 SE diameter) were fed semi-purified formulated diets supplemented with 1, 2.5, 4, 5.2, 6.4, 7.6, or 8.8% phospholipids (as fed) from soy lecithin for 12 weeks. Under the conditions of this study, a negative correlation between dietary phospholipid level and weight gain was observed. By 6 wk and continuing through 12 wk, sea urchins fed the 1 to 6.4% supplemented phospholipid diet (SPLD) had significantly higher total wet weight than sea urchins fed either the 7.6 or 8.8% SPLD (final wet weight ranged from 10.53 ± 0.41 g to 7.42 ± 0.65 g, for the 1 and 8.8% treatments, respectively, P P
Alexander Turra - One of the best experts on this subject based on the ideXlab platform.
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Assessment of microplastic toxicity to embryonic development of the sea urchin Lytechinus variegatus (Echinodermata: Echinoidea)
Marine Pollution Bulletin, 2015Co-Authors: Caio Rodrigues Nobre, M F M Santana, A Maluf, F. S. Cortez, C. D S Pereira, Augusto Cesar, Alexander TurraAbstract:Apart from the physiological impacts on marine organisms caused by ingesting microplastics, the toxicity caused by substances leaching from these particles into the environment requires investigation. To understand this potential risk, we evaluated the toxicity of virgin (raw) and beach-stranded plastic pellets to the development of embryos of Lytechinus variegatus, simulating transfers of chemical compounds to interstitial water and water column by assays of pellet-water interface and elutriate, respectively. Both assays showed that virgin pellets had toxic effects, increasing anomalous embryonic development by 58.1% and 66.5%, respectively. The toxicity of stranded pellets was lower than virgin pellets, and was observed only for pellet-water interface assay. These results show that (i) plastic pellets act as a vector of pollutants, especially for plastic additives found on virgin particles; and that (ii) the toxicity of leached chemicals from pellets depends on the exposure pathway and on the environmental compartment in which pellets accumulate.
William B. Stickle - One of the best experts on this subject based on the ideXlab platform.
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effects of temperature and salinity acclimation of adults on larval survival physiology and early development of Lytechinus variegatus echinodermata echinoidea
Marine Biology, 1993Co-Authors: Richard A. Roller, William B. StickleAbstract:Larval survival and developmental rates of Lytechinus variegatus (Lamarck) were determined as a function of temperature and salinity in two experiments by: (1) directly transferring fertilized eggs to 35, 30, 27.5, 25, 20, 15, and 10‰S seawater at 18 and 23°C, and (2) acclimation of adult sea urchins to the conditions described above for 1 to 4 wk prior to spawning. Developmental rates and percent survival of larvae prior to metamorphosis decreased at salinities below 35‰ (Q10 values for metamorphosis=0.380 to 0.384). Temperature and salinity significantly (P<0.05) affected metabolic rates of L. variegatus plutei. These results show that L. variegatus larvae are stenohaline when compared to larvae of other echinoderm species. LC50 values (‰S), developmental rates, and survival to metamorphosis indicate that acclimation of adult sea urchins to lower salinity prior to spawing and fertilization does not enhance development or survival of embryos exposed to low salinity.
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Effects of temperature and salinity acclimation of adults on larval survival, physiology, and early development of Lytechinus variegatus (Echinodermata: Echinoidea)
Marine Biology, 1993Co-Authors: Richard A. Roller, William B. StickleAbstract:Larval survival and developmental rates of Lytechinus variegatus (Lamarck) were determined as a function of temperature and salinity in two experiments by: (1) directly transferring fertilized eggs to 35, 30, 27.5, 25, 20, 15, and 10‰S seawater at 18 and 23°C, and (2) acclimation of adult sea urchins to the conditions described above for 1 to 4 wk prior to spawning. Developmental rates and percent survival of larvae prior to metamorphosis decreased at salinities below 35‰ (Q10 values for metamorphosis=0.380 to 0.384). Temperature and salinity significantly (P
