Author
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Weirich, Charles |
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Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only Publication Acceptance Date: 1/2/2006 Publication Date: 2/2/2006 Citation: Weirich, C.R. 2006. Salinity effects on early life stages of Florida pompano Trachinotus carolinus [abstract]. Aquaculture America 2006 Book of Abstracts. p. 348. Interpretive Summary: Technical Abstract: Florida pompano Trachinotus carolinus are currently being evaluated as a potential candidate for mariculture in the US. Presently, only limited information exists with respect to this species’ tolerance to varying environmental salinity and no work to date regarding this topic has been conducted using early developmental stages. To address this issue, experimental trials were conducted to determine the effect of salinity on pompano egg buoyancy, egg hatching, and larval survival. Egg buoyancy was determined via two trials using eggs from two separate spawning events. In each trial 250 ml glass containers were filled with 150 ml of sterilized seawater (temperature = 24 C; pH = 8.2) at salinities increasing in 1 g/L increments over the range of 25 to 34 g/L with four replicates per salinity. Fifty fertilized pompano eggs were placed in each container which was covered, inverted, and allowed to sit idle for 15 minutes. The percentage of floating, neutrally buoyant, and sinking eggs was then determined. The effect of direct transfer to salinities ranging from 2 to 50 g/L on egg hatching and larval survival at 1 and 8 days post-hatch (DPH) was determined using 1.0 L glass containers filled with 500 ml sterilized seawater. Two trials were conducted at each life stage using eggs or larvae obtained from separate spawning events with four replicates per salinity. In egg hatching trials 20 fertilized eggs were placed into containers and percent hatch was determined after 30 hours. In larval trials 10 larvae were placed in containers and percent survival was determined after 24 hours. Life Stage Parameter Detrimental effects observed Eggs Buoyancy < 34 g/L Eggs Hatching < 30 g/L Larvae (1 DPH) Survival < 10 and > 46 g/L Larvae (8 DPH) Survival < 6 and > 38 g/L Results (see table) indicate that environmental salinity must be at least 34 g/L to achieve > 95 % buoyancy of pompano eggs. Buoyancy decreased with decreasing salinity and at a salinity of 25 g/L no buoyant eggs were observed. Although percent hatch of eggs was not affected at salinities ranging from 30 to 50 g/L, hatching rates were substantially reduced at salinities < 22 g/L. Both 1 and 8 DPH larvae were found to tolerate direct transfer to a wide range of salinities. In addition to more detailed information, results of ongoing trials involving direct transfer of 16 DPH larvae and post-metamorphic juveniles (30 DPH) to different salinity levels will be presented. |
