Publication Date

2010-01-01

Availability

Open access

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Marine Affairs and Policy (Marine)

Date of Defense

2010-04-12

First Committee Member

Joseph E. Serafy - Committee Co-Chair

Second Committee Member

Daniel D. Benetti - Committee Co-Chair

Third Committee Member

Kenneth Broad - Committee Member

Abstract

Live juvenile cobia (Rachycentron canadum) transport methods were examined to determine opportunities for increasing packing density in closed containers for temporal durations up to 24 hours. Juvenile cobia (27 to 46 days-post-hatch (dph)) were tested for salinity tolerance following abrupt transfer from 35 ppt salinity water to salinities ranging from 0 ppt to 55 ppt. Results indicate a wide range of tolerance, with 100% survival at 24 hours post-transfer in salinities between 11 ppt and 45 ppt. Salinity preference was also tested to determine a possible correlation between acclimation salinity and salinity preference using an experimental horizontal salinity gradient with juvenile cobia (87 dph) over a period of 24 hours. Results of the salinity preference trials showed that salinity preference was directly related to acclimation salinity. Using two different salinities within the range tested in the tolerance trials (12 ppt and 32 ppt), a 24 hour simulated shipping trial was conducted comparing final survival between the two salinities at each of four packing densities (5 kg/m3, 10 kg/m3, 15 kg/m3, and 20 kg/m3). Results indicated a significant relationship between salinity and stocking density on survival of juvenile cobia following a 24 hour simulated shipment. At packing densities above 10 kg/m3, survival was significantly higher in the low salinity (12 ppt) treatments as compared to survival rates in the higher salinity (32 ppt) treatments. To help aquaculture professionals make accurate and economical decisions regarding the shipment of live juvenile cobia in closed containers, a bioeconomic model was constructed using survival data at different packing densities (1 kg/m3 to 20 kg/m3) and salinities (12 ppt and 32 ppt) obtained in the experimental trials combined with shipping cost and fingerling price data. The resulting model enables cobia fingerling producers to optimize their shipping methods and protocols, allowing for reductions in labor and material costs.

Keywords

Pelagic Teleost; Osmoregulation; Isosmotic; Behavioral Response; Aquaculture

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