Theses and Dissertations


Title: Collection and free amino acid enhancement of copepod nauplii for first-feeding larval red snapper Lutjanus campechanus

Name: Lindley, Laban C.

Degree: MS

Chair: Ronald P. Phelps

Resides:

University: Auburn University

Location: Auburn, Alabama

Date: 2004

Pages: 102

Keywords: amino acids, copepod nauplii, larval, red snapper, Lutjanus campechanus

Abstract:

This research consisted of two studies that were conducted in order to further develop collection techniques and improve nutritional qualities of copepod nauplii in order to benefit first-feeding larval red snapper (Lutjanus campechanus). The first study evaluated the use of two trapping methods for harvesting zooplankton, mainly copepod nauplii, from fertilized brackish water ponds. Nine, 0.11 ha brackish-water ponds (~2-7 %o salinity) were filled and fertilized with organic and inorganic liquid fertilizers. Following 7 d of monitoring zooplankton abundances, the nine ponds were randomly assigned one of three treatments. Three ponds were trapped with a large plankton net (Trap I), three with a pump and bag trap method (Trap II) and three ponds were not trapped to serve as a control. Beginning on day 8 of the study, the ponds were trapped with the corresponding method for 1 h per day, for 15 d. The number of rotifers, copepod nauplii and adult copepods harvested was recorded daily as well as pond zooplankton densities. The two trapping methods were similar in terms of their trapping efficiencies. Trap II collected approximately 79,500,000 more copepods greater than 75 ?m in size than Trap I. The use of the plankton net trapping method may be beneficial by removing a smaller amount of adult copepods from the ponds and thus preventing the decline of nauplii production. The second study conducted describes the free amino acid (FAA) profile of nauplii ofApocyclopspanamensis collected from brackish-water ponds. Further, this study addressed the effects of acclimation of nauplii to 30 %o seawater from brackish-water (~6-7 %o) on the FAA profile, and the feasibility of direct enrichment of nauplii with crystalline FAA. Seven treatments were carried out on copepod nauplii over a 3 h experimental period to determine the FAA profile, and to evaluate the effects of acclimation and enrichment on the FAA profile of copepod nauplii. The composition of the FAA pool of brackish-water nauplii was found to contain a total FAA content of 28.06 ? 3.54 nmol o mg w.w. nauplii-1, of which 55% was non-essential amino acids. In general, the direct enrichment of nauplii with crystalline FAA provided a significant increase in the total FAA content over that of nauplii collected directly from brackish water. Acclimation alone however, also provided a significant increase in the total FAA content. This indicates that enrichment of nauplii with crystalline amino acids may not be necessary.

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