Determining the effects of prey combination on larval Elacatinus colini standard length and survival from 2015-10-11 to 2015-11-30 (NCEI Accession 0291585)

Acquisition Description:
Rotifer density experiment: To determine optimal rotifer density for newly hatched E. lori and E. colini, survival and growth of larvae were evaluated under 4 different rotifer density treatments: 0 (unfed control), 10, 15, and 20 rotifers ml-1. Twelve, 6.5-L rearing bins were set up for each species, allowing for 3 replicates per density treatment. On the day of hatch (0 dph), 25 larvae were transferred to each rearing bin. Rotifer density treatments were assigned to bins at the start of trials using a complete randomized block design. Following daily water exchange, each rearing bin was dosed with the assigned rotifer density. There was no significant difference in water quality parameters among rotifer density treatments (all Kruskal-Wallis tests, p> 0.05). On day 6, all surviving larvae were collected from the rearing bins, counted and photographed using a dissection microscope. The photographs of larvae were used to compare larval size (SL) among rotifer density treatment. Artemia density experiment: To determine the optimal density of Artemia for culturing E. lori and E. colini larvae, the survival and growth of larvae were evaluated under 4 density treatments: 0 (unfed control), 3, 6, and 9 Artemia ml-1. A pilot experiment indicated that >40% of E. colini larvae began consuming Artemia nauplii at 6 dph. Therefore, for each species, larvae from a single clutch were reared communally in a 38-L rearing bin and fed 15 rotifers ml-1 from 0 – 6 dph. On day 6, surviving larvae were distributed evenly among twelve, 6.5-L rearing bins (3 bins per Artemia density treatment). Due to differential survival to day 6, the number of larvae distributed among the rearing bins varied by species (E. lori: n=20 larvae bin-1; E. colini: n=14 larvae bin-1). Artemia density treatments were assigned to bins at the start of trials using a complete randomized block design. Following daily water exchange, each bin was dosed with rotifers (15 ml-1) and the assigned Artemia density. The photographs of larvae were used to compare larval size (SL) among Artemia density treatments. Plankton, Rotifers and Artemia Experiment: To determine the suitability of wild caught plankton for rearing larvae in the lab in Belize, the growth and survival of E. colini larvae fed a combination of rotifers and Artemia (RA) was compared with larvae fed solely on wild caught plankton (P). Prey combination treatments were assigned to bins at the start of trials using a complete randomized block design. On the day of hatch (0 dph), 25 larvae were transferred to each of six, 6.5-L rearing bins (3 bins per prey combination). Rotifers (15 ml-1) or plankton (≤10 ml-1) were fed to larvae beginning at 0 dph. However, Artemia (3 ml-1) were not included in the RA diet until 6 dph. Due to natural variation in the quantity of plankton collected in the field each evening, the average density of plankton fed to larvae was 5.3 ± 3.8 prey ml-1 (mean ± SD). Following daily water exchange, each rearing bin was dosed with the assigned prey combination. Water quality parameters were not significantly different between prey treatments (all Wilcoxon Rank-sum tests, p > 0.05). On day 14, all remaining larvae were counted and photographed. The photographs of larvae were used to compare larval size (SL) among prey treatments.