Lin, T.J.

Alatina alata is a cubozoan species that forms spawning aggregations eight to ten days after each full moon. From October 2015 to January 2016, we collected jellyfish using hand­nets during spawning. Individuals were photographed, weighed, and gonad samples were collected to confirm gender in the laboratory. Observations of spawning behavior and post­spawning condition of four individuals were made in the laboratory.

The following parameters for spawning aggregations were documented: 1) all individuals were sexually matured (n = 147), 2) female to male ratios are significantly higher than the expected 1:1 for wild populations (χ 2 = 26.017; p ≤ 0.001) with a probability of 0.6­0.8 female per 0.05 individual encountered, and 3) females (54.8 ± 17.1 g) weigh significantly more than males (48.1 ± 10.2 g) (t­test , p = 0.017). Average wet weight of females is ~14% greater than males. No  differences in the ratio of length to width (χ = 29.819; p = 0.991) and wet weight to bell surface area (χ = 29.819; p = 0.999) were found between male and female individuals; indicating that there are no morphological differences. Laboratory observations of spawning showed no evidence of internal fertilization and that post­spawning mortality did not occur within 72 hours.