Background:

In any culturing of organisms, to calculate fecundity we need to know how many descendants are produced.

Goals

Marsupial and post-marsupial fecundity was calculated for Metamysidopsis elongata (Holmes, 1900) in two culturing generations (F1 and F2), and wild caught from Mazatlán Bay.

Methods

From September 2010 to October 2011, we carried out monthly sampling on foot with a plankton net with a mesh size of 1 000 µm and a mouth opening of 50 cm in diameter. The fecundity evaluation was calculated with organisms fixed with formaldehyde at 4%. Culturing occurred at a density of 5 ind • L-1 at 22 ± 1 ºC, salinity 32 ‰ with continuous aeration. The mysids were fed ad libitum with recently hatched Artemia nauplii.

Results

The average marsupial fecundity was 6.28 ± 2.94 embryos per female in wild mysids, 4.51 ± 1.20 in the F1, and 3.72 ± 0.89 in the F2. The average post-marsupial fecundity was 5.86 ± 1.45 in wild mysids, 3.74 ± 1.20 in the F1, and 3.32 ± 1.42 in the F2. No correlation between the length of females and fecundity was found.

Conclusions

The fecundity of the wild mysids was present throughout the sampling cycle and was lower than that of the cultivated ones.