Egg development times of Eurytemora affinis and Pseudodiaptomus forbesi (Copepoda, Calanoida) from the upper San Francisco Estuary with notes on methods

Abstract

Egg development times (DTs) of copepods are used to scale DTs of life stages to temperature and to calculate egg production rate in sac spawners. Here, we report egg DTs at various temperatures for two copepod species from the upper San Francisco Estuary measured using video observations of individual egg sacs. The egg DTs (days) of Eurytemora affinis and Pseudodiaptomus forbesi were related to temperature (T, °C) by DT = 11.5e−0.106T and DT = 22.7e−0.121T, respectively. Video observations decreased manpower requirements, increased the frequency of observations and provided more detailed observations of individual hatching patterns compared with historical techniques including direct observations and regression analysis.