NOTES ON THE LIFE-HISTORY OF THE CLAM SHRIMP, EULIMNADIA-TEXANA

Several life history measures (growth rate, egg production, molt frequ ency, age at maturity and lifespan) were measured on several clam shri mp hermaphrodites (Eulimnadia texana Packard) grown in a laboratory se tting under optimal growth conditions. Growth rates were high early in life, and then dropped dramatically when egg production began (day 5- 6). Early egg production was low, and increased until approximately da y 7, after which production leveled off for several days. Reproductive senescence was noted after day 17, with clutch sizes ,continuously dr opping until death. Average molts per day was approximately 1.1, and m olting seemed to be more closely associated with egg production than w ith growth. Growth and egg production were negatively correlated, indi cating a possible trade-off between these two traits. No other trade-o ffs were detected. These shrimp show typical early-colonist life histo ry traits, displaying high initial growth, early reproduction at a hig h rate, and then early senescence and death.