Effects of temperature on reproduction and survival of the calanoid copepod Pseudodiaptomus pelagicus

Abstract

Four experiments were conducted on the calanoid copepod, Pseudodiaptomus pelagicus, to determine the effects of temperature (24, 26, 28, 30, 32, and 34°C) on survival, development time, reproductive output, and population growth in order to define the optimal temperature for culture. The first experiment stocked early stage nauplii into 1 L beakers and cultured them using standard procedures until five days after the first mature adults were observed; from this survival, sex ratio, time to maturation, and fecundity were measured. The second and third experiments evaluated the effects of temperature on nauplii production by stocking individual pairs and 25 pairs of adults, respectively; in both experiments nauplii production was determined daily for 10 days. The fourth experiment determined the effects of temperature on population growth and composition of the population produced by stocking 10 adult pairs and culturing them for 10 days at six temperatures. Results indicate survival from early nauplii to adult was significantly affected by temperature and those cultured from 24-30°C had the highest mean survival. Time to first maturation and maturation of the entire population was significantly influenced by temperature and took from 6.8 to 12.8 days. Temperature significantly affected nauplii production in both individual and groups of paired adults. Temperature affected the mean daily nauplii production by decreasing the brood interval but did not affect the mean brood size. The number of nauplii produced by 25 adult pairs was significantly influenced by temperature; the optimal temperature was 27.5°C at which 1861 nauplii were produced. The distribution of developmental stages in the population was also affected by temperature; at lower temperatures the population consisted of a greater proportion of nauplii while at 32°C the population was comprised of more advanced staged individuals. When developing production objectives, aquaculturists must consider temperature because it has multiple effects on the culture of P. pelagicus. The optimal temperature range to achieve high survival and the greatest nauplii production is 26-30°C. To maintain long-term stock cultures the best temperature may be 24°C to slow maturation and growth while 28-32°C may be used to maximize nauplii production by decreasing time to maturation and decreasing brood intervals.

Seasonal variations in body length and fecundity of 2 copepod species: Thermocyclops crassus (Fischer, 1853) and Eudiaptomus drieschi (Poppe & Mrázek, 1895)

“…Some scientists suggest that temperature is the primary determinant of body size at maturity (Coker, 1933;Deevey, 1960;McLaren, 1963McLaren, , 1965 and that it is a key abiotic factor regulating the growth and reproductive potential of copepods in marine and freshwater systems. Additionally, temperature is a key variable in the development of production regimes (Rhyne et al, 2009).…”

Genetic and phenotypic relationships between immune defense, melanism and life-history traits at different temperatures and sexes in Tenebrio molitor

“…In ectotherms, especially, temperature can have profound effects on both life-history and immunological traits, as, for example, in the case of development time, which is a critical fitness component and is strongly determined by temperature (for example, Roff, 1992, Lazzaro et al, 2008, Rhyne et al, 2009. Likewise, the effects of temperature on host-parasite relationships are affected by the thermal sensitivity of both the host and the parasite.…”

Culture of Harpacticoid Copepods: Understanding the Reproduction and Effect of Environmental Factors

“…required high temperature (up to 25°C) for faster development. In addition, mean development time of calanoid copepod, Pseudocalanus newmani decreased exponentially with increasing temperature and reached the shortest duration at 32°C (Rhyne et al, 2009). Similarly, Williams & Jones (1994) clarified that fastest development for harpacticoid copepod T. battagliai o c c u r r e d i n t h e w a r m e r m o n t h s o f t h e y e a r w h i c h regarding to the highest production of superior food.…”

“…Although increasing temperature showed the positive effects, the development and survival reduces as temperature rises beyond a certain level (Chinnery & Williams, 2004). For example, temperatures greater than 30°C was unfavourable to survival, percent ovigerous females, and fecundity of Pseudodiaptomus pelagicus (Copepoda: Calanoida) (Rhyne et al, 2009).…”

“…Evidence from some laboratory studies proved that temperature has strong influence on reproductive and postembryonic development (Hicks & Coull, 1983;William & Jones,1999;Matias-Peralta et al, 2005). Rhyne et al (2009) found that 26 to 30°C was the best range for nauplii production while 28 to 32°C was the best for fast maturation rate of nauplii. A study by Williams & Jones (1994) also noted that a benthic harpacticoid, Tisbe battagliai has their best temperature at 20°C and increasing of temperature towards 25°C decreased the production rate.…”