Development, growth, and survivorship of the copepod Calanus marshallae in the laboratory

Abstract

Development times from egg to adult Calanus marshallae (Copepoda, Crustacea) were 36 d at 15 'C, 62 d at 11 "C and 64 d at 10 'C. Stage-by-stage development was not isochronal but followed a sigmoidal pattern. Egg, NI and N2 together took 3.4 d at 10 "C (= 5.3 % of the total development time). N3 had the second longest duration of any stage (6.8 d at 10 "C; 10.7 % of total development). Stage duration decreased from N3 through N6, with N6 having the shortest duration of any stage (2.6 d), then development became progressively slower through each copepodite stage. C5 had the longest duration (20.9 d; 32.8 % of total development time). Body lengths of laboratory-raised stages NI to C3 were the same as of field-collected specimens; C4 and C5 were shorter than in wild copepods, but laboratory-raised females were significantly longer than wild females. This suggests that laboratory growth conditions were probably as good as, if not better than, conditions in the field. Weight was gained at a rate of 0.05 pg pg-I d-I from egg through N4; 0.18 d-' from N5 to C5; 0.02 d -' from C5 to adult female. It is argued that observed deviations from isochronal development in Calanus marshallae may reflect differential mortality rates among developmental stages such that stages that on average experience high mortalities will develop most rapidly.

Testing for resistance of pelagic marine copepods to a toxic dinoflagellate

“…maturity). We calculated the median development time from the regression of the percent copepodites or adults in the cohort versus days (Peterson, 1986). The size at maturity and somatic growth were determined using prosome length measurements (after about the C-IV stage copepod sex could be determined and only female sizes were measured).…”

“…We employed the Statview Ò version 5.0.1 software for all statistical analyses. To determine the age to maturity and life-stage duration, we used the median development time (Peterson, 1986;Carlotti and Nival, 1991), which is defined as the age, x, at which 50% of the individuals reached a specific stage (e.g. maturity).…”

Influence of algal diet on growth and ingestion of Calanus helgolandicus nauplii

“…The major factors relevant to growth and development of nauplii include initial egg characteristics, temperature, food concentration and the type of food consumed by the nauplii. The initial egg characteristics result from the past feeding of the females producing the eggs (Peterson 1986, Guisande & Harris 1995, Melle 1998). …”

Exuvium analysis: A nondestructive method of analyzing copepod growth and development

“…data), so the variation we document here cannot be explained solely by heritable genetic differences (McLaren and Corkett 1978). Peterson (1986) found that families of Calanus marshallae that developed rapidly to one stage did not always maintain this lead. Although some of the individuals we followed showed a similar pattern, there were consistently rapid or slow developers among individuals, and mean instar durations or development times mask a great deal of interesting, persistent individual variation that has direct consequences for understanding lifehistory ecology and population dynamics.…”

“…Miller et al 1984;Peterson 1986). Median development time to a specific stage is then estimated as the time when 50% of the population has molted to that stage.…”