Cohort growth and survival of bay anchovy Anchoa mitchilli larvae in Biscayne Bay, Florida

Abstract

Egg and larval abundance of bay anchovy Anchoa mitchilh from 4 field experiments in Biscayne Bay, Florida, were analyzed to determine variability in growth and mortality rates of dailyspawned cohorts. Mean egg densities varied by more than an order of magn~tude in the 4 experiments. Otolith-aged larvae, validated by laboratory rearing, were used to construct the age-frequency distributions of 71 cohorts. Mean growth rate estimates ranged from 0.43 to 0.56 mm d-' and the means of cohort-specific instantaneous mortality rates ranged from 0.30 to 0.45 (26 to 36 % d-l). Egg mortality rates were generally higher and more variable than those for larvae. An approximate mean mstantaneous mortality rate for eggs was 1.94 (85.6 % d-l). Mean larval growth and mortality rates differed significantly among experiments, although reasons for the lfferences were not identified. On average, relative s u~v a l s of cohorts varied by a factor of 20 at 20 d after hatching among the 4 experiments. Estimated mean abundances of larval cohorts at 20 d varied by a factor of 45, reflecting differences in in~tial abundances of eggs and the variable mortality rates. Models of bay anchovy growth and mortality in relation to prey concentration, developed in previous laboratory expenments, were used to partition field-expenment mortalities into nutrition-related and presumed predabon-related components. Mean daily losses of a cohort to predation (18 to 28 %) were 2 to 3 times higher than losses to starvation (10 to 11 %).

Contribution of larval growth rate vairability to the recruitment of the Bay of Málaga anchovy (SW Mediterranean) during 2000-2001 spawning seasons

“…It is reasonable to expect a relationship between larval growth and recruitment because studies on other anchovy species have shown that survival within each ontogenic larval stage is size-specific and growth-dependent (Rilling and Houde, 1999), that mortality declines with age, and that one of its main causes is predation (Leak and Houde, 1987;Folkvord and Hunter, 1986). It is believed that the results of this study will shed some new evidence on the influence of upgraded anchovy larval growth on recruitment success.…”

“…A poor growth rate may lead to an increase in mortality due to the prolongation of time spans within vulnerable larval sizes (Folkvord and Hunter, 1986). Predation was shown to have a much higher impact on mortality than starvation in the Bay anchovy (Anchoa mitchilli) (Leak and Houde, 1987). Houde (1987) from literature derived data indicated that small variations in the growth rates could lead to major recruitment variations.…”

Sagittal otolith microstructure, early growth and development of Coilia ectenes in the Yangtze Estuary, China

“…Microstructure around the core area of sagittal otoliths of C. ectenes shows the general microstructural pattern of Engraulidae species for which daily periodicity of increments, and age of the first increment formation, have been confirmed [22,23] (see ''Discussion''). Based on those studies, we assumed that deposition of increments is daily and the first increment is formed on the 3rd day post hatching in sagittal otoliths of C. ectenes.…”

“…Time of the first increment formation and daily periodicity of the increments have been confirmed in Engraulidae species, though these validations have not been done for otoliths of C. ectenes [22,23]. In this study, we examined larvae and early juveniles of C. ectenes collected from the Yangtze Estuary.…”

The Effects of Front‐Associated Wind Events and Resultant Sediment Resuspension on Dietary Habits and Caloric Intake of Bay Anchovy and Age‐0 Atlantic Croaker in Mobile Bay, Alabama

“…We believe Bay Anchovy in warm-temperate and subtropical estuaries may balance capital breeding, in which compensatory feeding takes place in advance of breeding so that reproduction initially may be financed from stored energetic capital, with income breeding, in which reproduction is financed using current energetic income during long spawning seasons in which females spawn successively over many days (Thomas 1988;Stearns 1992). If this is true, it is during the early spring period that overwintering females must obtain sufficient nutrition to prepare for spawning once waters in the estuary reach 20 • C, which occurs in late April in Mobile Bay (Leak and Houde 1987;Zastrow et al 1991;Peebles et al 1996). These results are compelling if one considers that Bay Anchovy stomachs examined during 12 monthly sampling cruises in Mobile Bay under quiescent conditions contained little or no detritus (Jackson 2004).…”