Egg development rates for use in egg production methods (EPMs) and beyond

Aspects of Embryonic and Larval Development in Bighead Carp Hypophthalmichthys nobilis and Silver Carp Hypophthalmichthys molitrix

“…The CTU method of quantifying developmental rate requires that temperature be relatively constant (i.e., less than 2° C of variation), as large temperature fluctuations can affect survival, growth rate, developmental rate, and behavior [18,25,27,28]. The CTU method is also less accurate at temperatures near limits of thermal tolerances [24,27,29], although these rarely occur in natural settings [25]. Temperatures in this study were not near either the thermal maximum (39° C) or minimum (11-18°C) [13,30–32].…”

“…We found the degree of change small enough to use one T min for all embryonic stages and another for larval stages. T min is influenced by maternal history, acclimation temperature, stock and population differences and other environmental factors [25,26,29,32,33]. Values are best-fit data based on all temperature treatments for each species and are best used as an estimate for fish and conditions found in waterways of central North America.…”

Egg production methods in marine fisheries: An introduction

“…Advances such as the "spray method" (a method to separate fixed zooplankton and eggs; Eltink, 2007) or DNA identification methods (Heffernan et al, 2004;Fox et al, 2008;Lelievre et al, 2010) have allowed expansion of EPM applications to new fish species. Our knowledge of egg development dynamics has increased Geffen and Nash, 2012). Surveys of adults have developed to use various gears such as gill nets (Ward et al, 2009), purse seiners (Alheit et al, 1984), mid-water trawls (Picquelle and Stauffer, 1985), surface trawls (Lo et al, 2005) or a mixture of gears (Santos et al, 2011).…”

Where do egg production methods for estimating fish biomass go from here?

“…Understanding both the egg development rates and the variability of mortality is important to ensure an unbiased EPM. Statistical representation of the egg development rates through stages at different temperatures is being applied using multinomial models (Ibaibarriaga et al, 2007a, Bernal et al, 2008; see also Geffen and Nash, 2012). However the estimation of mortality, required to obtain the daily egg production at spawning time, is still imprecise and heavily influenced by the spatial variability of the egg abundance and the mortality process itself, governed by both biological and oceanographic variables (Helbig and Pepin, 1998;Bernal et al, 2011a;Pepin and Helbig, 2012).…”

“…ageing and mortality models for egg production, or lineal models of batch fecundity versus weight for adult parameters). A review of various incubation models (required for ageing) is discussed in Geffen and Nash (2012). The possibility to extend the models to also describe the spatial patterns of the DEPM adult parameters was also presented at the workshop, as well as previously suggested in ICES (2004), although a formal spatially and environmentally explicit Daily Egg Production approach has not yet been published.…”