Modelling gastric evacuation without meal size as a variable. A model applicable for the estimation of daily ration of cod (Gadus morhua L.) in the field

• Published in: ICES Journal of Marine Science
• Main Authors: Temming, Axel, Andersen, Niels G.
• Format: Text
• Language: English
• Published: Oxford University Press 1994
• Subjects: Articles; Gadus morhua
• Online Access: http://icesjms.oxfordjournals.org/cgi/content/short/51/4/429; https://doi.org/10.1006/jmsc.1994.1044

Data on gastric evacuation of cod from the International Data Base on Gastric Evacuation Experiments have been reanalysed. A general evacuation models was fitted to the data by means of non-linear regression techniques:<fd>$$\hbox{ dS }/\hbox{ dt }=-\hbox{ R }\times {\hbox{ S }}^{\hbox{ B }}\hbox{ or\; integrated }:{{\hbox{ S }}_{\hbox{ t }}}^{(1-\hbox{ B })}={{\hbox{ S }}_{1)}}^{(1-\hbox{ B })}-\hbox{ R }\times (1-\hbox{ B })\times 1,$$</fd>where S=stomach content, t=time after ingestion, R and B=constants. This model allows for various curve shapes, including linear (B=0) and exponential (B=1), and the curve shape (B) was estimated from the data. Meal size was included in the model by modifying the constant R=R′ × MD, with M=meal size in weight and D=constant. When meal size was included in the model, the resulting B values were strongly dependent on the food type and the estimated D values were negatively correlated with B: capelin, B=1.37, D= −1.16; herring, B=0.84, D= −0.57; and prawn, B=0.35, D= −0.14. When meal size was excluded from the model, the resulting B values were closer together (capelin, 0.47: herring, 0.43; and prawn, 0.27), the loses in explained variance, however, were small (capelin, 4% herring, 1%: and prawn, <1%).