318
J. Robertson et al.
Biomass Consumption Comparison 1977-1986 and 1987-1994
ESTIMATING PREDATOR CONSUMPTION RATES 1977-86:
Total consumption of each species for the 10 year period 1977-1986 were again
derived using the values given in Greenstreet (1996); numbers and mean weight at age
for each species in each quarter averaged over the years were taken from the MSVPA
(MSA Working Group, 1990) “key run”; the stomach composition was taken from the
1981 stomach data. Consumption by quarter between the key species over this longer
period is shown in network diagrams (see Figs. 12a, b, c and d).
ESTIMATING PREDATOR CONSUMPTION RATES 1987-94:
For the period 1987-94 an MSVPA was run using the revised 1991 stomach data (see
ICES CM 1996/Assess:6). Mean weight and numbers at age were taken from the
single species assessments where possible or an average was used from the MSVPA
key run. Data for 0 group whiting and saithe were taken from Daan (1973) and length-
J. Robertson et al.
Biomass Consumption Comparison 1977-1986 and 1987-1994
ESTIMATING PREDATOR CONSUMPTION RATES 1977-86:
Total consumption of each species for the 10 year period 1977-1986 were again
derived using the values given in Greenstreet (1996); numbers and mean weight at age
for each species in each quarter averaged over the years were taken from the MSVPA
(MSA Working Group, 1990) “key run”; the stomach composition was taken from the
1981 stomach data. Consumption by quarter between the key species over this longer
period is shown in network diagrams (see Figs. 12a, b, c and d).
ESTIMATING PREDATOR CONSUMPTION RATES 1987-94:
For the period 1987-94 an MSVPA was run using the revised 1991 stomach data (see
ICES CM 1996/Assess:6). Mean weight and numbers at age were taken from the
single species assessments where possible or an average was used from the MSVPA
key run. Data for 0 group whiting and saithe were taken from Daan (1973) and length-