Calculate the decrease in mass of food foraged by fed sand gobies when a predator was introduced, giving the units.

Compare the effect that starvation had on both species of goby when no predator was present.

Describe the effect the predator had on the foraging of the gobies.

Suggest a reason for the effect of the predator.

2.6 mg (units required) (accept answers in the range of 2.5 mg to 2.7 mg)
No working required.

both foraged more after starvation;
black goby increased the amount of food foraged more than the sand goby;

a. predator present causes both to forage for less food;
b. fed black gobies showed little change in foraging (with predator present);
c. starved gobies foraged more than fed gobies (with predator present);
d. relative foraging remains similar between the two species / black goby always forages less than sand goby;

a. gobies may feed on smaller mud shrimps when predator present;
b. gobies may hide rather than forage when predator present / gobies may feed less efficiently if they are watching out for predators;
c. predator may also eat shrimp so less for gobies;
d. if predator eats gobies the total mass of food foraged is less / OWTTE;

Generally well done, although some answers were a bit unclear.

Generally well done, although some answers were a bit unclear.

Generally well done, although some answers were a bit unclear.

Generally well done, although some answers were a bit unclear.