Frog Blog by Anna Jemmett

In the visitor centre at Forsinard we have a great aquarium display, with a tank, information boards and species ID cards, but it has been empty over the winter. So last week, I decided to collect some common frog (Rana temporaria) spawn from one of the pools on our Dubh Lochan trail. The aim was to watch the tadpoles grow in the tank until they reach the frogling stage and then be released into the same pool from which I collected the spawn. They have such an interesting lifecycle it will be great to follow them growing first hand. Unfortunately, by the time I had finished cleaning out the tank and setting it set up, the frogspawn in the pool had hatched! So we have started with young tadpoles.

We will be keeping the blog up to date with how the tadpoles are doing and how they are progressing. With photographs and updates until their release!

The lifecycle of the common frog.

Stage 1- Frogs breed and lay spawn in the water.

Stage 2- Embryos grow within the egg.

Stage 3- The embryos start to hatch, but they are still dependant on their egg yolk for nourishment.

Stage 4- The now free-swimming tadpoles develop feathery gills for absorbing oxygen (to breathe underwater)

Stage 5- The external gills start to disappear. The tadpoles are developing and breathing through an internal gill chamber.

Stage 6- The hind legs begin to grow. At this stage the tadpoles are very hungry!

Stage 7- The hind legs are developing and the lungs are devolving too. Tadpoles start to gulp for air at the surface of the tank.

Stage 8- The front legs begin to grow (as do the tongues and the eye lids)

Stage 9- The tail shrinks, the tadpoles are beginning to swim using their back legs. They are now breathing air.

Stage 10- The final stage of metamorphosis is when the tail disappears. These are now fully formed froglets.

Day 1: Tadpoles are safely housed in the aquarium in our visitor centre! The aquarium was set up before hand with gravel and water collected from the bog pools. The tadpoles were then gently collected from the pool and transported to the tank.

 

Week 1: Picture 1: Some of the tadpoles enjoying a meal of boiled lettuce.

Picture 2: They seem to particularly enjoy spinach! At this stage they are herbivores but as they grow they will need more protein and progress on to a more carnivorous diet.