Monday, March 30, 2015

Amphibian Egg Progress

The bulk of salamander and Wood Frog egg laying at Blue Jay Barrens occurred between March 13 and March 17.  In the two weeks since egg laying began, air temperatures have ranged from a low of 10oF to 75oF.  Water temperature has not suffered such wild fluctuations, due to the constant inflow of relatively warm spring water.  Despite these varying conditions, development of salamander eggs is progressing at a rapid pace.

Several of the Jefferson Salamander egg clusters show eggs with white colored centers.  This usually indicates the presence of fungus feeding on unfertilized and damaged eggs.

There are still plenty of live embryos in these masses, so there should be no shortage of larvae hatching into the pond.

Jefferson Salamanders concentrated their egg laying efforts on sticks floating in the pond.  Several large sticks are completely covered with Jefferson egg masses.  Streamside Salamanders made heavy use of the hard surface structure I placed in the pond for their use.

The structure was composed of a mixture of clay drainage tiles, bricks, rocks, and boards.  My thought was to see if the salamanders preferred one substrate over another.

Substrate type didn’t seem to matter.  There were eggs everywhere.

Once the lower surfaces were covered with eggs, the salamanders began attaching eggs wherever they could find a hard surface.  Next year I will try placing the material so there are more spaces between the various components.

Wood Frog egg masses are beginning to lose their cohesiveness and spread across the water surface.

Frog tadpoles are becoming free swimming and detaching from the egg masses.

Development of the eggs on the outside of this mass seems to be several days behind those eggs in the center.

Eggs in the top of the mass are most susceptible to damage from weather conditions.  Ice formed over the top of these eggs several times during the past two weeks.  Several embryos seem to have been killed from freeze damage.  Larvae hatching from that top layer of eggs also seem to have a tough time working their way out to open water.  Even so, plenty of live tadpoles will result from this hatching.

Attracted by the movement of hatching tadpoles, one of the breeding pond’s super predators moves in to investigate this newly available food source.  Red-spotted Newts will take their toll on the young salamander and frog larvae.  They can’t eat them all, even though they will try.  Plenty of young salamanders and frogs will live to add their efforts to future annual breeding activities.

6 comments:

  1. Thanks for the close up on the pond. I have watched and wondered about the different egg masses. Here I think the newts are most numerous.

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    1. Hi, Becky. I think the fact that this pond goes dry each summer helps to keep the newt population under control.

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  2. Fascinating! And so much earlier than anything here!

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    1. Hi, Furry Gnome. The salamanders I have around here are some of the earliest breeding species. Late breeding species don't have a chance to develop enough to leave the pond before hot, dry weather robs the pond of its water.

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  3. Wonderful post. I just came across it when searching for information about salamander eggs. Great pictures too!

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