Monday, February 27, 2012

Streamside Salamander Eggs

Frequent rains have given members of the mole salamander family many opportunities to migrate to their breeding pools.  Most species head for quiet pools where they lay a mass of eggs encased in a jelly-like envelope.  The exception is the Streamside Salamander, a species that utilizes intermittent headwater creeks as a depository for its eggs.

Streamside Salamanders anchor their eggs to the underside of flat rocks in the stream channel.  Large, well anchored rocks situated in moving water are ideal as a breeding site.  A rock such as this can accommodate several adult salamanders and allow them to perform courtship and egg laying activities completely hidden from the eyes of any aquatic predators.

Occasionally, a female will select as a breeding site a smaller rock that could be easily moved by fast moving water or a foraging Raccoon.  Eggs laid beneath a rock like this are typically lost, so those inappropriate survival genes are eliminated from the population.

This may not be a smart place to lay eggs, but it does give me an opportunity to get some pictures.  I never move the large rocks.  My tampering could easily damage the eggs as well as destabilize the rock’s position in the stream bed.  Based on the fact that the pools below the most promising large rocks fill with Streamside Salamander larvae each spring, I think have a pretty good idea of what goes on under those rocks.

Streamside Salamander eggs are laid individually.  Water flowing beneath the rock keeps the eggs clean and well oxygenated.

This salamander needs clean, rock bottomed creeks for breeding.  During most of the year, the adults spend their lives below ground in the neighboring forest.  Their appearance is almost identical to that of the Smallmouth Salamander.  I was told by one expert that the only way to be sure of a specimen in hand was to do a DNA analysis.  I just assume that those I find in the stream are Streamsides and those in the pond are probably Smallmouths.

The eggs are just beginning to develop.  The race is now on to make it through the larva stage before the creek dries up for the summer.

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