Frogs have a "sense" in most cases as to where to lay their eggs. For instance, they "know" if the body of water they are laying their eggs in will or will not dry up before their young can morph out and become miniature frogs. (as do toads) So my first thought is that they are were aware of the presense of the algae.
Many North American species of frogs eat algae as their main diet. And many use it to evade their natural predators, like dragonfly nymphs, etc.
My advice, would be to leave the mat algae alone, and just continue to observe. Algae also serves a function of filtering the water of excess nutrients and metals, so can benefit. Tadpoles are delicate to a degree, and changing the water balance right now/ie.; removing too much algae, could change that balance and kill them. Be careful about adding too mush untreated water (I don't know the gallonage of your pond) now too, use only aged water until they morph.
I hope I have helped :)
Nicci

Here is a link that might be useful: tadpole care

Thank you. Very interesting link. I have the southern leopard frog here. The same one for at least 2 years and he even stayed in my kiddy pool when I redid the pond last year to keep the new bigger pond his home. I felt so bad all last year when he called faithfully for a girlfriend and finally got my first eggs this year. Toad eggs come by the hundreds of masses, but so far two frog masses, one in the bog and the other inside the pond, on the side. I guess I'll have to trust mother nature to take its course. With all the rain lately the rain has been keeping my pond to full capacity, between 800-900 gallons (I don't know how to figure out plant shelves and bog areas so I'm taking 100-200 gallons out for those areas. I rarely have to add water for evaporation and when I do it is very little, even during drought. I did watch them today and they are eating everything they see and there is definitely enough algae to feed the abundance if mom and dad are still busy.

Wow!
If I were a froggy, 'I'd wanna come play at your pond!' :)
Nice gallonage! :)
It's so pleasant to hear how some people still care for the smaller creatures. Lol, I even still watch ants sometimes, like when I was a kid. The other day i had to kill a group of friteants that had gotten into a plant near a pond that my husband just installed for me, and hours later, the survivors floating on water's surface had made a 'floatilla' out of their own bodies, complete with a few eggs that had snatched so should they reach land they could create a new queen.
But I ramble.
I just got mine started, and it's purpose is truly for the frogs to come, so no fish. We got some of the plants in the canal behind our house to begin stocking it and get it to 'smell pond'. The very first night i had a southern toad in it, taking a soak (and I was still treating the water...eeek!)
My link above was broken, so will re-post here. Sorry.
What kind of plants do you keep in your pond?
Nicci

Here is a link that might be useful: tadpole care

I did get your link to work, just had to search from the main page.

I do have some goldfish in the pond and probably will have more after this spring. Started off with 2 and now have 20 so will give some to a local pet shop probably and give some to friends.

I love the toads and my one "pet" frog that made residence. The kids from the neighborhood love watching the cycle of life from mating, eggs, tadpoles, all the way to adults and some of the babies you can even regognize to adulthood by their odd coloring every now and then. Those ones get names. I'm so excited for my first sets of the southern leopard eggs though.

We have parrotfeather, hornwart apleanty and iris for the bog and 2 lilly plants and add water hyacinth in the summer. Probably will add in a couple weeks because don't do well if added to early. BTW--The toads do use the lillies, especially the babies during their inbetween stages. We'll often find them still with pointy tails on the pads. We also keep various other plants in the bog that "feeds" down to the pond, usually canna, elephant ear or impatience.

the tadpoles I found matted in the thick algae will this not suffocate them