So Muhammad tell us about Jews who broke the Sabbath and became apes.
What did they do?
In another place there's more info:
YUSUFALI: Ask them concerning the town standing close by the sea. Behold! they transgressed in the matter of the Sabbath. For on the day of their Sabbath their fish did come to them, openly holding up their heads, but on the day they had no Sabbath, they came not: thus did We make a trial of them, for they were given to transgression. (7:163)
The full explain on what happened we can hear from Tafsir Ibn Kathir :
They began using deceitful means to avoid honoring the Sabbath by placing nets, ropes and artificial pools of water for the purpose of fishing before the Sabbath. When the fish came in abundance on Saturday as usual, they were caught in the ropes and nets for the rest of Saturday. During the night, the Jews collected the fish after the Sabbath ended.
This Story,which repeat itself several times in Quran,Sound like a very non-authentic legend.
Is there a Story like this in Jewish tradition?
Yusuf Ali say:
There must have been a Jewish tradition about a whole fishing community in a seaside town, which persisted in breaking the Sabbath and were turned into apes; (Yusuf Ali's Commentary from QuranTrans)
But there's no such story in Jewish tradition!!!
Same story that end differently
And while the children of Israel were in the wilderness, they found a man gathering sticks upon the sabbath day. And they that found him gathering sticks brought him unto Moses and Aaron, and unto all the congregation. And they put him in ward, because it had not been declared what should be done to him.And the LORD said unto Moses: 'The man shall surely be put to death; all the congregation shall stone him with stones without the camp.' (Numbers 15:32-35)
So the punishment of breaking the Sabbath is death by the Jewish court of justice,this man didn't became to an ape!
Did The Jewish fishermen indeed broke the Sabbath?
According to Tafsir Ibn Kathir ,the Jews put the net before Shabbath,the fish were caught during the Sabbath and the Jews collected the fish after Shabbath,is that forbidden?
In Jewish law there's a debate weather it's allowed or not:
BETH SHAMMAI MAINTAIN: SNARES FOR WILD BEASTS, FOWLS, AND FISH, MAY NOT BE SPREAD UNLESS THEY CAN BE CAUGHT WHILE IT IS YET DAY; BUT BETH HILLEL PERMIT IT. (Mishna of Shabbath brought in Talmud Shabbath 17b - http://www.come-and-hear.com/shabbath/shabbath_17.html )
Hillel who was the Head of the Jewish court of justice about the 0 AC( http://en.wikipedia.org/wiki/Hillel_the_Elder ) said that one can put net before Shabbath to catch fish-cause he don't work during the Shabbath.
When Hillel and Shamai debate ,unless it said explicit ,The decision is by Hillel.
So according to the Jewish law it's allowed to put net before Shabbath,so fish will be caught during the Shabbath!!!
So this authentication of this story smell like a fish...