When news broke this month that oil giant BP had agreed to pay $20.8 billion in fines for its Deepwater Horizon disaster, the figure seemed huge.

But when placed against the number of fish and wildlife deaths BP has conceded its spill caused, the figure fades almost to insignificance.

The Natural Resources Damage Assessment that the fines are based on estimated that the oil released into the Gulf during the 87-day gusher 50 miles off the Louisiana coast caused the deaths of:

•     One billion oysters.
•     200 to 500 million shrimp.
•     2 to 10 billion blue crabs.
•     2 to 5 trillion larval fish and 37 to 68 trillion invertebrates that were floating on surface waters.
•     86 million to 26 billion fish larvae and 7 billion planktonic invertebrates in deep Gulf water.

These larval losses “likely translated into million to billions of fish that would have reach a year old.”

The Oil Pollution Act requires that a Natural Resources Damage Assessment be conducted.  Research teams from state and federal agencies and BP spread across the affected area to collect evidence of the effects. The two sides presented their cases to a federal judge, who approved the final counts.

The assessment was released along with the settlement Oct. 5.

While those staggering numbers led to $8.3 billion of the total fine, the report points out they are based on estimates, not actual body counts. The report says collecting hard evidence of fish and wildlife deaths during the spill was not possible because the area covered was so vast — 43,300 square miles — and was influenced by tides, currents and weather.

Since the spill occurred during the peak spawning months, most of the deaths listed were of tiny life stages “generally smaller than the letters on this page” the report noted.

BP is required to compensate the public for the losses, either by replacing the species that were killed, or by providing financial resources for recovery. Federal law requires the awards for these damages to be used only for restoration of those losses.

While catches of most of the harmed species have shown no sharp declines since the spill, the settlement includes $700 million for any possible future losses.