. >> it's amazing to see how resill yentd and how fast the river can come back. >> it started to recover within a week. >> mark is in charge of monitoring the site. >> probably within three to four years the fish population were essential recovered. >> he said the long term effects have been minimal thanks to a fishing ban on the river. the fish came back on their own. by 2005 r showed that most fish species had completely recovered. that was the last time fish and game took a comprehensive look at the river. but now an environmental group has been looking into it. >> it's a mixed bag. my main take away from the incident is that the river is fundamentally changed. >> rene is with the river exchange. he has been studying the river and there is evidence that some species are still struggling. >> based on the research that was done it seems like a.m. fill fibian populations haven't recovered. >> the fish and game department says there is no money for more studying. >> we have a lot of need for research assessment. >> it wasn't just wildlife that died when the river was poisoned. the town of