North Channel smelt count doubles, alewives missing in recent survey

LAKE HURON—For the 11th year in a row the United States Geological Survey (USGS) Great Lakes Science Center, in conjunction with United States Fish and Wildlife, conducted a lake-wide pelagic fish study aboard the vessel Sturgeon over September and October of last year and the findings could mean good news for smelt fisherpeople this spring.

Lake Huron, due to its size, is broken down into three basins: the main basin of Lake Huron, Georgian Bay and the North Channel.

Tim O’Brien, biological science laboratory technician with the science center, explained that the lake was sampled through 22 different transects—20 kilometre stretches of lake that are each sounded for acoustic data that captures the variation in depth. In addition, alewife, bloater and rainbow smelt are sampled (called a pelagic fish survey) through mid-water trolls, Mr. O’Brien explained, noting that the sampling ranges from depths of 15 metres to 200 metres, depending on the depth of the lake.

In terms of lake-wide averages, there is still no good news for the alewife (the favourite food of the salmon), which took a massive hit over a decade ago. According to Mr. O’Brien, there is no sign of the fish recovering. Only two individual alewives were actually caught in the entire lake, in Georgian Bay. Since 2004 there has been very little variation in the numbers of alewives caught in the annual survey, the technician explained.

Fish are documented by their age—either age zero (under one) or older. For rainbow smelt, the 2014 results showed the lowest number of age zero fish since the survey’s inception 11 years ago.

“Very few fish were hatched in this year, which could potentially be related to the very cold start to the season,” Mr. O’Brien said, referencing last year’s extreme cold temperatures and late spring, a situation which could very easily be replicated again this year.

For rainbow smelt aged one year and older, the technicians saw a slight increase in fish per hectare. “It was 60 percent of the long term average, but still a slight increase,” he added.

In the North Channel, the survey did detect a two-fold increase in smelt in 2014 over the previous year. This is potential good news for dip netters during the annual brief smelt fishing season come spring, Mr. O’Brien said. It is also good news for the populations of game fish including salmon, rainbow trout, lake trout and walleye that inhabit the North Channel.

For bloater, the USGS found a decrease from 2013 in age zero fish, which is likely weather-related as well, Mr. O’Brien surmised. However, an increase was found with older bloater by two-and-a-half times.

“It’s a pretty substantial increase with the caveat that the standard of error is large,” he explained. “There were areas of the lake where we saw a lot of bloater, but also areas where there was not much at all.”

Very few bloater, along with a few small Cisco, inadvertently, were caught in the North Channel. “There are only few parts of the North Channel that are the right depth for bloater.”