A massive die-off of alewives of all sizes in the past week likely was due to a rapid drop in water temperatures.

Temperatures plunged about 20 degrees after wind and currents from storms upwelled very cold water. Surface temps the mid-40s were seen, and readings as low as the upper 30s were recorded 50 feet down.

Anglers hope that there are no more major die-offs for two reasons: One, catches tend to slow down for a week or more during such events because there are lot of weakened baitfish doing death spirals; and two, alewives appear to be making a comeback this season, and preserving as many as possible to fuel the fishery is a priority.

Alewives are the favored forage of salmon and trout, key players in a multi-million-dollar Lake Michigan sport fishery.

However, a combination of factors — including quagga mussels impacting the bottom of the food chain and more wild-hatched salmon — has led to a drop in alewife year classes and size over the past 15 years or so.

Fisheries biologists implemented a series of salmon stocking cuts in hopes of preventing a baitfish collapse such as occurred in Lake Huron more than a decade ago, and salmon size and condition has improved.

After failing to top 30 pounds seven straight years (2004-2010) in the lake’s largest fishing contest, four of the past six Kewaunee/Door County Salmon Tournaments have featured 30-plus-pound winners. Last year’s 35.46-pounder was the heaviest since 1999.

That trophy potential lured a record 3,049 entrants in 2016. Tickets for the 35th annual contest are on sale now at Algoma BP, Kewaunee Marina and Lakeshore Lighthouse.

This year’s early bird prize is a drone, and all ticket purchasers are also in a draw for a Yamaha 9.9 horsepower motor from Shipyard Island Marina.

Fishy research

Research by Daniel Phaneuf, a University of Wisconsin-Madison professor of agricultural and applied and economics, found that anglers were willing to pay the most money to catch a chinook on a Lake Michigan trout and salmon fishing trip.

On Green Bay, walleyes were far and away the winner.

From the most recent data, Phaneuf multiplied the number of trips by the survey results to estimate that Lake Michigan fishing trips for chinook salmon generated $32 million in 2016, while lake trout trips produced $8 million and walleye trips $33 million.

Of course, without knowing just exactly what was asked — for example, are “lake” trout lakers, or all trout species? — I’d argue the lake trout economic impact number is way overinflated. Rainbow trout would be a much higher dollar amount, based not only on known angler preference but also catch statistics.

Bass rankings

The Little Sturgeon Bay to Fish Creek stretch of Door County was ranked No. 1 in the nation in Bassmaster’s annual compilation of the nation’s “100 Best Bass Lakes” in 2014, and No. 2 in 2015.

Mille Lacs Lake in Minnesota, ranked sixth a year ago, is the new No. 1. It took over the spot from back-to-back winner Toledo Bend Reservoir, which straddles the Texas and Louisiana border.

The Little Sturgeon to Fish Creek stretch was ranked fifth in the Central Division last year and sixth this year. It was not named in the top 12 nationally. Bassmasters will reveal its entire top 100 in the July/August issue, as well as online.

Besides Mille Lacs, the only other Midwest water to crack the top 12 nationally this year was Michigan’s Lake St. Clair (ninth).

Flip-flopping

Summer days mean flip-flops, but your feet don’t have to suffer from a cheap, uncomfortable fit.

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Check out the colorful lineup for men and women at www.ahhsoles.com.

Kevin Naze is a freelance outdoors writer. He can be reached by emailing [email protected] or calling 920-883-9792.

This article originally appeared on Wisconsin: Alewife die-off hopefully last of summer