Pete Wolf used a 6.5-inch rainbow trout pattern Big Hammer swimbait to hook this 32 yellowtail on a hot summer day. (Brian Kettler)

Prolonged heat waves have a profound impact on our local ocean waters and the fish we find there.

Combine the heat wave with still air and the oceanic hydraulic action of upwelling slows, lowering the thermocline (where the warm upper water mixes with the mid-layer cooler water) and creating a deeper surface layer.

A deep, warm surface layer, especially when there are great schools of baitfish milling about, as we have been seeing, is an open invitation to pelagic warm-water fish.

This past week we’ve seen an upswing in catches of yellowtail, a powerful-fighting and great-tasting member of the jack family (think amberjack and jack cravalle), bonito and barracuda.

We’ve had wild surface action on pelagic fish as far up the line as Hollister Ranch. The farther east and south you go, the more consistently warm the water is and the more regular the sightings of and hookups with fish that spend most of their time down south in warmer water.

This is a time that we fisher folk look forward to all year long because now we have some really fun battles with hard-fighting fish and many of them are very good table fare.

Local homeguard fish such as calico bass really enjoy the how the warm water cranks up their metabolism and we have some wide-open bites at local kelp beds and shallow reefs or wrecks. Sand Bass gather up in the 50- to 80-foot depths and ambush baitballs that wander too close.

Halibut likewise enjoy the warmer water because they like to stay warm as they lie flat on the ocean floor, waiting to ambush any small fish that swim within striking distance. We get some good late summer action on halibut in the shallows, by slow-trolling or drifting live baits.

Rockfish are deeper and live among the rocks at depths were the warmer water only has a milder affect.

Consequently, rockfish and lingcod action remains steadily good, which is a blessing because sometimes the pelagic fish aren’t to be found and we rely on groundfish populations for our family’s fresh fish dinners.

There are some valid concerns about the effects of prolonged warm-water events driven by heat waves and calm air.

If the conditions persist for too long, our kelp plants suffer somewhat and that in turns removes good habitat that fish and other sea critters need. The effect is not nearly as dramatic or devastating as powerful winter storm waves that rip out kelp beds.

Heat waves and calm air do good things, provided the conditions do not persist for too long. My feeling is that a full month of such conditions would have negative effects, but just a couple of weeks is beneficial.

— Capt. David Bacon operates WaveWalker Charters and is president of SOFTIN Inc., a nonprofit organization providing seafaring opportunities for those in need. Visit softininc.blogspot.com to learn more about the organization and how you can help. Click here to read previous columns. The opinions expressed are his own.

Capt. David Bacon is a boating safety consultant and expert witness, with a background in high-tech industries and charter boat ownership and operation. He teaches classes for Santa Barbara City College and, with a lifelong interest in wildlife, writes outdoors columns for Noozhawk and other publications. The opinions expressed are his own.