Daniel Powell

A mass stranding of deep-water species of anglerfish may be due to a rapid change in temperature.

Dock Totals 7/11 – 7/17: 5722 anglers aboard 230 trips out of San Diego landings this past week caught 939 barracuda, 2 black seabass (released), 3583 bluefin tuna (up to 230 pounds), 1 bonito, 3278 calico bass (1,867 released), 9 halibut, 4 lingcod, 740 rockfish, 1990 sand bass, 17 sculpin, 174 sheephead, 35 whitefish, 1 white seabass, 62 yellowfin tuna, and 250 yellowtail.

Saltwater: Of the factors seasoned anglers consider when approaching a fishery, whether freshwater or salt, water temperature ranks high in importance. Being much more dense than air, bodies of water will tend to have zones of temperatures as you travel through them vertically or horizontally. That most fish are cold-blooded and sensitive to temperature changes as slight as a half-degree Fahrenheit, and that technology has afforded today’s angler the ability to read exact temperatures on location, determining when and where a certain species might be actively feeding can be as simple as checking sea surface temperature (SST) charts or the temp reading on your fishfinder. But while temp breaks are beneficial, die-offs have been attributed to extreme changes in temperature when two currents collide. I recently found several dead deeper water fish, all of them sub-species of anglerfish, in the Pacific Transition Zone on a beach near Bahia Asunción, BCS, Mexico. Though I had never seen that species stranded, I was told by a local fisherman that it is not too unusual this time of year, when warmer water collides with the very cool coastal waters that account for the great abalone and lobster fishing in the area.

Bluefin tuna are one of a few species of fish that can regulate their body temperature the way warm-blooded animals do and so they are less subject to water temperature breaks, but their prey, mainly sardines and anchovies, can stack up in areas where there is a slight change. Tunas, yellowtail, and other pelagic migratory gamefish burn a lot of energy and need to feed often, so they will follow current edges where temperature changes can constrain masses of baitfish. For that reason, sportboat captains and private boaters will often check SST charts (found online at NOAA and other oceanographic or fishing sites) before they head out to fish for pelagic species. This past week, however, has been more about just getting a few miles outside the harbor and looking for the crowd.

The surface temps between the coast and San Clemente Island range from 69-71 degrees in that span, with the warmer water being at the coast and the southeast corner of the island, and the cooler water about midway between. There are reports of schools of bluefin tuna on or near just about every high spot from the 9-Mile Bank to the Mackerel Bank off the lee side of San Clemente. Bluefin are finicky biters, and though spotted feeding from the border to off Los Angeles, the best biters (and the main body of the fleet and private boaters) have been in a tight area about 10 to 12 miles off the La Jolla coast in 71- to 72-degree water. There are so many boats targeting one tight area off the north edge of 9-Mile Bank that, from land, their lights look like a small town lit up just a dozen miles west of the Pacific Coast Highway. There, bluefin from 18 to over 200 pounds have been straining gear, muscles, and sometimes, the patience of thousands of anglers through the week.

The area is so ‘hot’ that multi-day trips that usually venture hundreds of miles south are spending their entire outing between the coast and San Clemente Island. As these fish are also available to smaller private vessels, scores of boats are working so near each other that lines between anglers on different vessels tangle. There is an unwritten rule among those who fish the ocean about keeping distance from other vessels, as fish will often break off and escape when lines tangle. Generally, the distance to maintain from another vessel while fishing is about twice as far as well cast surface iron, or a hundred and fifty yards or so. In sportfishing lexicon, a tight crowd of boats fishing a hot bite is called a “parking lot,” and like its onshore namesake, common courtesy is often called for. But when the bite is hot, the usual protocol of distancing can get ignored and tempers can flare.

Warm water has brought an issue to light in the freshwater scene as well: lots of dead largemouth bass. In the summer months, when water temps rise dramatically in area lakes, largemouth bass move into the deeper cool water. Anglers often keep bass in live wells and release them at the dock after taking photos. This is usually not a problem, but as live wells draw in hot water at the surface and the bass are acclimated to the cooler water at depth, the temperature difference between where they were hooked and the live well can be over 20 degrees and the sudden change can shock their systems, which will cause the fish to roll. It is advisable to release bass as they are caught in these conditions to give them a better chance of survival.

Fishing events: 7/22, 5-11:30 pm, Summer Night Fishing at Santee Lakes

Fish Plants: 7/23, Santee Lakes, catfish (1000)