Kelp aka Calico Bass. Source: CDFG; Photo credit: Rob Johnson
Identifying threats to sea life isn’t always easy. What you see is often far from the whole story. Take kelp bass and barred sand bass, for example. These particular fish tend to get together in the same places at the same time of year. When it comes to spawning, they’re very much creatures of habit.
This makes it easy if your goal is catching them. These fish also conveniently gather in the summer, when ocean and weather conditions are at their friendliest. You (and a few thousand others) could catch your limit and still be under the impression that these fish populations are healthy.
The problem is, at least in the case of the barred sand bass, we’ve discovered where almost all of the fish are. During the spawn, the overall size of the population doesn’t affect catch levels, due to advanced fish-finding technology and efficient fishing techniques. Managing fisheries often presents the problem of distinguishing fish availability from fish abundance. Sometimes there are plenty of fish around and none interested in biting. Here we find the opposite: we can find fish to catch even as their overall numbers are in real decline.
The Times story refers to a new study led by Brad Erisman, a postdoctoral marine biology researcher at the Scripps Institution of Oceanography at UC San Diego:
“The populations of kelp bass and barred sand bass, two of the most popular — and easy to catch — saltwater fishes in Southern California, have plummeted 90% since 1980… but sport-fishing boats have been able to keep their catch rates high in part because they have consistently targeted bustling offshore spawning grounds, masking the dwindling numbers with an ‘illusion of plenty,’ the study concluded.”
This isn’t the first time these species have faced trouble. Back in the 1950s, commercial take of both was outlawed due to overfishing. And certainly sea conditions, particularly temperature changes, contribute to population ups and downs. But new, more efficient technology and techniques are facilitating unsustainable catch rates of kelp bass and barred sand bass during the seasonal spawn. Tens of thousands of fish are routinely caught summer weekends from June through August.
Historically, bass productivity has reliably cycled up and down in response to the regular ups and downs of ocean temperature cycles. But bass are not bouncing back this time around. Too many anglers targeting aggregations of fish is coming home to roost, and by the time anglers notice major catch declines, it’ll be far too late.
Thankfully, California was on the ball, and managers at the Fish & Game Department examined and backed up Scripps’ findings. But, in order to sustain this popular fishery and repopulate California kelp forests and sand flats with these important fish, we need to act now. Fish & Game scientists have identified three actions necessary to do the job:
• increase minimum size limits for these species from the current 12” limit
• reduce bag limits from a current 10 fish limit
• institute a prohibition on fishing for two weeks during the spawn to provide a period of uninterrupted spawning. Fishing is now open year-round.
But at what levels? Conservation advocates are recommending changes to recover these populations rapidly and fully. Others are urging slower, more incremental effort. Ocean Conservancy supports sustainable fisheries based on science, and believes a 15” minimum size, a two-fish bag limit, and a two-week closure during the height of the spawn is necessary, at least for now. Over the longer term a greater emphasis must be placed on early warning systems that alert managers and the public to fish population declines. Given the “hidden” nature of this decline, the proposed changes may seem a bitter pill. But strong medicine is required.