Jeff Stewart, the longtime captain of the Cape May Whale Watcher, recalled last seeing whales in Delaware Bay off Cape May County in 1990. Now, as then, the whales follow and prey on bigger schools of menhaden — a footlong fish used for fish-oil supplements, aquaculture feed and bait.

Seeing whales closer to shore is one benefit of the renewed abundance of menhaden, also called mossbunker or just bunker for short. Another is jobs in the menhaden fishery, which used to have operations in Cape May and Monmouth counties. More menhaden theoretically also helps the whales, striped bass, ospreys, dolphins and such that eat them.

This success story began in 2013, when the Atlantic States Marine Fisheries Commission set its first catch limits for menhaden in the waters from Maine to Florida. The fish has done so well since then that the quotas have been raised every year, to 216,000 metric tons.

In December, one of the leading certification bodies for the Marine Stewardship Council recommended that the Atlantic menhaden fishery be certified as sustainable. SAI Global said the fishery scored 83 for sustainability of the stock, 86 for minimizing environmental impacts, and 92 for effective fisheries management — each higher than the average score of 80 required for sustainability certification.

A sustainable and growing menhaden fishery, though, isn’t enough for some. Since at least 1888, when the Rod and Reel Association claimed commercial menhaden boats were taking fish better left as food for species they liked to catch and eat, people have fought over the best use for menhaden.

In the fall of 2017, a coalition of environmental and sport fishing interests, partly led by a unit of the Pew Charitable Trusts, successfully lobbied the fisheries commission to switch to a unique new management approach for a fishery, one based on estimates of how the menhaden population affects other fish and wildlife that prey upon it.

The theory is that by boosting the menhaden stock well above the scientifically established level of growth and sustainability, regulators could increase the populations of its predators as well — giving sport fishers more striped bass and the environmental community more ospreys, dolphins and such.

The science required for such engineering of nature seems well beyond current capabilities. The commission can barely assess fish stocks as it is, and now it will attempt to measure the influence of menhaden on the whole oceanic web of life. In the absence of solid objective scientific data, the subjective influence of interest groups seems likely.

The management-by-multiple-species approach is expected to take years to develop. Let’s hope the Atlantic States Marine Fisheries Commission also considers possible unintended consequences of this expansion of its mission. The balance of nature can be upset by too many menhaden or too many of their predators, too, possibly leading to bad outcomes. New Jersey managed white-tailed deer to fill the state with game for hunters, and got unintended habitat destruction and Lyme disease.

This open-ended extension of fisheries management also sends the wrong message to the fishing industry, that as soon as growth and sustainability are achieved, the rules will be changed to allow far greater restrictions for less scientifically supported reasons.

The fisheries commission will need to make a strong case that the ecosystem-based quota it is developing is scientifically valid, let alone considers all the important variables within such a wide analysis.

Perhaps it will find, as people continue to discover anew, that meddling with nature should be done as modestly and sparingly as possible.

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