Where Are The River Herring?

by Alan Pollock

            Whether they’re spawning in lower numbers because of development pressures on land, or whether they’re ending up in the nets of massive pair trawlers just offshore, river herring continue to be very scarce in Cape Cod herring runs this spring.

            The runs in Harwich and Chatham are all but devoid of the silvery baitfish, as they have been around the state for the last eight years.  Chatham Herring Warden Donald St. Pierre checks the run at Ryder’s Cove three times each day, and Tuesday morning, he saw only a few dozen fish.  “It’s not a lot.  I haven’t seen any schools,” he said.

            In the past, schools of 500 to 600 fish could be seen climbing the fish ladder in the evening or early morning, “but I haven’t seen any this year,” St. Pierre said.  Some say the precipitous dropoff is the result of subtle changes around the spawning grounds; others say it’s a simple case of overfishing.  But in either case, it spells trouble for the entire marine food chain, not to mention those who depend on it.

            The fish seen in herring runs are river herring, specifically alewives and blueback herring.  They are a separate species from the Atlantic herring, which is much more numerous and travels in immense schools offshore.  But in at least one sense, the distinction is superficial: both species are being heavily fished by pair trawlers, industrial fishing operations that haul enormous fine-mesh nets a quarter-mile apart, catching everything in a wide swath of ocean.  Pair trawlers routinely work the inshore waters off Chatham.

            In a single trip, pair trawlers can land a million pounds of herring.  The captains target Atlantic herring, but because river herring often school with them, large numbers of river herring are also caught.  Massachusetts and three other states have strict prohibitions on the possession of river herring, so when a pair trawl’s haul contains large numbers of alewives and blueback, they are either pumped overboard as dead bycatch, or landed in a state with friendlier river herring laws as an “incidental catch.”

            Harwich Natural Resources Officer Thomas Leach said in one trip the pair trawlers are capable of hauling the equivalent of all the fish to go up the town’s herring run last year.

            “It could be more than double that, in one shot.  And that’s just the bycatch,” he said.  “They’re taking the legs out of the bottom of the food chain, and they’re taking our runs with it.”  Leach said it’s also plausible that some of the decline is linked to nutrient loading in the ponds and streams where herring spawn.

            “It can cause a change in the whole chemistry of the run.  Because nitrogen and phosphate loading leads to lower dissolved oxygen, it makes it tougher on any specie in general to survive,” he said.  But in Harwich, not enough water quality data exists to make that connection, and the limited amount of information available now doesn’t show a marked decrease in dissolved oxygen in recent years.

            Mike Armstrong, the program manager for anadromous fisheries for the state division of marine fisheries, said the evidence just isn’t there to support the theory that pair trawlers are harming river herring populations.

            “Do they catch them?  Yes.  Is it enough to impact the stock?  We don’t know,” he said.  But what is clear, Armstrong said, is that streams around Massachusetts are drying up more often than they did in the past, keeping juvenile herring trapped in the ponds where they are vulnerable to predation.  On Cape Cod, because of the sandy soil, the problem is more acute, he said.  When the aquifer is drawn down by drought, or by private and public drinking water wells, the problem is exacerbated.  And nutrient loading from residential septic systems and other manmade sources also likely plays a role.

            “It’s tough to quantify, but when you look at a big, soupy mass of blue-green algae,” it’s not difficult to imagine, he said.

            But Armstrong admits there’s a problem with this theory: one would expect a sharp dropoff in river herring to have been caused by a sudden change in habitat, like a drought or a development boom.  Neither has happened in the last eight years.  In the past, herring numbers seemed to swell according to a five-year cycle, but we’re now in the eighth year of low numbers, he said.

            One possibility, Armstrong said, is that various pressures on river herring caused numbers to decline slightly, making them more vulnerable to other pressures like natural predation and overfishing.  “We don’t know what the driving force is,” he said.

            The Cape Cod Commercial Hook Fishermen’s Association has hosted a number of meetings of all the Cape’s herring wardens, and is actively pushing for conservation measures for Atlantic and river herring.  Operations Director Tom Rudolph said the association, the Coalition for the Atlantic Herring Fishery’s Orderly, Informed and Responsible Long-term Development (CHOIR), and other stakeholders joined together as the Herring Coalition, and have lobbied the New England Fisheries Management Council for better controls on the herring fishery.

            In 2005, the coalition successfully lobbied for a ban on mid-water pair trawling in the Gulf of Maine, allowing instead a less-intensive purse seine herring fishery in this “buffer zone” area.  Landings continue to decline around the region, however, and the conservation groups are now pushing for tighter controls for the herring fishery.  River herring have already been “pre-listed” as a “species of concern” under the federal Endangered Species Act, said Lara Slifka, herring program coordinator at the hook fishermen’s association. 

            “So at least it’s on the radar,” she said.

            Today, the New England Fishery Management Council is expected to vote on whether to adopt a scoping document from its herring committee identifying five objectives for the herring management program, to be known as Amendment 4.  Those objectives include closer monitoring of the herring fishery, compliance measures for catch limits, efforts to reduce bycatch, and the establishment of limited access privilege programs, like a herring sector allocation. 

            Rudolph said the time has come to start looking at river herring and Atlantic herring together.  Given catch data, “it’s now clear we’ve actually got a series of threats to all the herrings,” he said.  The danger isn’t just about herring, harvested for use as pet food and sardines, but for all the other commercially important species that rely on them.  Locally, with herring and mackerel species dwindling, about the only feeder fish left are sand eels.  “That’s it.  That’s our forage base,” he said.

            Armstrong said the division of marine fisheries has just hired a full-time herring fishery observer who will make spot-checks as pair trawlers unload their catch, documenting the bycatch that makes it to shore, and providing the first reliable numbers about the impacts of pair trawling on river herring.  “The data will be what they are.  If I have the data, I’ll jump on the bandwagon,” he said.

            St. Pierre said he understands concerns about shoreside development, water levels and other habitat issues, but those changes have been gradual, not sudden.  Maybe the large number of seals in Chatham Harbor plays a role, “but Harwich doesn’t have seals in front of the Herring River, and their run is horrible.  There’s only one thing you can blame it on, really.  I think it’s the fishing offshore.”        

            While the three-year moratorium on the taking of herring expires this year, both St. Pierre and Leach said they will recommend that the ban be extended for the foreseeable future to help stocks recover.  St. Pierre said he believes if all the factors align to create one strong year for herring stocks, it might be enough to start a general stock recovery.  Armstrong agreed.

            “We’ve got to keep the pressure off them,” he said.  If herring runs are kept clear and well-maintained and the harvest is limited, they’ll once again return in big numbers. 

            “I don’t think they’re all done.  They’ve been low before,” he said.

4/17/08