WINTER FISHERY HARD ON RELEASED BLACK SEA BASS

Slowly, salt water anglers have gotten used to regulation.

While size limits, bag limits and seasons have been a feature of fresh water fisheries management for a century or more, they are relative newcomers to the ocean, particularly in the Northeast.  When I was a boy growing up on the Connecticut shore of Long Island Sound during the 1960s, the only regulation we had was a 16-inch minimum size on striped bass, and a prohibition on its commercial sale.  Neighboring states had a similar limit, but sale of striped bass was allowed.

And those were the only rules that we saw for a very long time.  Beginning in the 1970s, when fluke began to be regularly caught in the western Sound, we had to remember that fish caught on the New York side were subject to a 14-inch minimum size, and late in that decade, when I started fishing offshore, there was a 4-fish per person bag on bluefin tuna.  But other than that, saltwater fish in our region went largely unregulated until the striped bass collapse of the late 1970s and early 1980s focused folks’ attention on the need to manage inshore stocks, and the Sustainable Fisheries Act of 1996 forced fishery managers to end overfishing and rebuild overfished stocks, something that couldn’t be done without meaningful regulation.

In many cases, the regulations, no matter how badly needed, weren’t welcomed by the angling community, who had gotten used to their unrestricted, freebooting ways.  But over time, most anglers have grudgingly accepted the regulatory process, understanding the need to limit harvest at the same time that many wish that their own harvest wasn’t limited quite so much.

Anglers have accepted the notion that size limits, bag limits and seasons are needed to regulate landings, but what they are still having some trouble with is the notion that some portion of the fish that they let go, either because the law says that they have to, or because they want to do it to help maintain the stock, are also going to die, and need to be considered when managers set annual limits.

Their understanding isn’t helped by the fact that estimates of such “discard mortality” usually represent the average number of fish that won’t survive release, and that the number can vary wildly, depending on multiple factors, including where a fish was hooked, how long it fought, water temperature, salinity, and how long it was kept out of the water.

Anglers do understand that a fish hooked in the gills, that comes to the boat with lines of blood streaming down its side, is likely to die if released.  And most understand that fighting a big fish too long, so that it comes to the boat exhausted, lying on its side and almost floating, is going to hurt that fish’s chances for survival.  And, more and more, today’s anglers are learning to fish in ways that promote released fishes’ survival.

But many anglers have a problem controlling, or even comprehending, other sources of mortality.  

One of the more challenging is barotrauma, a term that translates to something like “pressure wound,” which occurs when fish are hooked in deep water and dragged to the surface.  Often, when that occurs, the changing pressure causes gas in the fish’s swim bladder to expand, in extreme cases pushing some of the fish’s digestive tract out through the mouth, and making it impossible for the fish to do anything but float helplessly on the surface.  Even less extreme examples of barotrauma, which show few if any external signs, can render a fish unable to return to the depths and ultimately cause its death.

Barotrauma provides a challenge to anglers and fishery managers, because it is often impossible to catch some species and not have the fish fall victim to it.  In such cases, size limits do little good, as most undersized fish don’t survive when returned to the water; bag limits face similar problems, and make restrictive seasons one of the only tools that address the problem—and they only work if there are no other fish in the area that anglers will still be able to fish for; otherwise, the protected species will still be caught and killed, even though their season is closed.

In the case of badly overfished species, complete area closures may b e the only way to afford them enough protection.

Such closures were either imposed or proposed in some Pacific rockfish fisheries and in some snapper/grouper fisheries in the South Atlantic, actions which thrust barotrauma into the angling press and into anglers’ attention.

Here in the Northeast, angler-induced barotrauma isn’t threatening any badly overfished species, and isn’t leading regulators to consider any area closures, so it is generally ignored by the average angler.  But that doesn’t mean that barotrauma isn’t causing a lot of discard mortality in Northeastern fisheries.

One of the worst-affected is probably black sea bass.

When they’re caught inshore, either in the bays or on shallow ocean structure, barotrauma isn’t an issue.  It only starts to kick in when the fish are caught in 15 fathoms or more, but at that point, it becomes a rapidly increasing source of black sea bass mortality.  And the line between no barotrauma at all and significant losses seems to be very thin.

One of the wrecks that I fish lies in about 85 feet of water.  I’ve caught many hundreds of sea bass there, and the only one that didn’t immediately turn nose-down and speed back to the bottom had had its tail cut off by a bluefish (I think) some time ago, and couldn’t overcome its slightly inflated swim bladder with the remaining stub.

Another wreck lies just about 10 feet deeper, in 95 feet.  When I fish on that piece, about one in four sea bass released ends up floating away, instead of returning to the depths.  A lot of those will decompress enough, just a few minutes later, to make their way back down, but I’ve also seen enough float away to make me feel guilty, stop fishing there, and refuse to fish on a deeper piece until I could figure out a way to prevent such waste.

At the same time, black sea bass support an active late fall/winter/early spring fishery that targets them in much deeper water, sometimes over 200 feet.  The barotrauma losses in that fishery are severe enough to get the regulators’ attention.  When the Atlantic States Marine Fisheries Commission adopted Addendum XXX to its summer flounder, scup and black sea bass management plan in February 2018, it included, for the first time, a management approach that

“allows for a performance evaluation process that better incorporates biological information and efforts to reduce discard mortality into the metrics used for evaluation and management response by evaluating fisheries performance against the [annual catch limit].  This approach integrates information from the 2016 assessment into the management process, enhances the angling experience of the recreational community, improves the reporting of recreational information, and achieves meaningful reductions in discard mortality to better inform management responses to changes in the condition of this resource.”

Of course, in order to incorporate discard mortality into the management process, managers must know what the mortality rate actually is.  For many years, managers assumed that 15% of all released sea bass did not survive, and while that assumed rate might have been fine, or even overstated discard losses in the inshore fishery, most people who thought about the issue realized that the release mortality in the deep water fishery was probably far worse.

But they didn’t know for certain.

Recently, a study conducted at Rutgers University strongly suggests that most black sea bass released in the winter fishery do not survive.  The project, titled “Estimating and mitigating the discard mortality of the black sea bass in offshore recreational rod-and-reel fisheries,” was performed by the Partnership for Mid-Atlantic Fisheries Science.  It involved catching black sea bass on traditional hook-and-line gear during the winter, at depths typical for the winter fishery, fitting them with standard plastic and/or acoustic tags, and releasing them back into the water.  Half of the released fish were “vented,” meaning that their swim bladders were punctured to allow them to return to the bottom; the other fish were released without venting taking place.

The researchers found that, upon release

“black sea bass exhibited four release behaviors including erratic swimming, sinking, floating, or swimming down, with the vast majority exhibiting the latter two behaviors…fish total length, capture depth, venting and the presence of exopthalmia  [bulging eyes resulting from barotrauma] influenced release behavior, with larger fish, that were not vented, caught at deeper depths and experienced exopthalmia had a lower probability of swimming down.”

The study estimated

“mean discard mortality rates of 21% for vented and 52% for unvented black sea bass following capture and release in 45 m [about 150 foot] depth.  Given that venting is not commonly practiced in the fishery, the 52% estimate for unvented fish is more representative of the current discard mortality rate when the fishery operates at (or near) this depth.  However, due to increased fight times, the discard mortality rate is expected to be higher at greater depths.”

Yes, more than half of the black sea bass released in the winter fishery die.

Such 52% discard mortality rate is more than three times higher than the rate assumed in the black sea bass stock assessment, and used by managers to determine overall fishing mortality.  Although the deep-water black sea bass fishery sees much less effort than the warm-weather, shallow-water fishery, it produces mortality rates that are entirely disproportionate to the number of participating anglers.

That might lead to the conclusion that the deep-water fishery is too costly, in terms of discard mortality, to justify its continued existence, as the fish lost to discard mortality during the winter season could, instead, be converted into fish harvested during the primary summer/early fall fishing season.

However, more than half of the discard mortality attributed to the deep-water fishery could be eliminated by the simple expedient of venting fish before they are released.  The process involves inserting a hollow needle into the fish behind the pectoral fin, and pushing such needle deep enough to puncture the swim bladder and allow the expanded gas to escape, which in turn allows the fish to return to the bottom.  The damage from the needle soon heals, and the fish is much more likely to survive.

An alternative to venting is the use of a weighted “descending device” that attaches to the fish and carries it down to a depth where the pressure is great enough to allow it to again swim freely.  There are a number of such devices available, which can be as simple as an upside-down milk crate on a rope, weighted on all four corners, that is used to force the fish down to the required depth, or as elaborate as the “SeaQualizer” that I have begun using when fishing on deeper wrecks, which holds the fish’s jaw in a spring-loaded device that pops open upon reaching a pre-set depth.

Some fishery management bodies, including the South Atlantic Fishery Management Council, have begun requiring either venting or descending devices on boats participating in deep-water fisheries where barotrauma is an issue.

Yes, venting or using a descender does take a little bit of time out of each fishing day.

But if anglers wish to continue participating in fisheries such as the winter fishery for black sea bass, where barotrauma is currently causing a substantial waste of the resource, the use of venting tools or descending devices seems to be a very small price to pay for the privilege.