ACCIDENTAL REEFS

 

There isn’t much hard bottom in the mid-Atlantic Bight.  According to one study of the habitat requirements of black sea bass,

“The mid-Atlantic Bight stretches from North Carolina to Massachusetts…The nearshore continental shelf is composed primarily of unconsolidated sediments consisting of sand, silt, shells, and small gravels.  Bedforms consist mainly of sand waves, small hills, and gullies created by ancient riverbeds, with rare outcroppings of rock, consolidated sand, and clay.”

That doesn’t leave much to attract and hold structure-oriented fish such as black sea bass, nor to help fishermen find concentrations of such species.  As a result, fishermen tend to focus on various forms of man-made structure.

For decades, many of the states have conducted artificial reef programs, where they sink various items in hopes of creating structure that will hold sessile life forms such as mussels and sea anemones, which in turn create habitat used by crabs, other crustaceans, and bait fish, which then attract and hold recreationally important food and sport fish.

Years ago, many such reefs were created by filling bundles of tires with cement and dropping them in designated areas, or dumping chunks of broken up concrete or unwanted steel from demolished buildings, but that didn’t work all that well, with the former often breaking up and washing ashore during storms and the latter getting covered over with shifting sand and losing its utility.

But after a while, the states began to understand what they needed to do, and started sinking unwanted steel vessels of various sorts (after first scrubbing out any oil, grease, or other potential pollutants), surplus armored military vehicles, train cars, pieces of demolished bridges, and even “reef balls” and other items purpose-built to create artificial reefs.

There is no question that fishermen love artificial reefs, as they attract and concentrate fish and make them easier to find and catch.  Whether the artificial reefs also benefit the fish by creating additional habitat, particularly in regions where hard-bottom habitat is scarce, is a very different question, and one that remains open for debate.  As one scientific paper noted,

“Productivity in real terms in relation to artificial reef deployment relies on the assumption that artificial reefs provide additional critical habitat which increases the environmental carrying capacity and thereby the abundance and biomass of reef biota.  The reef potentially provides substrata for benthic fauna and, thereby, additional food and increased feeding efficiency; shelter from predation or tidal currents; a recruitment habitat for individuals that would otherwise be lost from the population; a reduction of harvesting pressure on natural reefs.  It can also serve to be purely an aggregating device, whereby the behavioral preferences of fish result in aggregation on and around artificial reefs, without any increase in biomass.  [citations omitted]”

The answer to that question may depend on the species of fish involved, the availability of suitable alternative habitat, the design of the reef itself, and other factors.  However, experts believe that, at least in some cases, artificial reefs do provide benefits such as additional spawning habitat.

Then, there are the unintentionally created artificial reefs, which take the form of shipwrecks.  Such wrecks abound off some areas, which were known for treacherous navigation conditions—particularly during the years before electronic navigation aids became commonplace—or were places where heavy shipping traffic created a target-rich environment for German U-boats during the Second, and to a much lesser extent, the First, World War.  The approaches to New York Harbor, ranging from eastern Long Island to southern New Jersey, earned the name “Wreck Valley” from scuba divers, for the hundreds of wrecks lining the bottom.

The fish are attracted to wrecks as much as, or more than, they are attracted to intentionally-created artificial reefs.

And then there are the “accidental” reefs—man-made structures that were intended for other purposes, but ended up attracting a plethora of fish, as well.  The oil rigs in the Gulf of Mexico are a well-known example, and need no further discussion here.  Instead, I’ll concentrate on a relatively new phenomenon, the attraction that recently-constructed wind farms hold for various species of fish.

Wind farm development off the East Coast of the United States has been controversial, for multiple reasons.  Real estate and resort interests consider them eyesores.  They can block commercial fishermen from using some gear types in traditional fishing grounds.  There have been allegations, so far completely unsupported by any kind of biological evidence, that they lead to cetacean deaths.  And they have become a sort of political litmus test, damned at one end of the political spectrum and praised at the other.

There has been concern that wind farms might harm fishing, with some real-world evidence that they may have negative impacts on fishing efforts during the construction process, although not once the structures have been built.

Otherwise, wind farms seem to have had little to no adverse impact on East Coast fish populations, although they are new enough that not too much post-construction research has been concluded and published.

One study that has been published, “Fish distribution in three dimensions around the Block Island Wind Farm as observed with conventional and volumetric echosounders,” which appeared in the October 31, 2023 issue of Marine and Coastal Fisheries, seemed to suggest that wind farm structures have about the same impact on fish as do intentionally created artificial reefs.  That article concluded,

“We observed enhanced levels of fish abundance within 200m of wind turbined at the [Block Island Wind Farm] during a 4-day survey in August 2023.  However, these higher levels were similar to abundance further away (i.e., hundreds to thousands of meters).  These observations suggest that the turbines are acting as aggregators at scales of tens of meters but that the effect tends to be limited at broader scales.  There was an indication that the turbines influenced (1) vertical distribution, with the acoustic center of mass being deeper within proximity to turbines, and (2) aggregative behavior, with the fish being more loosely distributed within proximity to turbines.  Our survey was conducted five years after completion of the BIWF, and our results may be indicative of established wind areas, where the fauna may have adapted to the presence of the turbines.  However, the BIWF consists of only 5 turbines, so it may not be large enough to affect broadscale distribution or population level changes.  In addition, other features of the habitat, such as wrecks, rocky reefs, or physical and biological oceanographic attributes that we did not measure, could affect distributions independently of the BIWF.”

Another, slightly earlier paper, “Demersal fish and invertebrate catches relative to construction and operation of North America’s first offshore wind farm,” published in the March 29, 2022 issue of the ICES Journal of Marine Science, which reported the findings of a more elaborately structured and longer-term trawl survey, had similar findings.

“Demersal fish and invertebrate [catch per unit effort] varied spatially between the [area of potential effect of the wind farm] and two reference areas and temporally between baseline [prior to wind farm operation] and operation time periods; however interactions indicating reduced CPUE at the [area of potential effect] were not apparent.  The CPUE of several fish species were higher near the wind farm during the operation time period relative to the reference areas, providing evidence for an artificial reef effect.  For example, black sea bass CPUEs were statistically higher during the operation period near the wind farm relative to a reference area, reflecting the structure-oriented behavior of this species.  Black sea bass were observed near the BIWF turbine foundations in diver-based photographic transects, are targeted near the turbine foundations by recreational fishermen, and increased nearly ten-fold in CPUE in trawls conducted at the [area of potential effect] over the reference areas in the first two years of wind farm operation…Atlantic cod CPUE also were higher near the wind farm after turbine installation.  Cod are targeted by recreational fishermen at BIWF, as they use underwater structure as refuge and foraging habitat…  [references omitted]”

The same study found that the wind farm seemed to have no impact, positive or negative, on Atlantic herring, scup, or butterfish, might have had a negative impact on two species of skate, little skate and winter skate, although that was far from certain, and might have had a positive impact on the abundance of spiny dogfish, although that, too, was not completely clear.

Anecdotal evidence regarding the impact of wind farms on fish has been generally positive.  One study, “Anglers’ support for an offshore wind farm:  Fishing effects or clean energy symbolism,” published in the May 2023 issue of Marine Policy, found that

“a quantitative survey of 199 anglers from Rhode Island, Connecticut, New York, and Massachusetts moderate support for the [Block Island] wind farm.  Experience fishing at the wind farm is associated with more positive beliefs regarding the development’s effects on catch-related aspects of fishing…”

While I’ve never fished the Block Island wind farm, Rhode Island anglers that I’ve spoken with have only good things to say about fishing around the site, and at least one well-regarded Montauk party boat regularly makes the long trip to the wind farm, rather than stay in local waters, when seeking black sea bass and big fluke, so I have to believe that the wind farm has a positive impact on fishing.

But what I find truly remarkable is how quickly fish will respond to the turbine installation.  Last year, construction began on a big wind farm located roughly south of Long Island’s Jones Inlet.  It only took about two weeks for black sea bass to move onto the structures, and maybe a month or so before local party boats began fishing within the wind farm, finding the area more productive than the scattered wrecks and artificial reefs that they had been fishing on before.

So it’s pretty clear that the wind farms really have turned into extensive, accidental artificial reefs that can hold real benefits for anglers.

Unfortunately, it appears that the current administration is doing all it can to discourage further wind farm development, and given how the United States has now tried to weasel out of signed agreements to develop new projects and reneged on licenses previously issued, it’s not at all clear that any corporation will trust the U.S. enough to enter into new agreements, even when this administration is gone.

But those anglers who live in areas with access to existing projects will still be able to enjoy what promise to be productive new fishing grounds well into the foreseeable future.