For years, fishermen have questioned whether environmental factors play
as significant a role in the decline of fish stocks as fishing effort,
only to have their queries dismissed by policy makers as "just another
Nils Stolpe, a private consultant in Doylestown, PA who does fisheries/aquaculture and environmental work, first raised this question in the August 1994 issue of Commercial Fisheries News.
Since then, Stolpe and Michael Moore, a marine toxicologist and visiting investigator with the Coastal Research Center of the Woods Hole Oceanographic Institution, organized the Boating Impacts Workshop. It was supported by the Island Foundation, Inc., The Woods Hole Oceanographic Institution, and the Institute of Marine and Coastal Sciences at Rutgers University.
Presentations during the workshop, which Stolpe and Moore describe here, generated more questions than answers, but they made one thing clear - this is a subject that may prove critical to the future of fish and fishermen.
Woods Hole, MA - In 1963 in an article titled "Pollutional Effects of Outboard Motor Exhausts-Laboratory Studies" in the Journal of the Water Pollution Control Federation a body of water was described as being subject to an "extreme critical" boating level, one having a significant toxic effect on fish life, if the boats on it burned 18 gallons of fuel per acre-foot of water (about a third of a million gallons) per year.
Eleven years later the USEPA funded "Analysis of Pollution from Marine Engines and Effects on Environment" (done under contract by the recreational boating industry) the "saturation boating" level determined for Lake Geneva, Wisconsin (assuming a 5 month boating season) yielded a 15 gallon per acre-foot per year fuel use.
Today in Barnegat Bay, a typical Mid-Atlantic estuary in New Jersey, the calculated recreational boating fuel use is about 50 gallons per acre-foot per year. This represents at least a three-fold increase over what were considered maximum levels two decades ago, and if the fuel efficiency of outboard motors has improved significantly in this period, present boating levels are even higher than this comparative fuel use per acre-foot would indicate.
These levels, unthinkable only a few years ago, have evidently come to be accepted as being normal and of little or no environmental importance. As a result, intensive boating activity and any possible impact it might have on the aquatic environment has been largely ignored by resource managers, researchers and the environmental community for two decades.
Not too surprisingly in view of this lack of concern, the current EPA draft outboard motor regulations focus solely on the effects of outboard motor emissions on air quality, ignoring any possible impacts on the aquatic environment.
But consider these factors:
- While precise or consistent statistics aren't easy to come by, it appears as if there are ten to fifteen million powered small boats in use the United States. About three quarters of these use outboard motors - with an average size of 65 horsepower.
The boats used in coastal states tend to be larger, they are powered by larger motors, and their average fuel consumption (and exhaust production) is greater.
And boating in coastal state waters is concentrated in estuaries - critical habitats for well over half of our commercially and recreationally important finfish and shellfish species, generally during their early and most vulnerable life stages.
- Production of many of these commercially and recreationally important species has been in a more or less continuous decline for the same two decades during which there has been a fairly steady increase in small boat activity.
- Most boating activity takes place in the warmer months, the time of greatest biological activity in our estuaries.
- Recreationally used marine engines stay in service for well over ten years and with the advent of fiberglass the hulls can remain serviceable for decades. About half of the boats currently in use are over twelve years old. As boats are built, rather than being used to replace older boats taken out of service they are added to an already large and continuously growing recreational fleet.
In the light of these considerations, is it reasonable to ask whether
boating activity in coastal and inland waters is adversely impacting normal
biological productivity in these ecosystems?
To begin to answer this question a group of over 40 marine researchers, education/extension specialists, public boating and fisheries administrators, environmentalists, private consultants and environmental writers primarily from Atlantic coastal states met at the Woods Hole Oceanographic Institution's Coastal Research Center in early December at the first Boating Impacts Workshop.
Although workshop organizers did seek their participation, no one from
the boating industry attended.
Participants also discussed the issue of boat mediated access in terms of the general role of human and noise disturbance of nesting seabirds and migrating shorebirds.
Studies have modeled avoidance flights and interruptions of foraging as a result of chronic repeated disturbances. The suggestion was made that noise and other disturbances from small boats on otherwise isolated islands and beaches could be a significant factor in reducing - to below critical levels - the energy reserves necessary for successful migration in certain species.
The biological effects of 2- and 4-cycle outboard emissions were described from experimental studies in Woods Hole and at Stockholm University in Sweden.
Biochemical and molecular damage from both engine types was described in various fish species, including the observation of a five-fold reduction in total polynuclear aromatic hydrocarbon (PAH) waterborne contaminants in 4-cycle vs. 2-cycle emissions
However, the chronically toxic 4- and 5-ring PAH's were not significantly different in 4- vs. 2-cycle engines. The relevance of these data was discussed in the context of other sources of the same chemicals in the marine environment.
Workshop participants also discussed the unique nature of outboard motors - that is, how their exhaust gases cool rapidly and leave some components condensed and in the water column rather than being released into the atmosphere.
This raised the question of the relevance to water pollution of the current EPA draft regulations for boating emissions, which focus on the qualities of the hot exhaust gases before they are injected into the water.
The potential - in terms of economics, practicality and emissions reductions - for the use of alternative fuels in 4-cycle inboards and outboards was also considered.
Outboards, jet skis
A discussion of the possible effects of boat- and propeller-induced turbulence began with a theoretical consideration of the amount of water impacted by the propeller/impeller generated turbulence compared with power plant entrainment - that is, water sucked into electricity-generating power plant cooling systems.
It was calculated that 60 powerboats traveling at 30 miles per hour impacted as much water per unit time as did an average nuclear power plant.
These calculations raised the previously unstudied question of the significance of propeller and water jet operation in the destruction of important estuarine and marine plankton that live under the surface of the water, animals such as comb jellies, and fish and shellfish eggs and larvae, which tend to be most prevalent in the water column during peak boating season.
Several workshop participants discussed the significance of boating-induced turbidity including how increased turbidity - water cloudiness caused by suspended particles - reduces the depth to which sunlight penetrates the water column. They questioned how this might affect the growth of submerged aquatic vegetation as well as the effect of increased turbidity on the behavior of planktonic organisms.
A presentation on aerial surveys of turtle grass beds in the Florida Keys Clear showed clear evidence of substantial damage to submerged aquatic vegetation caused by propeller scarring, hull passage, illegal dredging and careless mooring.
Also discussed were the effects on marine organisms of the chronically toxic leachates that seep from pilings - pressure-treated with chromium, copper and arsenate - used for the construction of dock and marina facilities everywhere along the coast.
Throughout much of the discussion participants expressed concern about the dramatic increase in the use of "personal watercraft" like jet skies and wave runners.
Large parts of our estuarine areas have been sheltered from much boating activity because of their shallow depths - up until now.
Personal watercraft, which are currently selling at twice the rate of any other types of vessels, are capable of traveling in extremely shallow water. As a result, these devices have opened virtually all of our estuaries to intensive boating use and to its associated impacts.
This workshop was the first attempt to identify and address the full spectrum of environmental impacts that could result from the high level of boating activity to which our waterways are now subjected.
One thing the gathering made clear was how little research has been done and how much more needs to be done before we can begin to realistically address boating impacts.
The workshop also focused attention on the peculiar predicament of some public agencies that are, on the one hand, responsible for maintaining and improving the quality of freshwater, estuarine and marine waters and, on the other hand, having to make these waters increasingly accessible to the boaters that "pay the rent."
Most importantly from a public policy perspective, the workshop showed us that, for several decades, we have been overlooking what might well be a major factor in limiting the productivity of the estuaries that are vital to our inshore fisheries.
Until we remedy this problem, we arent doing the job we should be doing in managing our waterways and fishery resources, or any of the other activities that impact on them.
On a positive note, the workshop prompted a number of researchers to agree to collaborate and begin to examine some of the many questions that were raised. The fruits of these cooperative efforts should be available at a second workshop that will be held in Woods Hole in October 1996.
Workshop organizers plan to publish the prceedings - including summaries of the presentations, discussions, and working group conclusions - within the first half of 1995. For copies of the proceedings call Nils Stolpe at (215) 345-4790 or fax (215) 345-4869.