date the results have been disappointing in terms of the failure to detect clear trends. The federal government plans to put a new national monitoring program in place in 1995. The program will make use of a statistical methodology for monitoring marine debris that was developed and reviewed by federal agencies and environmental organizations. Applications for this methodology also are being studied by Latin American and Caribbean countries.

Information about sources of shipborne garbage is useful because it can suggest where Annex V implementation efforts should be directed. The sources of garbage regulated by Annex V are ''all ships,'' where a ship is defined as "...a vessel of any type whatsoever operating in the marine environment and includes hydrofoil boats, air-cushion vehicles, submersibles, floating craft and fixed or floating platforms." (See Appendix B.) Thus, many diverse fleets and vessels are potential sources of garbage.

The true sources, of course, are the persons aboard these vessels who generate garbage as a normal consequence of all the sundry activities they pursue. The quantity and nature of vessel discards depend in part on the standards of crew or passenger accommodations. The amount of garbage is proportional to the community's standard of living; the higher the standard, the more seafarers are likely to use packaged prepared foods, supplies, and single-use items rather than provisions requiring added preparation and cleanup. (Moreover, the use of dis-

posable items and packaging has been encouraged by changes in ship practices, sanitation concerns, and a desire for convenience.) The result is added waste. When an individual is accustomed to a high standard of living on shore, he or she expects similar conveniences on a vessel, despite the cramped living space. Modem vessels are capable of providing many conveniences, even on long voyages.

The task of measuring the amounts of garbage produced during normal voyages is not well supported by present Annex V compliance and enforcement programs. The committee was unable to locate or develop any precise data for any phase of the garbage cycle.³ There are no reliable data on the characteristics and amounts of vessel garbage generated by all the maritime sectors to which Annex V applies. Nevertheless, drawing on numerous sources, the committee sought to characterize as completely as possible the various fleets and the garbage they generate. Nine major maritime sectors are addressed in this report.⁴ The information presented in this chapter is deliberately brief; additional details about each fleet and its garbage management practices are provided in Chapter 4.

The only all-inclusive estimates of amounts of garbage generated by U.S. maritime sectors were developed in support of MARPOL/MPPRCA rule making for the Department of Transportation by the Eastern Research Group (1988) and later revised (Cantin et al., 1990). (See Table 2-2.) These estimates, while based on some flawed assumptions, provide an initial perspective on sources of vessel garbage. The Cantin data identified recreational boaters as generating the largest amount of garbage (by weight), more than 50 percent of the total. Day boats and fishing vessels each were thought to contribute close to 20 percent of the total.

The Cantin data must be employed carefully because they are based on some fleet-specific assumptions that are either outdated or, in the committee's judgment, questionable. The former problem is obvious with regard to the merchant marine, for example. The maritime industry has changed considerably in recent years. Environmental awareness has increased within the industry, while the continued depression in worldwide shipping has spurred operators to reduce crew sizes, change organizational structures and voyage patterns, and expand shoreside responsibilities for vessel garbage management. These factors can influence the amounts of garbage generated. An example of a questionable assumption may be found in the Cantin calculations for the recreational boating sector, in which per-person garbage generation was presumed to be similar to that for cargo ships. This correlation seems doubtful, considering that boaters generally eat only one meal per voyage, while merchant mariners may consume three meals daily and generate additional garbage from food preparation. Thus, the Cantin estimate for

boaters' garbage seems high. Other salient observations on the Cantin data may be found in the forthcoming descriptions of each sector.

The data presented in Table 2-2 reflect garbage generation. The Cantin study also estimated amounts of garbage discharged ashore and overboard by each maritime sector, both before and after ratification of Annex V. These estimates were incorporated into a congressionally mandated study of plastic waste materials, including marine debris (U.S. Environmental Protection Agency, 1990). In the committee's judgment, neither the Cantin nor the EPA results with respect to garbage discharged overboard can be relied on, even to gain an initial perspective on disposal practices. The committee's misgivings are due primarily to the absence of any way to know whether the estimates are even reasonable. Indeed, little is known about the amounts of garbage discarded at sea, or, correspondingly, whether these disposal levels are environmentally acceptable. Examination of these issues is beyond the scope of the present report.

However, recognizing the shortcomings of available data, the committee developed its own estimates of vessel garbage generation based on weighting factors obtained from a variety of sources (see Table 2-3). These rough approxi-