Date of Award

12-2003

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Marine Policy

Advisor

Yong Chen

Second Committee Member

James A. Wilson

Third Committee Member

Robert S. Steneck

Abstract

The American lobster (Homarus americanus) supports the most valuable commercial fishery in the northeastern United States, thus the fishery is critical to Maine's economy. No systematic study has been done to collect information about, identify, and quantify the spatial dynamics of the Maine lobster fishery. This project helps to provide a better understanding of Maine's lobster fishery dynamics, and it will aid f'iture efforts to improve the stock assessment of Maine's lobster fishery. The analysis consists of three distinct parts: (1) comparison of data collected by two separate fishery dependent sampling programs; (2) spatial analysis of electronic logbook data; and (3) harbor gang temtoriality evidenced by electronic logbook data. The Maine Department of Marine Resources has established two fishery- dependent sampling programs: sea sampling and port sampling. Using data from 1998 - 2000, we evaluated the consistency in size composition and catch per unit of effort (CPUE) between the sea and port sampling programs. The overall pattern that emerged was a stronger relationship between sea and port sampling data over time from 1998- 2000, implying the two sampling programs were consistent in describing temporal variations in CPUE. This study suggests that either program should be sufficient in monitoring temporal trends of the lobster fishery. The American lobster fishery exhibits strong seasonal variations in spatial distributions of traps. In this study, we developed and applied two spatial statistical models, a moving window model and the empirical distribution function (EDF) model, to explore and describe data from the lobster fishery in order to quantify the spatial and temporal dynamics of fishing effort. This study suggests that fishing effort data were clustered rather than randomly distributed for the entire fishing season in the Stonington area. Therefore, we can state the data are not random in space or in time, but rather trap locations are clustered. Plots of nearest trap locations from May to December indicated that the trap locations were also not random at the smaller time scale. The nearest location distances of trap locations varied by month, but a general trend of decreased distances from May to September was observed, followed by increased distances from October to December. Electronic logbook data were displayed using GIs software to analyze the various boundaries observed by lobstermen. Management zone boundaries affected Stonington, Vinalhaven, Tenants Harbor, Spruce Head, New Harbor, and Long Island fishing areas to varying degrees in most seasons. Unofficial or territorial boundaries were assumed to have affected all areas, but some more obviously than others. Among these most affected were Stonington, Tenants Harbor, Port Clyde, Metinic, Round Pond, New Harbor, Cousins Island, and Harpswell. Territoriality among harbor gangs was shown to have at least partially structured the fishing areas observed through Thistle Marine data. These analyses have provided the DMR with important information on their current sampling programs, methodologies for future analysis of the fishery, and information affecting future management decisions and stock assessments.

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