A comparative study of American lobster fishery sea and port sampling programs in Maine: 1998-2000

The American lobster (Homarus americanus) supports the most valuable commercial fishery in the northeast United States. The fishery is critical to the Maine economy and society. To better manage this fishery, the Maine Department of Marine Resources has established two fishery-dependent sampling programs: sea sampling and port sampling. This, however, raises a question of consistency in describing the lobster fishery using data collected from the two programs. Using data from 1998 to 2000, we evaluated the consistency in size composition and catch per unit of effort (cpue) between the sea and port sampling programs. The strength of the statistical correlations between the two sampling programs varied depending upon the measure of cpue, the year, and whether time or area was the comparison variable. The overall pattern that emerged was a stronger relationship between sea and port sampling data over time from 1998 to 2000, implying the two sampling programs were consistent in describing temporal variations in cpue. However, mean yearly county cpue estimates showed significant differences between the two programs in all 3 years, suggesting an inconsistency in describing spatial variations in cpue between the two programs. Size composition reported by the two programs was very similar with significant differences in only 3 months out of the 21 tested. This study suggests that either program should be sufficient in monitoring temporal trends of the lobster fishery.