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5CJ9{1:J " _ 4 @ c.1 FINAL REPORT DISTRIBUTION AND ABUNDANCE OF HARBOR AND GRAY SEALS ACADIA NATIONAL PARK AREA Contract between the National Park Service and Maine Department of Sea and Shore Fisheries Contract No. 14-10-9-900-380 Period Covered - July 1, 1971 to July 1, 1973 Report Prepared by: DavidT. Richardson., Principal Investigator TABLE OF CONTENTS I .. Introduction 3 II - Present Abundance, Distribution ------------------------- 6 Abstract --------------------------------------------- 6 A. Study Area Description --------------------------- 8 B. Methods -----------------------'------------------- 11 C. Results: Aerial and Boat Census Methods ---------- 13 D. Discussion --------------------------------------- 23 E. Population Analysis -------------------------...:---- 27 III - Past Abundance, Distribution ---------------------------- 30 Abstract --------------------------------------------- 30 A. Methods ------------------------------------------ 31 B. Results 31 IV - Behavior, Reproduction ---------------------------------- 34 Abstract --------------------------------------------- 34 A. Behavior ----------------------------------------- 35 B. Reproduction ------------------------------------- 37 V - Seals and Man ------------------------------------------- 41 Abstract --------------------------------------------- 41 A. Hunting Habits: Relation to Conunercial.Fishing --- 41 B. Food Preferences --------------------------------- 43 C. Population Limiting Factors ---------------------- 44 D. Protection of Marine Mammals --------------------- 49 E. Recommendations ---------------------------------- 50 Acknowledgements -------------------------------------------- 54 Literature Cited -------------------------------------------- 55 References -------------------------------------------------- 57 Appendices: ' .. 1. Aerial Surveys (raw data) 2. P. L. 92-522 (Marine Mammal Protection Act of 1972) ... , «~i'2i'2 &1! I"~ XlIAII , ........ ,.".•. , ..... -., ~, ..... ----- 1*"< •... ,"' .. :..... -3- I - INTRODUCTION A two-year study of Harbor seals (Phoca vitulina) and Gray seals (Halichoerus grypus) on the Maine coast in the vicinity of Acadia National Park was initiated "in July 1971. The study was funded by the National Park Service, U. S. Department of Interior, Contract Number 14-10-9-900-380, I . and was contracted through the Maine Department of Sea and Shore Fisheries under the guidance of Marine Research Director, Robert Dow. David Richard- son was hired by the Department as a research biologist to carry out the study. The principal goals were: 1. To determine past distribution and abundance of the two seal species. 2. To determine present distribution and abundance, including a determination of feeding areas, resting or sleeping areas, whelping sites, and other significant seal habitat. 3. T·o find reasons for changes which have occurred in distribu tion and abundance, if any. 4. To determine if legislation is needed in order to protect present and future populations of harbor and gray seals and, if so, draft a bill which would adequately protect the two species. 5. To determine what opportunities now exist for park visitors to observe seals. 6. To provide a detailed explanatory· listing of research needs concerning the ecology of seals in the vicinity of Acadia National Park. In January, 1972, the first semi-annual report was submitted detailing the results of the first fifteen week summer field study. This report described in detail the study area, seal habits and ecology and factors thought most important in limiting the populations of seals. This first report also summarized the findings of two aerial surveys and boat surveil- ,. I -4- I lance techniques used in estimating the population and distribution of seals in the waters about Acadia National Park. I In July~ 1972, the second semi-annual report was submitted covering t ,f studies completed during the period January 1 to June 30~ 1972. This report detailed observations made of seals during the whelping period of mid-May ! to mid-June and summarized the findings of three completed aerial surveys j of the study area. The July report also summarized a proposed research r study of the hunting and feeding behavior of seals and its relation to commercial fishing and an expanded effort to census the seal populations of the Maine coast. The author is currently conducting these studies with support from the National Geographic Society and the Maine Department of Sea and Shore Fisheries. The third semi-annual progress report gave results of a thorough _aerial census completed in July, 1972 and also summarized census and dis- ). tribution data for the two summer field periods. Estimates of pup production were revised using fecundity~ pup~ and year-class mortality data from population studies of harbor seals carried out in the Canadian Maritime Provinces and in British Columbia. Updated information related to the past abundance of seals in the Acadia waters gained through personal interviews, a formal questionnaire, and extractions from a naturalist's field notes were dis- cussed. Finally, protection and management of Maine's seals afforded by the recent Marine Mammal Protection Act of 1972 were interpreted. This final report restates and discusses data pertinent to the afore- mentioned study goals regarding seal habits~ ecology and populations. In addition to presenting salient findings of the two summer field periods, this report recommends future research and encourages further use of wild life interpr-etive programs to heighten public awareness of marine mammals occurring in the area of the Park. rI~ -5- This report presents new data regarding the seasonal distribution of ~ray seals on the Maine coast and results of an aerial census of Blue Hill Bay on June 8, 1973. Given recent census flights of the coastal embayments and shoreline from Kittery to pemaquid Neck, some preliminary remarks are given regarding the relative importance of the waters about Acadia National Park as desirable breeding and resident habitat for harbor and gray seal populations. Each section of this report will begin with an abstract of pertinent findings and will then present the methodology, findings and analysis supporting that summary. -6- II - PRESENT ABUNDANCE, DISTRIBUTION Aerial and boat censuses of the waters about Acadia National Park, Mount Desert Island, reveal that 500 square nautical miles of water in Blue Hill, Frenchman and Jericho Bays and their approaches support an esti mated resident population of 1600 harbor seals and an estimated seasonal population of 40 gray seals.· An average density of 3.2 seals per square nautical mile and 26.3 seals per haulout area is estimated for the study area shown in Figures 1 and 2. Stated another way, there are 39.5 seals per linear nautical mile. The estimated numbers of seals and percent of the total population by regions are as follows: 484 or 29.7% in Blue Hill Bay north of Pond Island and Bass Harbor; 279 or 17.1% in the waters of Frenchman, Flanders and Sullivan Bays and the Skillings River; 127 or 7.8% in the waters and bays east and north of Schoodic Peninsula to Petit Manan; 720 or 44.1% in the Swans Island and Isle Au Haut archipeligo and Jericho Bay; 22 orl.3% in the waters of Somes Sound. The seasonal dis tribution of seals derived from four aerial censuses (Table 3 and Figure 3) indicates an apparent decline of approximately 9.~~ in both Blue Hill and Frenchman Bays during and following the May-June pupping season, and a con current increase of 16.4% in the numbers of seals in more offshore waters. Applying findings of Canadian maritime and west coast studies of harbor seals, it is estimated that from a postwhelping population of 1600 seals in 1972,20.47% or 328 pups (164 male and·164 female) were born to the study area that y~ar and that mortality rates differ for the sexes by age classes as predicted by the life table given (Table 6). -8- A. Study Area Description The study area includes all those open waters, bays, and rivers within the boundaries described as follows: (Refer to Figure 2, Study Area Map) Beginning at Petit Manan Point and running to Petit Manan f t Island to a point approximately N 440 22', W 67 0 52', thence 0 southwesterly (on a course 257 ) to a point southwest of Isle i! I Au Haut approximately N 43 0 56', W 68 0 42', thence northeasterly 0 (on a course 74 ) to a point northeast of Isle Au Haut approxi mately N 440 08', W 68 0 34', thence north-northeasterly (on a 0 0 course 39 0 ) to Naskeag Point approximately N 44 14', W 68 31'. The study area cited includes all the waters of Blue Hill and Frenchman Bays, the northeast waters of Isle Au Haut Bay, the eastern waters of Jericho Bay, and the smaller Gouldsboro and Dyer Bays east of Schoodic Point. The study area is approximately 41.5 linear nautical miles at its southern boundary, and the total water area, including upper bays and rivers, is estimated to be approximately 506 square nautical miles. For purposes of analysis, the total study area is divided into five major regions (refer to Figure 2). The hydrography of each is as follows: The Blue Hill Bay region (I) includes all the waters north of the 440 14' parallel (a line drawn from Naskeag Point to a point just north of Bass Harbor Light) and includes the more sheltered waters of the central bay, Blue Hill Harbor, Morgan Bay, Union River Bay, and the Western Bay east to Mt. Desert Narrows. These waters are protected from open ocean winds and swells and receive warm summer land breezes and

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