Download or read book 2012 Population Estimate for the Harbor Seal Phoca Vitulina Concolor in New England Waters written by Gordon T. Waring and published by . This book was released on 2015 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: This survey was conducted to obtain an abundance estimate for the New England harbor seal (Phoca vitulina concolor) population, as the previous estimate (2001) was outdated for stock assessment purposes. Aerial photographic surveys and radio tracking of harbor seals on ledges along the Maine coast were conducted during the pupping period in late May 2012. Twenty-nine harbor seals (20 adults and 9 juveniles) were captured and radio-tagged prior to the aerial survey. Of these, 18 animals (6 adult males, 6 adult females, 2 juvenile males and 4 juvenile females) were available during the survey to develop a correction factor for the fraction of seals not observed. The estimate of harbor seal abundance in 2012 was 75,834 (11,625 standard deviation [sd]; 0.153 coefficient of variation [CV]). Nmin, the lower 20% confidence limit, was 66,884. The 2012 point estimate is 24% lower than the 99,340 reported for 2001. Possible reasons for the lower estimate include changes in survey design, differences in the age/sex ratio of radio-tagged seals available for obtaining a correction factor, differences in harbor seal distribution between 2001 and 2012, and/or that the population has actually declined. [doi:10.7289/V5ZC80VT (http://dx.doi.org/10.7289/V5ZC80VT)]
Download or read book Ecology and Conservation of Pinnipeds in Latin America written by Gisela Heckel and published by Springer Nature. This book was released on 2021-03-28 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pinnipeds are marine mammals that include eared seals, true seals, and walruses. This book presents detailed reviews on the ecology and conservation of 10 pinniped species along the coasts and islands in Latin America, from Mexico to Chile and Argentina. Topics covered include their population dynamics, trophic ecology, reproduction, and behavior. In addition, the book addresses major conservation issues regarding climate change, interaction with fisheries, ecotourism, and other human activities.
Download or read book Estimating Population Size of Pacific Harbor Seals Phoca Vitulina Richardsi at Children s Pool Beach in La Jolla California Using Photo identification written by Traci A. Linder and published by . This book was released on 2011 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Children's Pool Beach in La Jolla, CA is a Pacific harbor seal (Phoca vitulina richardsi) rookery at the center of a large legal controversy. Due to the heated contention surrounding this rookery, very few scientific studies have been done on the population of harbor seals that use this haul-out site. Maximum daily haul-out counts rarely exceed 200, and management decisions have been framed around the assumption of a largely resident population of no more than approximately 250 seals. In this study I used photo-identification and mark-recapture methods to estimate the total population of Pacific harbor seals that used Children's Pool Beach as a haul-out site during January - October 2008. I photographed the ventral surfaces of adult harbor seals at Children's Pool Beach, and then entered each good to high quality photograph into an interactive computer-assisted photograph-matching system for individual identification. Each individual identification was confirmed by both a trained volunteer and myself, resulting in a 4% visual matching error rate. After analysis concluded, 480 unique adult harbor seals were individually identified after applying the 4% visual matching error rate. Abundance estimation was calculated using the Chapman-Petersen capture-recapture model. My calculations yielded a population estimate of 596 individuals during January - October 2008, which is two to three times larger than previously believed. These findings suggest a population that is at least partially open with considerable coastal movement, suggesting that Children's Pool Beach is potentially part of a regional network of interconnected haul-out site.
Download or read book Atlantic Herring Clupea Harengus Harengus Fishery Management Plan FWP written by and published by . This book was released on 1999 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diet Composition of Harbor Seals Phoca Vitulina Concolor Residing at Mount Desert Rock Maine written by Lauren Broderick and published by . This book was released on 2011 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Northwest Atlantic population of harbor seals (Phoca vitulina concolor) are known as opportunistic feeders and are found from the Gulf of St. Lawrence to North Carolina. Since the enactment of the Marine Mammal Protection Act (MMPA) of 1972, there have been concerns surrounding the steady population growth and perceived competition for fish between seal populations and fisheries stocks. This study was conducted to investigate changes in harbor seal prey preferences by collecting harbor seal scat samples during the summers of 2007, 2008, and 2010 on Mount Desert Rock in Maine. Diet composition was determined using traditional hard-part analysis of fish otoliths and cephalopod beaks. Diet indices used to evaluate scat samples were Relative Abundance (RA) and Percent Biomass (PB). Silver hake (Merluccius bilinearis) and Atlantic herring (Clupea harengus) were the most abundant species found in the seal diet in 2007 and Acadian redfish (Sebastes fasciatus) and Atlantic herring were the most abundant species in 2008. Atlantic herring age class 5 and 6 accounted for 76% of the ingested age class abundance for 2007, while age class 4 was 59% in 2008. Cephalopod beaks from the short-finned (Illex illecebrosus) and long-finned (Loligo pealei) squid relative abundance ingested was greater than the relative abundance found in the trawls. Squid consumption increased linearly from 2000 to 2010 (R2= 0.9188; P = 0.001). Harbor seals selectively chose to prey on squid species and Atlantic herring while feeding on Silver hake opportunistically. Overall the diet of harbor seals residing at Mount Desert Rock depicts that of a generalist feeder. Continued long term research into harbor seal diet would allow for a more complete picture of consumption trends instead of a snapshot in time.
Download or read book Status Review written by John L. Sease and published by . This book was released on 1992 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Population Biology of the Harbor Seal Phoca Vitulina Richardsi in the Waters of the State of Washington 1976 1977 written by Murray L. Johnson and published by . This book was released on 1983 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Population Evaluation of the Harbor Seal P hoca Vitulina Richardi in the Waters of the State of Washington written by Murray L. Johnson and published by . This book was released on 1977 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Feeding Habits of Harbor Seals Phoca Vitulina Concolor Along the Coast of Cape Cod Massachusetts and the Northern Gulf of Maine written by Amy Ferland and published by . This book was released on 1999 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Distribution and Abundance of Harbor Seals Phoca Vitulina Concolor in the Woods Hole Region written by Pieter Andrew Philip DeHart and published by . This book was released on 2002 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of a Unique Coloration of Harbor Seal Phoca Vitulina Concolor in the Northwest Atlantic Ocean written by Douglas M. Burn and published by . This book was released on 1982 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Distribution and Abundance of Harbor Seals Phoca Vitulina Concolor and Gray Seals Halichoerus Grypus in Southern New England Winter 1998 summer 1999 written by Margaret E. Barlas and published by . This book was released on 1999 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Harbor Seal Phoca Vitulina Biology and Management in Alaska written by A. Anne Hoover-Miller and published by . This book was released on 1994 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Abundance and Distribution for Pacific Harbor Seal Phoca Vitulina Richardsi on the Coast of California written by Doyle Alan Hanan and published by . This book was released on 1996 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gray Halichoerus Grypus and Harbor Seal Phoca Vitulina Bycatch and Depredation in New England Sink gillnet Fisheries written by Laura N. Sirak and published by . This book was released on 2015 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine mammals interact with commercial fisheries via competition for resources, depredation (feeding on fish caught in gear), entanglement, and bycatch in fishing gear. In New England, gray seals (Halichoerus grypus) and harbor seals (Phoca vitulina) are often taken as bycatch in sink-gillnet fisheries and are believed to depredate fish in gillnets. As seal populations increase, interactions with fisheries are also likely to increase, affecting both seal stocks and the New England fishing industry. This study aims to understand seal bycatch in the New England sink-gillnet fisheries by identifying the spatial and temporal trends in bycatch as well as the characteristics of seals that are taken most frequently as bycatch. Depredation is also a concern in the commercial fishing industry, however, there is some controversy among fishermen and scientists concerning the identification of the species responsible for depredation (e.g. seal vs. spiny dogfish (Squalus acanthias)). Therefore, a protocol for identifying seal and spiny dogfish depredation was developed and used to identify depredation in a small-scale study of the sink-gillnet fishery targeting skate. Data from the Northeast Fisheries Observer Program (NEFOP) from 2005-2013 were analyzed to assess seal bycatch in the Northeast sink-gillnet fishery. Male seals were taken significantly more frequently than females, with young of the year most commonly occurring as bycatch. Areas where seals were taken in New England shifted seasonally, generally following the annual life history of each seal species. Gray seal bycatch showed an increasing trend over the years of study, with highest bycatch occurring in the spring in areas closest to haul out sites: Muskeget and Monomy Island, MA, USA. Harbor seal bycatch was much more variable between years, with highest bycatch occurring in the winter near major harbor seals haul out sites along the southern Maine coast and southeastern Massachusetts. This study was a crucial step to understanding the complexities of seal-fishery interactions in New England. In order to mitigate damage from depredation, it is important to know the source of the damage. Characteristics of seal and spiny dogfish bites were identified using foam imprints from jaws and bites by captive animals in the soft tissue of fish. Measurements from bite imprints and damaged fish were used to develop a protocol for identifying damage in the field. In general, dogfish bites were clean (flesh completely removed), circular in shape, and wider than long (bite ratio (bite length/bite width) 0.6), whereas seal bites were ragged (flesh not completely removed, but partially torn from the bite), retangular or trapezoidal in shape, and usually longer than wide or equal in length and width (bite ratio 0.7). This protocol was used to identify damaged catch observed on a commercial gill-net fishing vessel targeting skate in New England waters June - August 2014. In this small-scale study, dogfish bites were identified as the damage source significantly more frequently than seal bites (Multifactor ANOVA: F [subscript, degree of freedom]=2,66 = 9.306, p=0.0003; Tukey HSD: p
Download or read book Marine Mammals in a Changing World written by Alexander J Werth and published by Mdpi AG. This book was released on 2022-01-29 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite tremendous advances in our understanding of marine mammals over the past several decades, numerous unanswered questions remain. These include fundamental questions in every biological discipline as well as other areas of science, including basic and applied chemistry and physics. Current studies of marine mammals reflect major improvements in technology as well as equally large changes in the ocean environment. Contributions for this Special Issue were invited in all areas of marine mammal research, especially those focusing on one (or both) of two themes: changing technological advances and changes in ocean habitats affecting marine mammals (including but not limited to changes in climate/temperature; ocean acidification; noise, plastic, or chemical pollution; vessel traffic and ship strikes; pathogenic viruses and microbes; trophic and salinity changes; fisheries impacts; habitat destruction; and related topics). The five articles published in this Special Issue focus on diverse areas of marine mammal research and health, including ecology, conservation, population biology and management, behavior, habitat and distribution, genetics, evolution, physiology, anatomy, acoustics, effects of noise and pollution, and new technologies.
Download or read book A Little Less Arctic written by Steven H. Ferguson and published by Springer Science & Business Media. This book was released on 2010-05-30 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Arctic Canada, Hudson Bay is a site of great exploration history, aboriginal culture, and a vast marine wilderness supporting large populations of marine mammals and birds. These include some of the most iconic Arctic animals like beluga, narwhal, bowhead whales, and polar bears. Due to the challenges of conducting field research in this region, some of the mysteries of where these animals move, and how they are able to survive in such seemingly inhospitable, ice-choked habitats are just now being unlocked. For example, are polar bears being replaced by killer whales? This new information could not be more salient, as the Hudson Bay Region is undergoing rapid environmental change due to global warming, as well as increased pressures from industrial development interests. A Little Less Arctic brings together some of the world’s leading Arctic scientists to present the current state of knowledge on the physical and biological characteristics of Hudson Bay.
