scholarly journals Estimating the Abundance of Marine Mammal Populations

2021 ◽  
Vol 8 ◽  
Author(s):  
Philip S. Hammond ◽  
Tessa B. Francis ◽  
Dennis Heinemann ◽  
Kristy J. Long ◽  
Jeffrey E. Moore ◽  
...  

Motivated by the need to estimate the abundance of marine mammal populations to inform conservation assessments, especially relating to fishery bycatch, this paper provides background on abundance estimation and reviews the various methods available for pinnipeds, cetaceans and sirenians. We first give an “entry-level” introduction to abundance estimation, including fundamental concepts and the importance of recognizing sources of bias and obtaining a measure of precision. Each of the primary methods available to estimate abundance of marine mammals is then described, including data collection and analysis, common challenges in implementation, and the assumptions made, violation of which can lead to bias. The main method for estimating pinniped abundance is extrapolation of counts of animals (pups or all-ages) on land or ice to the whole population. Cetacean and sirenian abundance is primarily estimated from transect surveys conducted from ships, small boats or aircraft. If individuals of a species can be recognized from natural markings, mark-recapture analysis of photo-identification data can be used to estimate the number of animals using the study area. Throughout, we cite example studies that illustrate the methods described. To estimate the abundance of a marine mammal population, key issues include: defining the population to be estimated, considering candidate methods based on strengths and weaknesses in relation to a range of logistical and practical issues, being aware of the resources required to collect and analyze the data, and understanding the assumptions made. We conclude with a discussion of some practical issues, given the various challenges that arise during implementation.

2003 ◽  

Marine Mammals: Fisheries, Tourism and Management Issues brings together contributions from 68 leading scientists from 12 countries to provide a comprehensive, up-to-date review on the way we manage our interactions with whales, dolphins, seals and dugongs. The book examines how we have fared conserving the world’s marine mammal populations, with a focus on the key issues of fisheries and tourism. From a unique southern hemisphere perspective, the authors consider how science informs the culling debate, how wild fisheries and aquaculture interact with marine mammal populations and how we might manage the effects of whale, dolphin and seal watching industries. The authors also address other issues such as the way in which ethics, genetics, acoustics, ecosystem models and pollution influence the management and conservation of marine mammals. Marine Mammals is an invaluable and accessible resource for all those involved with marine mammals, including scientists, managers, policy makers, industry representatives and students. Winner of a 2004 Whitley Award.


2020 ◽  
Vol 15 (3) ◽  
pp. 211-235
Author(s):  
Josephine Chazot ◽  
Ludovic Hoarau ◽  
Pamela Carzon ◽  
Jeanne Wagner ◽  
Stéphanie Sorby ◽  
...  

Whale-watching activities provide important socioeconomic benefits for local communities and constitute powerful platform incentives for marine mammals' protection or more broadly marine environments. However, these activities can cause adverse effects on targeted populations, with considerable downside associated risks of injuries and fatality for whale watchers during inwater interactions. France with its overseas territories has the second largest exclusive economic zone (EEZ), in which more than half of existing cetacean species are encountered. In these territories, recreational and commercial whale watching, including swim-with cetacean activities, have recently developed. Yet few studies focused on these activities and their associated impacts across French territories, leading to an unclear assessment of the situation. To address this issue, we reviewed cetaceans' occurrence within the French EEZ, whale-watching industry, targeted species, local management of marine mammal-based tourism activities, and regulations in France mainland and some overseas territories (Reunion Island, Mayotte, and French Polynesia). Fortyeight species are encountered in the French EEZ, and 15 are targeted by whale-watching activities. A total of 185 operators, including 34% offering swim-with-cetaceans tours, offered trips in France and overseas in 2019. While several more or less restrictive regulations exist locally, our results indicate that French's national legal framework for marine mammals' protection remains inadequate and insufficient to cope with the recent development of this activity. As conservation biologists, managers, and stakeholders from these French territories, we cooperated to provide general guidelines for a sustainable development of whale watching at a national scale. We urge (1) to legally acknowledge and regulate whale-watching commercial activities; (2) to create a national legal framework regarding whale watching and swim-with marine mammals practices, while accounting for local distinctiveness and disparities across regions; (3) to conduct more research to evaluate local short- and long-term impacts on targeted marine mammal populations as well as the socioeconomic benefits; and (4) to reinforce synergetic relations between the different stakeholders.


2021 ◽  
Vol 8 ◽  
Author(s):  
Michael Gilbert Mwango’mbe ◽  
Jane Spilsbury ◽  
Steve Trott ◽  
Judith Nyunja ◽  
Nina Wambiji ◽  
...  

In 2011, several non-governmental and government agencies established the Kenya Marine Mammal Network (KMMN) to provide a platform for the consistent collection of data on marine mammals along the Kenyan coast, identify areas of importance and engage marine users and the general public in marine mammal conservation. Prior to the KMMN, relatively little was known about marine mammals in Kenya, limiting conservation strategies. The KMMN collects data nationwide through dedicated surveys, opportunistic sightings and participative citizen science, currently involving more than 100 contributors. This paper reviews data on sightings and strandings for small cetaceans in Kenya collated by the KMMN. From 2011 to 2019, 792 records of 11 species of small cetaceans were documented. The most frequently reported inshore species were the Indo-Pacific bottlenose dolphin and Indian Ocean humpback dolphin. Offshore species, included killer whales, short-finned pilot whale and long-snouted spinner dolphin. Indo-Pacific bottlenose dolphins, long-snouted spinner dolphins, striped dolphins and Risso’s dolphins were recorded through stranding reports. The efforts of the KMMN were disseminated through international meetings (International Whaling Commission, World Marine Mammal Conference), national status reports, outreach and social media. Data has also supported the identification of three IUCN Important Marine Mammal Areas and one Area of Interest in Kenya. Further research is needed to improve estimates of cetacean abundance and distribution, particularly in unstudied coastal areas, and to assess the extent of anthropogenic threats associated with fisheries, coastal and port development, seismic exercises and unregulated tourism. The expansion of the network should benefit from the participation of remote coastal fishing communities, government research agencies, tourism and seismic operations, among others. The KMMN demonstrated the value of dedicated and citizen science data to enhance marine mammal conservation strategies to boost awareness and eco-tourism and to bring the public and science closer together, promoting research and effective conservation efforts.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242273
Author(s):  
Jean M. Herrman ◽  
Jeanine S. Morey ◽  
Ryan Takeshita ◽  
Sylvain De Guise ◽  
Randall S. Wells ◽  
...  

Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.


10.4085/11015 ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Mark R. Lafave ◽  
Glen Bergeron ◽  
Connie Klassen ◽  
Kelly Parr ◽  
Dennis Valdez ◽  
...  

Context: A published commentary from 2 of the current authors acted as a catalyst for raising some key issues that have arisen in athletic therapy education in Canada over the years. Objective: The purpose of this article is to report on the process followed to establish a number of consensus statements related to postsecondary athletic therapy education in Canada. The consensus statements should act as a future plan for entry-level athletic therapy education. Design: Content validation for consensus statements. Setting: Video-conference meetings at 7 Canadian postsecondary colleges/universities. Patients or Other Participants: Canadian Athletic Therapists' Association (CATA) program directors and CATA leaders from education, certification, and program accreditation committees. Main Outcome Measure(s): A Delphi method and modified Ebel procedure were used to gather opinions from participants about athletic therapy education. Results: We created 10 consensus statements, with a series of caveats that are presented in this article. All components received at least 80% consensus from the expert validation group. Conclusions: The final Education Task Force Report was created and content was validated by a group of experts in the topics associated with every consensus statement. The final report was presented to the CATA Board of Directors for adoption and implementation.


2019 ◽  
Vol 116 (52) ◽  
pp. 26682-26689 ◽  
Author(s):  
Jan Ohlberger ◽  
Daniel E. Schindler ◽  
Eric J. Ward ◽  
Timothy E. Walsworth ◽  
Timothy E. Essington

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North American range. This raises the question of whether size-selective predation by marine mammals is generating these trends in life-history characteristics. Here we show that increased predation since the 1970s, but not fishery selection alone, can explain the changes in age and size structure observed for Chinook salmon populations along the west coast of North America. Simulations suggest that the decline in mean size results from the selective removal of large fish and an evolutionary shift toward faster growth and earlier maturation caused by selection. Our conclusion that intensifying predation by fish-eating killer whales contributes to the continuing decline in Chinook salmon body size points to conflicting management and conservation objectives for these two iconic species.


Oryx ◽  
2007 ◽  
Vol 41 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Mark P. Simmonds ◽  
Stephen J. Isaac

Climate change is now known to be affecting the oceans. It is widely anticipated that impacts on marine mammals will be mediated primarily via changes in prey distribution and abundance and that the more mobile (or otherwise adaptable) species may be able to respond to this to some extent. However, the extent of this adaptability is largely unknown. Meanwhile, within the last few years direct observations have been made of several marine mammal populations that illustrate reactions to climate change. These observations indicate that certain species and populations may be especially vulnerable, including those with a limited habitat range, such as the vaquita Phocoena sinus, or those for which sea ice provides an important part of their habitat, such as narwhals Monodon monoceros, bowhead Balaena mysticetus and beluga Delphinapterus leucas whales and polar bears Ursus maritimus. Similarly, there are concerns about those species that migrate to feeding grounds in polar regions because of rapidly changing conditions there, and this includes many baleen whale populations. This review highlights the need to take projected impacts into account in future conservation and management plans, including species assessments. How this should be done in an adequately precautionary manner offers a significant challenge to those involved in such processes, although it is possible to identify at this time at least some species and populations that may be regarded as especially vulnerable. Marine ecosystems modellers and marine mammal experts will need to work together to make such assessments and conservation plans as robust as possible.


2016 ◽  
Vol 39 (1) ◽  
pp. 72-94 ◽  
Author(s):  
Kenneth Cruickshank ◽  
Jan Wright

The current discourse in Australian languages education is that if children study languages in the early years, then languages uptake in secondary schools will increase. There has been little coherent data collection and analysis, however, to support or challenge this discourse. This article draws on findings from an ARC Linkage study in NSW involving cross-sectoral languages study data (2007 to 2014), school case studies and teacher surveys to explore links between primary school provision, uptake and continuation to Year 12. The study focused on 348 schools in two demographic areas – inner city Sydney and Wollongong. The three key findings were that uptake in upper secondary school is primarily a factor of scaling for tertiary entry; that socioeconomic status (SES) is a key factor in K-10 languages provision and uptake and that community languages have been marginalised from day schools. The paper argues that language programs and policy need to be based not on common beliefs but on consistent data collection. It also argues that two key issues need to be addressed to reverse the decline in language study: a review of the tertiary scaling of languages and government strategies which work from issues of equity of access for students in lower-SES schools.


2006 ◽  
Vol 12 (1) ◽  
pp. 31 ◽  
Author(s):  
Catherine Bell ◽  
Peter Shaughnessy ◽  
Margie Morrice ◽  
Bob Stanley

Observers from the Australian Fisheries Management Authority worked on randomly chosen Japanese long-line vessels in the Australian Fishing Zone (AFZ) between 1980 and 1997. Observer reports (n = 451) were inspected for interactions or sightings of marine mammals. An operational interaction was defined as an activity or behaviour that involved direct contact between a marine mammal and fishing gear, bait, target fish or bycatch, or indications that the marine mammal was feeding. A sighting was defined as the recording of marine mammals that passed the vessel without changing course and/or did not appear to interact with the vessel or its gear. Observers witnessed 23 interactions and made another 44 sightings of marine mammals. A further 24 interactions and sightings were relayed by crew members. Killer whales were reported most frequently: most incidences of fish being damaged, taken or frightened away were attributed to them. Eleven marine mammals were caught: two died, seven were released, and the fate of two others was not recorded. Between 1991 and 1996, when observer coverage was 11.5% overall in the AFZ, the incidence of interactions was 1.71 per million hooks set. The estimated number of interactions in that seven-year period was 157 in the AFZ. Since 1997, the long-line fishery has been conducted by Australian vessels, primarily off the east coast of mainland Australia in warm-temperate waters. A higher proportion of interactions can be expected with killer whales and short-finned pilot whales in these waters, and fewer with seals.


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