Year: 2003
Type: dissertation
Abstract: As human impact on marine ecosystems continues to grow, so too does the need for\nsound conservation and management strategies that are informed by science.\nCetaceans, the whales, dolphins and porpoises, epitomise this challenge, because they\nare hard to study, they have been heavily exploited in the past, and because some of\ntheir habitats, behaviours and life-history strategies make them acutely vulnerable to\nhuman activities. Unfortunately, research on free-ranging cetaceans in remote areas is\ncostly, and financial resources are limited.\nThe approach used in this thesis to acquire inexpensive quantitative information on\ncetacean populations and behaviour was to seek out platforms of opportunity.\nTourism and environmental education projects provided access to remote areas of\nimportance to cetaceans. The topic was explored in two main areas. First, studies\nwere conducted to investigate the use of ships of opportunity in estimating distribution\nand abundance, namely of Antarctic baleen whales. The second area of interest was\nthe effect of boats on killer whales in the northeast Pacific.\nPlatforms of opportunity proved valuable for collecting data to model the role of\nmeasurement error on abundance estimation. Measurement error was found to be a\npotential source of bias in four distance estimation experiments. Platforms of\nopportunity could be used to train observers on protocols, and to learn to use range-\nfinding photogrammetric equipment well before conducting dedicated surveys, which\nwould eliminate this source of bias, as well as estimating abundance in some cases.\nAbundance and distribution of three whale species were modelled using data collected\naboard Antarctic tourist ships. Spatial modelling techniques were used to model\ndistribution of minke, fin and humpback whales using line-transect data collected from\na survey that could not be randomised. Strong gradients in animal density were\npredicted, which could be used to inform future surveys. In the meantime, rough\nestimates of abundance were obtained, and this approach shows promise for other\nareas where lack of resources makes systematic surveys prohibitively expensive.\nA government-funded environmental education project provided logistical support for\ntwo studies that dealt with effects of boats on killer whale behaviour. One quantified\nthe extent to which a particular style of whalewatching was disruptive to whale\nbehaviour, and commercial whalewatchers agreed to halt this activity. The other\nfound that a protected area conferred benefit to killer whales, even though it protects\nonly a fraction of the whales' habitat for a fraction of the year.\nThe thesis contains four case studies that illustrate how inexpensive methods may be\nused to obtain practical quantitative information to aid decision-making about\nconservation and management of wild cetaceans that interact with (i.e.,\nwhalewatching), compete with (i.e., fishing) or are exploited by (i.e., whaling)\nhumans.
Author: Rob Williams
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life below water
Open Access status: green
OpenAlex ID: W1479840052