by Deborah Thiele, IWC
The International Convention for the Regulation of Whaling, 1946 (ICRW) was adopted "to provide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry". As noted by Gambell (1993), interpretation and application of the Convention has undergone significant change due to "changing perceptions of how natural renewable resources should be managed and utilised". Gambell (1993) outlined a number of factors which had contributed to this evolution in the ICRW: developments under the United National Conference on the Law of the Sea (UNCLOS); increasing use of the precautionary principle in management; heightened awareness of the vulnerability of whales to over-exploitation through better scientific understanding and more exact mathematical analysis; and greater awareness by the public of environmental conservation.
The 1990's have seen profound changes in the development of ecological theory and practice as it relates to the conservation and management of marine ecosystems and marine species. These advances can also be seen within the International Whaling Commission (IWC) through it's Scientific Committee (SC), resulting in increased emphasis on ecology.
The changing emphasis has been most noticeable in the Small Cetaceans Sub Committee of the SC, and the establishment of a new Standing Working Group on Environmental Concerns (i.e. Ballance et al 1997, Fiedler et al 1997, Papastavrou and van Waerebeek 1997, Thiele et al 1997, Tynan and DeMaster 1997, Kasamatsu and Kamura 1998, Haug et al 1999, Moore et al 1999, Kasamatsu et al 1999). Much of the work of these groups is directed at understanding how human activities (particularly climate change) and physical and biological processes in cetacean habitat and ecosystems affect the distribution, movements, social behaviour and health of individuals and populations.
Resolution 1995-10 from the Commission resulted in a workshop on climate change and cetaceans, held in March 1996. The broad purpose of the workshop was to identify research that might enable the eventual prediction of the effects of environmental change on cetaceans, so that this information could be used for conservation and management. The workshop made research recommendations and noted that appropriate research must be multidisciplinary and have a multinational focus, and strongly recommended that the SC (and the Commission) consider ways to facilitate this work.
Two related workshops have since been held, at La Jolla in 1997 (SC/49/Rep5) and Edinburgh in March 1999. These workshops were held in response to directives from the Commission to further refine objectives and develop proposals for collaborative work in the Southern Ocean with the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and the International Global Ocean Ecosystem Dynamics (GLOBEC) program under the IWC Southern Ocean Whale Ecosystem Research (SOWER) program. The research program developed at the Edinburgh SOWER 2000 workshop (SC/51/Rep2) outlined a long-term aim:
"define how spatial and temporal variability in the physical and biological environment influence cetacean species in order to determine those processes in the marine ecosystem which best predict long-term changes in cetacean distribution, abundance, stock structure, extent and timing of migrations and fitness"
This objective is being pursued through collaboration with GLOBEC and CCAMLR using a multidisciplinary ecosystem approach to data collection, analysis and modelling.
Three specific objectives have been identified under the framework of the overall objective:
Characterise foraging behaviour and movements of individual baleen whales in relation to prey characteristics and physical environment.
Relate distribution, abundance and biomass of baleen whale species to same for krill in a large area in a single season.
Monitor interannual variability in whale distribution and abundance in relation to physical environment and prey characteristics.
The IWC has recognised that it lacks the data to determine baseline patterns of distribution (and the physical and biological processes responsible for such patterns) of baleen whales from which to judge the potential effects of climate change. Given its role in the management of whale populations, this is seen as a critical gap to fill.
Until recently, few marine research cruises in the Southern Ocean have attempted to simultaneously collect data on both cetaceans and their prey with the objective of integrating these and other biological and physical data to investigate linkages at fine and meso scales. However, where this has been attempted recently, significant insights into ecosystem processes have been made. SO-GLOBEC studies provide the ideal platform for such long-term studies, where scientists from a range of disciplines can conduct intensive focussed studies, within the framework of international collaboration and long term synthesis of data and planning provided by GLOBEC.
Given the shared objectives among the IWC, GLOBEC and CCAMLR, the IWC has determined that the most effective means of investigating these ecological issues is to focus a considerable body of cetacean research within the framework provided by these programs.
The GLOBEC process studies provide an ideal platform to further our understanding of the linkages between particular baleen whale species and krill dynamics. This will allow us in the future to more accurately interpret cetacean, krill and oceanographic data for distribution patterns of krill and cetaceans at a range of scales with oceanographic processes.
Cetacean ecology background
In parallel with the changes in emphasis in the IWC there has been a recognition of the need for rigorous and carefully directed research reflecting an increasingly sophisticated appreciation of the complexity of ecosystems in ecological theory (Wu and Loucks 1995). The oceans were once assumed to be relatively homogeneous landscapes over large spatial and temporal scales. As a result, many studies of long-lived marine mammals (i.e. abundance estimate surveys for whales) did not concern themselves with investigating the existence of, or determining the effects of, linkages between patterns of distribution and abundance of these animals and physical and biological patterns and processes. Ecology has since recognised that heterogeneity in patterns of organisms is the norm, and that this reflects complexity in processes of interaction between organisms and their environment (Johnson et al 1992). That (spatial and temporal) heterogeneity in landscapes drives much of this complexity is probably as true for the oceans as it is in terrestrial landscapes (e.g. Bax 1998; Steele 1998).
Not only are the oceans heterogeneous, but this heterogeneity is functional (i.e. it has ecological meaning for the organism) at a range of scales. Also, processes operating at different scales are unlikely to be independent (i.e. cascading effects between scales). For example, in the case of foraging by marine predators such as baleen whales and seabirds, patchiness in food resources may be continuous, rather than discrete, and over an hierarchical continuum of scales (Russell 1992, Pinel-Alloul 1995, Hofmann and Lascara 1998, Tynan 1998, Steele 1998). As such, patterns of association between predator and prey may be subtle, and not evident when examined at a single spatial scale (e.g. Reitsch & Veit 1994, Logerwell et al 1998).
Given the palaeontological view of the links between the development of the Antarctic Circumpolar Current in the Early Oligocene (35ma) and the evolution of baleen whales in response to the changed physical structure of the oceans and the concentration of food resources (Fordyce 1977, 1980, 1991), physical processes are likely to have a significant influence on the ecology of Southern Ocean baleen whales. In turn this is likely to apply at a range of scales, across and between oceans and systems (given the influence of the oceanographic processes in the Southern Ocean on major currents and processes in the southern Pacific, Atlantic and Indian Oceans; and the migration of baleen whale species through these regions) down to the finest scale of what is happening between prey and predator at the level of individual patch and whale (Steele 1989). The extent and strength of these linkages, and the extent to which different processes have in the past and still do drive the life history of baleen whales is as yet unknown.
The geometry of turbulence in important oceanic physical processes may
drive, and be reflected in the character (i.e. continuous, multiple-scaled)
of ecological linkages (Russell et al. 1992, Wu and Loucks 1995,
Steele 1989). For example we know that global and regional ocean-atmosphere
interactions affect the seasonal extent of sea-ice in the Antarctic (Nicol
and Allison 1997, de la Mare 1997), and that this in turn affects the distribution
and extent of areas of high productivity and prey distribution in that
region (Hewitt 1997, Ichii et al 1998, Loeb et al 1997, Nicol
al 2000) and in other regions (e.g. Papastavrou and van Waerebeek 1997),
and that this in turn will likely affect the timing of migrations of baleen
whales, their distribution on the feeding grounds, and the distribution
and movements of their prey (Hofmann et al 1998, Tynan 1998, Thiele
al 2000, de la Mare 1997).
The collaborative program has been developed in order that IWC research objectives, which are similar to the GLOBEC objectives outlined in the 'Implementation Plan', could be achieved through integration with planned CCAMLR and GLOBEC programs in the Southern Ocean for the 1999/2000 and 2000/2001 and future seasons.
For instance, one of the relevant GLOBEC primary regional science program initiatives (marine population variability and its relationship to environmental variability in the Southern Ocean) is a key objective for the IWC.
Cetacean data sets collected throughout this collaboration will potentially contribute to the interpretation of krill acoustic data series and the determination of linkages between top predators, prey and the environment. At present the focus region for this work is the Southern Ocean due to the international nature of existing national programs, and the focus on ecosystem management and international collaboration in association with CCAMLR and SO GLOBEC. IWC collaboration with GLOBEC programs in other regions will also be pursued.
Collaboration between IWC and CCAMLR commenced in the 1999/2000 Antarctic season with IWC research teams on United Kingdom, USA and Japanese CCAMLR projects in the Antarctic Peninsula region.
In the first half of 2001 the IWC will participate in GLOBEC studies to be conducted by national programs from the USA (Gould mooring deployment and Palmer survey cruise) and Germany (Polarstern survey cruise). Cetacean observers from the IWC Scientific Committee will conduct sighting surveys alongside the multidisciplinary national programs involved in the Globec year round study. These platforms will be used to produce a time series of continuously collected cetacean data simultaneous with krill and other physical and biological data suites.
The cetacean data collection and analysis will potentially complement krill process studies and contribute towards understanding the dynamics of krill swarms and life strategies. Prey species evolution and life strategies are shaped by a complex series of factors, including predator?s feeding strategies and life histories. Developing a deeper knowledge of baleen whale feeding ecology is dependent upon integrating cetacean studies with prey and physical processes. While a more comprehensive understanding of krill requires knowledge of the complex interactions and dynamics between both predator and prey, in the past and present.
It is hoped that the cetacean data will contribute to the legacy of GLOBEC well into the future by providing high quality standardised data series for cetaceans continuous with a wide range of other biological and physical parameters.
Standard IWC methodology for multidisciplinary studies will be used throughout all GLOBEC collaborative cruises. This will involve experienced cetacean researchers conducting line transect sightings survey throughout daylight hours in acceptable weather conditions. Data are recorded on a laptop based tracking program (Wincruz), and photo and video records are also obtained for species identification, group size verification, feeding (and other behaviour), ice habitat use and individual identification.