Thomas Okey | University of Victoria (original) (raw)

Papers by Thomas Okey

Proceedings of the National Academy of Sciences of the United States of America, Jun 3, 2024

Frontiers in Ecology and the Environment, Oct 1, 2004

Ecological Economics, Apr 1, 2005

The model presented recently in this journal byBazin et al. (2004) indicates that b...the quality... more The model presented recently in this journal byBazin et al. (2004) indicates that b...the quality of theenvironment can be improved when taxationincreasesQ, as long as the magnitude of the environ-mental tax is sufficient enough so that, b...thefinancial constraints imposed upon the consumerbecome too great and thus limit his desire to consumefurtherQ. In addition, Bosquet’s (2000) survey ofenvironmental tax reform examples indicated thatshifts in tax burdens from socially desirable activities(e.g., employment) to socially undesirable activities(e.g., pollution, resource depletion, and waste) canlead to a ddouble dividendT where both environmentaland economic values are improved. In terms of fueltaxes, the weight of evidence from theory, empiricalstudies, and history indicates their strong potential forsimultaneous enhancement of environmental quality,economic growth, and quality of life, as long as thesetaxes are sufficient and structured appropriately.Bazin et al. (2004) emphasize in their modelingthat the introduction of a small tax or penalty canactually increase the consumptive behaviors of peoplewho perceive the tax to be payment for the right toconsume, pollute, or otherwise degrade public resour-ces. That is to say, the environmental responsibility ofindividual actors can actually decrease with theintroduction of a tax or penalty if the penalty is toosmall. The main empirical example of this compensa-tory bcrowding out effectQ cited by Bazin et al. (2004)was the observation by Gneezy and Rustichini (2000,p. 3) of b...a steady increase in the number of parentscoming lateQ to pick up their children from day-careafter a small late penalty was introduced.It is reasonable to expect that imposing a nominalpenalty would erode parents’ punctuality at a day-carecentre, as these parents might perceive such a fine tobe a price for extracurricular services. We expect nosuch erosion of responsible behavior to occur withrespect to automobile fuel consumption, however,because the consumptive behaviors of typical driversare environmentally irresponsible to start with. UnlikeGneezy and Rustichini’s (2000) tardy parents, typicaldrivers have negligible feelings of responsibilitytowards those adversely affected by their driving(i.e., all people and all life including future gener-ations). If fuel taxes brought prices closer to dfull costpricingT, revenues could be used to defray collateral

Marine Policy, May 1, 2003

Reviews in Fish Biology and Fisheries, Feb 22, 2014

ABSTRACT The marine life of Canada’s Pacific marine ecosystems, adjacent to the province of Briti... more ABSTRACT The marine life of Canada’s Pacific marine ecosystems, adjacent to the province of British Columbia, may be relatively responsive to rapid oceanographic and environmental change associated with global climate change due to uniquely evolved plasticities and resiliencies as well as particular sensitivities and vulnerabilities, given this dynamic and highly textured natural setting. These marine ecosystems feature complex interfaces of coastal geomorphology, climate, and oceanography, including a dynamic oceanographic and ecological transition zone formed by the divergence of the North Pacific Current into the Alaskan coastal current and the California Current, and by currents transporting warm tropical waters from the south. Despite long-term warming in the region, sea surface temperatures in Canada’s Pacific have been anomalously cool since 2007 with La Niña-type conditions prevailing as we enter a cool phase of the Pacific Decadal Oscillation, possibly masking future warming. When warmer El Niño conditions prevail, many southern species invade, strongly impacting local species and reorganizing biological communities. Acidification and deoxygenation are anomalously high in the region due to the weakening ventilation of subsurface waters resulting from increased stratification. A broad spectrum of biological responses to these changes are expected. Non-climate anthropogenic stressors affect the capacity of biota to adapt to climate changes. It will be challenging to forecast the responses of particular species, and to map climate vulnerabilities accurately enough to help prioritize and guide adaptation planning. It will be more challenging to develop forecasts that account for indirect effects within biological communities and the intricate and apparently non-deterministic behaviours of highly complex and variable marine ecosystems, such as those of Canada’s Pacific. We recommend and outline national and regional climate assessments in Canada and adaptation planning and implementation including integrated coastal management and marine spatial planning and management.

Marine and Freshwater Research, 2008

When the biomass and area occupied by a stock decline together, catch rates can remain high (hype... more When the biomass and area occupied by a stock decline together, catch rates can remain high (hyperstability) and management with effort controls may be ineffectual. Banana prawn (Penaeus merguiensis) catches declined from 2000 until 2005 in the Albatross Bay area in the Gulf of Carpentaria (GOC), Australia. Data from commercial logbooks were used to investigate historical changes in the banana prawn fishery in this and other regions of the Northern Prawn Fishery to infer the potential causes of this decline. Data since 1970 were analysed using: (1) the mapping of catch and effort; and (2) normalised rank order catch curves, to determine the distribution of catches across fishing areas. These analyses show that there has been a marked contraction of the Albatross Bay fishery over 33 years of fishing into the centre of a stable ‘hotspot’, suggesting a potential mechanism for the observed negative relationship between catchability and biomass. We believe this is the first observation of a Peneaus prawn fishing ground contracting as biomass declines, supporting the view that the contraction of an area occupied by a stock as biomass declines, is a generalised phenomena observed widely across fisheries resources and not a dynamic confined to certain finfish and molluscs.

Ecological Modelling, Aug 1, 2008

Fish and Fisheries, Dec 1, 2007

Continental Shelf Research, Jul 1, 1997

... Hecker (1982) speculated that submarine landslides destroy existing communities, make new spa... more ... Hecker (1982) speculated that submarine landslides destroy existing communities, make new space available, select for mobile over sedentary species ... ecological (ie energy and nutrient) implications of mass wasting for the continental slope and the deep sea (Menzies and ...

Accumulations of sunken drift macrophytes are known to stimulate high secondary production in sub... more Accumulations of sunken drift macrophytes are known to stimulate high secondary production in submarine canyon heads, but the details of macroinvertebrate colonization of these subsidies are poorly known. I conducted a series of algal and macro- fanual sampling programs and manipulative algal-placement experiments in different Mon- terey Canyon head sub-habitats and seasons from 1988 to 1991 to elucidate the dynamics of macroinvertebrate associations with sunken drift macrophytes, severe annual sediment- flushing events, and the physical and chemical changes associated with these agents of subsidy and disturbance. Conducting these investigations in such a highly disturbed and subsidized setting, i.e., with multiple niche axes, would enable novel insights into how biological communities are structured. Up to 5.7 x 105 individual macrofauna/m2 inhabited naturally occurring patches of sunken drift algae in Monterey Canyon's shallow head (Monterey Bay, California, USA), and the seasonally changing mosaics of macrophyte subsidies led to conspicuously converse responses of amphipods and polychaetes. Amphipods dominated natural patches of sunken algae during winter and spring, while polychaetes dominated during late summer and fall. This community shift corresponded with temporal changes in algal composition, dissolved oxygen (DO), and annual flushing disturbances. Repeated algal-colonization experiments in different habitats further highlighted the contrasting responses of amphipods and poly- chaetes to drift algae and other habitat characteristics. Mean abundances of motile am- phipods increased between 8- and 148-fold within five days after placement of Entero- morpha patches (up to >4 X 105 individuals/m2) while abundances less than doubled in Macrocystis treatments. Amphipod species colonized Enteromorpha treatments in signifi- cantly greater numbers than any controls irrespective of date and sub-habitat. Polychaete species did not colonize algae treatments in significant numbers within five days, but experiments did reveal significant temporal and habitat differences in this group. Sampling of swimming macrobenthos in different canyon habitats and depths (including 30, 100, 300, and 500 m) revealed temporal and habitat patterns in crustaceans and provided explanations of guild functional contrasts. Attributes of two "evolutionary renegades," the phytic polychaete Platynereis bicanaliculata and the hypoxia-tolerant crustacean Nebalia sp., indicated that adaptive constraints inherent in the phenologies and life histories of the two partitioned guilds help reinforce normal functional boundaries. Maximum species rich- ness at intermediate DO and time since disturbance resulted from complementary responses of the two guilds to temporal and habitat characteristics that are shaped by an interacting regime of algal subsidy, hypoxia, and severe flushing disturbance.

Scientia Marina, Nov 11, 2011

with editorial contributions by