Conservation In Practice

A publication of the Society for Conservation Biology

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Fall 2005 (Vol. 5, No. 4)

Torn between Optimism and Cynicism
Issues raised in Peter Corkeron’s recent paper (featured in the Summer 2004 Journal Watch) have me torn between two views — those of the optimist and those of the cynic. The enormous quantities of fish that we lift from the oceans clearly qualify us as globally significant marine predators. With that in mind, how should we view other species that consume the same fish?

The optimist in me believes that, given our growing knowledge of how marine ecosystems function, we can no longer afford to view our preferred prey in isolation from the food chains from which they come. In other words, the benefit of taking fish must be tempered with the responsibility (and cost) of monitoring and maintaining the diversity of the ecosystems to which they belong. For this reason, I’m encouraged by the growing political recognition that whale and seal populations, for example, may be connected in one way or another to the fish we target. If we want to muscle our presence into an ecosystem, then we must be prepared to expect these other predators to take a hit, and so we must choose fishing quotas with this responsibility in mind.

However, the cynic in me wonders whether this ecosystem-based management approach can also be reached when our objectives and intended outcomes are entirely different. If we want to squeeze as much as we can from a fishery, then a good way to do it is to expand our perspective beyond just the target species. If we view the other predators as our competitors, then their reduction becomes our gain — in fact, a double gain if we can make use of their carcasses as well.

Therefore, when a nation champions an ecosystem-based approach to ocean management, we must be careful to see just what motives underlie it. The high moral ground of this holistic approach may not be so high as it might first appear.

BEN WILSON
Marine Mammal Research Unit, Fisheries Centre, The University of British Columbia, Vancouver, Canada

Mistaken Identity
I suspect that by now you have already received a raft of messages pointing out that the “coffeeberry” pictured on page 7 of the summer issue has as much relevance to the associated article as a lion fish would have to an article about the Serengeti. At least the caption was accurate, making it clear that this is a North American member of the Rhamnaceae, rather than the species of Rubiaceae that is the coffee of commerce. Mis-ID'd photos aside, I do find your magazine to be good reading and beautifully produced.

BRUCE A. STEIN
Vice President for Programs
NatureServe

Cleaning the Tanks
Shipping is currently the greatest source of introduced aquatic species. Over 80 percent of the world’s commodities are moved through shipping and around 3-5 billion tons of ballast water is transferred internationally each year. The International Convention for the Control and Management of Ships Ballast Water and Sediments was adopted in February 2004 with the aim of controlling introductions through ballast water, sediments, and tanks.

Thus, creative solutions such as the de-oxygenation of ballast water by bubbling nitrogen through ballast tanks are desperately needed (“Empty Tanks,” Summer 2004). This solution is environmentally friendly. It does not produce toxic waste (such as trihalo-methanes) associated with chlorination or release toxins or biocides that can negatively impact native communities. De-oxygenation is also effective under a wide range of water conditions, which limit the effectiveness of other methods.

De-oxygenation was initially considered to be too costly. However, the cost savings to shippers due to reduced tank corrosion will offset costs. There is a strong desire to find a solution that is 100 percent effective — safe for the environment and human health and cost-free.

However, such a solution is unlikely. We need continued research and testing of new methods to control unwanted introductions through shipping. In the meantime, it is paramount that we encourage and test innovative solutions such as de-oxygenation with nitrogen that reduce the risks of unwanted introductions and are safe and effective. The environmental and economic costs of not moving forward are too great.

DIANNA K. PADILLA
Department of Ecology and Evolution, Stony Brook University, NY