Ethical Debate: Bycatch and the Great Skua

ResearchBlogging.org

Most marine conservationists and environmentally conscious citizens believe that fisheries bycatch is a major problem that needs to be solved soon. In most cases, they are correct, but an

interesting paper from Nature shows that bycatch can sometimes be good for certain species. Consider the case of the Great Skua.

Image from BritishEcologicalSociety.org

The Great Skua is a large predatory seabird that lives in northern Europe. In the past, it has been known to feed on many smaller local seabird species, including the Leach’s Storm Petrel, the Northern Fulmar, the Northern Gannet, the Lesser Black-Backed Gull, and the Herring Gull. In the last few decades, Great Skua populations have increased tremendously.

Ordinarily, when the population of a predator increases, the populations of its prey decrease. This doesn’t seem to be the case among populations of the seabird species in northern Europe. How can this be?

The answer to this apparent ecological enigma has to do with fisheries bycatch. The oceans around northern Europe support many large-scale fisheries, such as the sandeel fishery. Like most large-scale fisheries, the sandeel fishery has a significant amount of bycatch (fish that were caught merely because they were swimming near the sandeel) associated with it. Since the fishermen only have a permit to sell sandeel, the bycatch species  are dumped overboard…where they are devoured by Great Skua.

In other words, Great Skua have found a new steady source of food. Great Skua populations have increased without a decrease in the populations smaller seabirds that they ate in the past.

Modern sentiments, however, have turned against bycatch. Efforts to reduce bycatch in commercial fisheries are underway in many countries worldwide. What will this mean for the seabird communities of northern Europe?

Well, it’s possible (and for the purposes of this discussion, we’ll assume it will definitely happen) that without their new source of food (bycatch dumped over the side of fishing  vessels), Great Skua will return to eating their previous prey- the smaller seabirds of northern Europe. Since there are many more Great Skua than there used to be, this would be very bad news for the smaller seabirds in the area, and could easily make several seabird species endangered.

The question for this week’s ethical debate is simple: Do you think that we should continue with efforts to reduce bycatch in Northern Europe even if it means that local seabird species will become endangered?

I should note that the authors of this paper stated that “it would not be appropriate to maintain current rates of discarding for the sake of seabirds”.

Votier SC, Furness RW, Bearhop S, Crane JE, Caldow RW, Catry P, Ensor K, Hamer KC, Hudson AV, Kalmbach E, Klomp NI, Pfeiffer S, Phillips RA, Prieto I, & Thompson DR (2004). Changes in fisheries discard rates and seabird communities. Nature, 427 (6976), 727-30 PMID: 14973483

~WhySharksMatter

Might as well eat ’em: A semi-serious April Fool’s Day ethical debate

Sushi! Image from OpenClipArt.org

Bluefin tuna are some of the most endangered fish in the sea. Prized by the sushi industry for their delicious flavor, populations of bluefin have declined precipitously in recent decades.

They also may be the first species of fish to be driven to extinction by commercial fishing. Normally, when populations of fish get low, it isn’t profitable to fish for them anymore- thus they are not driven to extinction. However, a single bluefin tuna can sell for hundreds of thousands of dollars, so it is still profitable to fish for the last one.

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Ethical Debate: Captive whale sharks

WhySharksMatter beneath a whale shark

Following the deaths of two whale sharks in 2007, many animal rights activists harshly criticized the Georgia Aquarium for keeping these animals captive in the first place.  I recently visited the Georgia Aquarium for blogger day, and the aquarium’s Chief Science Officer Dr. Bruce Carlson agreed to answer my questions about their whale sharks. I know that many of you have strong opinions about shark issues, but I wanted to provide the Georgia Aquarium’s side of the story.

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Ethical Debate: Animal rights, human health, and government understanding of science

Image from HumaneSociety.org

I am, in general, a supporter of animal rights. Animal abuse sickens me, and I really believe Ghandi’s famous quote that “you can judge a society by how it treats its weakest members”. That said, while it’s disturbing to see a rabbit which has gone blind from exposure to a potential new shampoo, I’d rather have a rabbit go blind than a human child. More importantly, while it is troubling to infect a chimpanzee with a disease in order to study how to cure that disease, such research unquestionably saves human lives.  That’s why I was surprised to learn about the Great Ape Protection Act.

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Ethical debate: saving owls by killing owls?

Image from OwlPages.com

This month’s Frontiers in Ecology and the Environment has a brief article about a new proposed conservation strategy that seems perfect for a Southern Fried Science ethical debate.  Northern spotted owls (Strix occidentalis caurina) are one of the most famous endangered species in the United States. While solutions to the destruction of their habitat by logging have been debated for years, a new threat has been recently identified- encroachment on their limited habitat by another species of owl (the barred owl, Strix varia).  Some conservationists now believe that we need to kill barred owls to protect spotted owls.

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Ethical debate: Patient consent and medical progress

Image from Unt.edu

The interwebs are abuzz with glowing reviews for Rebecca Skloot’s new book “The Immortal Life of Henrietta Lacks”. I’m currently #37 on the library reserve list (sorry, Rebecca, but I’m a poor grad student and I can’t afford to buy it). The book tells the story of the HeLa cell line, which are cells that were taken from a patient without her consent. These cells have led to important medical breakthroughs. But how isolated of an incident is this?

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