The Case Against Dolphin-Safe Tuna

Here’s another shining example of a post I should have had up a week ago before life intervened.  Last week the World Trade Organization ruled that the dolphin-safe label on canned tuna unfairly discriminates against Mexican fishermen.  The debate could result in trade sanctions against the U.S. and is centered on how “dolphin-safe” is defined.  However, aside from the societal impacts, there are some definite ecological reasons why it may be time to ditch the dolphin-safe label.

Before reading on, it’s recommended that you catch up with WhySharksMatter’s epic post on the issues with dolphin-safe methods.  Most of what I have to say below is based on things brought up in that post and the ensuing comments section.

In the Mexican fishery (and common practice before the onset of dolphin-safe methods), seine nets are set around pods of dolphins, which often associate with schools of tuna.  This is obviously risky for the dolphins and does result in some dolphin bycatch.  However, it doesn’t guarantee high dolphin mortality since the mammals are capable of jumping out of the net.  The dolphins are essentially used as living fish-aggregating devices.

In the open ocean where large-scale tuna fishing takes place, pelagic species will cluster around any floating debris and large pieces may generate whole mini-ecosystems with schools of small fish, juveniles, and large predators all spending their time in the area.  While setting around dolphins catches mostly tuna with some dolphins, setting around an inanimate FAD catches everything that was hanging around it.  Check out this table and watch the catch of literally everything else skyrocket in non-dolphin sets.

From Hall 1998 (stolen from southernfriedscience.com). Log sets = inanimate FADs, school sets = tuna schools spotted by planes.

Now what if I told you that you can still use animals as FADs as long as they’re not dolphins?  This is exactly what happens in the Pacific, where tuna seines are set around whale sharks.  Whale sharks are large and slow-moving, and can often be found with an entire entourage of remoras, jacks, cobias, and other large pelagic fish riding their slipstream.  This includes large schools of tuna.  Whales sharks, not being as acrobatic as either dolphins or tuna, usually end up dead as a result of this.  But hey, no dolphins were killed.

A totally dolphin-safe method. Image from change.org

The point I’m getting at is that the true definition of “dolphin-safe” seems to mean “safe only for dolphins.”  A lot of people seem to have the notion that dolphins are critically endangered because, well, we put a lot of effort into saving them so they must be right?  Lets look at the IUCN Red List for a minute.  The bottlenose dolphin and common dolphin are both listed as Least Concern, meaning a healthy population.  The spinner dolphin is admittedly data deficient.  Scrolling down the list for the term “dolphin” reveals most of the ocean-going dolphins are either in pretty good shape or have yet to be assessed, most likely because evidence for a decline isn’t there.  The whale shark?  Vulnerable with a decreasing population trend.

Though I’m known for having some fun at the expense of dolphins and dolphin-lovers, I do actually think dolphins are impressive and important animals.  However, they are “important” in the context of the entire ecosystem.  Dolphin-safe methods put into practice the idea that the life of an individual dolphin is worth more than dozens of billfish, hundreds of sharks, thousands of smaller fishes, and even the lives of species in more critical need of conservation.  It’s “cute animal syndrome” at it’s absolute worst.  Dolphins are a worthy species to keep around, but spiting the rest of the ocean to save one species isn’t doing anyone any good.

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