Original Paper: Albins, M. A. and P. J. Lyons. 2012. Invasive red lionfish Pterois volitans blow directed jets of water at prey fish. Marine Ecology Progress Series 448: 1–5.

Mark Albins and his colleagues asked what feeding behaviors the invasive lionfish Pterois volitans might use to be a successful predator on Atlantic and Caribbean coral-reef fish. They conducted field observations of lionfish feeding on small reef fish and noticed that lionfish typically face their prey, flaring their pectoral fins and moving very slowly within striking distance of the prey. During the approach, lionfish produced a strong, pulsed jet of water from their mouths and directed it toward the prey. To investigate this novel feeding behavior, Albins and his colleagues conducted feeding trials on lionfish and native goby prey.

In addition to the aquarium experiments, the researchers conducted field observations of the feeding behavior of lionfishes in different locations—their native Pacific Ocean and their non-native Atlantic Ocean. They found that, in the Atlantic Ocean, most successful captures by lionfishes did not require them to blow jets of water at their prey (only 18 percent of the captures involved this behavior). However, in the Pacific Ocean, they found that 56 percent of successful captures by lionfishes involved them blowing jets of water at their prey. The researchers also reported that an extensive literature search showed that blowing jets of water at prey appears to be unique to lionfishes.

QUESTIONS

Question 1

The researchers used both methods to collect data for two different purposes. In the open aquarium trials, they wanted to observe the behavior of the lionfish and its prey in a relatively natural setting to see what strategies the lionfish used to capture and eat the prey. They learned that the lionfish would capture the prey when the prey turned and oriented its head toward the head of the lionfish. This headfirst orientation allowed the lionfish to more easily capture its prey.
In the container trials, the researchers wanted to observe the behavior of the lionfish, particularly the production of water-jet pulses from its mouth, in a setting where the lionfish could see, but not capture or eat, the prey. In this way the researchers could measure the number of water jets produced and the maximum distance a water jet could travel, to get an idea of what behaviors a lionfish might employ when its prey was hard to catch (in this case, because the prey was in an inaccessible container).

Question 2

Given that fish prey in the Atlantic Ocean are more naive to lionfish predatory behavior than fish prey in the Pacific Ocean, it would make sense that lionfishes would need to produce fewer and closer jets of water to capture their fish prey in the Atlantic Ocean compared with the Pacific Ocean. The Pacific Ocean fish should be harder to catch and thus require more water jets produced from a greater distance from the prey.

Question 3

The field observations suggest that Pacific Ocean lionfishes need to resort to the water jet–blowing behavior to catch their prey more often than Atlantic Ocean lionfishes do. This pattern could be explained by the hypothesis that fish prey in the Atlantic Ocean are more naive to lionfishes and thus easier to catch. Atlantic Ocean fish prey are less likely to take appropriate evasive actions or require the use of the water jet–blowing behavior to confuse or disorient them. In addition, it is likely that the production of water jets is metabolically costly, and that lionfishes would use this behavior only when the cost of producing it is outweighed by the advantages it confers. Presumably this would be more likely to be the case for prey in the Pacific Ocean than for prey in the Atlantic Ocean.

A similar work with the data exercise may be assigned in LaunchPad.