TOP: Each Save Wave 

 has a microcomputer 

 that produces sound 

 either between 60- 

 150kHertzor5-90 

 kHertz. BOTTOM: 

 Lynne Williams uses a 

 hydrophone to listen for 

 echolocation behavior. 



Deterrent or Dinner? 



One of the biggest unknowns about Save 

 Waves is whether bottlenose dolphins will get 

 used to the noise with time, says Read. 



In previous studies, different acoustic 

 devices called "pingers" initially kept harbor 

 porpoises away from gill nets in the Gulf of 

 Maine. But pingers produce noise at a constant 

 interval, and the porpoises adapted. 



In a 2000 FRG study, Read worked with 

 two Hatteras fishermen to study bottlenose 



dolphin behavior around pingers. When the 

 devices were on, dolphins barely altered their 

 travel patterns. Read speculated that, like the 

 porpoises, the dolphins would grow accustomed 

 to the constant pinging noise. Moreover, Read 

 believed they might eventually associate the 

 sound with a net full of fish — a response he 

 calls the "dinner bell effect." 



But the noise from Save Waves changes 

 frequency, hopefully making it harder for 

 dolphins to acclimate. 



"Bottlenose dolphins can be stubborn 

 creatures, and they've proven to be in these 

 situations," Read cautions. 



On an overcast morning in Hatteras, 

 Erin Burke, a Duke graduate student, joins 

 Dave Swanner, captain of the Endurance and 

 Read's co-investigator. Burke is responsible for 

 attaching Save Waves to Swanner's nets and 

 documenting his catch. 



To properly randomize the study, Burke 

 flips a coin to decide if the Save Waves will 

 be activated during this trip. The coin lands on 

 tails, meaning the devices will be silent today. 

 Meanwhile, researcher Danielle Waples of Duke 

 joins Paul Dunn, captain of the Shannon D. Her 

 coin toss comes up heads, so the Save Waves on 

 Dunn's nets will be activated. 



Nearby, Read, researcher Kim Urian and 



graduate students Ari Friedlaender and Lynne 

 Williams board the Proteus and begin scouting 

 the area for dolphins. 



Swanner turns up his marine radio and 

 listens as a nearby captain reports only three 

 mackerel on the last set. Another voice chimes 

 in, reporting zero. Shaking his head, Swanner 

 decides to try his luck near Frisco. 



"It's basically a guess fishery," he says. 

 "You set a net and see if there is anything you 

 like." 



Swanner rums on the hydraulic net reel, 

 mounted on the back of his boat. The reel looks 

 like an oversized spool of thread, wrapped with 

 layers of green mesh netting that eventually will 

 stretch the length of the water column. 



Larger fish, like mackerel, are too big 

 to pass through the net and instead become 

 entangled in the mesh. 



As Swanner feeds the net into the water, 

 he halts the reel periodically so Burke can clip a 

 Save Wave onto the net's floathne. 



"The problem is we've got to take them on 

 and off every step of the way," she explains. 



Each Save Wave must be spaced 150 yards 

 apart to create optimum sound. But Swanner has 

 four 300-yard nets, meaning each net requires 

 two Save Waves. Come fall, it will be too time- 

 Continued 



COASTWATCH 25 



