647 
Entanglement and mortality 
of bottlenose dolphins, 
Tursiops runcatus, 
in recreational fishing 
gear in Florida 
Randall S. Wells 
Chicago Zoological Society, c /o Mote Marine Laboratory 
1600 Ken Thompson Parkway, Sarasota, Florida 34236 
E-maii address, rwells@mote.org 
Suzanne Hofmann 
Mote Marine Laboratory 
1600 Ken Thompson Parkway, Sarasota, Florida 34236 
Tristen L. Moors 
Chicago Zoological Society, c /o Mote Marine Laboratory 
1600 Ken Thompson Parkway, Sarasota, Florida 34236 
Effects of fishing gear interactions 
are among the most pressing issues 
currently being addressed by ma- 
rine mammal management agen- 
cies in the United States. Informa- 
tion is needed on the rates and fates 
of entangled dolphins for evalua- 
tion of mortality caused by differ- 
ent fisheries. Virtually the entire 
emphasis of management agencies 
has been on marine mammal inter- 
actions with commercial fisheries; 
little notice has been taken of the 
impacts of recreational fisheries. 
Along the central-west coast of 
Florida, near Sarasota, ongoing re- 
search initiated in 1970 on a resi- 
dent community of about 100 
bottlenose dolphins, Tursiops trun- 
catus (Scott et al., 1990; Wells, 
1991) has resulted in opportunities 
to examine closely the effects of in- 
teractions between dolphins and 
human activities, including both 
commercial and recreational fish- 
eries (e.g. Wells and Scott, 1994; 
1997). We report here on one case 
in which we removed a large quan- 
tity of fishing line trailing from a 
free-swimming bottlenose dolphin, 
and we include information on the 
behavior and health of the animal 
over the first year following en- 
tanglement and removal of the 
gear. We also compare the extent 
of commercial vs. recreational fish- 
ing interactions with dolphins. 
On 4 June 1996, a seven-year-old 
female bottlenose dolphin (“FB03”) 
was observed traveling alone near 
shore in the Gulf of Mexico off Anna 
Maria Island (27°33'N, 82°45'W), 
trailing large quantities of thin line 
that extended in clumps to 5 m be- 
hind the animal. The line was 
wrapped around the tail flukes and 
peduncle but did not appear to af- 
fect noticeably the dolphin’s swim- 
ming ability. The dolphin (FB03) 
was known from birth as a mem- 
ber of a four-generation maternal 
lineage (Wells et al., 1987; Wells, 
1991). She had been seen 146 times 
in this area prior to this incident, 
and was within her well-estab- 
lished home range. She had been 
observed six days earlier without 
any line. 
This dolphin was seen next at 
10:28 on 6 June 1996, in Palma Sola 
Bay (27°29'N, 82°40'W), several 
miles from her 4 June location and 
still within her home range. She 
was alone and surfacing slowly, still 
trailing the line. She was swim- 
ming more slowly than during the 
previous observation (as measured 
in relation to boat speed), and the 
clumps of line extended farther be- 
hind her, to a distance of about 8 
m. Ventilations occurred at average 
intervals of 35.7 sec (±12.71 sec SD, 
n= 58), comparable to previously 
measured rates for Sarasota dol- 
phins (Irvine et al., 1981; Waples, 
1995 ). The line was cutting into tis- 
sues of her flukes and peduncle. We 
decided to try to remove the line, 
assembled a team by 12:47, and 
approached the dolphin in our 6-m 
long research vessel powered by a 
115-hp outboard engine. Because 
the trailing line followed the dol- 
phin to the surface at each breath, 
we were able to reach and retrieve 
most of it. At 13:10 we secured the 
line with a boat hook, and cut all 
but about 2 or 3 m of line from the 
animal as she continued swimming. 
The dolphin swam rapidly and 
“porpoised” for about 3.7 km, left 
the bay, and continued to the south. 
We approached her again in shal- 
low water (<2 m deep) and she 
maintained position, riding slowly 
beneath the bow of our vessel for 
the next 38 minutes; this is the 
longest recorded instance of bow- 
riding in the history of our research 
program. Her position beneath the 
bow afforded us an opportunity to 
examine closely the wounds and 
remaining line. Cuts around the 
peduncle at the insertion of the 
flukes and through the anterior 
edges of the flukes were evident. 
The remaining line circled the pe- 
duncle once and two freely trailing 
ends were draped across and ex- 
tended about 1.3 m behind the 
Manuscript accepted 26 February 1998. 
Fishery Bulletin 96:647-650 (1998). 
