82 
Age, growth, and reproduction of 
dolphinfish ( Coryphaena hippums ) 
caught off the coast of North Carolina 
Email address for K. L. Schwenke: Kara.Schwenke@noaa.gov 
Department of Zoology 
Center for Marine Sciences and Technology 
North Carolina State University 
303 College Circle 
Morehead City, North Carolina 28557 
Present address (for K. L. Schwenke): National Ocean Service (NOS) 
National Oceanic and Atmospheric Administration (NOAA) 
1305 East West Highway 
Silver Spring, Maryland 20910 
Abstract— Age, growth, and repro- 
ductive data were obtained from 
dolphinfish (Coryphaena hippurus, 
size range: 89 to 1451 mm fork length 
[FL]) collected between May 2002 and 
May 2004 off North Carolina. Annual 
increments from scales (« = 541) and 
daily increments from sagittal otoliths 
(n = 107) were examined; estimated 
von Bertalanffy parameters were L„ 
(asymptotic length) = 1299 mm FL and 
k (growth coefficient) = l ,08/yr. Daily 
growth increments reduced much of 
the residual error in length-at-age 
estimates for age-0 dolphinfish; the 
estimated average growth rate was 
3.78 mm/day during the first six 
months. Size at 50% maturity was 
slightly smaller for female (460 mm 
FL) than male (475 mm FL) dolphin- 
fish. Based on monthly length-adjusted 
gonad weights, peak spawning occurs 
from April through July off North 
Carolina; back-calculated hatching 
dates from age-0 dolphinfish and prior 
reproductive studies on the east coast 
of Florida indicate that dolphinfish 
spawning occurs year round off the 
LT.S. east coast and highest levels 
range from January through June. 
No major changes in length-at-age or 
size-at-maturity have occurred since 
the early 1960s, even after substan- 
tial increases in fishery landings. 
Manuscript submitted 21 February 2007. 
Manuscript accepted 6 November 2007. 
Fish. Bull. 106:82-92(2008). 
The views and opinions expressed or 
implied in this article are those of the 
author and do not necessarily reflect 
the position of the National Marine 
Fisheries Service, NOAA. 
Kara L. Schwenke (contact author) 
Jeffrey A. Buckel 
The dolphinfish ( Coryphaena hippurus ) 
is a highly migratory oceanic pelagic 
fish found worldwide in tropical and 
subtropical waters. The distribution 
range for dolphinfish in the western 
Atlantic Ocean is from Nova Scotia 
(Vladykov and McKenzie, 1935; Tibbo, 
1962) to Brazil ( Shcherbachev, 1973). 
However, this species is most common 
from North Carolina, throughout the 
Gulf of Mexico and Caribbean, to the 
northeastern coast of Brazil where 
it is seasonally abundant (Oxenford, 
1999). Dolphinfish support economi- 
cally important recreational and com- 
mercial fisheries in the United States, 
Caribbean, and Brazil, and is thus a 
shared resource among multiple coun- 
tries. Previous reviews of the scientific 
literature on dolphinfish biology in the 
western Atlantic were completed by 
Palko et al. (1982) and Oxenford (1999). 
Landings of dolphinfish from the At- 
lantic, Caribbean, and Gulf of Mexico 
have increased. According to the Na- 
tional Marine Fisheries Service land- 
ings statistics, recreational landings 
in the Atlantic Ocean have increased 
gradually, whereas commercial land- 
ings in the Atlantic have increased 
dramatically from approximately 20 
metric tons (t) in the 1980s to over 
620 t in the 1990s. Although dol- 
phinfish are fast growing and mature 
early, concern has been raised about 
this trend in landings and the poten- 
tial for localized depletion of stocks. 
Intense harvesting may select for 
traits such as slow growth (Conover 
and Munch, 2002) or early maturity 
(Trippel, 1995); it is important to up- 
date growth and reproductive data to 
test for changes in these data and to 
provide current information for stock 
assessments. Unfortunately, the most 
recent estimates of these parameters 
for dolphinfish in the southeast Unit- 
ed States were based on data from 
the 1960s (Beardsley, 1967; Rose and 
Hassler, 1968). 
Here, we update the age and 
growth relationship and collect re- 
productive data on dolphinfish cap- 
tured in North Carolina from recre- 
ational and commercial sources and 
fishery-independent collections. Our 
specific objectives were 1) to deter- 
mine daily ages of age-0 dolphinfish 
and determine age-0 dolphinfish 
growth rates, 2) to identify the best 
method of aging >age-0 dolphinfish 
(either by otolith or scale annual 
marks) and, with the method deter- 
mined to be the best, to determine 
the annual ages of >age-0 dolphin- 
fish, 3) to validate annual marks, 
and 4) to estimate time of spawning 
and size-at-maturity. 
