156 
Fishery Bulletin 108(2) 
because of human alteration of the coastal zone (Brom- 
berg and Bertness, 2005), data are needed to quantify 
the importance of specific coastal habitat types in sus- 
taining tautog populations. 
Our long-term goal is to investigate the utility of 
naturally occurring habitat tags to determine habitat 
linkages in Narragansett Bay and other nearby es- 
tuarine systems by juvenile tautog. This is an initial 
crucial step to quantify the relative contribution of 
estuarine habitats for the population connectivity of 
adult tautog. 
Materials and methods 
Sampling of juvenile fish 
In Rhode Island, young-of-the-year (YOY) tautog of 45- 
64 mm fork length (FL) were sampled from three sites 
in Narragansett Bay: Mt. Hope Bay (MH), Gaspee Point 
(GP), and Rose Island (RS); and from two sites from the 
coastal ponds along the Rhode Island southern shore: 
Point Judith, lower pond (PJ), and Charlestown Pond 
(CP) (Fig. 1). The samples were obtained in coopera- 
tion with Rhode Island Department of Environmental 
Management, Division of Marine Fisheries (RIDEM), 
during August and September of 2005 and 2006. The 
sampling stations were selected to include different 
nursery areas and possibly different chemical back- 
grounds and according to information on juvenile tautog 
abundance from RIDEM. Average monthly surface tem- 
peratures and salinities at Gaspee Point for 2005 were 
22°C and 24.9%e, and for 2006 were 20.6°C and 22.5%e. 
For Mount Hope Bay, average surface temperatures 
and salinities were 21.7°C and 27.0 %c, and for 2006 
were 20.5°C and 24.9%c. Data from the closest point 
to Rose Island showed average surface temperatures 
and salinities for 2006 were 17.4°C and 30.8 %c. Twenty 
juveniles per site per year were captured for analysis. 
Sampled fish were kept frozen until dissection for the 
removal of otoliths. 
Laboratory processing of samples 
Before dissection, each fish was weighed (wet weight 
to the nearest 0.1 g) and measured (FL and standard 
length [SL] to the nearest 0.1 mm). Both sagittal oto- 
liths were removed from each fish, cleaned of adhering 
tissue, rinsed 3x with Milli-Q-filtered (Millipore Corp., 
Billerica, MA) water, and allowed to dry in a class-100 
laminar-flow hood. The left sagittal otolith was used 
for trace metal analysis and the right otolith was used 
for stable isotope analysis. A total of 164 otoliths were 
prepared for trace metal analysis. Each otolith was 
weighed on a Thermo Cahn microbalance (± 0.01 mg) 
(Thermo Fisher Scientific, Waltham, MA). Samples were 
then placed in acid-washed 2.5-mL snap-cap polypropyl- 
ene containers. The otolith weights ranged from 0.08 
to 0.34 mg and averaged 0.18 mg. Otoliths for trace 
metal analysis were transferred to 5-mL clean polypro- 
pylene tubes and 0.2 mL of triple-distilled 17% HN0 3 
was added to insure complete dissolution (in about 30 
seconds). An internal thulium single-element standard 
spike was added (to correct for variable matrix effects 
during the inductively coupled plasma mass spectrom- 
etry analyses) and then the solution was diluted to 1.8 
mL with triple-distilled water. This dilution resulted 
in a Ca concentration of approximately 40 ppm in the 
analyzed otolith solution. 
Otolith chemistry 
Elemental concentrations of YOY otoliths were deter- 
mined through solution-based ICPMS at the University 
of Rhode Island Graduate School of Oceanography. All 
measurements were carried out on a Finnigan ele- 
ment high-resolution inductively coupled plasma mass 
spectrometer (HR-ICPMS) (Thermo Fisher Scientific, 
Waltham, MA). A procedural blank was prepared in the 
same manner as had been used for the other samples, 
but with no otolith present. The procedural blank was 
compared to the system blank to determine if contami- 
nation occurred during processing. System blanks were 
made from the same acid used for sample dissolution 
and were run every four samples. A drift-correction 
standard was prepared by gravimetrically spiking a 
CaC0 3 standard solution with the appropriate concen- 
trations of Na, K, Rb, Mg, Ca, Mn, Ni, Cu, Zn, Sr, Ba, 
Co, and Pb to match the typical elemental composition 
of the otoliths. This drift-correction standard was ana- 
lyzed every four samples to track and correct for varia- 
tions in instrument sensitivity during each analytical 
time period. The choice of these thirteen elements for 
our study was based on previous studies of elemental 
composition of juvenile fish otoliths. Analytical results 
were expressed as absolute concentrations of elemental 
molar ratios with respect to calcium: Element:Ca ratios, 
expressed as units of mmol/mol or pmol/mol. 
The elements that were always above detection lim- 
its (Rb, Mg, Ca, Sr, and Ba) were used for subsequent 
analysis. The average relative standard deviations 
were as follows: Rb (3%), Mg (10%), Ca (1%), Sr (1%), 
and Ba (5%). The limits of detection were as follows 
(values in ppm): Rb (0.007), Mg (0.02), Sr (0.077), and 
Ba (0.014). The detection limits for the whole otolith 
dissolution-solution-based method were calculated as 
three times the standard deviation of the counts per 
second (cps) of the isotope of interest in acid blanks 
divided by the sensitivity in cps/ppm of the CRM22 
carbonate standard. For every isotope, these were in 
the sub-ppm range — a result that compares with the 
3 to 2000 ppm range of the elements of interest in the 
sample otoliths. 
Stable carbon and oxygen isotopes of these otolith 
samples were determined at Rosenstiel School of Marine 
and Atmospheric Sciences, University of Miami, by us- 
ing an automated carbonate device (Kiel III) attached 
to a thermo Finnigan delta-plus stable isotope mass 
spectrometer (Thermo Fisher Scientific, Waltham, MA). 
Data were expressed by using conventional d notation 
