146 
Fishery Bulletin 115(2) 
Front 
Channel 
22 
h20 
18 
16 
ug/L 
30 
20 
10 
0 
ntu 
Channel 
■10 
■ 7 
1-6 
5 
4 
10 9 
Distance upriver (km) 
Figure 2 
Hydrographic profiles of (A) salinity, (B) chlorophyll-a concen¬ 
tration (pg/L), and (C) turbidity (ntu) in the upper Navesink 
River, in New Jersey, at flood tide on 2 August 2007. Locations 
of station A at the salinity transition front and station B at a 
nearby channel that were sampled with gill nets are marked. 
the study in 1998 and 1999 (senior author and J. Man- 
derson, unpubl. data). In the field of potential prey, 
we included bay anchovy (Anchoa mitchilli, 50-110 
mm TL), Atlantic silverside {Menidia menidia, 60-130 
mm TL), and Atlantic menhaden (Brevoortia tyrannus, 
50-150 mm TL), as well as bluefish and weakfish <150 
mm TL. 
Telemetry 
Ultrasonic telemetry was used in 2006 and 2007 to 
monitor the movements of bluefish, weakfish, and 
striped bass by using methods described in detail by 
Manderson et al. (2014). Briefly, we moored an array 
of omnidirectional receivers (model VR2, Vemco, Bed¬ 
ford, Nova Scotia, Canada) ~80 cm above the bottom 
throughout the Navesink River from 15 May through 
3 October 2006 and from 18 April through 31 Octo¬ 
ber 2007. In 2006, the array consisted of 27 receivers. 
In 2007, 5 additional receivers were moored in marsh 
creeks and coves. Nearest neighbor distances between 
receivers in the river averaged 493 m (standard devia¬ 
tion 141 m), within a range of 216-788 m. Receivers 
moored in the middle and upper river had detection 
ranges of 350-600 m, whereas detection ranges were 
smaller and more variable in the topographically com¬ 
plex lower river (details of range tests are provided in 
Manderson et al., 2014). 
From 14 May through 8 September 2006 and from 
1 May through 2 October 2007, striped bass, bluefish, 
and weakfish were caught by hook and line when sea¬ 
sonally available. They were placed in coolers with 
cooled water from the laboratory and with battery- 
operated airstones and were transported within 1 h 
to the laboratory. Fish were anaesthetized with AquiS 
(AquiS New Zealand Ltd., Lower Hutt, New Zealand) 
at a concentration of 54 mg/L. A sterilized, uniquely 
coded ultrasonic transmitter (V9-6L, Vemco), with a 
frequency of 69 kHz and a repetition rate of 40-120 
s, was then inserted into the body cavity of each fish. 
Fish were held in the laboratory 2-48 h afterward so 
that we could be certain of their recovery and were 
