Occurrence and Distribution of Shortnose Sturgeon, Acipenser brevirostrum, in the Upper Tidal Delaware River

Estuaries ◽  
1987 ◽  
Vol 10 (4) ◽  
pp. 337 ◽  
Author(s):  
Robert W. Hastings ◽  
John C. O'Herron ◽  
Kevin Schick ◽  
Mark A. Lazzari
Estuaries ◽  
1993 ◽  
Vol 16 (2) ◽  
pp. 235 ◽  
Author(s):  
John C. O'herron ◽  
Kenneth W. Able ◽  
Robert W. Hastings

2012 ◽  
Vol 29 (1) ◽  
pp. 6-14 ◽  
Author(s):  
M. A. Matsche ◽  
K. M. Rosemary ◽  
H. M. Brundage ◽  
J. C. O'Herron

<em>Abstract.</em>—As part of an assessment of available remote sensing technologies for monitoring shortnose sturgeon <em>Acipenser brevirostrum</em>, field evaluations of a split-beam hydroacoustic monitoring system were conducted on the Delaware River in December 2002. The survey area selected for evaluation of the system was a section of the river near Bordentown, New Jersey, where adult shortnose sturgeon are known to aggregate during the winter months. Hydroacoustic measurements were collected on eight adult shortnose sturgeon captured in gill nets on December 4–6, 2002 by passing over these netted fish with a 200-kHz split-beam hydroacoustic system sampling a downlooking 15° transducer. The netted sturgeon were recovered following the acoustic sampling, physically measured, and released. The primary objective of this comparison was to determine if shortnose sturgeon could be detected by a hydroacoustic system, given their backscattering characteristics and general close proximity to the bottom. A secondary study objective evaluated shortnose sturgeon acoustic attributes relative to those of other coexisting fish species to assess if sturgeon exhibited any unique characteristics that might be used to distinguish them. The 2002 feasibility assessment determined that shortnose sturgeon could be detected in close proximity to the bottom by a scientific split-beam hydroacoustic system sampling at a relatively narrow (0.2 ms) broadcast pulse width. A netted sturgeon resting directly on the bottom was resolved by the acoustic system. Acoustic measurements of a tungsten carbide sphere determined that the target could be detected to within 12 cm of the substrate. The eight netted sturgeon returned mean target strength (TS) estimates of –26.5 decibels (dB), well above –80 dB ambient background noise levels. Relative to white sucker <em>Catostomus commersonii</em>, the other captured fish species, shortnose sturgeon differed in two measured acoustic parameters, mean fish TS, and distance from the bottom. Shortnose sturgeon were observed to return greater mean TS values (increased acoustic backscatter) and to be generally more associated with the bottom than the other evaluated fish species. Given the limited data set, these observations are only qualitative in nature, but indicate that shortnose sturgeon can be detected using split-beam echo sounding systems and may exhibit some unique acoustic characteristics allowing their differentiation from other fish species. Comparisons of shortnose sturgeon mean TS and total length determined that the attributes were positively correlated. Sturgeon mean TS measured during the experiments was greater than predicted for fish of equivalent length by the empirical TS-length relationship published by Love (1977).


2002 ◽  
Vol 18 (4-6) ◽  
pp. 491-494 ◽  
Author(s):  
M. R. Collins ◽  
D. W. Cooke ◽  
T. I. J. Smith ◽  
W. C. Post ◽  
D. C. Russ ◽  
...  

2007 ◽  
Vol 64 (9) ◽  
pp. 1248-1257 ◽  
Author(s):  
Xinhai Li ◽  
Matthew K Litvak ◽  
John E. Hughes Clarke

The overwintering habitat use of shortnose sturgeon (Acipenser brevirostrum) was investigated from January to March 2005 in the upper Kennebecasis River, New Brunswick, Canada, using a novel underwater video camera system and modeling approach. Following a random sampling procedure, 187 holes were drilled into the ice, and 234 sturgeon were counted and video-recorded. We found that sturgeon concentrated in a 2 ha area at the confluence of the Kennebecasis and Hammond rivers on a flat sandy substrate at a depth of 3.1–6.9 m. Generalized linear models were developed to describe the relationship of shortnose sturgeon density and habitat variables. The model indicated that the shortnose sturgeon had significant preference to deeper areas within this region. The total abundance of shortnose sturgeon in the area was estimated to be 4836 ± 69 (mean ± standard error) using the ordinary kriging method to interpolate sturgeon density at unsampled sites. This overwintering habitat of shortnose sturgeon can be defined as critical habitat following the identification policies of the Canadian Species at Risk Act (SARA).


<em>Abstract.</em>—The shortnose sturgeon, <em>Acipenser brevirostrum</em>, is a long-lived species that grows slowly, matures at an advanced age, and spawns only intermittently. In the Connecticut River, there are two distinct subpopulations of shortnose sturgeon, which have been separated by the Holyoke Dam for 157 years. My research addressed the viability and persistence for these two separate populations and the effects of dispersal, variation in survival and reproduction, and catastrophes. My risk-based approach used a stage-based metapopulation model that I constructed in RAMAS<sup>®</sup> GIS incorporating the available data. Based on the existing data, this population model for the shortnose sturgeon metapopulation in the Connecticut River made several predictions. The observed stability of the two subpopulations was possible either: with reproduction in both upper and lower subpopulations and small to moderate rates of dispersal between them; or with no reproduction in the lower subpopulation, very high reproduction in the upper subpopulation and high rate of net downstream dispersal. My results provided estimates of extinction risk for the shortnose sturgeon metapopulation under various management options and highlighted three key areas for future research, demonstrating the value of a risk-based approach. This approach is particularly useful for management of long-lived aquatic species.


Sign in / Sign up

Export Citation Format

Share Document