Matthew K. Litvak

Seminal plasma biochemistry and spermatozoa characteristics of Atlantic cod (Gadus morhua L.) of wild and cultivated origin.

Our objectives were to compare spermatozoa activity, morphology, and seminal plasma (SP) biochemistry between wild and cultivated Atlantic cod (Gadus morhua). Swimming velocities of wild cod spermatozoa were significantly faster than those of cultivated males. Wild males had a significantly larger spermatozoa head area, perimeter, and length, while cultivated males had more circular heads. Total monounsaturated fatty acids and the ratio of n-3/n-6 were significantly higher in sperm from wild males, while total n-6 from cultivated males was significantly higher than the wild males. Significantly higher concentrations of the fatty acids C14:0, C16:1n-7, C18:4n-3, C20:1n-11, C20:1n-9, C20:4n-3, C22:1n-11, and C22:6n-3 were observed in wild males, while significantly higher concentrations of C18:2n-6, C20:2n-6, and C22:5n-3 occurred in cultivated males. Osmolality, protein concentration, lactate dehydrogenase and superoxide dismutase activity of SP of wild males were significantly higher than the cultivated males. Antioxidant capacity of SP was significantly higher in cultivated males, while pH and anti-trypsin did not differ between fish origins. Four bands of anti-trypsin activity and nine protein bands were detected in SP. Performing a discriminant function analysis, on morphology and fatty acid data showed significant discrimination between wild and cultivated fish. Results are relevant to breeding programs and aquaculture development.

Automated sperm head morphology analyzer for open-source software

Sperm head morphology has been identified as a characteristic that can be used to predict a males semen quality. In the present study, we have developed an automated sperm head morphology analysis (ASMA) plug-in for open-source ImageJ software (http://rsbweb.nih.gov/ij/). We describe the plug-ins functionality, and confirm its validity for sperm head morphology analysis using fish sperm. Sperm head morphological measurements (length and width) made with the ASMA plug-in did not differ from manual measurements. Using the plug-in to measure sperm head-shaped objects of known size, the associated plug-in error rate was < 0.5%. Brightness and contrast ratios influenced sperm head measurements, suggesting the need for standardized protocols. This plug-in was effective at measuring elliptical (i.e., Atlantic cod) as well as slightly irregular (i.e., Chinook salmon) shaped sperm heads. In conclusion, our ASMA plug-in represents a versatile alternative to costly sperm morphology software.

Oceanic Distribution, Behaviour, and a Winter Aggregation Area of Adult Atlantic Sturgeon, Acipenser oxyrinchus oxyrinchus, in the Bay of Fundy, Canada

Seasonal distribution of adult Atlantic sturgeon was examined using pop-up satellite archival tags (PSATs) and ultrasonic transmitters deployed in the Saint John River, New Brunswick, Canada. Seven MK10 PSATs programmed for release in June 2012 and seven MiniPAT PSATs programmed for release in February and April 2013 were deployed in August 2011 and 2012, respectively. Eleven of 14 PSATs surfaced and transmitted depth and temperature data archived for the duration of their deployment (121–302 days). Among these eleven PSATs, five were recovered and 15-sec archival data was downloaded. Following exit from the Saint John River in the fall, tagged fish occupied a mean monthly depth of 76.3–81.6 m at temperatures as low as 4.9˚C throughout the winter before returning to shallower areas in the spring. The majority of ultrasonic detections occurred in the Bay of Fundy, but fish were detected as far as Riviere Saint-Jean, Quebec, approximately 1500 km from the Bay of Fundy (representing long-distance migratory rates of up to 44 km/day). All PSATs were first detected in the Bay of Fundy. Tags that released in February and April were found 5–21 km offshore of the Saint John Harbour, while tags that released in June were first detected in near shore areas throughout the Bay of Fundy. The substrate at winter tag release locations (estimated from backward numerical particle-tracking experiments) consisted primarily of moraines and postglacial mud substrate with low backscatter strength, indicative of soft or smooth seabed. Based on the proximity of winter tag release locations, the consistent depths observed between fish, and previous research, it is suspected that a winter aggregation exists in the Bay of Fundy. This study expands the understanding of the marine distribution and range of Atlantic sturgeon on the east coast of Canada.

Timing and Extent of Drift of Shortnose Sturgeon Larvae in the Saint John River, New Brunswick, Canada

Abstract Little is known about the dispersal of Shortnose Sturgeon Acipenser brevirostrum larvae in the wild. In the Saint John River, New Brunswick, we captured a total of 2,251, 460, 2,100, and 2,083 larvae in 2008–2011, respectively; abundance estimates ranged between 21,000 (2009) and 244,687 larvae (2008). A substantial reduction in larval numbers (49–76%) was recorded over the 4.5-km distance between the two sampling transects deployed in 2008–2010. We found no consistent pattern of larval distribution across the channel, but we recorded a consistent, significant preference for nighttime (dusk to dawn) over daytime dispersal. Generalized linear models were used to examine the timing and extent of larval migration in the Saint John River during the study period. Logistic models incorporating water temperature and Mactaquac Dam discharge provided good predictions of the timing of larval migration. The probability of larval presence was highest when water temperature reached 15°C. At this temperature, ...

Sustaining Atlantic Sturgeon: Stitching a Stronger Scientific and Governance Net

This research was supported by the Ocean Tracking Network (OTN) through a network project grant (NETGP #375118-08) from the Natural Sciences and Engineering Research Council of Canada (NSERC) with additional support from the Canadian Foundation for Innovation (CFI, Project #13011), and the Social Sciences and Humanities Research Council (SSHRC #871-2009-0001). The authors thank Andrew McMaster, Senior Policy Analyst, International Affairs Directorate, Fisheries and Oceans Canada, for his assistance and valuable comments. Any errors remain the authors’ responsibility. ∗ Professor, Department of Sociology and Social Anthropology, Dalhousie University, Halifax, Canada. ∗∗ Professor, Department of Biology, Acadia University, Wolfville, Canada. ∗∗∗ Doctoral Student, Marine & Environmental Law Institute, Schulich School of Law, Dalhousie University, Halifax, Canada. †Professor, Department of Biology, Mount Allison University, Sackville, Canada. ††M.Sc. Student, Department of Biology, Acadia University, Wolfville, Canada. †††Assistant Professor and Canada Research Chair in Ecology of Coastal Environments, Department of Biology, Acadia University, Wolfville, Canada. #M.Sc. Student, Department of Biology, Mount Allison University, Sackville, Canada. ##Professor and Canada Research Chair in Ocean Law and Governance, Marine & Environmental Law Institute, Schulich School of Law, Dalhousie University, Halifax, Canada.

Modeling the Effect of Environmental Parameters on Feeding Ecology of the Shortnose Sturgeon in the Saint John River, New Brunswick

Abstract We examined the effects of spatial, temporal, and environmental parameters on the feeding habits of the shortnose sturgeon Acipenser brevirostrum. We sampled sturgeon gut contents using colonic flushing, a new, low-impact technique. We found that heavy feeding continued until at least November, when water temperature reached 8°C. In all seasons, foraging shortnose sturgeon used shallow water (2–8 m); however, in late fall this trend was even stronger, when 50% of the sturgeon were captured in less than 3 m depth. Over 60 families of prey items were identified from 166 colonic samples collected at four points between spring and late fall from seven locations throughout the lower Saint John River, New Brunswick. Samples from freshwater sites contained mainly Gastropoda, Sphaeriidae, Chironomidae, and Gammaridae. Samples from saline and brackish environments contained mostly Gammaridae, Corophiidae, softshell clam Mya arenaria, Cyathura polita, and Chironomidae. We used sensitivity analysis to deter...

Age and Population Size Estimates of Overwintering Shortnose Sturgeon in the Saint John River, New Brunswick, Canada

Abstract The densities and overall abundances of overwintering shortnose sturgeon Acipenser brevirostrum were estimated using underwater video at the Kennebecasis River overwintering site in 2009 and 2011. In 2009, underwater cameras coupled with lasers provided image-based estimates of fish lengths (and therefore ages). The precision and accuracy of laser-based measurements were estimated by laboratory experiments. In total, 362 and 222 overwintering shortnose sturgeon were counted in the 0.02-km2 area during 2009 and 2011, respectively. The fork lengths of 83 overwintering shortnose sturgeon measured in 2009 ranged from 54 to 119 cm, corresponding to ages of 11–57 years (20.3 ± 7.9 years [mean ± SD]). Length measurement accuracy was highest (±10% fork length) when fish were positioned at 0 ± 30° or 180 ± 30° to the cameras lens. Three different models of spatial fish density estimated a total of 3,852–5,222 shortnose sturgeon in 2009 and 2011, similar to the 2005 local population estimate of 4,836 shor...

Timing and Location of Spawning Based on Larval Capture and Ultrasonic Telemetry of Atlantic Sturgeon in the Saint John River, New Brunswick

AbstractThe timing and location of spawning of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus were investigated using larval sampling and ultrasonic telemetry in 2010–2014 in the lower Saint John River, New Brunswick, Canada. Larval sampling was conducted to identify potential spawning areas using anchored D-frame drift nets and towed bongo nets. Forty-four adult Atlantic Sturgeon (138–213 cm) were ultrasonically tagged and passively tracked using hydrophone receivers located throughout the river. Spawning was confirmed with the first capture of Atlantic Sturgeon larvae in the river. Four Atlantic Sturgeon yolk sac larvae (13.44–14.43 mm) were captured on July 23, 2011, and one exogenous feeding larva (22.6 mm) on July 25, 2011, at river kilometer (rkm) 106 near Burton, New Brunswick. Spawning time was estimated using larval growth models and is likely to have occurred July 6–13, 2011, above rkm 106. Eleven tagged fish returned to the river in May and June after a minimum of 2 years at large: nine male...