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Populations of river herring (Alewife Alosa Pseudoharengus and Blueback Herring A. aestivalis, collectively), once abundant in coastal rivers along the Atlantic coast, have seen precipitous population declines, likely due to many factors, including commercial fishing, habitat degradation, and dam construction. Efforts to restore populations include the construction of fishways at dams, but upstream passage success of fish through fishways is variable. To evaluate passage efficiency of a fishway on the Lamprey River in Newmarket, New Hampshire, Alewives were PIT tagged in 2013 (n = 621) and 2014 (n = 501) and antennas monitored fish in 2013–2015. Potential handling effects, diel movement patterns, and fishway saturation negatively affected passage success. The probability of Alewives successfully passing through the fishway into the river above the dam increased with total length. The estimated probability of passage success of an Alewife of mean total length (280 mm and 292 mm for males and females, respectively) that migrated back to the dam at least 1 year after tagging was 0.63 for males and 0.64 for females. Fishway selectivity presents a potential bias in data collection in freshwater systems, and our results suggest that sampling below a fishway should be coupled with data collected from within and above the fishway for a more complete demographic sample of the migratory population. [ABSTRACT FROM AUTHOR]

Objective: The Striped Bass Morone saxatilis is an anadromous teleost with a native range extending north from the Gulf of Mexico into Canadian waters. Far‐ranging coastal migrations support one of the most popular recreational fisheries in the United States. Identifying the underlying population genetic structure of the spawning populations and the genetic markers capable of differentiating among them advances our understanding of these economically and ecologically important fish and enables more targeted management to occur. Methods: We used a restriction site‐associated DNA sequencing approach to identify neutral and adaptive single‐nucleotide polymorphisms (SNPs), and we determined the population genetic structure of 438 adult Striped Bass sampled from nine spawning locations along the Atlantic coast from the Roanoke River, United States, to the Miramichi River, Canada. Result: The two Canadian populations (Shubenacadie and Miramichi rivers) were genetically distinct from U.S. populations and from each other. Neutral loci differentiated Striped Bass from U.S. waters into four genetically distinct populations: Roanoke River, Hudson–Kennebec River, Upper Chesapeake Bay–Potomac River–Delaware River, and Choptank River (eastern Chesapeake Bay). Outlier loci further differentiated the Delaware River from the Chesapeake Bay tributaries, suggesting that there may be local adaptation in the face of gene flow. We identified 1300 highly informative SNPs (the top 10% [with respect to the genetic differentiation index FST] of the full suite of 13,361 SNPs in our study) capable of assigning fish with at least 90% accuracy to their river of origin; through simulations, we established their applicability for conducting robust mixed‐stock analyses of the coastal migratory Striped Bass fishery. Conclusion: This study demonstrated that neutral and adaptive loci together provide evidence for fine‐scale population structure of migratory Striped Bass, and these loci provide the most informative genetic panel for mixed‐stock analysis of Striped Bass to date, capable of assigning fish to their spawning river of origin. Impact Statement: Migratory Striped Bass that occur along the Atlantic coast of the USA and Canada are structured into genetically distinct populations, corresponding to their spawning river of origin. We identified a suite of genetic markers that will enable fishery managers to determine the stock composition of the mixed coastal Striped Bass fishery. [ABSTRACT FROM AUTHOR]

As feed is a major cost in finfish aquaculture, considerable economic advantages can be gained by optimizing feeding efficiency. In the present study, the effects of reducing feeding frequency were evaluated in Gulf of Mexico strain Striped Bass Morone saxatilis raised in recirculating systems. Juvenile Striped Bass (~170 g) were raised for 84 d at 21°C and fed three or five times weekly at 3% of body weight (% BW) or three, five, and seven times weekly at 2% BW. In another experiment, subadult fish (~720 g) were raised at 15°C for 84 d and were fed three or five times weekly at 2% BW. In all experiments, feeding frequency did not affect growth rates or efficiency and fish that were fed less frequently consumed more feed per feeding but typically had reduced feed consumption over the length of the experiment. These results indicate that labor and feed costs may be reduced by limiting the feeding frequency of Striped Bass in recirculating systems. [ABSTRACT FROM AUTHOR]

Striped bass, Morone saxatilis, is an anadromous fish native to the North American Atlantic Coast and is well recognized as one of the most important and highly regarded recreational fisheries in the United States. Decades of research have been conducted on striped bass and its hybrid (striped bass × white bass Morone chrysops) and culture methods have been established, particularly for the hybrid striped bass, the fourth largest finfish aquaculture industry in the United States (US $50 million). Domesticated striped bass have been developed since the 1990s and broodstock are available from the government for commercial fry production using novel hormone‐free methods along with traditional hormone‐induced tank and strip spawning. No commercial‐scale intensive larval rearing technologies have been developed at present and current fingerling production is conducted in fertilized freshwater ponds. Larval diets have not been successfully used as first feeds; however, they have been used for weaning from live feeds prior to metamorphosis. Striped bass can be grown out in marine (32 ppt) or freshwater (<5 ppt); however, they require high hardness (200+ ppm) and some salinity (8–10 ppt) to offset handling stress. Juveniles must be 1–10 g/fish prior to stocking into marine water. Commercially available fingerling, growout, and broodstock feeds are available from several vendors. Striped bass may reach 1.36 kg/fish in recirculating aquaculture by 18 months and as much as 2.27 kg/fish by 24 months. Farm gate value of striped bass has not been determined, although seasonally available wild‐harvested striped bass are valued at about US $6.50 to US $10.14 per kg and cultured hybrid striped bass are valued at about US $8.45 to US $9.25 per kg whole; the farm gate value for cultured striped bass may be as much as US $10.00 or more per kg depending on demand and market. The ideal market size is between 1.36 and 2.72 kg/fish, which is considerably larger than the traditional 0.68 to 0.90 kg/fish for the hybrid striped bass market. [ABSTRACT FROM AUTHOR]

Populations of anadromous European smelt Osmerus eperlanus (L.) are declining across its geographical range in northern Europe, but no practical culture techniques exist to develop stock enhancement programmes for this species. In this study, a culture protocol is described to rear fish from fertilised eggs to mature adults in 2 years involving the use of 'green water', live feed and artificial diets. The sequence of embryonic development for eggs incubated at 10°C/0 ppt was described and photographed. To determine the optimum conditions for larval culture, fertilised eggs were reared at a range of salinities (0–20 ppt) and temperatures (5–18°C) until first feeding. Best hatching success (ca. 97%), size at hatch (ca. 0.8 mm) and survival to first feeding (ca. 96%) of larvae were achieved under combined conditions of low salinity (0–0 ppt) and temperature (5–10°C). No larvae survived a salinity of 20 ppt. The time taken from fertilisation to hatch (FtH) and hatching duration (HD) were temperature‐dependent ranging from 42 days FtH and 10 days HD at 5ºC, to 10 days FtH and 2 days HD at 18°C irrespective of salinity. The results indicate that conservation programmes could utilise existing salmonid hatchery facilities (i.e. freshwater, ≤10°C water temperature) for stock enhancement. Since on‐growing of smelt involves the logistical and technical problems of live feed production, it is recommended that smelt enhancement programme utilise freshwater hatchery facilities to rear fish until hatching, and then stock out onto known spawning grounds in rivers allowing hatched larvae to drift into estuaries to complete the larval and juvenile phases. This approach would minimise the time spent in the hatchery post‐hatching, eliminate the need for live food production, prevent the development of predator‐naïve fish, and hence would mimic the natural life cycle of the species as closely as possible. [ABSTRACT FROM AUTHOR]

The demand for Striped Bass Morone saxatilis as food and sport fish has generated interest in developing effective transport and handling protocols. Studies have shown that anesthetics and elevated salinity can reduce transport stress in Striped Bass, but no studies have compared stress responses among strains or compared and combined treatments to maximize efficacy. In this study, 1‐h transport trials were conducted with subadults produced from wild‐caught (Florida strain) and domesticated Striped Bass. Fish were transported in freshwater (FW; 0‰) or brackish water (SW; 10‰) alone or containing either metomidate hydrochloride (hereafter, "metomidate"; 1 mg/L) or tricaine methanesulfonate (MS‐222; 25 mg/L). After transport, half the fish from each treatment were sampled for cortisol or stocked in a freshwater recirculating system to monitor their health and behavior for 7 d. In preanesthesia trials, Florida‐strain fish were netted and transferred to baths containing a single anesthetic (induction doses; 5‐mg/L metomidate or 150‐mg/L MS‐222), observed for nociception and recovery, and bled 1 h after anesthesia for cortisol analysis. Results from this traditional approach were compared to results for fish that were first exposed to low anesthetic doses (1‐mg/L metomidate or 25‐mg/L MS‐222) added directly to the culture tank prior to netting and then were transferred to baths containing induction doses of the same anesthetic. In transport studies, cortisol was elevated in the MS‐222 and FW treatment groups compared to the metomidate and SW treatment groups, respectively. Strain, feed consumption, and health were not correlated with cortisol measured following the transport stressor. In the preanesthesia study, metomidate blocked cortisol synthesis if added prior to or following handling, while MS‐222 blocked nociception. [ABSTRACT FROM AUTHOR]

Acadian RedfishSebastes fasciatuswere captured by otter trawl from inshore and offshore sites in the Gulf of Maine. Fish weights and lengths were recorded, sagittal annuli were counted for age determination, and ovarian histology was conducted to develop ogives for length and age at maturity for females. Maximum observed ages of males and females were 25 and 37 years, respectively, but very few males greater than 21 years and females greater than 25 years of age were observed. Growth functions were significantly different between males and females, and similar growth rates (k) but higher maximum length (L∞) and lowert0values were observed in females. Mature female Acadian Redfish ranged in length and age from 17 to 39 cm and from 4 to 37 years, respectively, attaining 100% maturity at ~26 cm and ~10 years. Median length at maturity (L50) was 21.7 cm and median age at maturity (A50) was 6.6 years. Smaller, immature fish were primarily sampled from inshore locations. The results of this study were very similar to previous data from a depleted Acadian Redfish population in the Gulf of Maine from 1975 to 1980, suggesting that these population parameters have not changed despite population recovery. Received March 16, 2016; accepted September 12, 2016Published online December 20, 2016 [ABSTRACT FROM AUTHOR]