Roger A. Rulifson

Recruitment of Juvenile Striped Bass in the Roanoke River, North Carolina, as Related to Reservoir Discharge

Abstract A multiagency committee was established to examine potential effects of reservoir management and hydroelectric power activities in the lower Roanoke River, North Carolina, on downstream resources and their users. Striped bass Morone saxatilis was selected as a key species because of the extensive long-term data base on spawning activity and nursery utilization established in the late 1950s. Specifically, the juvenile abundance index (JAI) values for young-of-year striped bass in Albemarle Sound (1955–1987) were compared to preimpoundment (1912–1950) and post-impoundment (1955–1987) flows of the Roanoke River during the spawning season (1 March–30 June). Recruitment was best (JAI > 5.0) for years in which river flows were low to moderate (5,000–11,000 ft3/s) and was poor (JAI 5.0) most closely resembled preimpoundment...

Life History and Population Characteristics of Striped Bass in Atlantic Canada

Abstract Populations of striped bass Morone saxatilis occur in three regions of Atlantic Canada: the St. Lawrence River and estuary in Quebec; the Gulf of St. Lawrence from Chaleur Bay through Northumberland Strait; and rivers in New Brunswick and Nova Scotia draining into the Bay of Fundy. At least nine rivers are known or believed to sustain spawning populations: the St. Lawrence River (where the spawning stock may be extirpated); the Nepisiguit River in Chaleur Bay; the Tabusintac, Miramichi, Kouchibouguac, and Richibucto rivers in the western Gulf of St. Lawrence; the Saint John and Annapolis rivers in the outer Bay of Fundy; and the Shubenacadie–Stewiacke river system in the inner Bay of Fundy. Historically, commercial striped bass landings in Atlantic Canada were lower than those of the U.S. eastern seaboard, the largest landings being made in New Brunswick. Angling catches are substantial but difficult to verify. Spawning occurs in tidal streams several weeks after ice leaves the system. Adults exh...

Striped Bass Spawning in a Tidal Bore River: The Shubenacadie Estuary, Atlantic Canada

Abstract The only remaining self-sustaining population of striped bass Morone saxatilis in the Bay of Fundy spawns in the tidal bore-dominated Shubenacadie–Stewiacke watershed, Nova Scotia, but how this population spawns in such a harsh watershed is unknown. Egg deposition and water quality were monitored in the Stewiacke River about 2 km downstream of the spawning grounds from May 23 to June 15, 1994. Replicate samples taken every 1.5 h (16 times/d) were cued to within 30 min before and after the tidal bore and 15 min after high slack tide. On spring tide, the tidal bore and flood tide changed the river elevation 3.7 m and the salinity from 0‰ to 20‰ within 1 h; neap tide changes were the smallest measured during the study. Three major spawning peaks were observed: June 2–4, 6–9, and 13–14. Major spawning activity was cued to the neap tide, which had the smallest fluctuations in salinity (0–8‰) and temperature (16.2–18.1°C) and the greatest water clarity (10–45 cm). Major spawning activity commenced when...

Life history strategies of striped bass, Morone saxatilis, populations inferred from otolith microchemistry

Otolith microchemistry was used to investigate genetic, demographic and life history characteristics of striped bass, Morone saxatilis. Striped bass were collected from three river systems along the eastern seaboard: the Neuse River and Roanoke River, North Carolina, USA and the Stewiacke River, Nova Scotia, Canada. The elemental ratios Mn:Ca, Fe:Ca, Br:Ca, Zn:Ca, Cu:Ca and Sr:Ca were measured in otolith nuclei using broad-beam particle induced X-ray emission (PIXE) spectroscopy. Elemental ratios were not significantly different between several Roanoke River genotypes. Two dorsal coloration patterns found in Stewiacke River striped bass indicate the presence of ocean-going (green) and resident (black) contingents, but results of trace elemental analysis showed no differences in elemental signatures of otolith nuclei suggesting that the contingents originate from the same population. Observed Sr:Ca ratios were not stable between Roanoke River year classes; decreased levels of strontium found in 1 year class corresponded with a flooding event. Discriminant analysis using these six elemental ratios correctly identified approximately 88% of the Neuse River, 79% of Stewiacke River, and 47% of the Roanoke River striped bass to the river system from which they were caught during spawning activity. Misclassified individuals might be a result of environmental variability from subhabitats or represent wandering individuals from other populations. The Neuse River population, which is considered to be an endemic riverine population, had no obvious outliers. Results of this study show the increased power of information gathering provided by otolith microchemistry when used in concert with phenotypic and genotypic classification techniques.

Multi-way analysis of trace elements in fish otoliths to track migratory patterns

Abstract Spawning striped bass in the Shubenacadie watershed of Nova Scotia, Canada exhibit three dorsal coloration patterns: green, indicative of fish from the ocean; black, indicative of fish that overwinter in a fresh headwater lake, and mottled fish of unknown origin. Microchemical analysis of growth rings in fish otoliths (calcareous particles found in the inner ear of certain lower vertebrates), measured by laser ablation-inductively coupled plasma/mass spectrometry (LA-ICP/MS), from fish captured during the 1999 Shubenacadie spawning period were analyzed by Tucker-3 multi-way principal component models. Using this technique, multidimensional patterns were discovered in the trace element measurements indicating that migratory patterns of individual striped bass can be tracked from the time-dependent trace element record deposited in the otoliths. Of the nine fish analyzed by LA-ICP/MS, trace element composition at year 0 suggested that all nine fish originated from the same locale. Differentiation in the trace element record was observed in subsequent years. Clustering of the trace element data for six fish unambiguously coincided with dorsal coloration. The three remaining fish exhibited trace element patterns that suggested migration between freshwater and marine conditions at one or more periods during life.

Finfish Catch Reduction in South Atlantic Shrimp Trawls Using Three Designs of By-catch Reduction Devices

Abstract Standard shrimp trawls used in the southeastern U.S. commercial fishery were modified in an attempt to reduce the amount of unwanted fish (by-catch) retained during normal shrimp trawling procedures. A sampling design was used to test the effectiveness of by-catch reduction devices (BRDs) towed in combination with unmodified nets in coastal waters off Brunswick, Georgia, in 1990. Several problems hampered statistical analysis of the data, including slight differences in the towing of port and starboard nets, onboard modification of BRDs during testing to correct design deficiencies, and seasonality of shrimp catches in combination with large masses of sargassum and jellyfish in trawls during fall sampling. The modified Parrish turtle excluder device (TED) was the only BRD that had a significant reduction (alpha = 0.05) in the percent difference in total biomass compared to the control net. By-catch reduction was not consistent for other designs. No significant loss of marketable-sized fish was ob...

Potential Impact of Large-Scale Tidal Power Developments in the Upper Bay of Fundy on Fisheries Resources of the Northwest Atlantic

Abstract Construction of large-scale, hydroelectric tidal power developments in the upper Bay of Fundy is receiving serious consideration. Potential designs involve ebb-generation with 1400- 5300-MW plants using 7.6 m diameter, straight-flow, low-head turbines installed in dams up to 8 km in length. Discharge through individual turbines will be 400 m3/second at 50 rev/minute with draft tube velocities of 11.4 m/second. Calculated parameters for these turbines are a water length of 2.26 m, impact velocity of 23.99 m/second, blade tip velocity up to 28.7 m/second and a total pressure flux of 1.7 atm. The existing environment is macrotidal (tide range 11–16 m). Embayments are homogeneous estuaries with extremely turbid water. The intertidal biological community is a salt marsh-mudflat biome. The pelagic zone supports large populations of migratory fishes, particularly the alosids, Alosa sapidissima, A. aestivalis, A. pseudoharengus, and Clupea harengus. Striped bass, spiny dogfish, Atlantic salmon, and Atlan...

Maturation and Fecundity of Roanoke River-Albemarle Sound Striped Bass

Abstract Since the early 1940s, several investigators have determined age-at-maturity schedules for female striped bass Morone saxatilis at various locations along the Atlantic coast of the USA. These researchers have used one of two sets of criteria to determine whether a female is sexually mature; however, recent work suggests that these methods may underestimate the number of females entering the spawning population at an early age (e.g., ages 3 and 4). The objectives of our study were (1) to compare three methods and criteria for establishing sexual maturity and (2) to use all three methods in establishing a maturity schedule for female striped bass. Also, we estimated potential fecundity of the fish as a function of size, weight, and age. Two hundred sixty-five female striped bass were collected from the Roanoke River–Albemarle Sound system of North Carolina during the prespawning and spawning seasons (March–May) of 1989 and 1990. Females ranged in size from 344 to 1,172 mm fork length and in age fro...

Variation in lipid and fatty acid contents of Atlantic croakers, striped mullet, and summer flounder

Abstract Lipid and fatty acid contents of fillets (with skin) of Atlantic croakers Micropogonias undulatus, striped mullet Mugil cephalus, and summer flounder Paralichthys dentatus were determined for three harvest dates over a 1-year period. In striped mullet and Atlantic croakers, total lipid increased significantly (P ≤ 0.05) in late summer (from 21.72 to 31.78% and 12.68 to 31.94% of dry weight, respectively). No significant change in total lipid content was noted in the leaner summer flounder (9.38–9.87%). However, polyunsaturated fatty acid (PUFA) content of fillets of summer flounder varied significantly (P ≤ 0.05), ranging from low levels in June and August (6.24 and 3.33% of dry weight, respectively) to much higher levels (17.32%) in January. The difference in PUFA content of fillets was due mainly to a significant increase in docosahexaenoic acid (22: 6n3). The PUFA content of Atlantic croakers (22:6n3) also increased significantly (from 3.19 to 6.16%) from August to January, but the PUFA conten...

Finfish Utilization of Man-Initiated and Adjacent Natural Creeks of South Creek Estuary, North Carolina Using Multiple Gear Types

Three gear types were used to collect finfish species from several tributaries of the South Creek estuary near Aurora, North Carolina, to ascertain whether a man-initiated marsh and creek system resembled adjacent natural areas in finfish species composition and abundance. Project Area II was the man-initiated area constructed in 1983 as up-front mitigation by North Carolina Phosphate Corporation prior to its anticipated mining in the headwaters of nearby natural wetlands. Two creeks served as controls throughout the study: Drinkwater Creek and Jacks Creek. Otter trawls were used monthly from July 1984 through December 1988. Wegener rings were used in April, July, and October from 1984 through 1987. An experimental gill net was used monthly from June 1984 through 1985. A total of 48 finfish species was captured during the study; only 14 species (29.2%) were common among gear types. The species collected were mud sunfish, blueback herring, alewife American shad, striped anchovy, bay anchovy, inland silverside, American eel, silver perch, Atlantic menhaden, crevalle jack, common carp, spotted seatrout, weakfish, sheepshead minnow, gizzard shad, ladyfish, chain pickerel, banded killifish, mummichog, striped killifish, rainwater killifish, mosquitofish, naked goby, green goby, white catfish, brown bull-head, pinfish, longnose gar, green sunfish, pumpkinseed, bluegill, redear sunfish, spot, Atlantic croaker, largemouth bass, white perch, striped bass, striped mullet, white mullet, golden shiner, summer flounder, southern flounder, yellow perch, bluefish, Atlantic needlefish, hogchoker, andTilapia species. Abundance of finfish species was a function of gear type. Bay anchovy and spot represented about 85% of all fish in trawl samples. The remainder was comprised of 27 other species. In Wegener rings, five species—bay anchovy, menhaden, rainwater killifish, spot, and inland silverside—each represented over 10% of all fish collected. Croaker and striped mullet each comprised more than 5% of all fish collected in Wegener rings, but were present in substantial numbers only in 1985. Based on trawl samples, the total number of finfish collected from Project Area II during the period 1984–1988 was statistically similar to those collected from the control creeks; Wegener ring data analysis indicated significantly greater catches in Project Area II compared to the control creeks. Bay anchovy catches were not significantly different among the three creeks by either trawl or Wegener ring. The same result was true for Atlantic menhaden and southern flounder. The abundance of spot in trawl samples from Project Area II was significantly greater than for the control creeks; abundance in ring samples from Project Area II was statistically similar to Jacks Creek, but significantly higher than Drinkwater Creek. The number of Atlantic croaker in Project Area II trawl samples was significantly lower than for the cotnrol creeks. Wegener rings did not sample croaker effectively.