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James P. Clugston

Publications and source records attributed to James P. Clugston.

7 recordsLinked to original sources
USGS2014

Survival of hatchery Gulf sturgeon ( Acipenser oxyrinchus desotoi Mitchill, 1815) in the Suwannee River, Florida: a 19-year evaluation

An experimental release of 1192 hatchery-reared, individually PIT tagged, 220 days old (296&ndash;337 mm TL) Gulf sturgeon, Acipenser oxyrinchus desotoi , was undertaken in 1992 in the Suwannee River, Florida. The original objectives of the 1992 release experiment were to: (1) evaluate survival rate of cultured Gulf sturgeon in the wild vs survival rate of their wild 1992 cohort counterparts, (2) determine the differential effect of release site within the river upon long-term survival, and (3) evaluate comparative growth rates of recaptured hatchery vs captured wild 1992 cohort Gulf sturgeon. The present investigation addressed those original objectives, plus an additional fourth objective: (4) evaluation of hatchery fish recapture rate change over the 19-year experiment. The primary objective was to determine efficacy of potential conservation aquaculture for this species in terms of long-term survival in the wild. Follow-up 1993&ndash;2011 gill net sampling in freshwater reaches (rkm 4&ndash;237) and the estuarine river mouth (rkm &minus;6 to 4) yielded recaptures representing 13.0% of the total released. Mean annual hatchery fish mortality (including emigration) rate estimated for the 19-year period (1993&ndash;2011) was more than twice that for same cohort wild fish. Mark-recapture survival probability (phi) for hatchery fish, 1993&ndash;2011, was substantially lower (0.733) than for their wild counterparts (0.888). Mean annual hatchery fish recapture rate, as a percentage of all 1992 cohort fish recaptures, declined significantly after age-7, coinciding with age of onset of migration into the open Gulf of Mexico. Hypothesized causal factors may be differentially lower fitness in the marine habitat or permanent outmigration due to natal river imprinting failure. Hatchery fish recapture rates varied significantly for fish from the ten release sites, being highest near the river mouth, and lowest for the furthest upriver sites in the Suwannee River and its Santa Fe River tributary. Hatchery fish also displayed a significantly lower growth rate than their wild counterparts through age 3000 days. Cumulative hatchery fish mortality of 99.87% over 19 years predicts <3 individuals would have survived through 2011. From the results of the 1992 release experiment, hatchery supplementation as a Gulf sturgeon conservation measure does not appear to be an effective option.

Florida↗
USGS1999

Recent advances in life history of Gulf of Mexico sturgeon, Acipenser oxyrinchus desotoi, in the Suwannee River, Florida, USA: A synopsis

Gulf sturgeon spawn on portions of three sites in the upper Suwannee River, which may appropriately be described as spawning reefs. The same areas are utilized from year to year. Habitat factors important in spawning site determination include gravel/cobble substrate, the presence of eddy fields, a neutral to slightly alkaline pH, and an empirically observed range in calcium ion content (6-18 mg/L Ca++, corresponding to a conductivity range of 40-110??S). Eggs are deposited contagiously within a small area (< 10,000 m2) with very little scatter, suggesting little if any current drift. They are not found from samplers on immediately adjacent sand substrate. The broadcast spawner model does not seem to fit the Gulf sturgeon. Spawning begins 4-7 days after the March new moon, with water temperature above 17.0 oC, and extends for 9-23 days as discrete events involving individual females. Spawning may continue, if water temperature remains below 21-22oC. The total annual pool of spawning females in the Suwannee population is estimated at 80 individuals. Young of the year utilize open sand habitat away from shoreline and vegetated habitat. They disperse widely, and occur over freshwater reaches from rkm 10-237; no particular affinity with spring water habitat is evident. Larger Gulf sturgeon tend to congregate in deep holes serving as summer-fall holding areas. They fast and lose weight while remaining in freshwater, but more than compensate this loss during winter feeding in marine waters. The major downriver migration to the estuary takes place in October-November. After a period of river mouth staging, subadults and adults migrate into Gulf of Mexico nearshore mesohaline waters. They move further out and into deeper water (> 3 m) when water temperatures drop in mid-December, but final destinations in mid-winter remain unknown. Age-2 through 6 juveniles remain in the river mouth estuary over winter. In late January through early February YOY migrate downriver for the first time, joining larger juveniles to overwinter and feed. Tag and recapture data yield a Suwannee River population of Gulf sturgeon estimated at 7,650 individuals, with an annual turnover rate of 16%. Based on stability in cumulative recapture rates from 1991-1998, population size is stable with an effective balance between recruitment and mortality. However, population structure is dynamic, controlled by the juxtaposition, conjunction, and summation of successive strong and weak year classes. Length/age frequency distributions for 1995 and 1998 populations censuses are very different. The 1995 distribution is bimodal with a dominant mode of 9-14 year old subadults/adults, and a sub-dominant of mode of 2-4 year old juveniles. The 1998 distribution is trimodal, but overwhelmingly dominated by 6-9 year old subadults. Erosion by 1998 of the major subadult/adult mode from the 1995 census illustrates that large adults encounter the same high mortality as smaller fish. Ultimate adult size in the population has remained constant at 2.2 cm TL over 13 years, indicating a maximum life expectancy of 25 years for Suwannee River Gulf sturgeon.

Conference Paper↗
USGS1998

Early life history stages of Gulf sturgeon in the Suwannee River, Florida

Egg sampling confirmed that Suwannee River Gulf sturgeon Acipenser oxyrinchus desotoi , a subspecies of Atlantic sturgeon A. o. oxyrinchus use the same spawning site at river kilometer (rkm) 215 from the mouth of the river each year. Forty-nine eggs were recorded in 1995, and 368 were recorded in 1996. Spawning began 4–7 d after the March new moon in both years and lasted 10–11 d; in 1996, a second 10-d spawning round began on the April new moon. Developmental synchrony among eggs recovered suggested several discrete spawning events in both years. Total eggs deposited for three 1996 sampling days was estimated as 405,600–711,000/d, approximating the fecundity range of a large female Gulf sturgeon . Eggs were found only in the southern half of the river , an area with surface currents of 0.5–1.5 m/s and numerous eddies producing reverse bottom currents of 0.1–0.5 m/s. Egg substrate consisted of bedrock limestone thinly overlain by fine sand and densely distributed elliptical gravel 2–10 cm in diameter. Eggs were found predominantly in depths of 2–4 m at water temperatures of 17–21°C, conductivities of 50–100 μS, and dissolved oxygen levels exceeding 5.0 mg/L. The Cody Scarp, 15 rkm above the spawning ground, may mark the upstream limit of spawning areas in the river . Three 2–4-month-old riverine juveniles (82–115 mm total length, TL) collected are the smallest yet captured from any river . Data for 18 riverine age-0 juveniles (to 350 mm TL) suggest that this stage lasts 6–10 months, terminating with migration of fish to the river mouth in January–February. Less than 2% of 461 juveniles captured at the estuarine river mouth (1990–1993) were under 350 mm TL. Riverine age-0 fish were collected over long shallow stretches (typically <4 m deep) of relatively barren sand (rkm 12–238).

Florida↗
USGS1986

Strategies for reducing risks from introductions of aquatic organisms: The federal perspective

The Lacey Act of 1900 and subsequent amendments have provided the basis for existing federal regulations on species introductions. The 1981 version repealed the Black Bass Act and corrected certain insufficiencies in the original Lacey and Black Bass Acts. A 1977 executive order instructs federal agencies, to the extent permitted by law, to restrict the introductions of exotic species into federally owned or controlled lands and waters. The National Environmental Policy Act of 1969 and the Endangered Species Act of 1973 indirectly relate to the stocking of exotic fish. The first requires each federal agency to prepare an environmental impact statement if a proposed action, such as a species introduction, may significantly affect the environment. The second regulation prohibits the importation of endangered or threatened animals, and specific exotic fishes could be in one of these categories. The U.S. Fish and Wildlife Service, as part of the Department of Interior's charge, initiated a program in 1977 at Gainesville, Florida, to conduct and coordinate research on non-native fish introduced or considered for stocking into United States waters. Construction of a fishery laboratory and other research facilities began in 1984 and are scheduled for completion in 1987.

Fisheries↗