Catching air - those magnificent jumping Suwannee sturgeons
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Florida;Georgia↗
Geology topics
K. J. Sulak
Publications and source records attributed to K. J. Sulak.
Evidence of autumn spawning in Suwannee River Gulf sturgeon, Acipenser oxyrinchus desotoi (Vladykov, 1955)
Evidence of autumn spawning of Gulf sturgeon Acipenser oxyrinchus desotoi in the Suwannee River, Florida, was compiled from multiple investigations between 1986 and 2008. Gulf sturgeon are known from egg collections to spawn in the springtime months following immigration into rivers. Evidence of autumn spawning includes multiple captures of sturgeon in September through early November that were ripe (late-development ova; motile sperm) or exhibited just-spawned characteristics, telemetry of fish that made >175 river kilometer upstream excursions to the spawning grounds in September–October, and the capture of a 9.3 cm TL age-0 Gulf sturgeon on 29 November 2000 (which would have been spawned in late September 2000). Analysis of age-at-length data indicates that ca. 20% of the Suwannee River Gulf sturgeon population may be attributable to autumn spawning. However, with the very low sampling effort expended, eggs or early life stages have not yet been captured in the autumn, which would be the conclusive proof of autumn spawning. More sampling, and sampling at previously unknown sites frequented by acoustic telemetry fish, would be required to find eggs.
Florida↗
Defining winter trophic habitat of juvenile Gulf Sturgeon in the Suwannee and Apalachicola rivermouth estuaries, acoustic telemetry investigations
Three automated listening post-telemetry studies were undertaken in the Suwannee and Apalachicola estuaries to gain knowledge of habitats use by juvenile Gulf Sturgeons ( Acipenser oxyrinchus desotoi ) on winter feeding grounds. A simple and reliable method for external attachment of small acoustic tags to the dorsal fin base was developed using shrink-tubing. Suspending receivers on masts below anchored buoys improved reception and facilitated downloading; a detection range of 500–2500 m was realized. In the Apalachicola estuary, juvenile GS stayed in shallow water (< 2 m) within the estuarine transition zone all winter in the vicinity of the Apalachicola River mouth. Juvenile GS high-use areas did not coincide with high density benthic macrofauna areas from the most recent (1999) benthos survey. In the Suwannee estuary, juveniles ranged widely and individually throughout oligohaline to mesohaline subareas of the estuary, preferentially using mesohaline subareas seaward of Suwannee Reef (52% of acoustic detections). The river mouth subarea was important only in early and late winter, during the times of adult Gulf Sturgeon migrations (41% of detections). Preferred winter feeding subareas coincided spatially with known areas of dense macrofaunal benthos concentrations. Following a dramatic drop in air and water temperatures, juvenile GS left the river mouth and estuary, subsequently being detected 8 km offshore in polyhaline open Gulf of Mexico waters, before returning to the estuary. Cold-event offshore excursions demonstrate that they can tolerate full-salinity polyhaline waters in the open Gulf of Mexico, for at least several days at a time. For juvenile sturgeons, the stress and metabolic cost of enduring high salinity (Jarvis et al., 2001; McKenzie et al., 2001; Singer and Ballantyne, 2002) for short periods in deep offshore waters seems adaptively advantageous relative to the risk of cold-event mortality in shallow inshore waters of lower salinity. Thus, while juveniles can tolerate high salinities for days to weeks to escape cold events, they appear to make only infrequent use of open polyhaline waters. Throughout the winter foraging period, juvenile GS stayed primarily within the core area of Suwannee River mouth influence, extending about 12 km north and south of the river mouth, and somewhat seaward of Suwannee Reef (< 5 km offshore). None were detected departing the core area past either of the northern or southern acoustic gates, located 66 and 52 km distant from the river mouth, respectively.
Florida↗
In situ video observations of two manefishes (perciformes: Caristiidae) in the mesopelagic zone of the northern Gulf of Mexico
This paper describes direct video observations of two manefishes, likely Paracaristius sp., from the mesopelagic waters of the north-central Gulf of Mexico. One fish was observed with a remotely operated vehicle at a depth of 829 m by an industrial ROV as part of the SERPENT Project. The second was observed at 496 m from a manned submersible. Little is known about the behavior of manefishes because most records result from net-collected material. Our observation demonstrates that manefishes are capable of precise locomotory and posture control using extended, erect fins and that the pelvic fins of these fishes are extended in a parachute-like manner. Moreover, one of the specimens exhibited an unusual vertical, sinusoidal oscillation of its caudal fin. One of the observations took place in association with a physonect siphonophore. These observations may include the deepest published record for a manefish in the Gulf of Mexico.
Copeia↗
Frequency of sublethal injury in a deepwater ophiuroid, Ophiacantha bidentata, an important component of western Atlantic Lophelia reef communities
The occurrence and relative abundance of tissue (arm) regeneration in the ophiuroid, Ophiacantha bidentata (Retzius), was examined in individuals collected primarily among colonies of the deep-water coral Lophelia pertusa off the southeastern United States. Seven deep-water coral sites (384-756 m), located between Cape Lookout, NC, and Cape Canaveral, FL, were sampled in June 2004 using a manned submersible. The presence of regenerative tissue was evaluated by visual inspection of each individual ophiuroid, and the proportion of regenerating arms per individual was examined relative to size of individual, geographic location, and depth of collection. Ophiacantha bidentata, the dominant brittle star collected, commonly displayed signs of sublethal injury with over 60% of individuals displaying some evidence of regeneration. These levels of regeneration rival those reported for shallow-water ophiuroids. Larger individuals (>6.5 mm disc size) had a higher incidence of regeneration than smaller individuals. Size of individual and percent of regeneration were negatively correlated with depth. Although O. bidentata was significantly less abundant in southern versus northern sites, ophiuroid abundance did not appear to be influenced by amount or density of coral substratum. Presence of dense aggregations of O. bidentata indicates that they are an important component of the invertebrate assemblage associated with deep-water coral habitat especially in the northern part of the study area. Assuming that observed frequencies of injury and subsequent regeneration represent predation events then dense ophiuroid aggregations in deep-water coral habitats represent an important renewable trophic resource within these communities. ?? 2007 Springer-Verlag.
Marine Biology↗
Deep-water chaunacid and lophiid anglerfishes (Pisces: Lophiiformes) off the Southeastern United States
Recent research cruises to deep (80–910 m) reef habitats off the south-eastern U.S. and in the northern Gulf of Mexico have provided new information on the diagnostic characteristics, behaviours, colour patterns in life, bottom associations, distributions and maximum sizes of species of the anglerfish genera Chaunax , Lophiodes and Sladenia . Chaunax stigmaeus occurred much further south than previously known (Blake Plateau off South Carolina), and all C. stigmaeus observed were found associated with dense beds of dead coral ( Lophelia pertusa ) rubble or on broken hard bottom. In contrast, Chaunax suttkusi was found on soft bottoms. Chaunax stigmaeus and C. suttkusi appear to be sympatric over a major portion of their ranges. Because knowledge of pigmentation in live or freshly caught Chaunax is critical to distinguish some members of the genus, changes in the colouration of C. suttkusi were noted and documented photographically immediately after death and after fixation. The yellow spots found on some, but not all specimens, temporarily disappeared completely after death, but they reappeared after fixation, slowly disappearing thereafter along with other carotenoid pigments. Lophiodes beroe and Lophiodes monodi were collected for the first time off the Atlantic coast of the U.S., being previously known only from the Gulf of Mexico, Caribbean Sea and the northern coast of South America. For both species ( L. beroe and L. monodi ), the collections included the two largest known representatives of the species (400 and 325 mm standard length, respectively). Lophiodes beroe commonly occurred on L. pertusa rubble, and seemed to prefer this habitat. Occupying such a habitat that is deep and difficult to sample probably explains how this common species escaped detection. Only a single L. monodi was collected or observed, so this species appears to be uncommon in this geographic area or at least so on coral rubble habitat. Detailed aspects of the colour patterns of both species were noted. In particular, L. beroe displayed a characteristic pattern of white patches in life that were not apparent after death. The first photographic documentation of the colour pattern in life and of the pharyngeal pigmentation of Lophiodes reticulatus is provided. The third known specimen of Sladenia shaefersi , and the first to be taken in U.S. waters was collected from coral rubble near the base of a steep 200 m scarp on the Blake Plateau.
Gulf of Mexico↗
Stable isotope data from deep-water antipatharians: 400-Year records from the southeastern coast of the United States of America
In this study, time-series stable isotope results (δ 13 C and δ 15 N) from three deep-water Leiopathes glaberrima (Esper, 1788) specimens Collected off the southeastern Coast of the United States of America and one specimen from the Gulf of Mexico are presented. The specimens were Collected live in 2004 and are estimated to be 200–500 yrs old based on 210 Pb measurements and band Counts. The δ 13 C and δ 15 N long-term trends are reproducible within and among specimens from a similar location, suggesting a common environmental influence. Three western Atlantic specimens have average δ 13 C values of −15.7‰, −16.3‰, and −16.1‰, with the most depleted values from the oldest specimen. The oldest specimen records an enrichment in 13 C of 0.5‰ corresponding to the Little Ice Age. All three specimens show a depletion of 13 C over the past 150 yrs Corresponding to the δ 13 C Suess Effect. The fourth specimen from the Gulf of Mexico has an average δ 13 C value of −16.4‰ and shows no trend in 13 C value with time. All four specimens Contain an enrichment in 15 N over the most recent 75 yrs, with the largest enrichment (3‰) in the Gulf of Mexico specimen. This enrichment is likely a result of increased terrestrial effluent (sewage and manure) reaching the offshore specimens.
Bulletin of Marine Science↗
Anguilliform larvae collected off North Carolina
The distinctive larval stage of eels (leptocephalus) facilitates dispersal through prolonged life in the open ocean. Leptocephali are abundant and diverse off North Carolina, yet data on distributions and biology are lacking. The water column (from surface to 1,293 m) was sampled in or near the Gulf Stream off Cape Hatteras, Cape Lookout, and Cape Fear, North Carolina during summer through fall of 1999-2005, and leptocephali were collected by neuston net, plankton net, Tucker trawl, and dip net. Additional samples were collected nearly monthly from a transect across southern Onslow Bay, North Carolina (from surface to 91 m) from April 2000 to December 2001 by bongo and neuston nets, Methot frame trawl, and Tucker trawl. Overall, 584 tows were completed, and 224 of these yielded larval eels. The 1,295 eel leptocephali collected (combining all methods and areas) represented at least 63 species (nine families). Thirteen species were not known previously from the area. Dominant families for all areas were Congridae (44% of individuals, 11 species), Ophichthidae (30% of individuals, 27 species), and Muraenidae (22% of individuals, ten species). Nine taxa accounted for 70% of the overall leptocephalus catches (in order of decreasing abundance): Paraconger caudilimbatus (Poey), Gymnothorax ocellatus Agassiz complex, Ariosoma balearicum (Delaroche), Ophichthus gomesii (Castelnau), Callechelys muraena Jordan and Evermann, Letharchus aliculatus McCosker, Rhynchoconger flavus (Goode and Bean), Ophichthus cruentifer (Goode and Bean), Rhynchoconger gracilior (Ginsburg). The top three species represented 52% of the total eel larvae collected. Most leptocephali were collected at night (79%) and at depths > 45 m. Eighty percent of the eels collected in discrete depth Tucker trawls at night ranged from mean depths of 59-353 m. A substantial number (38% of discrete depth sample total) of larval eels were also collected at the surface (neuston net) at night. Daytime leptocephalus distributions were less clear partly due to low catches and lower Tucker trawl sampling effort. While net avoidance may account for some of the low daytime catches, an alternative explanation is that many species of larval eels occur during the day at depths > 350 m. Larvae of 21 taxa of typically shallow water eels were collected at depths > 350 m, but additional discrete depth diel sampling is needed to resolve leptocephalus vertical distributions. The North Carolina adult eel fauna (estuary to at least 2,000 m) consists of 51 species, 41% of which were represented in these collections. Many species of leptocephali collected are not yet known to have juveniles or adults established in the South Atlantic Bight or north of Cape Hatteras. Despite Gulf Stream transport and a prolonged larval stage, many of these eel leptocephali may not contribute to their respective populations. ?? 2006 Springer-Verlag.
Marine Biology↗
Patterns of fish use and piscivore abundance within a reconnected saltmarsh impoundment in the northern Indian River Lagoon, Florida
Nearly all saltmarshes in east-central, Florida were impounded for mosquito control during the 1960s. The majority of these marshes have since been reconnected to the estuary by culverts, providing an opportunity to effectively measure exchange of aquatic organisms. A multi-gear approach was used monthly to simultaneously estimate fish standing stock (cast net), fish exchange with the estuary (culvert traps), and piscivore abundance (gill nets and bird counts) to document patterns of fish use in a reconnected saltmarsh impoundment. Changes in saltmarsh fish abundance, and exchange of fish with the estuary reflected the seasonal pattern of marsh flooding in the northern Indian River Lagoon system. During a 6-month period of marsh flooding, resident fish had continuous access to the marsh surface. Large piscivorous fish regularly entered the impoundment via creeks and ditches to prey upon small resident fish, and piscivorous birds aggregated following major fish movements to the marsh surface or to deep habitats. As water levels receded in winter, saltmarsh fish concentrated into deep habitats and emigration to the estuary ensued (200% greater biomass left the impoundment than entered). Fish abundance and community structure along the estuary shoreline (although fringed with marsh vegetation) were not analogous to marsh creeks and ditches. Perimeter ditches provided deep-water habitat for large estuarine predators, and shallow creeks served as an alternative habitat for resident fish when the marsh surface was dry. Use of the impoundment as nursery by transients was limited to Mugil cephalus Linnaeus, but large juvenile and adult piscivorous fish used the impoundment for feeding. In conclusion, the saltmarsh impoundment was a feeding site for piscivorous fish and birds, and functioned as a net exporter of forage fish to adjacent estuarine waters. ?? Springer 2006.
Wetlands Ecology and Management↗
Deep-water antipatharians: Proxies of environmental change
Deep-water (307-697 m) antipatharian (black coral) specimens were collected from the southeastern continental slope of the United States and the north-central Gulf of Mexico. The sclerochronology of the specimens indicates that skeletal growth takes place by formation of concentric coeval layers. We used 210Pb to estimate radial growth rate of two specimens, and to establish that they were several centuries old. Bands were delaminated in KOH and analyzed for carbon and nitrogen stable isotopes. Carbon values ranged from -16.4??? to -15.7???; oldest specimen displayed the largest range in values. Nitrogen values ranged from 7.7??? to 8.6???. Two specimens from the same location and depth had similar 15N signatures, indicating good reproducibility between specimens. ?? 2006 Geological Society of America.
Geology↗
Fate of fish production in a seasonally flooded saltmarsh
Although saltmarshes are thought to enhance the productivity of open estuarine waters, the mechanism by which energy transfer occurs has been debated for decades. One possible mechanism is the transfer of saltmarsh production to estuarine waters by vagile fishes and invertebrates. Monthly estimates of fish standing stock, net fish ingress, and predation were used to develop a biomass budget to estimate annual production of fishes and the relative yield to predatory fish, birds, and direct migration to the estuary. Annual production of saltmarsh fishes was estimated to be 31.0 g m-2 saltmarsh, which falls within the range of previously reported values for estuarine fish communities. The relative yields were 12 to 20% to piscivorous fishes, 8 to 13% to piscivorous birds, and 18 to 29% to export. Annual export of fish biomass was 5.6 g fish m-2 saltmarsh, representing about 1 to 2% of saltmarsh primary production. Saltmarsh fishes convert marsh production to high-quality vagile biomass (fishes concentrate energy, protein, and nutrients as body mass) and move this readily useable production to the estuary, providing an efficient link between saltmarshes and estuarine predators. ?? Inter-Research 2006.
Marine Ecology Progress Series↗
Quantitative assessment of benthic food resources for juvenile Gulf sturgeon, Acipenser oxyrinchus desotoi in the Suwannee River estuary, Florida, USA
Gulf sturgeon, Acipenser oxyrinchus desotoi , forage extensively in the Suwannee River estuary following emigration out of the Suwannee River, Florida. While in the estuary, juvenile Gulf sturgeon primarily feed on benthic infauna. In June–July 2002 and February–April 2003, random sites within the estuary were sampled for benthic macrofauna (2002 n = 156; 2003 n = 103). A mean abundance of 2,562 ind m −2 (SE ± 204) was found in the summer, with significantly reduced macrofaunal abundance in the winter (mean density of 1,044 ind m −2 , SE ± 117). Benthic biomass was significantly higher in the summer with an average summer sample dry weight of 5.92 g m −2 (SE ± 0.82) compared to 3.91 g m −2 (SE ± 0.67) in the winter. Amphipods and polychaetes were the dominant taxa collected during both sampling periods. Three different estimates of food availability were examined taking into account principal food item information and biomass estimates. All three estimates provided a slightly different view of potential resources but were consistent in indicating that food resource values for juvenile Gulf sturgeon are spatially heterogeneous within the Suwannee River estuary.
Florida↗
Further evidence for the invasion and establishment of Pterois volitans (Teleostei: Scorpaenidae) along the Atlantic Coast of the United States
We document the continued population expansion of red lionfish, Pterois volitans, the first documented successful introduction of an invasive marine fish species from the western Pacific to Atlantic coastal waters of the United States. Red lionfish are indigenous to the Indo-Pacific and have apparently established one or more breeding populations on reefs off the southeastern United States. Fifty-nine specimens, most presumably adult red lionfish, were documented or collected on live-bottom reefs off North Carolina, South Carolina, and Florida, and on a manmade structure off Georgia. Observation/collection depths and bottom water temperatures for these fish ranged from 40-99 m and 13.8-24.4??C, respectively. Eleven juvenile lionfish, believed to be expatriated from southeastern waters, were collected in estuaries along the coast of Long Island, NY, at depths of 0-5 m and water temperatures ranging from 13.8-16.5??C. Twelve of the total 70 specimens collected or observed were positively identified as red lionfish. Based on histological assessment of gonad tissue, two reproductively-active males and one immature female were collected. The life history of red lionfish, especially their reproductive biology and food habits, should be investigated along the east coast of the US to determine the potential impacts of this species on ecosystems they have invaded.
Southeastern Naturalist↗
Marine fishes new to continental United States waters, North Carolina, and the Gulf of Mexico
Along the southeastern coast of the United States, hardground systems support a high diversity of sub-tropical and tropical fishes. Many of these hardgrounds occur in deep (ca. ??? 50 m) waters and their fauna is still poorly described; however, with concentrated sampling in these deeper areas, new records of fishes continue to emerge. In the northeastern Gulf of Mexico and off North Carolina, we used the Johnson-Sea-Link submersible, remotely operated vehicles, trawling gear, and angling gear to sample deep reef systems (38-248 m). We document five records of fishes new to continental United States waters, including Liopropoma aberrans, Parasphyraenops incisus, Lipogramma regia, Apogon gouldi, and Prognathodes guyanensis. We also report range extensions for eleven species: Gymnothorax hubbsi, Gymnothorax vicinus, Lepophidium staurophor, Cypselurus comatus, Liopropoma mowbrayi, Serranus annularis, Rypticus saponaceus, Caranx lugubris, Prognathodes aculeatus, Centropyge argi, and Canthigaster jamestyleri.
Southeastern Naturalist↗
Movements of Gulf sturgeon (Acipenser oxyrinchus desotoi) in nearshore habitat as determined by acoustic telemetry
Gulf sturgeon were tagged with telemetry tags and were tracked and relocated in fall and early winter of 1996 and 1998 to determine migration patterns and winter feeding habitats after they emigrated from the Suwannee River, Florida, into the Gulf of Mexico. We hypothesized that their migration would generally follow the drowned Suwannee River channel across the West Florida shelf. Fish left the river in late Oct. or early Nov., about the time river water temperatures fell below 20 C. Tracked and relocated fish moved slowly and remained offshore of Suwannee Sound in nearby shallow (<6 m) marine-estuarine habitats until at least mid or late Dec. The relatively small area (~115km 2 ) within which fish were consistently relocated in 1998 probably is a critically important feeding habitat because adult Gulf sturgeon, which do not feed while in the river, occupy it for up to half their short (4-5 mo) marine residency. The fish left the area in late Dec. or early Jan., most likely in response to powerful cold front-generated weather conditions (under which, boat-based acoustic tracking is infeasible). A large (1,760 km 2 ) adjacent area was searched for sonic-tagged sturgeon in early Jan. 1999, but only one was relocated (~50 km northwest of the Nov.-Dec. area). Although we were unable to address the hypothesis that their migration follows the Suwannee paleochannel, the results do indicate that Gulf sturgeon move to yet unknown, distant, late-winter feeding areas of the Gulf of Mexico before returning to the river in spring.
Florida↗
Why do sturgeon jump? Insights from acoustic investigations of the Gulf sturgeon in the Suwannee River, Florida
No abstract available.
Florida↗
Understanding sturgeon life history: Enigmas, myths, and insights from scientific studies
No abstract available.
Journal of Applied Ichthyology↗
Physiography and late Quaternary-Holocene processes of Northeastern Gulf of Mexico outer continental shelf off Mississippi and Alabama
High-resolution multibeam mapping of the mid- and outer continental shelf and upper slope off Mississippi and Alabama reveals a complex bathymetry that reflects conditions during the last eustatic rise and the present high stand of sea level. The most prominent bathymetric features are pinnacles and hardgrounds that are scattered throughout the area. These features generally stand <10 m above the surrounding seafloor, cover large areas, and display a variety of morphologies. Almost all the reef pinnacles and hardgrounds have zones of high acoustic backscatter on their summits and on the seafloor immediately adjacent to their southwest walls. In addition, they also have erosional moats on the seafloor to the southwest. Large fields of bedforms are scattered throughout the mapped area. The asymmetries and orientations of the bedforms suggest that they were formed by excursions of the northeast-flowing Loop Current. In contrast, the pervasive ponding of sediment on the northeast sides of bathymetric highs indicates that one of the predominant directions of sediment transport has been to the south and southwest. The shelf break is a zone of numerous landslides of various sizes and complexities. The morphology of several landslide scars indicates that some of the failures occurred recently. One large reef-capped salt dome was mapped in the area, surrounded by a large field of pock-marks. Fields of pockmarks are also scattered on the shelf. The growth and demise of the reefs are related to the fluctuating transgression of eustatic sea level during the last deglaciation. Two episodes of reef drowning are correlated with the increased rates of sea-level rise during documented melt-water pulses; the first occurred from 14.8 to 14.2 ka and the second from 11.8 to 11.2 ka. Rates of sea-level rise exceeded the maximum growth rate of hermatypic corals only during these two intervals since the last glacial maximum and thus drowned the coral communities.
Alabama, Mississippi↗