Sheepshead Archosargus Probatocephalus Research Articles

Morphological, histopathological, ultrastructural and phylogenetic analysis of Henneguya archosargus n. sp. (Cnidaria, Myxosporea) infecting the sparid fish Archosargus probatocephalus in Brazilian waters

The introduction of new fish species to the aquaculture industry is essential to halt the progressive decline of natural fish stocks. The sheepshead Archosargus probatocephalus is a commercially valuable sparid fish with potential for breeding in captivity, but with limited information regarding parasitic infections that could pose a significant threat for its sustainable production. Thus, the present study aimed to study the myxozoan diversity infecting A. probatocephalus. A novel Henneguya sp. was detected forming plasmodia in the gill lamellae of specimens inhabiting the Brazilian coast, and is characterized based on morphological, histopathological, ultrastructural, molecular, and phylogenetic data. Myxospore total length was 21.3 ± 0.8 μm, with myxospore body 10.0 ± 0.5 μm long, 6.2 ± 0.3 μm wide, and 4.8 ± 0.5 μm thick. Caudal appendages were 10.3 ± 0.5 μm long and did not present any type of coating. Two pyriform polar capsules, 3.4 ± 0.3 μm long and 1.5 ± 0.2 μm wide, each containing an isofilar polar tubule with 4–5 coils. Histopathological analyses showed large intralamellar polysporic plasmodia associated with vascular congestion of the gill filament and gill lamellae, as well as epithelial hyperplasia causing partial or total fusion of gill lamellae. Maximum likelihood and Baysesian inference SSU rDNA-based phylogenetic analyses showed the novel sequence grouped within the marine clade of Henneguya spp. that mostly parasitize fishes belonging to Eupercaria incertae sedis.

A method for long-term retention of pop-up satellite archival tags (PSATs) on small migratory fishes.

Achieving long-term retention of pop-up satellite archival tags (PSATs) has proven difficult for all fishes but is particularly challenging for small migrant species due to the relatively large size of tags. In this study, the authors tested the latest and smallest PSAT model on the market, the mark-report satellite tag (mrPAT), and developed a simple, cost-effective method of tag attachment on sheepshead Archosargus probatocephalus (Walbaum 1792), a small marine fish. During laboratory trials, the method of tag attachment used in this study outperformed the existing methods with two c. 40 cm fish retaining their tags for 3 months (the duration of the laboratory study). During field deployments, data were successfully obtained for 17 of the 25 tagged fish [37-50 cm fork length (FL)]. Of these, 14 tags (82%) remained on the fish until the pre-programmed release date resulting in tag retention times of up to 172 days (mean: 140 days). The investigation represents the first extensive study into the feasibility of PSATs for monitoring fishes in this size range. The authors demonstrate that their method of attachment and this latest PSAT model are feasible for c. 5-month deployments on fishes that are relatively small (c. 45 cm FL). These results with A. probatocephalus represent a potentially significant advance in PSAT methodology for fishes of this size. Future investigations are needed to determine if this method is transferrable to other species in the same size range.

Bycatch in a Coastal Black Drum Trotline Fishery

AbstractBycatch remains a challenging issue for many fisheries across the globe. Due to the cost and effort of (bycatch) observer programs, many fisheries—particularly those not in U.S. federal waters—operate with little information about bycatch. The Black Drum Pogonias cromis and Sheepshead Archosargus probatocephalus fishery in Louisiana comprises one of the largest fisheries by volume and in recent years has exceeded US$5 million in annual value. The vast majority of Black Drum and Sheepshead are harvested by the baited trotline fishery that operates in state waters. Very little is known about the bycatch from this fishery; however, because of the magnitude of the fishery quantifying bycatch is needed for the management of this resource. We observed 59 baited trotline sets on 13 different dates spanning 2 years of sampling (2020–2021). The total bycatch (n = 1,392) was similar in number to the harvest of the target species (n = 1,265). However, most bycatch species were nongame fishes and were released alive. Of all the bycatch caught, only 4% was dead and the majority of that 4% (47 out of 57 fish) consisted of Gafftopsail Catfish Bagre marinus and Hardhead Catfish Ariopsis felis, both species for which there is little fishery and no known issues with the populations. We also found that catch rates for bycatch did not vary by season or between the two areas fished. The catch rate of bycatch did not increase as the catch rate of target species increased; although, as expected, bycatch mortality did significantly increase as water temperature increased. Overall, the baited trotline fishery for Black Drum and Sheepshead catches about one individual of bycatch for one target individual; however, the overall extremely low bycatch mortality (of common species) suggests that this fishery operates with few adverse effects on nontarget species.

Underwater Video as a Tool to Quantify Fish Density in Complex Coastal Habitats

Habitat loss is a serious issue threatening biodiversity across the planet, including coastal habitats that support important fish populations. Many coastal areas have been extensively modified by the construction of infrastructure such as ports, seawalls, docks, and armored shorelines. In addition, habitat restoration and enhancement projects often include constructed breakwaters or reefs. Such infrastructure may have incidental or intended habitat values for fish, yet their physical complexity makes quantitatively sampling these habitats with traditional gears challenging. We used a fleet of unbaited underwater video cameras to quantify fish communities across a variety of constructed and natural habitats in Perdido and Pensacola Bays in the central northern Gulf of Mexico. Between 2019 and 2021, we collected almost 350 replicate 10 min point census videos from rock jetty, seawall, commercial, public, and private docks, artificial reef, restored oyster reef, seagrass, and shallow sandy habitats. We extracted standard metrics of Frequency of Occurrence and MaxN, as well as more recently developed MeanCount for each taxon observed. Using a simple method to measure the visibility range at each sampling site, we calculated the area of the field of view to convert MeanCount to density estimates. Our data revealed abundant fish assemblages on constructed habitats, dominated by important fisheries species, including grey snapper Lutjanus griseus and sheepshead Archosargus probatocephalus. Our analyses suggest that density estimates may be obtained for larger fisheries species under suitable conditions. Although video is limited in more turbid estuarine areas, where conditions allow, it offers a tool to quantify fish communities in structurally complex habitats inaccessible to other quantitative gears.

Trophic Ecology of Sheepshead and Stone Crabs at Oil and Gas Platforms in the Northern Gulf of Mexico's Hypoxic Zone

AbstractOil and gas platforms (platforms) may provide important habitat for reef‐associated organisms in the Gulf of Mexico's hypoxic zone. While summer hypoxia typically affects the bottom 3.0 m of the water column, platforms span from the bottom to above the surface and provide hard substrate in oxygenated waters overlaying hypoxia. However, little is known about the effects of hypoxia on organisms living at these platforms. We compared diets of Sheepshead Archosargus probatocephalus and Gulf stone crabs Menippe adina during early and late summer at platforms with mild (shoal platforms) and intense hypoxia (seaward platforms) using a combination of stable isotopes (δ13C and δ15N) and gut contents analyses. We hypothesized that diets at seaward platforms would shift from bottom to platform‐dwelling prey during late summer when hypoxia had fully developed and decimated benthic communities, but no such effect was found. Barnacles (Balanidae) were the most common prey found in Sheepshead guts for all samples collected (64.1% of gut contents). Sheepshead gut contents showed high predation of mantis shrimp (Squillidae; 35.2% of gut contents) soon after the formation of hypoxia at seaward platforms, likely reflecting Sheepshead exploiting benthic prey that were vulnerable because of hypoxia. These findings indicate that hypoxia affected the behavior of mantis shrimp in a way that altered their availability for Sheepshead associated with platforms. Comparisons of Sheepshead and stone crab isotope values (δ13C and δ15N) to those of their potential prey and basal sources suggested a high dependence on barnacles (proxy for water column particulate organic matter) and filamentous algae throughout the summer. However, comparisons of isotope values in early and late summer indicated no apparent effect of hypoxia. High contributions of barnacles to Sheepshead diet showed that platform‐dwelling prey were an important resource for Sheepshead.

Sheepshead Foraging Patterns at Oil and Gas Platforms in the Northern Gulf of Mexico

AbstractIn the northern Gulf of Mexico, there are over 2,000 oil and gas platforms (hereafter, “platforms”) that are de facto artificial reefs. The ecological importance of platforms is the subject of debate, but little information exists on the extent to which fish feed on platform‐dwelling benthic organisms. We used a camera array to characterize the frequency and duration of incidents in which Sheepshead Archosargus probatocephalus foraged on platform‐dwelling benthic organisms. We also characterized abundances and distributions of select platform‐dwelling benthic organisms (barnacles, blennies, and stone crabs). Sheepshead foraging was more strongly associated with dissolved oxygen (DO, mg/L; measured at each camera) and time to slack tide (high or low) than other biological (prey densities), physiochemical, locational, or temporal variables. The number of Sheepshead foraging incidents increased by 18.9 incidents·m−2·h−1 (95% confidence interval [CI] = 4.6–33.3) when DO increased by 1.0 mg/L; foraging incidents increased by 4.5 incidents·m−2·h−1 (95% CI = 1.6–7.4) when time to slack tide increased by 1.0 h. The time Sheepshead spent foraging increased by 245.4 s·m−2·h−1 (95% CI = 144.1–346.7) when DO increased by 1.0 mg/L, and time spent foraging increased by 78.0 s·m−2·h−1 (95% CI = 60.5–95.5) when time to slack tide increased by 1.0 h. Abundances of barnacles and blennies decreased with increasing depth. The presence of hypoxia near the seafloor during the late summer appeared to cause barnacle mortality, which shifted barnacle depth distributions upward (i.e., 1–3 m shallower). Platform‐dwelling benthic organisms persisted throughout the hypoxia season and served as prey for Sheepshead.

Teeth penetration force of the tiger shark Galeocerdo cuvier and sandbar shark Carcharhinus plumbeus.

This study examined the minimum force required of functional teeth and replacement teeth in the tiger shark Galeocerdo cuvier and the sandbar shark Carcharhinus plumbeus to penetrate the scales and muscle of sheepshead Archosargus probatocephalus and pigfish Orthopristis chrysoptera. Penetration force ranged from 7·7-41·9 and 3·2-26·3 N to penetrate A. probatocephalus and O. chrysoptera, respectively. Replacement teeth required significantly less force to penetrate O. chrysoptera for both shark species, most probably due to microscopic wear of the tooth surfaces supporting the theory shark teeth are replaced regularly to ensure sharp teeth that are efficient for prey capture.

Omnivory dampens trophic cascades in estuarine communities

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 507:197-206 (2014) - DOI: https://doi.org/10.3354/meps10815 Omnivory dampens trophic cascades in estuarine communities Keith D. Johnson1,*, Jonathan H. Grabowski2, Delbert L. Smee3 1Department of Biological Sciences, Stevenson University, 1525 Greenspring Valley Road, Stevenson, MD 21153, USA 2Marine Science Center, Northeastern University, 430 Nahant Road, Nahant, MA 01908, USA 3Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Dr., Corpus Christi, TX 78412, USA *Corresponding author: kdjohnson@stevenson.edu ABSTRACT: Predators often have large effects on prey populations and entire communities, but the nature of top-down control in speciose food webs is often difficult to assess due to consumer interactions such as complementarity, predator interference, and omnivory. To assess how top and intermediate predators affect community structure, we used predator exclusion experiments designed to isolate predator effects at different trophic levels in a species-rich community. Using oyster Crassostrea virginica reefs as a model system, predators were excluded using mesh-covered cages with openings of 1.0 cm2 (small mesh) to exclude all potential oyster predators, 5.0 cm2 (large mesh) to allow intermediate consumers but not large predators to access oyster reefs, and controls with complete predator access. Natural oyster settlement and survival were greatest in the small mesh cage when oysters were completely protected from consumers. Meanwhile, abundances of adult Panopeus herbstii, the Atlantic mud crab, an intermediate consumer and known oyster predator, were an order of magnitude greater in the large-mesh cage than in the other treatments. Oyster survival did not differ between the large-mesh cage and controls, suggesting that top predators such as blue crabs Callinectes sapidus and sheepshead Archosargus probatocephalus are likely consuming mud crabs (or inducing mud crabs to avoid controls) and consuming juvenile oysters on these oyster reefs. Top-down processes are known to be important on oyster reefs, but in this system, omnivory can overwhelm density-mediated cascading effects of top predators. We also found mud crabs to induce oysters to grow heavier shells and less soft tissue. Efforts to model the direct and indirect effects of predators on ecological communities will benefit from a more thorough understanding of the relative strength of omnivory on cascading effects of top predators. KEY WORDS: Crassostrea virginica · Indirect effects · Lethal and non-lethal effects · Mud crabs · Predator–prey interactions · Food web · Top-down Full text in pdf format PreviousNextCite this article as: Johnson KD, Grabowski JH, Smee DL (2014) Omnivory dampens trophic cascades in estuarine communities. Mar Ecol Prog Ser 507:197-206. https://doi.org/10.3354/meps10815 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 507. Online publication date: July 17, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Fish Assemblages of Shoal‐ and Shoreline‐Associated Seagrass Beds in Eastern Gulf of Mexico Estuaries

AbstractAssemblage structure of fishes associated with seagrasses (order Alismatales) is affected by factors such as depth, seagrass coverage, location of seagrass beds, and proximity of seagrass beds to adjacent habitats. Although these relationships have been well explored for small‐bodied fishes, few studies have examined seagrass habitat use by large‐bodied fishes (>100 mm SL). To examine the effects of habitat characteristics on assemblages of large‐bodied fishes, two seagrass habitat types were sampled in three eastern Gulf of Mexico estuaries (2008–2010) with a 183‐m haul seine: (1) seagrasses immediately adjacent to shorelines and (2) seagrasses associated with shoals (seagrass beds >100 m from shoreline). Within each estuary, fish density was greater (as much as two times greater) in shoal seagrass beds than in those along shorelines. Fish assemblage structure also differed significantly between the two habitat types. Species that distinguished the seagrass shoreline (e.g., Spot Leiostomus xanthurus, Redfin Needlefish Strongylura notata) had affinities for habitats that were relatively shallow, gently sloped, less saline, and muddy with less seagrass coverage. Species that distinguished seagrass shoals (e.g., Pigfish Orthopristis chrysoptera, Silver Perch Bairdiella chrysoura) had affinities for habitats that were deeper, steeply sloped, sandy, and more saline, with greater seagrass coverage. Among economically important fishes, some were more abundant along shorelines (e.g., Common Snook Centropomus undecimalis, Sheepshead Archosargus probatocephalus, and Striped Mullet Mugil cephalus), while others were more abundant on shoals (e.g., Gag Mycteroperca microlepis, Spotted Seatrout Cynoscion nebulosus, and Scaled Sardine Harengula jaguana). This study demonstrates that seagrass shoals, which are being lost in some estuaries, provide different environmental conditions than those along shorelines, support unique fish assemblages, and host greater densities of several economically important species.Received November 12, 2013; accepted March 18, 2014

Age, Growth, and Reproduction of Sheepsheads in South Carolina

AbstractThe sheepshead Archosargus probatocephalus is a common estuarine and reef species that is found year round in South Carolina. Although not commercially important, the sheepshead is a significant recreational species, and most of the fishing pressure occurs in state waters. From 1990 to 2005, 5,692 sheepsheads were collected from fishery‐dependent and fishery‐independent monitoring programs in South Carolina. Fish ranged from 102 to 605 mm in fork length (FL) and were caught during every month of the year. Ages ranged from 0 to 19 years for males and from 0 to 23 years for females; the dominant age‐classes were ages 2–5. Marginal increment analysis confirmed the formation of a single annulus per year, and annulus formation began in May. Males and females did not significantly differ in FL at age t(FLt) or total weight at age t (Wt); the pooled von Bertalanffy growth models were FLt = 498[1 − e −0.297(t + 1.10)] and Wt = 3,778[1 − e −0.165(t − 0.548)]2.997. Both males and females exhibited the first signs of sexual maturity at age 1, and 100% maturity was reached at age 4. Batch fecundity estimated late in the spawning season ranged from 18,400 to 738,500 oocytes/spawning event and averaged 235,000 oocytes/spawning event. Fork length, W, and age were positively correlated with fecundity. Although size was a better predictor of fecundity than age, the relationship was weak due to the high variability in size at age. Comparisons of growth parameters for sheepsheads studied in the southeastern United States indicated that South Carolina sheepsheads tend to have a larger maximum FL and a greater maximum age than fish found in the Gulf of Mexico.Received May 24, 2010; accepted July 26, 2011

Monogenoidean parasites of the gill lamellae of the sheepshead Archosargus probatocephalus (Walbaum) (Perciformes: Sparidae) from the Indian River Lagoon, Florida, with descriptions of four new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae)

Examination of the gill lamellae of three sheepshead Archosargus probatocephalus (Walbaum) from the Indian River Lagoon in Florida revealed six species of Monogenoidea: Microcotyle archosargi MacCallum, 1913 (Microcotylidae); Neobenedenia sp. (Capsalidae); and four new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae). The prevalence of all helminths was 100%, except for Neobenedenia sp., which was represented by a single immature specimen. The four new species, Euryhaliotrema carbuncularium n. sp., E. dunlapae n. sp., E. amydrum n. sp. and E. spirulum n. sp., are described and with E. carbunculus (Hargis, 1955) Kritsky & Boeger, 2002 apparently constitute a monophyletic clade of Euryhaliotrema spp. that parasitise sparid hosts in the western hemisphere. The Indian River Lagoon in Florida represents a new locality record for M. archosargi, and the sheepshead is apparently a new host record for a member (Neobenedenia sp.) of the Capsalidae.

Aphanomyces invadans and Ulcerative Mycosis in Estuarine and Freshwater Fish in Florida

In the spring of 1998, the Florida Fish and Wildlife Research Institute received numerous reports of lesioned or ulcerated fish primarily from the St. Lucie Estuary on the southeast coast of Florida, an area known since the late 1970s for lesions of the ulcerative mycosis (UM) type. From these and archived reports, as well as others received from different areas of Florida, we documented that diseased specimens had randomly distributed skin ulcers (usually reddened or hemorrhagic) with raised irregular margins and, in some cases, deeply penetrating hyphae in the surrounding muscle tissue. Since 1998, 256 fish (comprising 18 species) with ulcerative lesions (from 15 different locations) were confirmed with hyphae in fresh squash preparation or by histological evaluation. Squash preparations revealed nonseptate, sparsely branching, thick-walled hyphae; histological sections revealed mycotic granulomas in the dermis that occasionally penetrated into the skeletal muscle. These pathological characteristics were consistent with UM caused by the oomycete Aphanomyces invadans in Southeast Asia, Japan, Australia, and the United States. For specific identification, six isolates from ulcerated fish were cultured and prepared for molecular characterization using established diagnostic methods. Ribosomal RNA gene sequence analysis identified three isolates as Aphanomyces invadans, one as the oomycete Achlya bisexualis, and two as the ascomycete Phialemonium dimorphosporum. A more extensive survey of 67 ulcerated skin samples from fish collected between 1998 and 2003 was performed using a polymerase chain reaction assay specific for Aphanomyces invadans. Of these, 26 (38.8%) samples from seven fish species and nine collection locations were positive. Confirmation of UM associated with Aphanomyces invadans represents new host records in Florida for the sheepshead Archosargus probatocephalus, striped mullet Mugil cephalus, white mullet Mugil curema, silver perch Bairdiella chrysoura, black drum Pogonias cromis, largemouth bass Micropterus salmoides, and American shad Alosa sapidissima.

Guanine in strata argentea of fish eyes

Guanine was found to be the main component in extracts of argentea of redfish Sciaenops ocellata (Sciaenidae) and chorioids of sheepshead Archosargus probatocephalus (Sparidae). The argenteum of the redfish contained 1.55 mg guanine/cm2 surface area of chorioid. Hypoxanthine content was about [Formula: see text] that of guanine. The purines occurred as bisymmetrical hexagonal crystals ranging in shape from needles to platelets.