Vertical migration of blue crab Callinectes sapidus megalopae: implications for transport in estuaries

Following larval development in coastal waters, postlarvae (megalopae) of the blue crab Callinectes sapidus Rathbun enter inlets and, against the net seaward flow of estuarine waters, move upstream to juvenile habitats. Abundance and vertical distribution of blue crab megalopae in the York River, Virginia, USA, a subsetuary of Chesapeake Bay, was quanitified to examine the hypothesis that megalopae are not transported simply as passive particles, but display behaviors that augment their immigration. Megalopal abundance and depth distribution and environmental variables were measured at shallow (3 to 4 m) sites in 1988 and 1989 and at a deep (10 m) site in 1990. Megalopae were more abundant in the water column during flood than ebb, indicating a net upstream flux of megalopae. Densities were always low during ebb. Highest densities occurred during night flood tides, when megalopae were aggregated near the surface. During day flood tides, megalopae were generally less abundant and distributed deeper in the water column. Occasionally, however, they were abundant during day flood, concentrated near the bottom in deep water. At shallow sites, megalopae were never abundant during day, apparently not ascending into well-lit water. Abundance and depth distribution of megalopae were not affected by current speed, wind speed, water temperature or salinity. A conceptual model of vertical migration of estuarine blue crab megalopae is presented. Megalopae which behave according to this model should lower their susceptibility to predation in the water column by selectively utilizing flood currents to rapidly reach juvenile nursery grounds while avoiding well-lit waters

Introduction to the Proceedings of the Blue Crab Recruitment Symposium

The blue crab, Callinectes sapidus Rathbun, is found in all major coastal habitats along the mid-Atlantic, South Atlantic and Gulf of Mexico coasts of the United States, including large embayments, barrier island-lagoonal systems, and coastal marsh, mangrove and seagrass systems. Ecologically important, blue crabs may control abundances of other estuarine benthic species (Hines et aI., 1990). The blue crab also supports valuable commercial and recreational fisheries from New Jersey to Texas; commercial landings of 249.3 million pounds of hard blue crabs in 1993 had a dockside value of 126.6 million dollars (NMFS, 1994). Blue crab stocks vary interannually within and between regions as reflected in fishery catch records, which have been compiled since the early 1900s, and in fisheryindependent data sets. This variability apparently is unrelated to fishing pressure and has been attributed to environmental influences on blue crab recruitment. Published studies of blue crab biology date back to the turn of the century (Hay, 1905), but our understanding of the early life history of the species has been markedly refined over the past 3 decades. The complete larval development (7 zoea and I megalopa) of the blue crab was not described until 1959 (Costlow and Bookhout, 1959), and early accounts of blue crab life history suggested that the larval stages were retained within estuaries (Churchill, 1919; Van Engel, 1958). During the 1960s and early 1970s, however, studies of larval/postlarval distributions indicated that blue crab larvae might not be retained in estuaries but instead are exported to coastal waters with subsequent return by postlarvae (megalopae) or juveniles (Nichols and Keney, 1963; Tagatz, 1968; Dudley and Judy, 1971; King, 1971; Williams, 1971; Sandifer, 1975)

Variation In Planktonic Availability And Settlement Of Blue-Crab Megalopae In The York River, Virginia

Blue crab, Callinectes sapidus, megalopae and juveniles were sampled in the plankton and on natural (grassbeds) and artificial settlement substrates (collectors) at two sites in each of two areas of a lower Chesapeake Bay tributary (York River, Virginia) to examine spatial variability in blue crab recruitment. Spatial patterns of abundance were not consistent across habitats (plankton, artificial collectors and grassbeds) or time. Densities of planktonic megalopae were homogeneous at 1-2 m (within site) but varied at spatial scales of hundreds of meters (between sites) and kilometers (between areas). Settled megalopae were distributed unevenly within and between sites, but their abundance did not differ between areas. Densities of megalopae and first-stage juveniles in grass beds correlated with megalopal abundance in the plankton. Settlement on collectors, however, was not correlated with planktonic density, probably because of low sample size. Total juvenile abundance exhibited lower spatial and temporal variability in grassbeds than that of megalopae or first-stage juveniles, suggesting high post-settlement mortality or migration from areas of high settlement

A prospective investigation of swallowing, nutrition, and patient-rated functional impact following altered fractionation radiotherapy with concomitant boost for oropharyngeal cancer

Altered fractionation radiotherapy for head and neck cancer has been associated with improved locoregional control, overall survival, and heightened toxicity compared with conventional treatment. Swallowing, nutrition, and patient-perceived function for altered fractionation radiotherapy with concomitant boost (AFRT-CB) for T1–T3 oropharyngeal squamous cell carcinoma (SCC) have not been previously reported. Fourteen consecutive patients treated with AFRT-CB for oropharyngeal SCC were recruited from November 2006 to August 2009 in a tertiary hospital in Brisbane, Australia. Swallowing, nutrition, and patient-perceived functional impact assessments were conducted pretreatment, at 4–6 weeks post-treatment, and at 6 months post-treatment. Deterioration from pretreatment to 4–6 weeks post-treatment in swallowing, nutrition, and functional impact was evident, likely due to the heightened toxicity associated with AFRT-CB. There was significant improvement at 6 months post-treatment in functional swallowing, nutritional status, patient-perceived swallowing, and overall function, consistent with recovery from acute toxicity. However, weight and patient perception of physical function and side effects remained significantly worse than pretreatment scores. The ongoing deficits related to weight and patient-perceived outcomes at 6 months revealed that this treatment has a long-term impact on function possibly related to the chronic effects of AFRT-CB

2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal wall hernias may be associated with worsen outcome and a significant rate of postoperative complications. There is no consensus on management of complicated abdominal hernias. The main matter of debate is about the use of mesh in case of intestinal resection and the type of mesh to be used. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh. The recurrence rate is an important topic that influences the final outcome. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013 with the aim to define recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. In 2016, the guidelines have been revised and updated according to the most recent available literature.Peer reviewe

WSES guidelines for emergency repair of complicated abdominal wall hernias

Peer reviewe

Laparoscopic ventral hernia repair: a systematic review

BackgroundLaparoscopic ventral hernia repair may be an alternative to open mesh repair as it avoids a large abdominal incision, and thus potentially reduces pain and hospital stay. This review aimed to assess the safety and efficacy of laparoscopic ventral hernia repair in comparison with open ventral hernia repair.MethodA systematic review was conducted, with comprehensive searches identifying six randomised controlled trials (RCTs) and eight nonrandomised comparative studies.ResultsThe laparoscopic approach may have a lower recurrence rate than the open approach and required a shorter hospital stay. Five RCTs (Barbaros et al., Hernia 11:51-56, 2007; Misra et al., Surg Endosc 20:1839-1845, 2006; Navarra et al., Surg Laparosc Endosc Percutan Tech 17:86-90, 2007; Moreno-Egea et al., Arch Surg 137:266-1268, 2002; Carbajo et al., Surg Endosc 13:250-252, 1999) reported no conversion (0%) to open surgery, and four nonrandomised studies reported conversions to open surgery ranging from 0% to 14%. Open approach complications generally were wound related, whereas the laparoscopic approach reported both wound- and procedure-related complications and these appeared to be less frequently reported.ConclusionBased on current evidence, the relative safety and efficacy of the laparoscopic approach in comparison with the open approach remains uncertain. The laparoscopic approach may be more suitable for straightforward hernias, with open repair reserved for the more complex hernias. Laparoscopic ventral hernia repair appears to be an acceptable alternative that can be offered by surgeons proficient in advanced laparoscopic techniques.Clarabelle T. Pham, Caryn L. Perera, D. Scott Watkin, Guy J. Madder