Effects of harvesting methods on sustainability of a bay scallop fishery: dredging uproots seagrass and displaces recruits

Fishing is widely recognized to have profound effects on estuarine and marine ecosystems (Hammer and Jansson, 1993; Dayton et al., 1995). Intense commercial and recreational harvest of valuable species can result in population collapses of target and nontarget species (Botsford et al., 1997; Pauly et al., 1998; Collie et al. 2000; Jackson et al., 2001). Fishing gear, such as trawls and dredges, that are dragged over the seafloor inflict damage to the benthic habitat (Dayton et al., 1995; Engel and Kvitek, 1995; Jennings and Kaiser, 1998; Watling and Norse, 1998). As the growing human population, over-capitalization, and increasing government subsidies of fishing place increasing pressures on marine resources (Myers, 1997), a clear understanding of the mechanisms by which fishing affects coastal systems is required to craft sustainable fisheries management

Some Observations on Electron Micrographs of Quartz Sand Grains

Author Institution: Department of Geology, The Ohio State University, Columbus, Ohio 43210Electron micrographs of sand grains from southern Piedmont saprolites, temperate and polar glacial deposits, and the St. Peter Sandstone are presented. Sand-grain surface features of saprolite grains are described for the first time and from these some concept of the initial surface of a quartz sand grain is obtained. Micrographs of the sand grains from glacial deposits whose erosional history was limited to ice action uniformly show strongly striated surfaces. Comparison of the features described here with those offered as criteria for a glacial history by previous workers suggests the need for further evaluation of the published criteria. Further study should be made of sand-grain surfaces using sands which have been exposed to a single erosional agent to allow for the determination of more rigorously denned criteria for the interpretation of their geologic history

The influence of seagrass cover on population structure and individual growth rate of a suspension-feeding bivalve, Mercenaria mercenaria

The average density of Mercenaria mercenaria in 216 ¼-m2 samples taken in spring 1980 from an eelgrass (Zostera marina) bed in Back Sound, North Carolina, was 9.0 m–2, more than five times the average density (1.6 m–2) in 216 ¼-m2 samples from a nearby sand flat. Size-frequency distributions differed between environments, with the sand flat containing a larger fraction of its Mercenaria in the smallest size class (0–1 cm). Use of internal growth lines to age all Mercenaria collected revealed that age-frequency distributions also differed between environments but that average Mercenaria age was identical in the two collections. The average sizes of 0-, 1-, and 2-year-class Mercenaria were significantly greater in the seagrass collection. Furthermore, the logarithmic growth curve fit through the mean sizes of each year class for the seagrass collection fell significantly above the analogous sand-flat curve for all ages, implying higher growth rates inside the seagrass environment. The seagrass environment contained a higher proportion of finer sediments, more silts and clays, and higher organic content both in surface (0–2 cm) and-in deep (0–20 cm) cores. Current velocities measured by dye release in the field demonstrated a substantial baffling effect by the seagrass, with average surface velocities above the blades about 3–5 × average velocities at depths within the seagrass canopy. This baffling by seagrass reduced currents near the bottom, where Mercenaria feeds, to levels 50% lower than those measured simultaneously on the sand flat. The paradoxically higher growth rate of the filter-feeding Mercenaria in the lower current regime inside the seagrass bed may be a consequence of higher particulate food concentrations produced by the hydrodynamic baffling of the emergent vegetation

Ecological consequences of mechanical harvesting of clams

A field experiment was performed in 1,225 m2 plots in each of two shallow estuarine habitats, a seagrass bed and a sand flat. in Back Sound, North Carolina (USA), to test the impact of clam raking and two different intensities of mechanical harvesting of clams ("clam kicking") for up to 4 years on 11 hard clam, Mercenaria mercenaria, recruitment, 2) seagrass biomass, 3) the density of benthic macroinvertebrates, and 4) the density of bay scallops, Argopecten irradians. The removal of adult hard clams with the contingent sediment disturbance had ambiguous effects on the recruitment of hard clams: in the sand flat recruitment tended to be lower (but not significantly) in intense-clam-kicking matrices than in controls, whereas in seagrass recruitment of hard clams did not not show a clear response to treatment. In the raking and light-clam-kicking matrices, seagrass biomass fell immediately by ≌25% below controls but full recovery occurred within a year. In the intense-clam-kicking matrices, seagrass biomass fell by ≌65% below levels expected from controls; recovery did not begin until more than 2 years passed, and seagrass biomass was still ≌35% lower than predicted from controls 4 years later. Clam harvest did not affect either the density or species composition of small benthic macroinvertebrates from sediment cores, probably because of their rapid capacity for recolonization and generally short life spans. In all treatments, densities of benthic macroinvertebrates (mostly polychaetes) were substantially higher in the seagrass than in the sand flat during October samplings but equal during March samplings. Bay scallop density declined with declining seagrass biomass across harvest treatments, but the intense-clamkicking matrices contained even fewer bay scallops than their seagrass biomass would predict, perhaps because of enhanced patchiness of the remaining seagrass. The relative inertia of the change in seagrass biomass following extensive destruction in the intensely kicked matrices suggests that seagrass replanting may be an extremely important means of returning disturbed, unvegetated areas to seagrass systems. Emergence during summer of a between-habitat gradient in infaunal densities (higher in seagrass than in sand) supports the hypothesis that seagrass provides a partial prey refuge for infaunal invertebrates. The failure of the benthic macroinvertebrate density to respond to clam harvest treatments in both sand flats and seagrass beds implies that the polychaetes which dominate recover rapidly from disturbance and are probably not adversely affected by clam harvest. The negative and long-lasting impact ofintense hard clam harvest on seagrass biomass with its effects on other fisheries, including bay scallops, implies that hard clam fisheries should be managed to minimize the intensity of harvest within seagrass beds

The Isotopic Composition of Strontium in Fossils from the Kendrick Shale, Kentucky

Author Institution: Department of Geology and Mineralogy, The Ohio State UniversityNine analyses of the isotopic composition of strontium in the carbonate shells of marine fossils from the Kendrick Shale (Lower Pennsylvanian) of Kentucky indicate an average 87Sr/86Sr ratio of 0.7086^O.OOOSS at the 95 percent confidence limit. This value is in satisfactory agreement with previous measurements by Peterman et al. (1970) and confirms that strontium in the oceans during Early Pennsylvanian time was anomalously enriched in radiogenic 87Sr, compared to that in earlier and later periods. The isotopic composition of strontium in skeletal clacium carbonate of cephalopods, gastropods, and brachiopods from the Kendrick Shale appears to be the same in spite of the different feeding habits of these animals

Basin-scale coherence of population dynamics of an exploited marine invertebrate, the bay scallop: implications of recruitment limitation

Direct effects of a red tide (Ptychodiscus brevis) outbreak on bay scallops Argopecten irradians concentricus in North Carolina, from October 1987 to February 1988 were necessarily limited to the two generations then present (adults of the year-class fished in winter 1987-88 and their progeny harvested in 1988-89), yet the three subsequent year-classes of bay scallops also have been extremely depressed. The fishery crashed to 10-15% of the recent (25 yr) historical average harvest; no recovery has yet begun. This inability to recover quickly along with evidence of a previous gradual (5-12 yr) though erratic recovery from low population size in the early 1970's implies that this scallop population may be recruitment-limited at low density, probably by mesoscale or sound-wide abundance of spawning adults, creating lasting effects of the red tide propagated through basin-scale population inertia. -from Author

Insoluble Residue Studies of the Columbus and Delaware Limestones in Ohio

Author Institution: Department of Geology, The Ohio State University, Columbus 10 ; Columbus, Ohio ; Standard Oil Company of Texas, Houston Texas and Lion Oil Company, Denver Colorad

Clinical and cost-effectiveness of an adapted intervention for preschoolers with moderate to severe intellectual disabilities displaying behaviours that challenge: the EPICC-ID RCT

Background: Stepping Stones Triple P is an adapted intervention for parents of young children with developmental disabilities who display behaviours that challenge, aiming at teaching positive parenting techniques and promoting a positive parent-child relationship. Objective: To evaluate the clinical and cost-effectiveness of level 4 Stepping Stones Triple P in reducing behaviours that challenge in children with moderate to severe intellectual disabilities. Design, setting, participants: A parallel two-arm pragmatic multisite single-blind randomised controlled trial recruited a total of 261 dyads (parent and child). The children were aged 30-59 months and had moderate to severe intellectual disabilities. Participants were randomised, using a 3 : 2 allocation ratio, into the intervention arm (Stepping Stones Triple P; n = 155) or treatment as usual arm (n = 106). Participants were recruited from four study sites in Blackpool, North and South London and Newcastle. Intervention: Level 4 Stepping Stones Triple P consists of six group sessions and three individual phone or face-to-face contacts over 9 weeks. These were changed to remote sessions after 16 March 2020 due to the coronavirus disease 2019 pandemic. Main outcome measure: The primary outcome measure was the parent-reported Child Behaviour Checklist, which assesses the severity of behaviours that challenge. Results: We found a small non-significant difference in the mean Child Behaviour Checklist scores (-4.23, 95% CI -9.98 to 1.52, p = 0.146) in the intervention arm compared to treatment as usual at 12 months. Per protocol and complier average causal effect sensitivity analyses, which took into consideration the number of sessions attended, showed the Child Behaviour Checklist mean score difference at 12 months was lower in the intervention arm by -10.77 (95% CI -19.12 to -2.42, p = 0.014) and -11.53 (95% CI -26.97 to 3.91, p = 0.143), respectively. The Child Behaviour Checklist mean score difference between participants who were recruited before and after the coronavirus disease 2019 pandemic was estimated as -7.12 (95% CI -13.44 to -0.81) and 7.61 (95% CI -5.43 to 20.64), respectively (p = 0.046), suggesting that any effect pre-pandemic may have reversed during the pandemic. There were no differences in all secondary measures. Stepping Stones Triple P is probably value for money to deliver (-\ua31057.88; 95% CI -\ua33218.6 to -\ua346.67), but decisions to roll this out as an alternative to existing parenting interventions or treatment as usual may be dependent on policymaker willingness to invest in early interventions to reduce behaviours that challenge. Parents reported the intervention boosted their confidence and skills, and the group format enabled them to learn from others and benefit from peer support. There were 20 serious adverse events reported during the study, but none were associated with the intervention. Limitations: There were low attendance rates in the Stepping Stones Triple P arm, as well as the coronavirus disease 2019-related challenges with recruitment and delivery of the intervention. Conclusions: Level 4 Stepping Stones Triple P did not reduce early onset behaviours that challenge in very young children with moderate to severe intellectual disabilities. However, there was an effect on child behaviours for those who received a sufficient dose of the intervention. There is a high probability of Stepping Stones Triple P being at least cost neutral and therefore worth considering as an early therapeutic option given the long-term consequences of behaviours that challenge on people and their social networks. Future work: Further research should investigate the implementation of parenting groups for behaviours that challenge in this population, as well as the optimal mode of delivery to maximise engagement and subsequent outcomes. Study registration: This study is registered as NCT03086876 (https://www.clinicaltrials.gov/ct2/show/NCT03086876?term=Hassiotis\ub1Angela&draw=1&rank=1). Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: HTA 15/162/02) and is published in full in Health Technology Assessment; Vol. 28, No. 6. See the NIHR Funding and Awards website for further award information.Research shows that in children without learning disabilities, parenting groups which support parents to develop skills to manage behaviours that challenge in their child can be helpful. The National Institute of Health and Care Excellence recommended that more research was needed to strengthen the evidence for such interventions for children with moderate to severe learning disability who are more likely to display behaviours that challenge in England. In this study, we tested in real-world conditions a programme called level 4 Stepping Stones Triple P, which has shown positive results in trials outside of the United Kingdom. Trained therapists delivered six groups and three individual sessions over 9 weeks to parents of children aged 30–59 months with moderate to severe learning disabilities. Two hundred and sixty-one parents were allocated to one of two arms by chance (randomisation): one received Stepping Stones Triple P and treatment as usual and the other treatment as usual only. Treatment as usual included support and advice by general practitioners or community child development teams. Our primary outcome was parent-reported child behaviour at 12 months after randomisation. We also collected data on other outcomes and carried out interviews with parents, service managers and therapists to find out their views about Stepping Stones Triple P. We did not find that Stepping Stones Triple P reduces behaviours that challenge in the child more than treatment as usual at 12 months. However, when we looked at people who received more than half of the sessions, there was a larger reduction in behaviours which suggests that Stepping Stones Triple P works for families if they attend the full programme. Stepping Stones Triple P seems to be good value for money, as we found that at 12 months (covering 10 months of costs), the Stepping Stones Triple P cost \ua31058 less than treatment as usual from a health and social care perspective. As such, Stepping Stones Triple P is fairly cheap to deliver and a suitable early intervention for behaviours that challenge especially because of positive feedback from parents. Throughout the trial, we included a Parent Advisory Group that oversaw study materials, interview topic guides and promotion of the study