A technique for expediting comprehensive written feedback on assignments

Providing detailed feedback in large classes is challenging. We describe how we develop an archive of comments while marking – noting good points, what needs improvement, and how to correct shortcomings. Comments are recorded in a single document with codes. Relevant codes are marked on students’ work where issues arise. Each student’s annotated assignment is returned with a copy of the comments for the class. Thus, they receive specific feedback on their own work, plus all comments given to the class. Instructors save on marking time because comments are written once on the master list, and only codes and a personalized summary statement are written on the assignment. Markers may collaborate in preparing comments to assist in moderation; some generic comments (e.g., presentation and grammar) are portable across different assignments and years; and comments from past years may form a rubric for sharing with students before they start an assignment

Evaluating the effects of artificial oxygenation and hypoxia on biota in the Upper Swan Estuary: Final report

In 2010, the Swan River Trust commissioned Murdoch University to evaluate the effects of artificial oxygenation on the benthic macroinvertebrate (BMI) fauna of the Upper Swan Estuary (USE). The project involved the collection of BMIs monthly between January 2010 and December 2011, at five locations in the USE between Ron Courtney Island and just upstream of Middle Swan Bridge (i.e. the Jane Brook confluence). Specifically, the project had two components; 1) to describe any spatial and/or temporal patterns in the BMI community during eight consecutive seasons in 2010 and 2011 and 2) to assess the ecological and management implications of the findings, with specific reference to the effects of hypoxia (low dissolved oxygen) and of the artificial oxygenation program

Assessment of the condition of the Swan-Canning Estuary in 2015, based on the Fish Community Indices of estuarine condition. Final report to the Department of Parks and Wildlife

This report, commissioned by the Department of Parks and Wildlife, describes the monitoring and evaluation of fish communities in the Swan Canning Riverpark during 2015 and applies the Fish Community Indices (FCI) that have been developed in recent years as a measure of the ecological condition of the Swan Canning Estuary. These indices, developed for the shallow, nearshore waters of the estuary and also for its deeper, offshore waters, integrate information on various biological variables (metrics), each of which quantifies an aspect of the structure and/or function of estuarine fish communities and responds to a range of stressors affecting the ecosystem. Fish communities were sampled using different nets at six nearshore and six offshore sites in each of four management zones of the estuary (Lower Swan Canning Estuary, LSCE; Canning Estuary, CE; Middle Swan Estuary, MSE; Upper Swan Estuary, USE) during summer and autumn of 2015. As many fish as possible were returned to the water alive after they had been identified and counted. The resulting data on the abundances of each fish species from each sample were used to calculate a Fish Community Index score (0-100). These index scores were then compared to established scoring thresholds to determine ecological condition grades (A-E) for each zone and for the estuary as a whole, based on the composition of the fish community

The Contrasting Ecology of Temperate Macrotidal and Microtidal Estuaries

Tidal range is a master factor governing the differences in physico-chemical and biological characteristics between microtidal (2 m) estuaries, which, for convenience, thus include mesotidal estuaries (2–4 m). Microtidal estuaries differ from macrotidal estuaries in geomorphology, tidal water movements, salinity regimes, residence times, turbidity, sedimentology and intertidal area. Consequently, their phytoplankton, microphytobenthos and macrophytes communities differ in biomass and production, areal extent, distribution patterns and composition. Mesozooplankton comprise predominantly autochthonous species in microtidal estuaries and allochthonous species in macrotidal estuaries. Meiobenthos in microtidal estuaries have greater densities in subtidal than intertidal areas and species persist along the estuary. Macrobenthos is dominated by small deposit-feeding species in microtidal estuaries, whereas macrotidal estuaries contain some larger species and suspension feeders. Species richness and abundance of estuarine-resident fish species and the contributions of diving piscivorous birds and wading invertebrate-feeding birds are greater in microtidal estuaries. As paradigms regarding estuarine ecology have been based mainly on northern hemisphere macrotidal systems, this review has redressed this imbalance by detailing the extent of differences between microtidal and macrotidal estuaries. In particular, it uses data and case studies for southern hemisphere microtidal systems to demonstrate that the physico-chemical characteristics and ecology of the main flora and fauna of microtidal estuaries are frequently not consistent with those paradigms

Can biotic indicators distinguish between natural and anthropogenic environmental stress in estuaries?

Because estuaries are naturally stressed, due to variations in salinity, organic loadings, sediment stability and oxygen concentrations over both spatial and temporal scales, it is difficult both to set baseline reference conditions and to distinguish between natural and anthropogenic environmental stresses. This contrasts with the situation in marine coastal and offshore locations. A very large benthic macroinvertebrate dataset and matching concentrations for seven toxic heavy metals (i.e. Cr, Ni, Cu, Zn, Cd, Hg and Pb), compiled over three years as part of the UK's National Marine Monitoring Programme (NMMP) for 27 subtidal sites in 16 estuaries and 34 coastal marine sites in the United Kingdom, have been analysed. The results demonstrate that species composition and most benthic biotic indicators (number of taxa, overall density, Shannon–Wiener diversity, Simpson's index and AZTI's Marine Biotic Index [AMBI]) for sites in estuarine and coastal areas were significantly different, reflecting natural differences between these two environments. Shannon–Wiener diversity and AMBI were not significantly correlated either with overall heavy metal contaminant loadings or with individual heavy metal concentrations (‘normalized’ as heavy metal/aluminium ratios) in estuaries. In contrast, average taxonomic distinctness (Δ+) and variation in taxonomic distinctness (Λ+) did not differ significantly between estuarine and coastal environments, i.e. they were unaffected by natural differences between these two environments, but both were significantly correlated with overall heavy metal concentrations. Furthermore, Δ+ was correlated significantly with the Cu, Zn, Cd, Hg and Pb concentrations and Λ+ was correlated significantly with the Cr, Ni, Cu, Cd and Hg concentrations. Thus, one or both of these two taxonomic distinctness indices are significantly correlated with the concentrations for each of these seven heavy metals. These taxonomic distinctness indices are therefore considered appropriate indicators of anthropogenic disturbance in estuaries, as they allow a regional reference condition to be set from which significant departures can then be determined

Re-establishing recreational prawning in the Swan-Canning Estuary

This project builds on the work of a previous Recreational Fishing Initiatives Fund Project to pilot the culture and of the Western School Prawn (Metapenaeus dalli) in to the Swan-Canning Estuary and increase interest in prawning via a citizen science/community engagement project. Having developed, for the first time, successful aquaculture techniques for this species in the former project, the current project utilised these techniques to release ~2 million hatchery-reared post-larval M. dalli in to the Swan-Canning Estuary. It also produced good-quality data to inform the management of this iconic species, re-engaged community with the prawns and stewardship of the estuary through a citizen science program (Prawn Watch) and developed a refined citizen science monitoring program for M. dalli that could be used in the future

The influence of sediment compositions on the decline of Metapenaeus dalli in a temperate Australian estuary

Abundances of the western school prawn (Metapenaeus dalli) in the Swan-Canning Estuary have declined markedly in the last fifty years. Together with the decrease in abundance, there is strong anecdotal evidence from recreational fishers that the spatial distribution of this penaeid has changed as this species no longer being caught in the middle and upper reaches of the estuary. This is a marked shift in distribution, as work conducted in the 1980s showed that individuals of this species moved upstream from the lower reaches of estuary once salinity in these upstream areas reached 30. While, declining rainfall has resulted in these waters being more saline, our data show that these reaches are not utilised to the same extent by individuals of M. dalli. The research presented in this poster investigates the hypothesis that changes in sediment composition may be responsible for this shift in the spatial and temporal use of the estuary by this species. The implications of this research on the restocking program for M. dalli are discussed

Factors influencing marked variations in the frequency and timing of bar breaching and salinity and oxygen regimes among normally-closed estuaries

The aim of this study was to determine the factors that influence the breaching of the bar at the mouth of estuaries that are normally-closed to the ocean and the trends exhibited by salinity and oxygen concentration in those systems during protracted periods of closure. Collated data for 1972 to 2016 demonstrate that the frequency and timing of bar breaching of three normally-closed estuaries, located along 100 km of coastline in a low rainfall region of temperate south-western Australia, differ markedly. Breaching occurred in 12 years in Stokes Inlet, ≥ eight in Hamersley Inlet and only three in Culham Inlet. Breaching in each estuary was related to relatively very high volumes of fluvial discharge. Although breaching typically occurred following exceptional winter rainfall in Stokes Inlet, whose catchment received by far the greatest winter rainfall, it usually took place in Hamersley and Culham inlets following atypically high summer and autumn rainfall, often associated with cyclonic activity. Salinity, oxygen concentration and water temperature were measured seasonally between summer 2002 and spring 2004, during which period each of these estuaries was closed to the ocean following major natural breaches of each system and the influx of substantial volumes of oceanic water. Mean salinities in the estuary basins rose by markedly different extents during the three years of closure. They thus increased from 30 in Stokes Inlet, 35 in Hamersley Inlet and 52 in Culham Inlet, to maxima of 64, 143 and 293, respectively, with the highest individual salinity of 313 in the latter estuary the greatest yet recorded for any estuary worldwide. In contrast, oxygen concentrations declined to minima of 5.5, 2.5 and 0.6 mg L−1, respectively, and were inversely related to salinity in the basin of each estuary (r = −0.7 to −0.8). Although salinities in the main river of each estuary did not become as highly elevated as in its basin, they still reached 221 in that of Culham Inlet. The very different extents to which salinity increased and oxygen concentration declined among the three estuaries reflect variations in amount of rainfall and thus fluvial discharge, the area and depth of basin relative to discharge and resilience of the bar at the estuary mouth. Thus, while a suite of factors contribute to bar breaching and physico-chemical trends in normally-closed estuaries, variations in their importance as ‘drivers’ among estuaries should be considered when studying the ecology of a given system

Assessing the sediment preference of a penaeid prawn to inform release strategies

The abundance of the Western School Prawn (Metapenaeus dalli) declined markedly in the Swan-Canning Estuary after the 1960s, resulting in the initiation of a restocking program in 2012. Further to the decline in abundance, anecdotal evidence from recreational fishers indicated that there had been a spatial shift in the distribution of this prawn. To test the hypothesis that a change in sediment composition may be responsible, the density of M. dalli, recorded monthly between October 2013 and August 2014, was correlated against sediment organic matter content and grain size distribution. Densities of M. dalli were found to differ among sediment types in summer, but not winter. Controlled laboratory experiments were used to investigate whether M. dalli exhibited a preference for sediments from either the upper or lower reaches of their distribution within the estuary. Prawns exhibited a preference for nearshore and offshore sediments that contained a lower percentage contribution of larger grain sizes and/or a higher percentage contribution of finer grain sizes, i.e. sediments from the lower rather than upper reaches. These experiments also revealed that emergence and activity rates of M. dalli are strongly related to photoperiod, with individuals preferring to remain buried during daylight hours and become active during darkness. Visual observations also indicated that the prawns were able to bury more rapidly in finer than coarse sediments, thus reducing their length of exposure to predators. The implications of these findings on the current restocking program for M. dalli in the Swan-Canning Estuary are discussed