Discard Behaviour Research Articles

Antler working by the last European Pleistocene hunter-gatherers of Santimamiñe cave (Northern Iberian Peninsula): technological implications of osseous equipment during the Magdalenian

This paper assesses the exploitation of osseous raw materials, namely antler, used by hunter-gatherer populations in the Late Upper Palaeolithic of Santimamiñe cave. The different categories of products (waste products, blanks, and finished objects) are analysed from a technological perspective to identify the fabrication methods employed by Magdalenian groups. A predominant operational scheme is identified, extraction by the double grooving procedure, related to the production of highly standardised rods. This study will allow us to explore possible cultural variations in the application of this procedure. It also addresses other aspects in relation to the circulation of osseous implements, the mobility of hunter-gatherer groups, and the useful life of the weapons, as regard maintenance and discard behaviour.

Shark discards in selective and mixed-species pelagic longline fisheries.

The conservation status of several pelagic shark species is considered vulnerable with declining populations, yet data on shark fishing mortality remain limited for large ocean regions. Pelagic sharks are increasingly retained by mixed-species fisheries, or are discarded and not reported by selective fisheries for tunas (Thunnus spp.) or swordfish (Xiphias gladius). We estimated the fishing mortality of sharks (landings plus discard mortalities) in a South African-flagged pelagic longline fishery with diverse targeting and discard behaviour. A hierarchical cluster analysis was used to stratify the fleet according to the relative proportions of tunas, swordfish, blue sharks (Prionace glauca) and shortfin mako sharks (Isurus oxyrinchus) landed by individual vessels between 2013 and 2015. A spatial analysis of logbook data indicated that subfleets operated in distinct fishing areas, with overlap. Approximately 5% of all commercial longlines set during 2015 were sampled by a fisheries-independent observer, and the species, discard ratios and physical condition at discard of 6 019 captured sharks were recorded. Blue sharks and shortfin makos dominated observed shark catches, which were comprised of nine species and two species groups. Some 47% of observed sharks were retained and 20% were discarded in good physical condition. Only 4% of shortfin makos were discarded, compared to 68% of blue sharks. Blue shark discard mortality rates were twice as high as published at-vessel mortality rates, suggesting that onboard handling, among other factors, contributed to discard mortalities. Extrapolation to total fishing effort indicated a near 10-fold increase in blue shark and shortfin mako fishing mortality compared to an earlier study (1998-2005). Escalating shortfin mako fishing mortality was attributed to increased targeting to supply higher market demand. Discarding of blue sharks by selective fishing for tunas and swordfish had a greater impact on their fishing mortality than retention by shark-directed fleets. Higher levels of observer sampling are required to increase confidence in discard ratio estimates.

Inclusion of discards in stock assessment models

AbstractA large portion of the catch in many stocks may comprise discards which need to be accounted for in assessments in order to avoid bias in estimates of fishing mortality, stock biomass and reference points. In age‐structured assessment models, discards are sometimes treated as a separate fleet or are added to the landings before fitting so that information about discard behaviour and sampling error is lost. In this paper, an assessment model is developed to describe the discard process with size as a covariate while retaining age‐structured population dynamics. Discard size selection, high grading and bulk dumping of fish at sea are modelled so that the temporal dynamics of the process can be quantified within the assessment. The model is used to show that discarding practices have changed over time in a range of Northeast Atlantic demersal fish. In some stocks, there is a substantial increase in high grading and evidence for bulk discarding which can be related to regulatory measures. The model offers a means of identifying transient effects in the discard process that should be removed from both short‐term forecasts and equilibrium reference point calculations.

An evaluation of socioeconomic factors that influence fishers’ discard behaviour in the Greek bottom trawl fishery

A newly introduced regulation renders the discarding of certain commercially important species illegal within the European waters progressively until 2019 (Article 15, EC Regulation 1380/2013). Thorough research is required in order to understand fishers’ perceptions and to achieve effective implementation of the regulation, as it is possible that certain implications might arise within the fishing industry and the associated communities after the shift to the new management regime. In this paper, fishers’ socio-economic behaviour is analyzed in relation to discarding practices under the “discrete choice” framework. Specifically, a variety of socioeconomic attributes, in the form of principal components that may affect the choices of the Greek bottom trawl fishers on three key discards’ drivers are analyzed to identify possible links between these. Utilizing the same attributes, eight hypothetical management tools that can be adopted for a smoother implementation of the discard ban are examined and the main results are discussed afterwards. Consistent patterns were revealed regarding fishers’ behaviour. An association of vessels’ efficiency with the probability to discard due to market limitations was evident, along with the association of different socioeconomic factors, such as the fishers’ age and the vessel’s crew size, with the incentives proposed regarding the introduction of awareness seminars. It is important to study these patterns carefully to understand the drivers and fishers’ motivation towards discarding. Their preferences on management tools that can be adopted by the EU member will also be considered, which can lead to a successful introduction of the regulation and a meaningful contribution into an effective management framework within which stakeholders can behave sustainably.

Investigating maintenance and discard behaviours for osseous projectile points: A Middle to Late Magdalenian (c. 19,000–14,000 cal. BP) example

The importance of investigating maintenance and discard behaviours in Palaeolithic osseous technological systems is only now becoming clear, thanks to recent advances in our understanding of how these implements were repaired in various techno-complexes. While significant work has been completed on European assemblages, the issues of maintenance and discard behaviour have generally received only passing mention, and thus, the nature and frequency of Palaeolithic osseous projectile point rejuvenation and discard remains largely unknown. This paper presents the trace and formal analysis of more than 4400 Middle–Late Magdalenian antler projectile point artefacts excavated from two central datasets (Isturitz, Pyrénées-Atlantiques and La Vache, Ariège), and complemented by examination of a further 22 collections recovered from throughout France and southern Germany. Analysis of individual artefacts, collections, and regional samples resulted in significant new insights into the use life of the iconic Magdalenian barbed point, as well as single and double bevel based point technologies. These insights concern not only how the projectile points were resharpened, reworked, and reused, but also cultural ideals concerning point form, and even potential differences in functionality.

Taphonomy and Behaviour at the Acheulean Site of Kariandusi, Kenya

In this article, Louis Leakey’s previously unpublished field reports are used to describe the 1929–1931 excavation campaign at the Acheulean site of Kariandusi. Using the sample of artefacts from this campaign housed in the Pitt Rivers Museum, Oxford University, I attempt to understand the natural and behavioural factors contributing to site formation at Kariandusi. The matrix adhering to the artefacts and the degree of rounding on the artefacts are used to assess the depositional environments at the site. The artefact types represented at the site are used to reconstruct hominin discard behaviour. Descriptions and measurements of the bifaces are used to determine how these tools were made and whether they were resharpened. In conclusion, I provide a model of the life history of a Kariandusi biface.

Ethnoarchaeology of Ceramic Reuse and Discard Behaviour of the Andro of Manipur

Ethnoarchaeology of Ceramic Reuse and Discard Behaviour of the Andro of Manipur

Cultural Logic and Practical Reason: the Structure of Discard in Ancient Maya Houselots

Since the 1980s, archaeologists have challenged the idea that prehistoric actions were guided primarily by practicality and expedience. Rubbish disposal, a superficially mundane activity, provides a critical case for exploring the depth to which cultural logics penetrate. Ethnoarchaeological research on discard behaviour in Mesoamerican houselots has modelled rubbish disposal as a matter of expedience predictable by factors such as density of settlement and length of occupation. At the Classic period site of Chunchucmil, Yucatan, such models based on practical reason succeed only partly in predicting the distribution of rubbish. Ethnographic and ethnohistorical accounts of rubbish in Mesoamerica suggest that fully understanding its distribution requires attention to cultural logics. At Chunchucmil, ancient Maya cosmology explains the location of dumps within households. Thus, both practical and cultural logics structured discard. The case of Maya subsistence farming suggests that practical logic is subsumed by cultural logic, rather than the two logics conflicting. These findings show how broadly-held beliefs and predispositions are instantiated and reproduced in daily life.

Discards of Spanish trawler fleets operating in the Bay of Biscay in 2000

A stratified sampling programme by gear and port was carried out by observers on board vessels in 2000 to study the discard behaviour of trawler fleets operating off Spanish North Atlantic coasts. No relationship between discards in weight or numbers and haul duration was found, so the results in weight are presented in kilograms per haul instead of kilograms per hour, as is usual for catches. The data were analysed in order to find groups of ports with a similar behaviour and to reduce the number of strata (30 as a result of the crossing of 10 main ports and 3 types of towed gears). The reduction in the number of strata (from the 30 original strata to the 9 new groups obtained) would mean a high improvement in efficiency for raising purposes, for stock assessment needs and for new Spanish sampling programmes. Significant differences in discards between groups of ports were found. Species composition of discards by stratum is given as a percentage of the total weight, based on data collected by the observers on board vessels. There are also differences in the discarded species composition for the different groups of ports obtained.

Dynamic modelling of packaging material flow systems

A dynamic model has been developed for reused and recycled packaging material flows. It allows a rigorous description of the flows and stocks during the transition to new targets imposed by legislation, product demand variations or even by variations in consumer discard behaviour. Given the annual reuse and recycle frequency and packaging lifetime, the model determines all packaging flows (e.g., consumption and reuse) and variables through which environmental policy is formulated, such as recycling, waste and reuse rates and it identifies the minimum number of variables to be surveyed for complete packaging flow monitoring. Simulation of the transition to the new flow conditions is given for flows of packaging materials in Greece, based on 1995--1998 field inventory and statistical data.

A neural basis for collecting behaviour in humans

Collecting behaviour is commonplace in the normal population, but there has been little investigation of its neural basis in humans. The observation that collecting behaviour can assume pathological proportions in patients with certain patterns of brain damage led us to hypothesize that dysfunction in a system encompassing mesial prefrontal cortices accounts for abnormal collecting and may guide normal collecting. We tested the hypothesis in 86 subjects with focal lesions of the telencephalon, by relating the neuroanatomical placement of the lesions to the presence of repetitive and indiscriminate acquisition behaviour and impaired discard behaviour. The subjects had no history of psychiatric disease or abnormal collecting behaviour prior to lesion onset. Lesions were analysed with high-resolution three-dimensional MRI. Collecting behaviour was evaluated with a standardized questionnaire completed by a close relative of each subject. Thirteen subjects exhibited abnormal collecting, characterized by massive and disruptive accumulation of useless objects. In all cases, the abnormality of collecting behaviour was severe and persisted despite attempted interventions and obvious negative consequences. There were no differences between pathological collectors and non-collectors on tests of executive functions or anterograde memory. All subjects with pathological collecting behaviour had damage to the mesial frontal region (including the right polar sector and the anterior cingulate), but there was no damage to most of the subcortical structures that, in species such as rodents, are known to drive the acquisition and retention of objects. The evidence suggests that damage to the mesial frontal region disrupts a mechanism which normally modulates subcortically driven predispositions to acquire and collect, and adjusts these predispositions to environmental context.

Late Pleistocene behavioural variation and time trends: the case from Tasmania

AbstractThe newly discovered archaeological site of Parmerpar Meethaner, located in the Forth River valley Tasmania, is described. This important site, 1) has evidence of repeated long term human occupation extending from c.780 BP to c.34,000 BP, 2) crosses all the major large scale climatic events such as the beginning, middle and end of the LGM and the late Pleistocene/Holocene boundary, 3) supports the notion that Tasmania was first occupied 35,000 radiocarbon years ago, 4) has a different settlement history to sites in Southwest Tasmania, and 5) provides the missing archaeological evidence of human responses to changing forested conditions. The paper describes the material from Parmerpar Meethaner and examines how they fit with what is currently known about late Pleistocene Tasmanian occupation in terms of dating patterns of discard behaviour, Bass Strait landbridges and colonising events.

A Bioeconomic Analysis of the Greenland Shrimp Fishery in the Davis Strait

This paper presents a bioeconomic analysis determining the resource rent and optimum effort of the shrimp (Pandalus borealis) fishery in the Davis Strait, taking into account the discard behaviour of the fleet. It is demonstrated that, from an economic point of view, the shrimp stock in the Davis Strait is substantially overfished. In order to obtain the maximum economic yield, the effort must be reduced by at least 40% compared to the effort level of 1991. The gain in resource rent by reducing effort is estimated to be at least 20% compared to the resource rent of 1991.

Origins and environmental significance of shell and earth mounds in Northern Australia

AbstractExamination of northern Australian shell and earth mound data suggests that mounds previously attributed to human agencies should be more properly attributed to generations of nesting scrub‐fowl. A connection between Aboriginal discard behaviour and scrub‐fowl nesting processes is also proposed. Mounds containing artefactual material may represent middens or campsites reworked by scrub‐fowl. Environmental, stratigraphic and ethnographic data tend to support this. Mound distribution may be used to assess local vegetation changes, and this explains the apparent geographic discontinuities of mounds in some areas. Trends in the basal dating of mound sites support Lees and Clements (1987) proposal that regional rainfall increased around 1600 BP. A reassessment of the archaeological significance of northern Australian mound sites is warranted.