Indigenous sex-selective salmon harvesting demonstrates pre-contact marine resource management in Burrard Inlet, British Columbia, Canada

To gain insight into pre-contact Coast Salish fishing practices, we used new palaeogenetic analytical techniques to assign sex identifications to salmonid bones from four archaeological sites in Burrard Inlet (Tsleil-Waut), British Columbia, Canada, dating between about 2300–1000 BP (ca. 400 BCE–CE 1200). Our results indicate that male chum salmon (Oncorhynchus keta) were preferentially targeted at two of the four sampled archaeological sites. Because a single male salmon can mate with several females, selectively harvesting male salmon can increase a fishery’s maximum sustainable harvest. We suggest such selective harvesting of visually distinctive male spawning chum salmon was a common practice, most effectively undertaken at wooden weirs spanning small salmon rivers and streams. We argue that this selective harvesting of males is indicative of an ancient and probably geographically widespread practice for ensuring sustainable salmon populations. The archaeological data presented here confirms earlier ethnographic accounts describing the selective harvest of male salmon.

Evaluation of Grain Quality-Based Simulated Selective Harvest Performed by an Autonomous Agricultural Robot

Grain price differences due to protein content can have economic effects on the farm as well as environmental effects when alternative protein sources are imported. Grain protein variability can vary from year to year due to environmental factors and can be addressed by site-specific management practices. Alternatively, it can be addressed at harvest time by selective harvest. Agricultural autonomous robots can accurately follow alternative harvesting routes that are subject to grain quality maps, making them suitable choices for selective harvest. This study addresses therefore the potential revenue of selective harvest performed by the route planner of an autonomous field robot. The harvest capacity and potential economic revenues of selective harvest in a Danish context were studied for a set of 20 winter wheat fields with four hypothetical scenarios. The results showed significant differences in harvest capacity between conventional and selective harvest. Even though in some scenarios selective harvest did not require notable additional harvest times, the cost–benefit analysis showed small economic returns of up to 46 DKK ha−1 for the best scenarios, and for most cases losses up to 464 DKK ha−1. Additionally, the location of the high protein content areas has great influence on the profitability of selective harvest.

Implementation and applications of harvest fleet route planning

In order to support the growing global population, it is necessary to increase food production efficiency and at the same time reduce its negative environmental impacts. This can be achieved by integrating diverse strategies from different scientific disciplines. As agriculture is becoming more data-driven by the use of technologies such as the Internet of Things, the efficiency in agricultural operations can be optimised in a sustainable manner. Some field operations, such as harvesting, are more complex and have higher potential for improvement than others, as they involve multiple and diverse vehicles with capacity constraints that require coordination. This can be achieved by optimised route planning, which is a combinatorial optimisation problem. Several studies have proposed different approaches to solve the problem. However, these studies have mainly a theoretical computer science perspective and lack the system perspective that covers the practical implementation and applications of optimised route planning in all field operations, being harvesting an important example to focus on. This requires an interdisciplinary approach, which is the aim of this Ph.D. project. The research of this Ph.D. study examined how Internet of Things technologies are applied in arable farming in general, and in particular in optimised route planning. The technology perspective of the reviewing process provided the necessary knowledge to address the physical implementation of a harvest fleet route planning tool that aims to minimise the total harvest time. From the environmental point of view, the risk of soil compaction resulting from vehicle traffic during harvest operations was assessed by comparing recorded vehicle data with the optimised solution of the harvest fleet route planning system. The results showed a reduction in traffic, which demonstrates that these optimisation tools can be part of the soil compaction mitigation strategy of a farm. And from the economic perspective, the optimised route planner of an autonomous field robot was employed to evaluate the economic consequences of altering the route in selective harvesting. The results presented different scenarios where selective harvest was not economically profitable. The results also identified some cases where selective harvest has the potential to become profitable depending on grain price differences and operational costs. In conclusion, these different perspectives to harvest fleet route planning showed the necessity of assessing future implementation and potential applications through interdisciplinarity.

Crab Fisheries

The principal crab fisheries around the world are reviewed with regard to patterns of exploitation and existing management systems. Thirty-five species and thirty fisheries were evaluated using a series of sustainability indexes based on landings, biological information, and assessment data. Indexes were scored as Good, Fair, or Poor, adapting the traffic light approach of Caddy et al. (2005). Examples include Jonah crab (Cancer borealis), for which landings have increased by a factor of 6.5 since 2000 (Poor); gazami (Portunus trituberculatus), which supports the largest crab fishery in the world (Fair); and blue crab (Callinectes sapidus), which has had stable landings for decades (Good). Management systems that incorporate stock assessment, biological information, and rights-based management (quota systems) generally outperform those without such attributes. Challenges for sustainable management were identified, including selective harvest (especially use of minimum size limits), climate change and its impacts on reproduction, and bycatch and discard mortality. Conserving populations and sustaining fisheries will require solving these problems in the near future.

Impact of Distance between Strip Roads on Productivity and Costs of a Forwarder in Commercial Thinning of Pinus Taeda Stands

Demand for higher value-added wood products stimulates research for new, mainly mechanized, thinning operations in order to increase productivity and reduce production costs. In this context, the aim of this study was to evaluate the impact of distance between strip roads on forwarder productivity and costs of thinning operations in Pinus taeda stands. The study was carried out in 10-year-old Pinus taeda stands located in Parana State, Brazil. Two thinning methods were evaluated: (1) TH5: systematic harvest in every fifth tree row and selective harvest in adjacent rows; and (2) TH7: systematic harvest in every seventh tree row and selective harvest in adjacent rows. Working cycle times, productivity and costs were determined through a time-motion study of the forwarder. The additional variables evaluated were wood assortments (industrial wood and energy wood) and extraction distances (50, 100, 150 and 200 m), and mean values were compared between thinning methods using t tests for independent samples (α=0.05). Loading and unloading elements consumed the most time in the working cycle, with lower participation time in TH7 due to greater availability of logs along the strip roads (higher pile volumes), influencing total cycle time up to the mean distance of 150 m for both assortments. TH7 consequently showed 6% higher productivity, its energy yield was 5.3% lower and its production cost was 3.0% lower.

Effect of ammoniation and harvest method on waste and consumption of corn residue bales fed to cows in a round bale feeder

To determine the effects of harvest method and ammoniation (3.7% of dry matter) on consumption and waste of baled corn residue, a 6 × 6 Latin square with a 3 × 2 factorial treatment structure was conducted. Six treatments consisted of either nonammoniated or ammoniated residue, harvested one of three ways: conventional rake and bale (CONV), New Holland Cornrower with two rows of stem chopped into the windrow with tailings (2ROW), or EZBale system (EZB) with a disengaged combine spreader and tailings dropped in a windrow. Open cows were grouped by body weight to produce a light block of two pens (448 kg ± 49.6) and a heavy block of four pens (649 kg ± 65.9). One bale was fed to each pen during each of six 7-d periods using round bale ring feeders with closed bottom panels. Residue falling around (waste) and remaining in (refusals) the feeder was collected. The daily nutrient intake was estimated as the difference between what was offered and what remained (waste plus refusals). Crude protein (CP) of residue offered did not differ (P = 0.58) among harvest methods. The digestible organic matter (DOM) content of residue offered in 2ROW and EZB bales did not differ (P = 0.86) and was greater (P < 0.01) than CONV. Ammoniation increased (P < 0.01) CP and DOM content of the residue offered. Total wasted and refused residue did not differ (P = 0.12) between 2ROW (29%) and EZB (37%), while CONV (42%) was greater (P = 0.02) than 2ROW but did not differ (P = 0.34) from EZB. Ammoniation reduced (P = 0.03) total waste and refusals from 41% to 32%. The nutrient content of both waste and refusals did not differ (P ≥ 0.34) among harvest methods and, with the exception of CP, was not affected (P ≥ 0.15) by ammoniation. The CP content of the waste was greater (P = 0.02) and refusals tended to be greater (P = 0.08) from ammoniated bales. The CP intake of 2ROW was greater (P ≤ 0.02) than both EZB and CONV, while EZB tended (P = 0.06) to be greater than CONV. The CP intake of all ammoniated residues was greater (P < 0.01) than the nonammoniated residue. The DOM intake of nonammoniated 2ROW and EZB did not differ (P = 0.61) but was greater than nonammoniated CONV (P < 0.01). Ammoniation increased (P < 0.01) DOM intake. Overall, ammoniation had much larger effects than harvest method, resulting in reduced waste and refusals and greater intake of DOM and CP. However, the combination of both ammoniation and selective harvest (2ROW or EZB) was needed to result in energy and protein intakes that would meet the needs of a mature cow in mid-gestation.

Individual behavior drives ecosystem function and the impacts of harvest

Current approaches for biodiversity conservation and management focus on sustaining high levels of diversity among species to maintain ecosystem function. We show that the diversity among individuals within a single population drives function at the ecosystem scale. Specifically, nutrient supply from individual fish differs from the population average >80% of the time, and accounting for this individual variation nearly doubles estimates of nutrients supplied to the ecosystem. We test how management (i.e., selective harvest regimes) can alter ecosystem function and find that strategies targeting more active individuals reduce nutrient supply to the ecosystem up to 69%, a greater effect than body size–selective or nonselective harvest. Findings show that movement behavior at the scale of the individual can have crucial repercussions for the functioning of an entire ecosystem, proving an important challenge to the species-centric definition of biodiversity if the conservation and management of ecosystem function is a primary goal.