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Soil compaction-induced physical degradation is a threat to sustainable crop production and environmental performance. While measures have been evaluated to alleviate compaction, the impact of catch crops establishment on soil physical recovery following winter grazing remains underexplored. Six New Zealand trials over different years investigated: (1) the effects of soil compaction induced by winter forage crop grazing on soil health, and (2) the effectiveness of catch crops establishment in facilitating soil recovery. Our findings revealed that winter grazing resulted in significant soil physical degradation in the top 10 cm, evidenced by significant reduction in total porosity, macroporosity, available water content, saturated hydraulic conductivity (Ks), and soil quality S index. The degree of soil degradation was higher under increased grazing intensity (fodder beet grazing compared with kale grazing) and wetter conditions. For example, in Te Pirita-2019 with kale, changes in Ks were not significant. However, in Te Pirita-2019 with fodder beet, Ks decreased significantly from 1548 mm day-¹ to 88 mm day-¹, representing a 94.3 % reduction. Compared with fallow after grazing, growing catch crops promoted soil restoration. Conventional moldboard ploughing and the recently introduced single-pass ‘spader-drill’ outperformed direct drill for soil recovery. This study highlighted the importance of catch crop establishment using conventional tillage and spade drill to mitigate soil degradation resulting from winter forage crop grazing. The spader-drill, where soil conditions allow, is preferred because it allows earlier sowing of catch crops, leading to broader benefits such as increased crop biomass and reduced nitrogen leaching.

The South Australian Rock Lobster Fishery uses baited pots, traditionally ‘beehive’ in shape, to capture Southern Rock Lobster (Jasus edwardsii). Fishery harvest is controlled through annual quota that is set relative to performance indicators of relative abundance (Catch Per Unit Effort) for legal-size and pre-recruit lobsters. Under quota-based controls, improvements in catch efficiency through alternative pot designs offer an opportunity to reduce input costs and improve net economic return with low risk to stock sustainability. However, for performance indicators such as CPUE to remain robust, any changes in fishing efficiency must be accounted for in stock assessment. This study collected data from 13 fishers over 768 sampling days resulting in five treatments and 14,006 individual potlifts from the South Australian Northern Zone Rock Lobster Fishery. Geo-statistical methods, developed to control for temporal and spatial covariates, and variable lobster abundance, indicated higher catch efficiency of legal-size and undersize lobsters in ‘batten’ pots compared to ‘beehive’ pots. Ratios of mean legal-size catch weight ρˆCWPUEand undersize lobster (number) (ρˆPRI)from beehive pots to batten pots were estimated to be 0.62 and 0.68, respectively. Applying the ratio ρˆCWPUEwith respect to effort, fishers adopting batten pot designs may reduce future effort (potlifts) to take quota by up to 38 %. Potential increases in undersize catches of up to 32 % for fishers using batten pot designs would be offset by an overall reduction in effort. The taxonomic composition of bycatch was similar in batten pots and beehive pots. Generally lower catches of all bycatch were observed from batten pots and further reductions in bycatch discard rates would be likely where effort is reduced via their use to take quota. The number of depredated lobsters recorded during testing was similar between batten pots and beehive pots also indicating that reduced effort to attain quota with batten pots could lower the absolute number of dead lobsters landed each season. Methods to account for differences in pot-specific catch efficiency in future harvest strategy decision rules are discussed.

Evaluating drivers and the predictability of catch is valuable for the management of mixed fisheries. Drivers can represent or help to identify levers for management and predictable catch compositions are a key component of simulation tools and dynamic management strategies. But modelling mixed fisheries can be challenging due to the large number of taxa, and analysis typically focuses on a few key species or highly aggregated taxa. Here we employ seven types of stacked and joint species distribution models to explore the drivers and predictability of trawl-level catches in an ocean prawn trawl fishery, in New South Wales, Australia. Catch data was sourced from an observer program, with 130 taxa able to be modelled. The main drivers of catch composition were latitude, depth, and seasonality represented here by water temperature. Water column mixing, lunar illumination, and fishing effort were also important for some taxa. Up to 60–80 taxa were predicted with good predictive skill (AUC>0.8, >35 % decline in mean absolute error relative to an intercept-only model), and an additional 40–60 taxa were predicted with lower but still useful predictive skill (AUC>0.7, 25–35 % decline in error). However, the level of predictive skill varied considerably among model type. The best framework for prediction was stacked random forests using a hurdle modelling approach, followed by a spatial joint species distribution model. Our results show that predictive models at a fine spatial-temporal and taxonomic resolutions can be a viable information tool for highly mixed fisheries, but these tools ultimately need to be tested against specific management objectives and performance metrics, such as spatial closures and bycatch:target catch ratios.

The Suez Canal has three lakes including Timsah, and the Great and Little Bitter Lakes, which are important fishery resources in Egypt. These lakes produce highly economically important fish species, viz. grey mullet, shrimp, cuttlefish, striped piggy, crab, soles, gastropods and bivalves. The Timsah Lake is located nearly halfway along the Suez Canal between 30° 13' 00" to 32° 35' 18" N and 32° 16' 30" to 32° 18' 30" E. It is a shallowwater basin with an average depth of about 6m and a surface area of nearly 15km2. It is a brackish lake with significant variations in salinity. The Bitter Lakes (30°20' N, 32°23' E), the largest water bodies along the Suez Canal, are saline lakes with a surface area of about 250km². The total annual commercial landings from Suez Canal lakes varied between 6289 and 2260 tons during the last 20 years. In 2020, a total of 3428 tons landed corresponded to a value of almost 300 million LE. A number of fishing methods are used in the lakes including gill nets, crab nets, shrimp nets, beach seine, hattata and trammel nets. The present work investigated the fishing methods used in Suez Canal lakes, their characteristics, the catch composition, catch trend and the relative abundance of different commercial species measured by the catch per unit fishing effort CPUE. [ABSTRACT FROM AUTHOR]

An attempt has been made to develop a system for sequentially counting the number of fish caught using images taken on board. Fish catch counting for each local sea area contributes to fishery resource management and decision support for efficient operation. In this case, visual information is helpful for an intuitive explanation. The developed system consists of fish detection, fish tracking, and overdetected track deletion: to count fish robustly to its movement around on a deck, the fish detection stage attempts to absorb changes in the appearance of the fish, while the tracking stage dares not to use the appearance information to prevent the tracks from being unduly disconnected. Experimental comparisons using onboard video data of bullet tuna trolling demonstrated that the system could count fish with 89% precision and 87% recall.

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