Use Of Catch Research Articles

Effect of Catch Them Early Approach on Expository Reading Skills of Grade 7 Students

Effect of Catch Them Early Approach on Expository Reading Skills of Grade 7 Students

Use of catch and effort data to monitor trends in economic performance in fisheries

Abstract In many low-valued fisheries, the quantity and types of data that might be available to support fisheries management are often limited. Generally, information on the economic performance of the fishery is low in priority in these fisheries. Basic catch and effort information, however, may contain implicit information about economic performance of the vessels. From these data, technical efficiency scores and measures of capacity utilization can be derived. The technical efficiency score can provide a proxy measure of the distribution of economic performance, while changes in capacity utilization theoretically reflect changes in the economic conditions in the fishery. Given this, changes in these measures over time should also reflect changes in economic outcomes and performance. To test this, we use data from a data-rich fishery, including catch and effort information as well as detailed economic information (i.e. vessel-level profitability). Key technical performance measures are estimated using data envelopment analysis and compared with the economic performance measures. We show that these technical performance measures can provide useful indicators of changes in economic performance when economic information is not available.

Rice field fisheries: Wild aquatic species diversity, food provision services and contribution to inland fisheries

The need to produce sufficient food for people whilst also maintaining biodiversity and ecosystem integrity is one of the most pressing challenges in the 21st century. This challenge is exemplified in wetlands and deltas of Southeast Asia that have been transformed to intensify rice production and have subsequently lost the naturally present wild aquatic species that previously bolstered local food and nutrition security. In contrast, rice producing areas where natural hydrologic flows and ecosystem processes are retained can sustain aquatic biodiversity and fisheries. These rice field ecosystems are present in many Asian countries, but are sparsely documented, underappreciated, and currently face development pressure including farming intensification and habitat fragmentation from infrastructure development. To understand the fisheries and food security contributions of wild aquatic species in contemporary rice field ecosystems, we examine the Tonle Sap region of Cambodia. We used household surveys and experimental fishing to measure wild aquatic species richness present in rice field ecosystems and in local catch. We also used household surveys to estimate rice field fishery productivity (as annual catch weight per hectare) and to examine variation in fishing effort and total catch weight across seasons and habitats. Finally, we investigated catch use and the contribution of fish catch to household consumption. We identified a total of 158 wild aquatic species, which included around twice the number of finfish species (n = 135) identified by previous studies (n = 35–70). Overall, 92% of fish catch (by weight) was from five habitat types within rice field ecosystems. Fishing effort and catch weights were relatively evenly spread across habitats during the dry season and were primarily from rice fields during the flood season. In both flood and dry seasons, rice field fishery catch provided around 60% of the fish and aquatic animals consumed in surveyed households. Our findings illustrate the substantial contributions rice field fisheries make to household food security and to national fisheries production. Drawing on lessons from rice farming intensification across the region, we discuss the implications of our findings for rice field ecosystems, food security, and rice intensification policy futures in Cambodia and other rice-producing nations.

Forage Fish as Food: Consumer Perceptions on Baltic Herring

Using fish resources for food supply in a sustainable and efficient way requires an examination of the feasibility of prioritising the use of forage species. The present paper deals with the issue from the consumer perspective. Using Baltic herring as a case study, the role of sociodemographic determinants, the drivers and barriers of Baltic herring consumption are investigated in four Baltic Sea countries, based on an internet survey. The drivers and barriers of Baltic herring consumption are compared to those relating to Baltic salmon, to identify the main differences in consumer perceptions on species that are primarily used as feed and food. The present paper concludes that prioritising forage species primarily for human consumption calls for proactive catch use governance, which (1) acknowledges the species- and country-specific intricacies of forage fish consumption, (2) improves the availability of safe-to-eat fish on the market, and (3) provides consumers with sufficient information on the species (e.g., the type of herring and its origin), the sustainability of the fisheries, and the related health risks and benefits.

Food security and safety in fisheries governance – A case study on Baltic herring

One of the objectives of the EU Common Fisheries Policy (CFP) is to increase the contribution of fisheries to fish food availability and self-sufficiency. Still, the use of catch is often a secondary concern in fisheries governance and management – or not a concern at all – while the focus is on harvesting. This paper examines how the use of forage fish for human consumption can be increased within the limits of sustainability, using Baltic herring as a case study. Baltic herring contains high levels of dioxins and the human consumption is very low: the catches are mostly used for industrial purposes. The paper uses a participatory backcasting exercise to define a desirable future vision for the use of Baltic herring catch and to develop pathways of actor-specific governance actions to increase the use of the fish as a safe-to-eat food. The results reveal that increasing the contribution of forage fish, such as Baltic herring, to food security entails a paradigm shift in fisheries governance that involves 1) inclusion of well-defined objectives for catch use in the EU CFP and the related regional multiannual plans, 2) broadening the scope of the MSY-driven governance and management to one that addresses catch use, and 3) proactive catch use governance.

A typology of fisheries management tools: using experience to catalyse greater success

AbstractFisheries provide nutrition and livelihoods for coastal populations, but many fisheries are fully or over‐exploited and we lack an approach for analysing which factors affect management tool performance. We conducted a literature review of 390 studies to assess how fisheries characteristics affected management tool performance across both small‐scale and large‐scale fisheries. We defined success as increased or maintained abundance or biomass, reductions in fishing mortality or improvements in population status. Because the literature only covered a narrow set of biological factors, we also conducted an expert elicitation to create a typology of broader fishery characteristics, enabling conditions and design considerations that affect performance. The literature suggested that the most commonly used management tool in a region was often the most successful, although the scale of success varied. Management tools were more often deemed successful when used in combination, particularly pairings of tools that controlled fishing mortality or effort with spatial management. Examples of successful combinations were the use of catch limits with quotas and limited entry, and marine protected areas with effort restrictions. The most common factors associated with inadequate biological performance were ‘structural’ issues, including poor design or implementation. The expert‐derived typologies revealed strong local leadership, high community involvement and governance capacity as common factors of success across management tool categories (i.e. input, output and technical measures), but the degree of importance varied. Our results are designed to inform selection of appropriate management tools based on empirical data and experience to increase the likelihood of successful fisheries management.

Post-release survivorship studies on common thresher sharks (Alopias vulpinus) captured in the southern California recreational fishery

The common thresher shark (Alopias vulpinus) is the focus of a popular southern California recreational fishery that targets individuals using multiple fishing gears and techniques. Despite increasing trends in the use of catch and release techniques in the recreational fishery for thresher sharks, a comprehensive estimate of post-release survival is not available for all modes of capture. This study focused on assessing post-release survival in two modes of capture routinely observed in the southern California recreational fishery: (1) sharks that are caught using caudal-based angling techniques and unintentionally released with trailing gear left embedded and (2) sharks that are caught and released using mouth-based angling techniques. Post-release survivorship was assessed using pop-up satellite archival tags programed for 10- and 90-day deployments, with the former used for mouth-caught sharks and the latter for individuals with trailing gear. Post-release survivorship estimates for the trailing gear studies were based on data from nine common thresher sharks (111-175cm FL) while the mouth-based experiments utilized data from an additional seven sharks (125-187cm fork length, FL). For the trailing gear studies, six sharks died within 5days after release, one died after 81days, and two sharks survived the deployment period for an overall survivorship rate of 22%. All seven mouth-hooked common thresher sharks survived the acute (∼10days) effects of capture (100% survivorship). These results suggest that in the southern California recreational thresher shark fishery, caudal-based angling techniques, which often result in trailing gear left embedded in the shark, can negatively affect post-release survivorship. This work also reveals that mouth-based angling techniques can, when performed properly, result in high survivorship of released sharks.

Evaluating the Performance of Two Salmon Management Strategies using Run Reconstruction

AbstractCommercial salmon fisheries in Alaska are managed to obtain escapement goals within a fixed range while attempting to maximize sustained yield. Two management strategies currently being used are emergency order authority and a fixed fishing schedule. We analyzed and compared the historical performance of these two management strategies for Bristol Bay, Alaska, fisheries targeting Egegik River and Togiak River Sockeye Salmon Oncorhynchus nerka. To accomplish this, we reconstructed the daily runs to each river through the use of catch, effort, and tower count data. Our results showed that management by emergency order openings resulted in (1) the catch of a higher percentage of returning fish, (2) less yearly variation in escapement, and (3) escapements that were always above the minimum escapement goal. A fixed fishing schedule resulted in less yearly variation in catch and a harvest rate that was spread more evenly throughout the run; the more even harvest rate likely provides better protection of substocks and the sex ratio. Emergency order authority gives a manager greater control over the fishery but requires more informative data. A fixed fishing schedule provides a more predictable catch but carries a higher risk of overharvest. Each of the two management strategies was successful and was suited to the circumstances of its fishery.Received December 7, 2012; accepted September 13, 2013Published online February 10, 2014

Economic characteristics and management challenges of the Hawaii pelagic longline fisheries: Will a catch share program help?

To date, none of the fisheries in the U.S. Pacific Islands Region is managed under a catch share program. In light of the NOAA policy to encourage the use of catch shares as a fishery management tool, the Western Pacific Fishery Management Council (WPFMC) listed six commercial fisheries, including the Hawaii pelagic longline fishery, the largest in the region, as potential candidates for catch share programs. This study examines the baseline economic characteristics and the main challenges facing the Hawaii pelagic longline fishery and evaluates the impact of these on the desirability and feasibility of a catch share program for this particular fishery.

Effect of habitat patchiness on the catch rates of a Mediterranean coastal bottom long-line fishery

Use of catch per unit effort (CPUE) as an index of abundance relies on a range of assumptions that are often not met. Variation in habitat is likely to affect catch rates of species and consequently should be taken into account when estimating abundance from CPUE data, yet this is not generally possible due to a lack of spatially detailed habitat information. Mediterranean artisanal fisheries often operate in coastal areas where habitat is patchy, and consequently catches may not be related to effort if a portion of the gear has been set over unsuitable habitats for the target species. We investigate the effect of habitat patchiness on CPUE using bottom long-line by including detailed habitat and bathymetric information in the calculation of CPUE for eight commonly caught species. Comparison of CPUE estimated with and without taking into account habitat information showed exclusion of hooks in “unfavourable” habitats generally increases CPUE estimates for species of restricted mobility and strict habitat associations, while estimates for more mobile species, or those with lower habitat specificity, differ less. We also compare two methods for calculating habitat fished by each hook, one that used the habitat at the hook location, and another that included habitats within a 200m radius. The former method had the highest effect on CPUE. Results demonstrate habitat information can be usefully incorporated into CPUE estimates, while the effect on CPUE will vary depending on how specific species–habitat preferences are.

Vessel time allocation in the US Illex illecebrosus fishery

The Illex illecebrosus fishery in the northwestern Atlantic Ocean is trawl-based. I. illecebrosus normally lives less than 1 year. One option for managing such a short-lived species is the use of catch and effort data obtained from fishing vessels during the fishing season to manage the fishery in real time. Verification of the accuracy of data reports is important. Conceivably, information contained in the data stream of vessel position and time provided by a remote data logger could be used to reconstruct the vessel’s activities to assess the reliability of industry reports. This study describes quantitatively the types of vessel operating activities that take place on a typical I. illecebrosus fishing trip and assesses the possibility of reconstructing these activities reliably from the simple data stream of vessel position and time. Seven activities were identified, six of which occurred commonly: steaming to and from port, searching, towing, set-up time between tows, steaming overnight and laying-to overnight. Processing the catch, as a discrete activity, occurred rarely. Each activity could be characterized in terms of its duration and distance traveled, the average vessel speed, and the tendency for vessel speed to change during the activity. Most activities were conducted in a linear manner. Accordingly, reasonable estimates of the distance and duration of these activities could be obtained simply from the knowledge of the starting and ending position and time. Analysis of search time and subsequent catch revealed that searching did not improve catch. More squid would have been caught had the vessels used this time for towing. Catch per unit effort (CPUE) can be calculated using duration or distance in the denominator. In this set of fishing trips, the two were equivalent. Catch bore a nonlinear relationship with CPUE. In particular, larger catches were associated with incrementally larger CPUEs. The uniqueness of each activity when described by its characteristic speed, duration and distance, and the consistency of these characteristics for each activity between vessels suggests that vessel behavior might be assessed remotely using a time series of position and time. Such a capability might be important in any real-time management plan where industry vessels necessarily must be depended upon for data on catch and CPUE.

Continuation-Based Multiprocessing

Any multiprocessing facility must include three features: elementary exclusion, data protection, and process saving. While elementary exclusion must rest on some hardware facility (e.g., a test-and-set instruction), the other two requirements are fulfilled by features already present in applicative languages. Data protection may be obtained through the use of procedures (closures or funargs), and process saving may be obtained through the use of the catch operator. The use of catch, in particular, allows an elegant treatment of process saving. We demonstrate these techniques by writing the kernel and some modules for a multiprocessing system. The kernel is very small. Many functions which one would normally expect to find inside the kernel are completely decentralized. We consider the implementation of other schedulers, interrupts, and the implications of these ideas for language design.

On the Odds of Catching Fish with Angling Gear

Abstract We have developed a probabilistic theory of angling for fish by which specific stochastic models of fishing are derived for the situation where encounter of baits (lures) by fish is random and where the fish are randomly distributed on the fishing ground. We have also developed maximum likelihood and moment estimators of population density which support the use of catch per unit soak time as an index of abundance. Methodology is presented for fishing depletion experiments and then applied to experimental data obtained from multispecies fishing near the Mariana Islands, western Pacific Ocean. We show that abundance estimates obtained with our methodology differ significantly (P < 0.05) from those obtained with a standard Leslie depletion morphology.

The Activity and Catchability of the Lobster (Homarus americanus) in Relation to Temperature

The activity (walking rate) of lobsters acclimated to various temperatures increased from 2 to 10 °C. and from 20 to 25 °C. but was constant between 10 and 20 °C. Lobsters acclimated to low temperatures were most active above the acclimation temperature. Those acclimated to intermediate and high temperatures were most active at the acclimation temperatures. Experimental fishing of a relatively constant stock showed that the catch per 100 standard trap hauls (index of catchability) was linearly related to temperature. Slope of line is, however, dependent on stock density. Catchability is shown to be proportional to activity minus a constant. This relationship permits use of catch per unit effort and accumulated catch data to estimate lobster populations.