Productivity and Management of Renewable Resources: Why More Efficient Fishing Fleets Should Fish Less

This article analyses the effect of productivity improvements on optimal fisheries management. It is shown that when harvest costs are independent of resource stock and the stock is below its steady state level, then for any given stock it is optimal to reduce harvest levels in response to a productivity increase unless optimal harvest rate is already zero. If harvest costs are stock dependent this result is modified; for stock dependent harvest costs there exists an interval of stock sizes below the steady state where it is optimal to reduce the harvest rate for any given stock size whereas if the harvest rate is close to an economically optimal steady state it is optimal to increase the harvest rate.

Spatial Distribution of Different Age Groups of Herring in Norwegian Sea, May 1996–2020

The commercially important Norwegian spring spawning herring is characterized by its extensive annual migrations and, on a decadal timescale, large shifts in migration patterns. These changes are not well understood, but have previously been linked to temperature, food availability, and size and age composition of the stock. Acoustic and trawl data from the International Ecosystem Surveys in the Nordic Seas, carried out annually in May since 1996, were used to analyze the spatial distribution of herring in the period 1996–2020. The dataset was disaggregated into age classes, and information about where the different age classes feed in May was derived. The analysis of herring feeding patterns in May confirms that the youngest age classes are generally found close to the Norwegian shelf, whereas the older age classes display larger variations in where they are distributed. During the period 1996–1998, the oldest age classes were found in the central and western Norwegian Sea. During the period 1999–2004, the whole stock migrated north after spawning, leaving the regions in the southern Norwegian Sea void of herring. Since 2005 the oldest herring has again congregated in the south-western Norwegian Sea, in the frontal zone between the cooler East Icelandic water and the warmer Atlantic water. There was a significant positive relationship both between stock size and distribution area and between stock size and density. Moreover, it is likely that the strong year classes 1991/1992 and 1998/1999, which were relatively old when the respective changes in migration patterns occurred, were important contributors to the changes observed in 1999 and 2005, respectively.

Burrow emergence rhythms of Nephrops norvegicus by UWTV and surveying biases

Underwater Television (UWTV) surveys provide fishery-independent stock size estimations of the Norway lobster (Nephrops norvegicus), based directly on burrow counting using the survey assumption of “one animal = one burrow”. However, stock size may be uncertain depending on true rates of burrow occupation. For the first time, 3055 video transects carried out in several Functional Units (FUs) around Ireland were used to investigate this uncertainty. This paper deals with the discrimination of burrow emergence and door-keeping diel behaviour in Nephrops norvegicus, which is one of the most commercially important fisheries in Europe. Comparisons of burrow densities with densities of visible animals engaged in door-keeping (i.e. animals waiting at the tunnel entrance) behaviour and animals in full emergence, were analysed at time windows of expected maximum population emergence. Timing of maximum emergence was determined using wave-form analysis and GAM modelling. The results showed an average level of 1 visible Nephrops individual per 10 burrow systems, depending on sampling time and depth. This calls into question the current burrow occupancy assumption which may not hold true in all FUs. This is discussed in relation to limitations of sampling methodologies and new autonomous robotic technological solutions for monitoring.

Characteristic and evaluation of sustainability artisanal bonito (Auxis spp.) fisheries in the Prigi Bay and surrounding waters

Bonito plays an important role as the main ingredient for marinated products and provides a livelihood for coastal communities. Given the emergence of Indonesia's over-exploited small-scale marine fisheries resources, this study aims to characterize and evaluate fishery’s sustainability based on bioeconomic analyses. Time series catch and effort data were collected from 2005 to 2019 provided by Archipelagic Fishing Port of Prigi. Five surplus production models were also employed to generate catch-and-effort-based biological parameters, namely intrinsic growth rate (r), catchability (q), and carrying capacity (K). By adding economy parameters such as cost and price, the sustainability of catch and effort was also estimated at three management conditions. The catch abundance was peaked in April and September, characterized by the lack of rain. The CPUE was varied inter-annually. However, it declined during the last decade, indicating that the stock size was decreased. Although the average catches from 2015-2019 (9,984 tons) are lower than CMSY (11,695 tons). However, the effort in 2019 (15,239 trips) has exceeded EMEY (14,237 trips). Hence, reducing fishing efforts or maintaining it at E2018 level was suggested as a precaution to keep the fishery’s sustainability and simultaneously generate optimum profit.

Growth Analysis and the Determinants of Entrepreneurial Orientation in the Small-Scale Poultry Subsector in Delta State, Nigeria

Entrepreneurial orientation is vital to growth and development, but lacking in many small-scale enterprises. This study investigated growth and entrepreneurial orientation in the small-scale poultry subsector of Delta State, Nigeria. It also ascertained the drivers of poultry entrepreneurial orientation in the study area. A multistage sampling procedure was used to collect primary data from 180 poultry farmers, through a questionnaire. A four-point Likert scale of five items was used to measure entrepreneurial orientation from innovativeness, proactiveness, and risk-taking. The data were analyzed using descriptive and inferential statistics, including gross margins, an autoregressive lag model, and logistic regression. The majority (57.7%) of the farmers are female. The small-scale poultry entrepreneurs had an orientation that was above average. The autoregressive lag model result indicated an increase in stock size and gross margins of poultry enterprises. It was forecast that the growth trend would increase up to 2022. Furthermore, the ANOVA result was statistically significant at 0.002*** and 0.001*** for stock size and gross margins, respectively. Years of experience and training in poultry farming and noninvolvement of entrepreneurs in other occupations influence their entrepreneurial orientation. Poultriy entrepreneurs must be trained while they adopt poultry farming as their principal occupation.

ECONOMIC ANALYSIS OF ARTIFICIAL INSEMINATION OF BROILER PRODUCTION IN NIGERIA

Artificial Insemination (AI) in poultry production is a veritable technique in solving the problem of breeding and meeting the increasing demand. This study assesses the economics of artificial insemination in broiler production among sixty randomly selected broiler farmers in Nigeria. The analytical techniques employed include descriptive statistics, gross margin analysis, and stochastic frontier. The result discovered that most of the farmers are male and are at their prime age. Majority of the livestock farmers have some form of formal education and a minimum of 5 (five) year experience in poultry farming. The capital was mostly sourced from the bank. Majority of the farmers has a stock size of more than 25,000 birds. They have a gross margin of N341, 933,406. Only 20% of gross income was used for operating expenses with a return on capital invested of 4.3. The mean technical efficiency was 80.70%. Feed, vaccine and stock size were statistically significant in determining efficiency while education and extension visits are the statistically significant variable influencing technical inefficiency. It is therefore recommended that affordable and accessible input, as well as training should be made available to farmers to achieve self-sufficiency and improve the economy.

Measuring fisheries management performance

How do we assess the performance of national and international fisheries management organizations? Many organizations produce measures of the extent of overfishing, typically classifying individual stocks as overfished if they are below some biomass threshold. Most agencies then report their overall status (i.e. percentage overfished, fully exploited, etc.) by giving equal weight to all stocks, regardless of stock size or potential yield. We review the range of indices used to assess overfishing levels and apply them to the data from US fisheries to show how they depict very different performance of fisheries. Given that overfishing is a concept imbedded in the maximization of long-term harvest, we evaluate how well these indices reflect the extent to which fisheries have maximized sustainable yield. Indices that are weighted by the potential yield of the stock much better reflect the regional performance of fisheries but are still limited by the arbitrary use of a threshold abundance. For the United States, weighting by maximum sustainable yield or value suggests that the losses from overfishing are less than existing methods using equal weighting and that underfishing is much more common than overfishing.