scholarly journals A Stochastic Model for the Management of the Northwestern Atlantic Harp Seal (Pagophilus groenlandicus) Population

1977 ◽  
Vol 34 (8) ◽  
pp. 1155-1187 ◽  
Author(s):  
Patrick F. Lett ◽  
Terje Benjaminsen
Keyword(s):  
Stochastic Model ◽  
Population Size ◽  
Management Strategies ◽  
High Arctic ◽  
Maximum Sustainable Yield ◽  
Future Research ◽  
Total Allowable Catch ◽  
Stock Size ◽  
Pagophilus Groenlandicus ◽  
Scientific Arguments

Advice from the scientific advisers under the auspices of ICNAF to the international commissioners for 1977 was that the total allowable catch (TAC) for harp seals (Pagophilus groenlandicus) should not exceed 170,000. This advice, in part, was based on the scientific arguments presented in this paper. A stochastic model is developed that takes into account the variations in natural mortality and the landsmen's high arctic and Greenland catches. The Canadian–Norwegian large vessel hunt is controlled under quota regulations. The model is nonlinear, a result of changes in fertility and fecundity rates in response to shifts in population size. The maximum sustainable yield (MSY) 1 + population size is determined to be 1.6 million seals, or a breeding stock size of 375,000 seals. The MSY is approximately 240,000 seals assuming the hunt continues its present pattern. The 240,000 can further be split into 200,000 pups and 40,000 1 + seals. Present stock size is approximately 1.2 million and a TAC of 170,000 seals will allow the population size to reach to MSY level in 10–15 yr. A number of other management strategies are considered, in addition to prospects for future research.

Production, Mortality, And Sustainable Yield Of Northwest Atlantic Harp Seals (Pagophilus groenlandicus)

1978 ◽  
Vol 35 (9) ◽  
pp. 1249-1261 ◽  
Author(s):  
G. H. Winters
Keyword(s):  
Population Size ◽  
Total Population ◽  
Historical Data ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Natural Mortality ◽  
Northwest Atlantic ◽  
The Past ◽  
Relative Contribution ◽  
Pagophilus Groenlandicus

From recent and historical data the natural mortality rate of adult harp seals (Pagophilus groenlandicus) is estimated to be 0.10 which is within the range of previous estimates (0.08–0.11). New estimates of bedlamer and 0-group natural mortality rates were not significantly different from those of adult seals. Pup production estimates from survival indices agreed well with those from sequential population analyses and indicated a decline from about 350 000 animals in the early 1950s to about 310 000 animals in the early 1970s. Over the same period the 1+ population size declined from 2.5 to 1.1 million animals but has been increasing at the rate of 3%/yr since the introduction of quotas in 1972. The relative contribution of the "Front" production to total ("Front" plus Gulf) production during the past decade has fluctuated from 49 to 87%, the average of 64% being very similar to the 61% obtained previously. These fluctuations suggest some interchange between "Front" and Gulf adults and it is concluded that homing in the breeding areas is a facultative rather than obligatory aspect of seal behavior. Thus the heavier exploitation of the "Front" production is probably sufficiently diffused into the total population to avoid serious effects on "Front" production. The maximum sustainable yield of Northwest Atlantic seals harvested according to recent patterns is estimated to be 290 000 animals (80% pups) from a 1+ population size of 1.8 million animals producing 460 000 pups annually. The sustainable yield at present levels of pup production (335 000 animals) is calculated to be 220 000 animals which is substantially above the present TAC of 180 000 animals and coincides with present harvesting strategies designed to enable the seal hunt to increase slowly towards the MSY level. Key words: mortality, production, sustainable yield, population dynamics, marine mammal

scholarly journals Evaluating management strategies to implement the recovery plan for Iberian hake (Merluccius merluccius); the impact of censored catch information

2009 ◽  
Vol 67 (2) ◽  
pp. 258-269 ◽  
Author(s):  
Ernesto Jardim ◽  
Santiago Cerviño ◽  
Manuela Azevedo
Keyword(s):  
Management Strategies ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fishing Mortality ◽  
Merluccius Merluccius ◽  
Total Allowable Catch ◽  
Recovery Plan ◽  
Stock Biomass ◽  
Spawning Stock ◽  
The Impact

Abstract Jardim, E., Cerviño, S., and Azevedo, M. 2010. Evaluating management strategies to implement the recovery plan for Iberian hake (Merluccius merluccius); the impact of censored catch information. – ICES Journal of Marine Science, 67: 258–269. Iberian hake assessment revealed an increase in fishing mortality (F) despite enforcement of a recovery plan. Recent landings exceeded the total allowable catch and discarding rates were high. Alternative management strategies based on F control were evaluated with respect to the probability of recovering spawning-stock biomass (SSB), expected profits, and robustness to uncertainty on catch information and stock dynamics. Results showed that the use of censored catch data, i.e. excluding the Gulf of Cádiz or discards, may lead to inappropriate conclusions. Reducing fishing mortality was necessary for SSB to recover. An Fmax strategy with discard reduction showed the highest probability of rebuilding SSB and led the fishery to sustainable exploitation, with an expected %SPR of 30–40% in 2025, mean individual weight in the landings of 450 g in 2015, and yield increasing by >20%. Because of uncertainty in the estimates of maximum sustainable yield, management strategies based on FMSY were least robust, but all strategies were robust to alternative stock–recruit models.

scholarly journals IMPLIKASI MODEL BIOEKONOMI TERHADAP MANAJEMEN PERIKANAN TANGKAP: STUDI KASUS DI PANTAI SELATAN YOGYAKARTA

2003 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Suadi Suadi ◽  
Soeparno Soeparno ◽  
Retno Widianingroem
Keyword(s):  
Management Strategies ◽  
Maximum Sustainable Yield ◽  
South Coast ◽  
Small Scale ◽  
Free Access ◽  
Sustainable Yield ◽  
Total Revenue ◽  
Total Allowable Catch ◽  
Bargaining Position ◽  
Technology Improvement

Small-scale marine capture fisheries have contributes to community welfare at Yogyakarta’s south coast. Government has planned some programs to develop fisheries. The development supposed only at rational effort in which fishers still gain advantages. Precautionary approach using bio-economic model of Gordon-Schaefer was applied to analyze the issue. The linear regression model of catch per unit of effort (C/f) (CPUE) and effort (f) was C/f = 59,851 – 0,0005f (R2 = 82, 71%). Fish price assumed at Rp 7,735.19 /kg with operational cost of Rp 59,835.67/trip. Total revenue and effort at maximum sustainable yield was predicted at Rp 13,396 billion and 56,860 trip (equals to 327 vessels), respectively. Fisher income at this level was Rp 167,774.51/trip/vessel. Fish exploration level in this area has already closed to total allowable catch. Free access equilibrium in which cost is equal to revenue might reach at effort of 102,231 trip (equals to 568 vessels). Managing fisheries at maximum economic yield might rise fisher income 17.83% comparing to maximum sustainable yield, but total revenue decreased 1.77% at 56.13% of existing effort. Some management strategies should be promoted and regulated for the fishery exploitation. Based on the results, those possible strategy were 1) limiting investment through regulation and permission; 2) improvement of fishers productivity through technology improvement to exploit  under-used fish resources; 3) expanding the fisheries activity to offshore through harbor development and social preparation; 4) marketing improvement through revitalization of fish action; 5) improving hadling and post harvest fish technology through training and extension; 6) the increasing of bargaining position through empowering fishers group; 7) promoting alternate incomes through integrated coastal tourism development; and 8) avoiding competition and conflict through developing Java’s south coast cooperation. Participatory approach in planning, developing and evaluating should be promoted to develop fishery a southern coast of Yogyakarta.

Understanding Limited Use of Amplification in Infants and Children Who Are Hard of Hearing

2015 ◽  
Vol 25 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Ryan W. McCreery ◽  
Elizabeth A. Walker ◽  
Meredith Spratford
Keyword(s):  
Hard Of Hearing ◽  
Hearing Aid ◽  
Management Strategies ◽  
Infants And Children ◽  
Future Research ◽  
Research Needs ◽  
Case Examples ◽  
Hearing Aid Use ◽  
Wide Range ◽  
In Infants And Children

The effectiveness of amplification for infants and children can be mediated by how much the child uses the device. Existing research suggests that establishing hearing aid use can be challenging. A wide range of factors can influence hearing aid use in children, including the child's age, degree of hearing loss, and socioeconomic status. Audiological interventions, including using validated prescriptive approaches and verification, performing on-going training and orientation, and communicating with caregivers about hearing aid use can also increase hearing aid use by infants and children. Case examples are used to highlight the factors that influence hearing aid use. Potential management strategies and future research needs are also discussed.

scholarly journals A qualitative investigation of LGBTQ+ young people’s experiences and perceptions of self-managing their mental health

2021 ◽  
Author(s):  
Rosa Town ◽  
Daniel Hayes ◽  
Peter Fonagy ◽  
Emily Stapley
Keyword(s):  
Mental Health ◽  
Young People ◽  
Management Strategies ◽  
Intervention Development ◽  
Community Support ◽  
Self Management ◽  
Future Research ◽  
Youth Groups ◽  
Coping Methods ◽  
Group A

AbstractThere is evidence that young people generally self-manage their mental health using self-care strategies, coping methods and other self-management techniques, which may better meet their needs or be preferable to attending specialist mental health services. LGBTQ+ young people are more likely than their peers to experience a mental health difficulty and may be less likely to draw on specialist support due to fears of discrimination. However, little is known about LGBTQ+ young people’s experiences and perceptions of self-managing their mental health. Using a multimodal qualitative design, 20 LGBTQ+ young people participated in a telephone interview or an online focus group. A semi-structured schedule was employed to address the research questions, which focussed on LGBTQ+ young people’s experiences and perceptions of self-managing their mental health, what they perceived to stop or help them to self-manage and any perceived challenges to self-management specifically relating to being LGBTQ+ . Reflexive thematic analysis yielded three key themes: (1) self-management strategies and process, (2) barriers to self-management and (3) facilitators to self-management. Participants’ most frequently mentioned self-management strategy was ‘speaking to or meeting up with friends or a partner’. Both barriers and facilitators to self-management were identified which participants perceived to relate to LGBTQ+ identity. Social support, LGBTQ+ youth groups and community support were identified as key facilitators to participants’ self-management of their mental health, which merits further investigation in future research. These findings also have important implications for policy and intervention development concerning LGBTQ+ young people’s mental health.

scholarly journals When the Day Goes Awry: Families Caring for Persons With Dementia

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 638-639
Author(s):  
Karen Roberto ◽  
Jyoti Savla ◽  
Steven Zarit
Keyword(s):  
Family Caregivers ◽  
Rural Areas ◽  
Service Use ◽  
Management Strategies ◽  
Care Quality ◽  
Future Research ◽  
Full Time ◽  
Daily Lives ◽  
Formal Service ◽  
Formal Services

Abstract The daily lives of family caregivers of persons with dementia (PwD) often require that they manage multiple competing demands in a context of unpredictability. Memory and behavior changes associated with dementia can cause PwD to act in random and irrational ways that create stress and influence all aspects of caregivers’ everyday life. Supportive others, including informal helpers and formal service professionals, should provide relief to primary caregivers; however, help may not alleviate caregiver stress and can sometimes compound the burden of care. This symposium draws on daily diary surveys and face-to-face interviews to focus on four aspects of managing everyday care of PwD among family caregivers in rural areas. Brandy Renee McCann explores how caregivers’ vigilance on behalf of PwD care quality interacts with service use. Karen Roberto examines the ways in which caregivers manage PwD resistance to help, including their use of forceful care strategies. Rosemary Blieszner focuses on competing caregiver roles and demands that may contribute to or alleviate caregiver stress. Tina Savla addresses the unexpected, and often hidden, challenges involved in using formal services. Collectively, the four presentations provide in-depth insight into the complicated daily lives of families coping with dementia and the ways in which they meet the demands of full-time caregiving under often difficult and challenging circumstances. Discussant Steve Zarit considers the efficacy of these management strategies for various aspects of everyday care and offers suggestions for future research and person-centered programs and interventions to reduce health disparities among caregivers in rural areas.

scholarly journals A Three-Pronged Approach to Studying Sublethal Insecticide Doses: Characterising Mosquito Fitness, Mosquito Biting Behaviour, and Human/Environmental Health Risks

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 546
Author(s):  
Mara Moreno-Gómez ◽  
Rubén Bueno-Marí ◽  
Miguel. A. Miranda
Keyword(s):  
Environmental Health ◽  
Population Size ◽  
Mosquito Species ◽  
Management Strategies ◽  
Adult Mortality ◽  
Negative Control ◽  
Environmental Health Risks ◽  
Vector Management ◽  
Sublethal Doses ◽  
Biting Behaviour

Worldwide, pyrethroids are one of the most widely used insecticide classes. In addition to serving as personal protection products, they are also a key line of defence in integrated vector management programmes. Many studies have assessed the effects of sublethal pyrethroid doses on mosquito fitness and behaviour. However, much remains unknown about the biological, physiological, demographic, and behavioural effects on individual mosquitoes or mosquito populations when exposure occurs via spatial treatments. Here, females and males of two laboratory-reared mosquito species, Culex pipiens and Aedes albopictus, were exposed to five different treatments: three doses of the pyrethroid prallethrin, as well as an untreated and a negative control. The effects of each treatment on mosquito species, sex, adult mortality, fertility, F1 population size, and biting behaviour were also evaluated. To compare knockdown and mortality among treatments, Mantel–Cox log-rank tests were used. The results showed that sublethal doses reduced mosquito survival, influencing population size in the next generation. They also provided 100% protection to human hosts and presented relatively low risks to human and environmental health. These findings emphasise the need for additional studies that assess the benefits of using sublethal doses as part of mosquito management strategies.

A semi-hybrid model for malaria with limited superinfection

1998 ◽  
Vol 30 (04) ◽  
pp. 1027-1057 ◽  
Author(s):  
Philippe Picard
Keyword(s):  
Stochastic Model ◽  
Population Size ◽  
Hybrid Model ◽  
Human Population ◽  
Threshold Level ◽  
The Other ◽  
The Difference ◽  
The One

Modelling malaria with consistency necessitates the introduction of at least two families of interconnected processes. Even in a Markovian context the simplest fully stochastic model is intractable and is usually transformed into a hybrid model, by supposing that these two families are stochastically independent and linked only through two deterministic connections. A model closer to the fully stochastic model is presented here, where one of the two families is subordinated to the other and just a unique deterministic connection is required. For this model a threshold theorem can be proved but the threshold level is not the one obtained in a hybrid model. The difference disappears only when the human population size approaches infinity.

scholarly journals The status of Japanese fisheries relative to fisheries around the world

2017 ◽  
Vol 74 (5) ◽  
pp. 1277-1287 ◽  
Author(s):  
Momoko Ichinokawa ◽  
Hiroshi Okamura ◽  
Hiroyuki Kurota
Keyword(s):  
Maximum Sustainable Yield ◽  
Production Model ◽  
Structured Population Model ◽  
Total Allowable Catch ◽  
Quick Recovery ◽  
Stock Status ◽  
Surplus Production Model ◽  
The Status ◽  
Stock Recruitment ◽  
Age Structured

We present the first quantitative review of the stock status relative to the stock biomass (B) and the exploitation rate (U) that achieved the maximum sustainable yield (MSY) (BMSY and UMSY, respectively) for 37 Japanese stocks contributing 61% of the total marine capture production in Japan. BMSY and UMSY were estimated by assuming three types of stock-recruitment (S-R) relationships and an age-structured population model or by applying a surplus production model. The estimated stock status shows that approximately half of the stocks were overfishing (U/UMSY > 1), and approximately half of the stocks were overfished (B/BMSY < 0.5) during 2011–2013. Over the past 15 years, U decreased and B slightly increased on average. The rate of decrease in the U of the stocks managed by the total allowable catch (TAC) was significantly greater than that of the other stocks, providing evidence of the effectiveness of TAC management in Japan. The above statuses and trends were insensitive to the assumption of the S-R relationship. The characteristics of Japanese stocks composed mainly of resources with relatively high natural mortality, i.e. productivity, suggest that Japanese fisheries have great potential of exhibiting a quick recovery and increasing their yield by adjusting the fishing intensity to an appropriate level.

Linking Residential Parking to Automobile Transportation Impact Outcomes at a Development Level

2020 ◽  
pp. 036119812096479
Author(s):  
Kristina M. Currans ◽  
Gabriella Abou-Zeid ◽  
Nicole Iroz-Elardo
Keyword(s):  
Travel Behavior ◽  
Travel Demand ◽  
Demand Management ◽  
Management Strategies ◽  
Land Development ◽  
Future Research ◽  
Alternative Mode ◽  
Travel Demand Management ◽  
Development Level ◽  
Automobile Demand

Although there exists a well-studied relationship between parking policies and automobile demand, conventional practices evaluating the transportation impacts of new land development tend to ignore this. In this paper, we: (a) explore literature linking parking policies and vehicle use (including vehicle trip generation, vehicle miles traveled [VMT], and trip length) through the lens of development-level evaluations (e.g., transportation impact analyses [TIA]); (b) develop a conceptual map linking development-level parking characteristics and vehicle use outcomes based on previously supported theory and frameworks; and (c) evaluate and discuss the conventional approach to identify the steps needed to operationalize this link, specifically for residential development. Our findings indicate a significant and noteworthy dearth of studies incorporating parking constraints into travel behavior studies—including, but not limited to: parking supply, costs or pricing, and travel demand management strategies such as the impacts of (un)bundled parking in housing costs. Disregarding parking in TIAs ignores a significant indicator in automobile use. Further, unconstrained parking may encourage increases in car ownership, vehicle trips, and VMT in areas with robust alternative-mode networks and accessibility, thus creating greater demand for vehicle travel than would otherwise occur. The conceptual map offers a means for operationalizing the links between: the built environment; socio-economic and demographic characteristics; fixed and variable travel costs; and vehicle use. Implications for practice and future research are explored.

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