scholarly journals Length-based indicators for the management of sport fishery in Yucatan, Mexico

2020 ◽  
Vol 48 (4) ◽  
pp. 637-648
Author(s):  
Jorge A. López-Rocha ◽  
Laura Vidal-Hernández ◽  
Arturo Bravo-Calderón
Keyword(s):  
Fishing Effort ◽  
Commercial Fishing ◽  
Sport Fishing ◽  
Optimal Length ◽  
Monitoring Method ◽  
Priority Level ◽  
Sport Fishery ◽  
Mycteroperca Bonaci ◽  
Sphyraena Barracuda ◽  
The Impact

Sportfishing is an activity of increasing popularity that involves a large number of users and high levels of fishing effort. In Yucatan, most of the target species in sport fishing are the same as those of commercial fisheries. However, there is no record of fishing effort or catch volumes. Thus the impact of sport fishing on these populations is unknown. This study analyzes the catches made by users of sport fisheries of nine species (Epinephelus morio, Haemulon plumieri, Seriola dumerili, Lutjanus synagris, Ocyurus chrysurus, Calamus bajonado, Sphyraena barracuda, S. guachancho and Mycteroperca bonaci) through length-based indicators. Samples of species’ sizes were obtained from the catches made during 10 fishing tournaments held in Yucatan's three-port towns (Sisal, Yucalpeten, and Telchac) between 2015 and 2016. The catch variables that were evaluated included: the number of mature individuals Pmat, optimal length Popt, and the number of mega-spawners Pmega. Length measures were derived from 1,252 individuals. Only H. plumieri, L. synagris, and S. guachancho exhibited sustainable indicator values, while E. morio and C. bajonado demonstrated extremely low values. In most species, sport fishing affects a high proportion of juveniles. The results suggest that sportfishing contributes to the fishing pressure of a species and commercial fishing, due to the capture of juveniles of economically important fish. It is essential to establish a systematic monitoring method of such activities and increase the priority level of the evaluation and management of this fishery.

scholarly journals The impact of commercial fishing on the determination of habitat associations for sea scallops (Placopecten magellanicus, Gmelin)

2009 ◽  
Vol 66 (9) ◽  
pp. 2043-2051 ◽  
Author(s):  
Stephen J. Smith ◽  
Jerry Black ◽  
Brian J. Todd ◽  
Vladimir E. Kostylev ◽  
Mark J. Lundy
Keyword(s):  
Variance Reduction ◽  
Survey Design ◽  
Fishing Effort ◽  
Habitat Associations ◽  
Commercial Fishing ◽  
Placopecten Magellanicus ◽  
Bottom Type ◽  
Sea Scallops ◽  
The Impact

Abstract Smith, S. J., Black, J., Todd, B. J., Kostylev, V. E. and Lundy, M. J. 2009. The impact of commercial fishing on the determination of habitat associations for sea scallops (Placopecten magellanicus, Gmelin). – ICES Journal of Marine Science, 66: 2043–2051. The sea scallop (Placopecten magellanicus) population off southwestern Nova Scotia in Scallop Fishing Area 29 has been monitored by an annual drag survey since the fishery started there in 2001. A new stratification scheme based on surficial geology maps from a multibeam bottom mapping and geology ground-truth project completed in 2004 in the area have been used for survey design since 2005. Survey data from before 2005 have been post-stratified using the new strata. The efficiency of the design with respect to variance reduction appears to have diminished over time suggesting that the association between scallop abundance and bottom type may not have been as strong or constant as first assumed. Modelling of the association between scallop abundance and bottom type and depth using a Bayesian hierarchical approach confirms this diminishing relationship. Comparison of the results from the model with spatial measures of fishing effort based on satellite vessel monitoring data suggests that increasing exploitation may be masking the relationships as scallop beds are targeted and fished down. These results could have implications on the interpretation of species habitat associations from areas where data are only available from periods when the populations have been exploited over a long time. In these cases, the spatial distribution of fishing effort may be a better indicator of species habitat associations than the estimates from surveys.

scholarly journals Nonstationary Responses of Demersal Fishes to Environmental Variations in Temperate Waters of the Northwestern North Pacific under a Changing Climate

Fishes ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 22
Author(s):  
Qingsong He ◽  
Shuyang Ma ◽  
Qinwang Xing ◽  
Wenchao Zhang ◽  
Haiqing Yu ◽  
...  
Keyword(s):  
North Pacific ◽  
Negative Relationship ◽  
Demersal Fish ◽  
Fishing Effort ◽  
Asian Winter Monsoon ◽  
Changing Climate ◽  
Sst Variability ◽  
Environmental Variations ◽  
The Impact ◽  
Demersal Fishes

Although nonstationarity in marine ecosystems has attracted great attention, the nonstationary responses of demersal fishes to environmental variations induced by the changing climate are still not well understood. Here, we collected 21 time series of demersal fishes from 1956 to 2015 to investigate the climate-induced nonstationary responses in temperate waters of the northwestern North Pacific (NWP). We showed that these demersal fishes experienced state shifts in approximately 1986/87, accompanied by abrupt warming over this region. Moreover, the relationships between demersal fishes and sea surface temperature (SST) were found to change between the two identified eras (i.e., a weak relationship before 1986 and a strong negative relationship after 1986), which may be primarily caused by the alternating dominance of the East Asian winter monsoon and mega-ENSO on SST in temperate waters of the NWP. The identified climate-induced nonstationary responses of demersal fishes to SST variability in this study may provide implications for understanding climate-induced biological dynamics, predicting demersal fish fluctuations, coping with potential ecological risks, and the sustainable exploitation of fishery resources in the future climate. Note that the impact of fishing on the demersal fishes in temperate waters of the NWP was not assessed in this study due to the lack of fishing effort data and therefore the conclusions of our research should be approached with caution.

Spatial and Temporal Overlap of the American Lobster (Homarus americanus) and Sea Scallop (Placopecten magellanicus) as Related to the impact of Inshore Scallop Dragging

1992 ◽  
Vol 49 (7) ◽  
pp. 1486-1492 ◽  
Author(s):  
D. L. Roddick ◽  
R. J. Miller
Keyword(s):  
Nova Scotia ◽  
Homarus Americanus ◽  
Fishing Effort ◽  
The Other ◽  
American Lobster ◽  
Placopecten Magellanicus ◽  
Time And Space ◽  
Sea Scallop ◽  
The Impact ◽  
Temporal Overlap

Assessment of the damage of one fishery by another requires knowledge of the overlap, in time and space, of the damaging fishing effort and the abundance of the damaged species, as well as a measure of the rate of damage. This approach was used to measure the impact of inshore scallop dragging on lobsters in Nova Scotia. Areas of reported co-occurrence of lobster and scallop grounds were surveyed by divers to determine the extent of overlap. Only 2 of 52 sites surveyed had lobsters on scallop grounds that could be dragged. Divers surveyed one site six times during 1987 and 1988 and found lobsters most abundant during August and September. Only 2% of the lobsters in the path of scallop drags were either captured or injured. The estimated value of lobsters destroyed by dragging for scallops during periods of peak lobster abundance was minor: $757 at one site and $176 at the other. Restricting dragging to periods of low lobster abundance significantly reduces this cost.

Fishing the line: catch and effort distribution around the seasonal haddock (Melanogrammus aeglefinus) spawning closure on the Scotian Shelf

2013 ◽  
Vol 70 (7) ◽  
pp. 973-981 ◽  
Author(s):  
A. van der Lee ◽  
D.M. Gillis ◽  
P. Comeau ◽  
P. Hurley
Keyword(s):  
Ideal Free Distribution ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Rate ◽  
Melanogrammus Aeglefinus ◽  
Boundary Line ◽  
The West ◽  
Fishing The Line ◽  
The Impact ◽  
Effort Distribution

Permanent and seasonal area closures are a common regulatory strategy in multispecies fisheries; however, few studies have closely examined seasonal closures. We examined the impact of the Browns Bank spawning closure on the spatial distribution of fishing effort and how the fleet utilized a “fishing the line” strategy. Generalized estimating equations were used to examine changes in effort distribution when the closure was and was not in effect. Effort displaced from the bank concentrated primarily within two areas up to 30 km from the closure boundary, one along the east boundary line and one along the west. Trends in catch rate (as value) with distance from the line were further examined using generalized additive models during the closed period, with results differing between regions. In the east, areas of greater catch rate could be identified and typically corresponded to areas of greater effort, while in the west region, no trends in catch rates were often observed, potentially indicating vessel distributions that correspond to the ideal free distribution. Implementation of a seasonal area closure on Browns Bank resulted in concentrations of vessels near the closure boundary, suggestive of a fishing the line strategy, with specific catch rate trends depending on vessel spatial distributions and target species.

scholarly journals Characteristics of Marine Recreational Fishing in the anakkale Strait (Turkey)

2010 ◽  
Vol 11 (2) ◽  
pp. 315 ◽  
Author(s):  
V. UNAL ◽  
D. ACARLI ◽  
A. GORDOA
Keyword(s):  
Time Of Day ◽  
Recreational Fishing ◽  
Commercial Fishing ◽  
Catch Per Unit Effort ◽  
Pomatomus Saltatrix ◽  
Night Time ◽  
Policy Information ◽  
Surveillance Programs ◽  
Catch Composition ◽  
The Impact

The economic and harvest impacts of Marine Recreational Fishing (MRF) in Çanakkale Strait were analysed along with fishing policy, sociology and habits of fishers. Data sources included field survey data carried out along the entire length of the Çanakkale strait and policy information gathered from published sources. MRF policy is commendable, even in the fishing tourism sector, and is better developed than that in many other European countries. In Çanakkale, 9.9% of the population is recreational fishers. Recreational fishers are typically men (90%), primarily those between the ages of 25 and 49 yrs. The occupation of the recreational fishers ranged from self-employed (28%), students (28%), retired persons (22%) and public employees (15%), to currently-unemployed persons (7%). An analysis of diel behaviour showed that most recreational fishers preferred fishing during the day (56.1%), while the evening was the next most preferred time for fishing (18%), followed by the night-time (9.8%), while a substantial number of recreational fishers (16.1%) reported that they fished at any time of day. The most popular type of fishing was shore-based (68%), followed by boat-based (21%), and underwater fishing (11%). The mean daily fishing times were 6.07 h d-1, 6.18 h d-1 4.75 d-1 for boat-based, underwater and shore-based fishing, respectively. Summer and autumn were the preferred seasons for shore-based and underwater fishing, while autumn and winter were preferred for boat-based fishing. The highest Catch per Unit Effort (CPUE) was observed for boat-based fishing (2.77 kg h-1), followed by underwater (0.97 kg h-1) and shore-based fishing (0.81 kg h-1). The catch composition included 51 species, though the catch composition of each fishing type was mostly comprised of only 3 or 4 species. The impact of the MRF harvest was high (30% of commercial fishing), particularly for bluefish (Pomatomus saltatrix) and picarel (Spicara smaris) species. The economic impact of MRF was highly negative. Several indicators including the following revealed a high percentage of trading catch (47%) being conducted under the guise of a recreational label: annual fishing intensity, total costs, target species, and sales. At present, it is evident that the highly developed recreational fishing policy in Turkey is not sufficient to ensure that recreational fishing is sustainable or to prevent fishing conflicts in Turkey. This study revealed the need for establishing monitoring, control and surveillance programs to ensure the sustainability of fish resources and fisheries including MRF.

scholarly journals Numerical Model of Fish Exploitation – structure and application

2019 ◽  
Vol 27 (2) ◽  
pp. 86-101
Author(s):  
Paweł Buras ◽  
Wiesław Wiśniewolski
Keyword(s):  
Numerical Model ◽  
Simulation Models ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Recreational Fisheries ◽  
Fisheries Resources ◽  
Fish Exploitation ◽  
The Common ◽  
Common Bream ◽  
The Impact

Abstract Fisheries simulation models are tools used for forecasting the effects of exploitation and determining the directions of managing fisheries resources. The Numerical Model of Fish Exploitation (NMFE) and its capabilities were tested on a population of common bream, Abramis brama (L.) in a dam reservoir that is exploited by commercial and recreational fisheries. Based on the designated population parameters of N0, Fij, Mi, and ei and the size and structure of the common bream population in the reservoir, the model was used to examine hypothetical simulation variants of changes in fishing intensity E1 with nets and rods, changes in fishing intensity based on actual fishing effort with nets, changes in natural mortality, changes in the size of fish caught, and the impact of this on the size of the resources. Initial catches with nets and rods were calculated. Increasing fishing effort did not translate proportionally to increased catches, and the function was curvilinear. The results of simulations that reduced the intensity of fishing with nets and decreased catch sizes concurred with data from actual catches. Simulations of changes in natural mortality had various effects on the size of catches. Reducing parameter M did not impact the level of catches, while increasing parameter M reduced the size of catches significantly.

scholarly journals Importance and Impact of the Poultry Red Mite (Dermanyssus Gallinae) in Layer Farms - Analysis of Farmers’ Perception

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Miroslav Kjosevski ◽  
Danijela Horvatek Tomić ◽  
Aleksandar Dodovski
Keyword(s):  
Crude Oil ◽  
Pest Management ◽  
Descriptive Statistics ◽  
Dermanyssus Gallinae ◽  
Bayes Classifier ◽  
Poultry Red Mite ◽  
Monitoring Method ◽  
Poultry Farms ◽  
And Control ◽  
The Impact

Abstract Poultry red mite (PRM), Dermanyssus gallinae, causes egg drop production, anemia and can be a vector in transmitting diseases. The PRM control mainly focuses on usage of the conventional chemical biocides. The objective of this study was to analyze the farmers’ perception regarding the impact, management and control of PRM in Macedonian layer farms. The data were collected with direct on-site visits using a unified questionnaire. In total, 29 poultry farms (28% of farms in the country), all with conventional cages, were part of this study. The data were analyzed by descriptive statistics, inferential statistics and Naïve Bayes Classifier technique. In 30% of the poultry farms the farmers had observed that the flock was infested with PRM. In total, 32 different treatments against PRM were reported from the farmers, and three of them were non-biocide treatments. The most used biocides (17% of the farms) were crude oil, Formalin, Neopitroid® and disinfectants. The highest agreement regarding biocides application among the farms (38%) was before the production starts. Most of the farmers applied biocides routinely, before the infestation is evident (75%). The median costs for PRM treatment were 175€ per flock, higher in the infested farms 493±677€ compared to non - infested 100±71€, p<0.05. None of the Macedonian farmers included in the study was using monitoring method for PRM infestation, contributing to poor data records. This study highlights the need of developing unified strategy for PRM control included in the Integrated Pest Management in poultry layer farms.

scholarly journals ASPECTOS BIOLÓGICOS E SOCIOECONÔMICOS DA PESCA ESPORTIVA NO “DECK DO PESCADOR" DE SANTOS (SP, BRASIL)

2016 ◽  
Vol 20 (1) ◽  
Author(s):  
Walter Barrella ◽  
Natália Cachola ◽  
Milena Ramires ◽  
Matheus Marcos Rotundo
Keyword(s):  
Biological Characteristics ◽  
Commercial Fishing ◽  
College Degree ◽  
Sport Fishing ◽  
Target Species ◽  
Fish Stocks ◽  
Trichiurus Lepturus ◽  
Socioeconomic Profile ◽  
Micropogonias Furnieri

Sport fishing is one of the fastest growing leisure categories in today's world. In Brazil it is also practiced as a sport or leisure, noncommercial purposes. However, few studies are conducted in order to manage this activity in a sustainable manner. This study aimed to analyze sport fishing, practiced the "Fisherman’s Deck" (Santos, SP, Brazil), describing their biological characteristics and the socioeconomic profile of its participants. We interviewed 150 fishermen, aged between 12 and 82 years, 85% male. The majority (56%) has a college degree and resides near the fishing spot. The target species are swordfish (Trichiurus lepturus), bass (Centropomus spp.), Hake (Cynoscion spp.), betara (Menticirrhus americanus), corvina (Micropogonias furnieri) and hake-yellow (Macrodon atricauda). Three types of fishing, bottom fishing, surface and crab were identified. Fishermen indicated that fish stocks have declined due to increased commercial fishing and pollution. Each fishery lasted on average 5.0 (S.D.=2.1) hours and captured 850,8g (S.D.=962.5) g / angler / day. The estimated catch for the study period was 1314.8 (S.D.=1919.1) kg, representing less than 3% of fish landed by commercial fishing. Therefore, sport fishing from "Fisherman’s Deck" causes low impact to regional fish stocks.

scholarly journals An investigation of human vs. technology-induced variation in catchability for a selection of European fishing fleets

2011 ◽  
Vol 68 (10) ◽  
pp. 2252-2263 ◽  
Author(s):  
Stéphanie Mahévas ◽  
Youen Vermard ◽  
Trevor Hutton ◽  
Ane Iriondo ◽  
Angélique Jadaud ◽  
...  
Keyword(s):  
Linear Models ◽  
Generalized Additive Models ◽  
Technical Information ◽  
Fishing Effort ◽  
Additive Models ◽  
Induced Variation ◽  
Fishing Fleets ◽  
The Impact ◽  
Selection Of ◽  
Experience Effect

Abstract Mahévas, S., Vermard, Y., Hutton, T., Iriondo, A., Jadaud, A., Maravelias, C. D., Punzón, A., Sacchi, J., Tidd, A., Tsitsika, E., Marchal, P., Goascoz, N., Mortreux, S., and Roos, D. 2011. An investigation of human vs. technology-induced variation in catchability for a selection of European fishing fleets. – ICES Journal of Marine Science, 68: 2252–2263. The impact of the fishing effort exerted by a vessel on a population depends on catchability, which depends on population accessibility and fishing power. The work investigated whether the variation in fishing power could be the result of the technical characteristics of a vessel and/or its gear or whether it is a reflection of inter-vessel differences not accounted for by the technical attributes. These inter-vessel differences could be indicative of a skipper/crew experience effect. To improve understanding of the relationships, landings per unit effort (lpue) from logbooks and technical information on vessels and gears (collected during interviews) were used to identify variables that explained variations in fishing power. The analysis was undertaken by applying a combination of generalized additive models and generalized linear models to data from several European fleets. The study highlights the fact that taking into account information that is not routinely collected, e.g. length of headline, weight of otter boards, or type of groundrope, will significantly improve the modelled relationships between lpue and the variables that measure relative fishing power. The magnitude of the skipper/crew experience effect was weaker than the technical effect of the vessel and/or its gear.

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