scholarly journals Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the Galapagos Marine Reserve

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7278 ◽  
Author(s):  
Juan Carlos Murillo-Posada ◽  
Silvia Salas ◽  
Iván Velázquez-Abunader
Keyword(s):  
Monitoring System ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Per Unit Effort ◽  
Monthly Basis ◽  
Galapagos Marine Reserve

Management of low-mobility or benthic fisheries is a difficult task because variation in the spatial distribution and population dynamics of the resources make the monitoring and assessment of these fisheries challenging. We assumed that environmental, spatial, and temporal factors can contribute to the variability of the relative abundance of such species; we used Generalized Additive Models for Location Scale and Shape (GAMLSS) to test this hypothesis using as a case study the lobster fishery (targeting two species) in the Galapagos Marine Reserve, Ecuador. We gathered data on each of the two species of lobster on a monthly basis over seven years, including: (a) onboard observers’ records of catch data, fishing effort, and ground location by trip, and (b) data from interviews undertaken with fishers at their arrival to port, recording the same type of information as obtained from onboard observers. We use this information to analyze the effect of the measured variables and to standardize the Catch per Unit Effort (CPUE) in each case, using the GAMLSS. For both species, the temperature, region, fishing schedule, month, distance, and the monitoring system were significant variables of the selected models associated with the variability of the catch rate. ForPanulirus penicillatus, CPUE was higher at night than during the day, and forPanulirus gracilisit was higher during the day. Increased temperature resulted in a decrease of CPUE values. It was evident that temporal, spatial scales and monitoring system can influence the variability of this indicator. We contend that the identification of drivers of change of relative abundance in low-mobility species can help to support the development of monitoring and assessment programs for this type of fisheries.

scholarly journals Comparación entre dos modelos estructurados por edades, aplicados a la pesquería de langosta, Panulirus Argus (Latreille, 1804), en la región suroriental de Cuba

2012 ◽  
Vol 3 ◽  
pp. 131
Author(s):  
Romina Alzugaray Martínez ◽  
Rafael Puga Millán
Keyword(s):  
Linear Models ◽  
Population Analysis ◽  
Spiny Lobster ◽  
Information Criterion ◽  
Fishing Effort ◽  
Panulirus Argus ◽  
Catch Per Unit Effort ◽  
Raw Data ◽  
Linear Relationships ◽  
Exploitation Status

La langosta común, Panulirus argus, es una de las especies con mayor valor comercial en el Atlántico Centro Occidental. En Cuba se han realizado numerosos estudios para conocer y actualizar su estado de explotación y recomendar medidas de manejo. A pesar de estas medidas, las capturas continúan disminuyendo, por lo que el objetivo del presente estudio consistió en evaluar la dinámica de la población de langosta en la región suroriental de Cuba, a través de dos estrategias analíticas diferentes. A partir de datos de captura y esfuerzo pesquero de 1979-2010, se aplicaron un análisis de población virtual (VPA) y un análisis estadístico de captura por edades (SCA). Se examinó la relación lineal entre los datos primarios y las variables estimadas por los modelos. El ajuste de los modelos lineales de los datos se evaluó mediante el Criterio de Información de Akaike corregido (AICc). Según ambos métodos de captura por edades, el tamaño poblacional y el reclutamiento de langostas con un año de edad han disminuido en la región en el período estudiado, aunque el SCA muestra estabilización en la última década. Mientras, la biomasa poblacional disminuyó hasta estabilizarse en la última década, lo cual puede relacionarse con el comportamiento histórico de la captura por unidad de esfuerzo. Existen asociaciones lineales significativas entre los datos primarios y las variables estimadas. Según los valores de Δi, el modelo VPA garantiza el mejor ajuste de las variables a las relaciones lineales estimadas. Abstract Spiny lobster, Panulirus argus, is one of the most commercially valuable species in the Western Central Atlantic. Although numerous studies have been conducted in Cuba to learn and update its exploitation status and to recommend management measures, catches continue to decline. Consequently, the objective of this study was to evaluate the dynamics of the lobster population in Cuba’s southeastern region, through two different analytical strategies. Using catch and fishing effort data from 1979-2010, a Virtual Population Analysis (VPA) and a Statistical Catch-at-age Analysis (SCA) were applied. We examined the linear relationship between raw data and the variables estimated by the models. The fit of the linear models to data was assessed using the corrected Akaike Information Criterion (AICc). According to both age-structured methods, population size and recruitment of one year old lobster have declined in the region during the study period, although the SCA shows stabilization in the last decade. Population biomass decreased to stabilize in the last decade, this may relate to the historical behavior of the catch per unit effort. There are significant linear associations between raw data and estimated variables. According to Δi values, the VPA model ensures the best fit for the variables of estimated linear relationships.

Impacts of spatial scales of fisheries and environmental data on catch per unit effort standardisation

2009 ◽  
Vol 60 (12) ◽  
pp. 1273 ◽  
Author(s):  
Siquan Tian ◽  
Yong Chen ◽  
Xinjun Chen ◽  
Liuxiong Xu ◽  
Xiaojie Dai
Keyword(s):  
Spatial Scale ◽  
Stock Assessment ◽  
Spatial Scales ◽  
Additive Models ◽  
Environmental Data ◽  
Catch Per Unit Effort ◽  
The North ◽  
Unit Effort ◽  
Data Collection And Analysis ◽  
North Western

Spatial scale is an important factor that needs to be considered in data collection and analysis in ecological studies. Studies focusing on the quantitative evaluation of impacts of spatial scales are, however, limited in fisheries. Using the Chinese squid-jigging fishery in the north-western Pacific Ocean as an example, we evaluated impacts of spatial scale used in grouping fisheries and environmental data on the standardisation of fisheries catch per unit effort (CPUE). We developed 18 scenarios of different spatial scales with a combination of three latitudinal levels (0.5°, 1° and 2°) and six longitudinal levels (0.5°, 1°, 2°, 3°, 4° and 5°) to aggregate the data. We then applied generalised additive models to analyse the 18 scenarios of data for the CPUE standardisation, and quantified differences among the scenarios. This study shows that longitudinal and latitudinal spatial scale and size of the spatial area for data aggregation can greatly influence the standardisation of CPUE. We recommend that similar studies be undertaken whenever possible to evaluate the roles of spatial scales and to identify the optimal spatial scale for data aggregations in the standardisation of CPUE and fisheries stock assessment.

scholarly journals Evidence that spillover from Marine Protected Areas benefits the spiny lobster (Panulirus interruptus) fishery in southern California

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hunter S. Lenihan ◽  
Jordan P. Gallagher ◽  
Joseph R. Peters ◽  
Adrian C. Stier ◽  
Jennifer K. K. Hofmeister ◽  
...  
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Fishing Ground ◽  
Catch Per Unit Effort ◽  
Panulirus Interruptus ◽  
The Status ◽  
Larval Production ◽  
And Behavior

AbstractMarine Protected Areas (MPAs) are designed to enhance biodiversity and ecosystem services. Some MPAs are also established to benefit fisheries through increased egg and larval production, or the spillover of mobile juveniles and adults. Whether spillover influences fishery landings depend on the population status and movement patterns of target species both inside and outside of MPAs, as well as the status of the fishery and behavior of the fleet. We tested whether an increase in the lobster population inside two newly established MPAs influenced local catch, fishing effort, and catch-per-unit-effort (CPUE) within the sustainable California spiny lobster fishery. We found greater build-up of lobsters within MPAs relative to unprotected areas, and greater increases in fishing effort and total lobster catch, but not CPUE, in fishing zones containing MPAs vs. those without MPAs. Our results show that a 35% reduction in fishing area resulting from MPA designation was compensated for by a 225% increase in total catch after 6-years, thus indicating at a local scale that the trade-off of fishing ground for no-fishing zones benefitted the fishery.

Simulating spatial dynamics to evaluate methods of deriving abundance indices for tropical tunas

2010 ◽  
Vol 67 (9) ◽  
pp. 1409-1427 ◽  
Author(s):  
Thomas R. Carruthers ◽  
Murdoch K. McAllister ◽  
Robert N. M. Ahrens
Keyword(s):  
Population Dynamics ◽  
Relative Abundance ◽  
Spatial Dynamics ◽  
Selection Criterion ◽  
Information Criterion ◽  
Fishing Effort ◽  
Catch Per Unit Effort ◽  
Applied Model ◽  
Thunnus Obesus ◽  
Abundance Indices

Relative abundance indices derived from nominal catch-per-unit-effort (CPUE) data are a principle source of information for the majority of stock assessments. A particular problem with formulating such abundance indices for pelagic species such as tuna is the interpretation of CPUE data from fleets that have changed distribution over time. In this research, spatial population dynamics are simulated to test the historical pattern of fishing effort as a basis for making inferences about relative abundance. A number of age-structured, spatially disaggregated population dynamics models are described for both Atlantic yellowfin tuna ( Thunnus albacares ) and bigeye tuna ( Thunnus obesus ) to account for uncertainty in spatial distribution and movement. These models are used to evaluate the reliability of standardization methods and a commonly applied model selection criterion, Akaike’s information criterion (AIC). The simulations demonstrate the pitfalls of aggregating CPUE data over spatial areas and highlight the need for data imputation. Simulations support simpler models than those selected using AIC for extracting reliable indices of relative abundance.

scholarly journals Trade-offs in marine protection: multispecies interactions within a community-led temperate marine reserve

2016 ◽  
Vol 74 (1) ◽  
pp. 263-276 ◽  
Author(s):  
Leigh M. Howarth ◽  
Pascal Dubois ◽  
Paul Gratton ◽  
Matthew Judge ◽  
Brian Christie ◽  
...  
Keyword(s):  
Marine Reserve ◽  
Fishing Effort ◽  
Catch Per Unit Effort ◽  
Physical Damage ◽  
Unit Effort ◽  
Trade Offs ◽  
Commercially Important ◽  
Low Levels ◽  
Multispecies Interactions ◽  
Catch Rates

This study investigated the effects of a community-led temperate marine reserve in Lamlash Bay, Firth of Clyde, Scotland, on commercially important populations of European lobster (Homarus gammarus), brown crab (Cancer pagurus), and velvet swimming crabs (Necora puber). Potting surveys conducted over 4 years revealed significantly higher catch per unit effort (cpue 109% greater), weight per unit effort (wpue 189% greater), and carapace length (10–15 mm greater) in lobsters within the reserve compared with control sites. However, likely due to low levels of recruitment and increased fishing effort outside the reserve, lobster catches decreased in all areas during the final 2 years. Nevertheless, catch rates remained higher within the reserve across all years, suggesting the reserve buffered these wider declines. Additionally, lobster cpue and wpue declined with increasing distance from the boundaries of the marine reserve, a trend which tag–recapture data suggested were due to spillover. Catches of berried lobster were also twice as high within the reserve than outside, and the mean potential reproductive output per female was 22.1% greater. It was originally thought that higher densities of lobster within the reserve might lead to greater levels of aggression and physical damage. However, damage levels were solely related to body size, as large lobsters >110 mm had sustained over 218% more damage than smaller individuals. Interestingly, catches of adult lobsters were inversely correlated with those of juvenile lobsters, brown crabs, and velvet crabs, which may be evidence of competitive displacement and/or predation. Our findings provide evidence that temperate marine reserves can deliver fisheries and conservation benefits, and highlight the importance of investigating multispecies interactions, as the recovery of some species can have knock-on effects on others.

Can vessel monitoring system data also be used to study trawling intensity and population depletion? The example of Australia's northern prawn fishery

2005 ◽  
Vol 62 (3) ◽  
pp. 611-622 ◽  
Author(s):  
Roy Deng ◽  
Cathy Dichmont ◽  
David Milton ◽  
Mick Haywood ◽  
David Vance ◽  
...  
Keyword(s):  
Monitoring System ◽  
Fishing Effort ◽  
Catch Per Unit Effort ◽  
Fishing Vessels ◽  
Tiger Prawn ◽  
System Data ◽  
Stock Depletion ◽  
Using Data ◽  
The Impact ◽  
Northern Prawn Fishery

We explore the potential of using data from Australia's northern prawn fishery (NPF) vessel monitoring system(s) (VMS) to examine trawl track, trawling intensity, and stock depletion due to trawling. We simulate VMS data by subsampling global positioning system (GPS) fixes from the NPF fishing vessels at different polling intervals to examine their accuracy in describing trawl tracks. The results of the simulations suggest that VMS data with polling intervals longer than 30 min cannot accurately estimate trawl tracks. The analysis of high-polling-frequency VMS data collected in four (later reduced to three) 6 nautical mile × 6 nautical mile grids that historically received high levels of fishing effort showed that trawling was not random and some areas were trawled up to 28 times in the tiger prawn fishing season and the impact varied among years. The results of a catch-depletion analysis suggest that fishery catch-per-unit-effort and cumulative catch may not be proportional to overall target-species biomass in areas with highly aggregated trawl effort. The VMS data also showed a large number of trawls can occur in productive areas and that trawling impacts on benthos may be quite marked.

Evaluating the effectiveness of coastal no-take zones of the Galapagos Marine Reserve for the red spiny lobster, Panulirus penicillatus

Marine Policy ◽  
2018 ◽  
Vol 88 ◽  
pp. 204-212 ◽  
Author(s):  
Salomé Buglass ◽  
Harry Reyes ◽  
Jorge Ramirez-González ◽  
Tyler D. Eddy ◽  
Pelayo Salinas-de-León ◽  
...  
Keyword(s):  
Marine Reserve ◽  
Spiny Lobster ◽  
Galapagos Marine Reserve

Use of a marine reserve to determine the direct and indirect effects of fishing on growth in a New Zealand fishery for the spiny lobster Jasus edwardsii

2012 ◽  
Vol 69 (5) ◽  
pp. 894-905 ◽  
Author(s):  
Debbie J. Freeman ◽  
Paul A. Breen ◽  
Alison B. MacDiarmid
Keyword(s):  
Growth Rates ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Catch Per Unit Effort ◽  
Density Dependent ◽  
Time Period ◽  
Jasus Edwardsii ◽  
Negative Effect ◽  
Similar Growth ◽  
Positive Effect

The effects of fishing on growth in a spiny lobster, Jasus edwardsii , were explored by using a no-take marine reserve as a control for these effects. We analysed data from lobster tag–recapture studies outside the reserve from 1975 until the present and tag–recapture from inside the reserve during a recent 8-year study. We explored whether recent and historical data showed similar growth and, using catch per unit effort (CPUE) data from research potting and commercial returns, whether growth rates in this lobster species were affected by population density. Despite the confounded nature of the data, recent growth rates appeared to be lower than in earlier years, growth appeared weakly density-dependent, and the reserve appeared to have a positive effect on lobster growth. The strongest effect was the time period, but the density-dependent and reserve effects appeared real. The reserve effect suggests a negative effect of handling of sublegal-sized lobsters on growth.

An integrated stock assessment for red spiny lobster (Panulirus penicillatus) from the Galapagos Marine Reserve

2016 ◽  
Vol 177 ◽  
pp. 82-94 ◽  
Author(s):  
Cody S. Szuwalski ◽  
Mauricio Castrejon ◽  
Dan Ovando ◽  
Brandon Chasco
Keyword(s):  
Stock Assessment ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Galapagos Marine Reserve
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