ICCAT stock assessments of Atlantic billfish

2003 ◽  
Vol 54 (4) ◽  
pp. 361 ◽  
Author(s):  
Victor Restrepo ◽  
Eric D. Prince ◽  
Gerry P. Scott ◽  
Yuji Uozumi
Keyword(s):  
Fishing Effort ◽  
Data Sets ◽  
Historical Overview ◽  
Catch Per Unit Effort ◽  
Historical Trends ◽  
Istiophorus Platypterus ◽  
Catch Data ◽  
Makaira Nigricans ◽  
Stock Assessments ◽  
The Status

This paper presents a historical overview of the assessments of the Atlantic stocks of blue marlin (Makaira nigricans), white marlin (Tetrapturus albidus) and sailfish (Istiophorus platypterus) that have been conducted by the International Commission for the Conservation of Atlantic Tunas between 1977 and 2000. Details are presented on the data sets used and the models applied, noting the strengths and weaknesses of the assessments. The major causes of uncertainty in the current perception of the status of the stocks are related to some of the data used and to their interpretation, especially historical trends in catch per unit effort. In particular, there are uncertainties about historical catch data, including discards, and about the degree to which longline fishing effort overlaps with billfish habitat. The paper concludes with an account of the efforts that should be made to reduce these uncertainties.

scholarly journals RESPONSIBLE FISHERIES MANAGEMENT OF MINI PURSE SEINE IN THE LAMPUNG BAY AREA

2017 ◽  
Vol 8 (2) ◽  
pp. 713-728
Author(s):  
Yulia Estmirar Tanjov ◽  
Roza Yusfiandayani ◽  
. Mustaruddin
Keyword(s):  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Purse Seine ◽  
Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Small Pelagic Fish ◽  
Bay Area ◽  
Fisheries Resources ◽  
The Status

Lempasing is a Coastal Fishing Port (CFP) which located in Bandar Lampung. It is one of the centers of fisheries activities in the city. One of the fishing gear which operated by most of fishermen in Lempasing is mini purse seine. Mini purse seine fishing activities in the Lampung Bay Area and Lempasing CFP is not in accordance with the conditions of the surrounding waters area. The research was conducted in the Lampung Bay Area and Lempasing CFP, Lampung. This study aims to: 1) determine the status of fisheries resources utilization, 2) to describe the dominant fish caught by mini purse seine.  Analysis methods were used in this study namely: 1) Fishing Power Index (FPI), Catch Per Unit Effort (CPUE), and Maximum Sustainable Yield (MSY) to determine the status of fisheries resource utilization. The dominant small pelagic fishes caught were scad fish Selaroides sp., mackerel fish Rastrelliger sp., longnose trevally fish Carangoides chrysophrys. The result showed that Fox model was the best fits models with estimated maximum sustainable yield of 15.5 ton and fishing effort of 992 trip/year for mini purse seine. The longnose trevally fish in lampung bay area in do not exceeded the optimal catch fish condition can be used to sustainably. In these condition is necessary to wisely manage and setting the catches to not exceed the allowable catch of the small pelagic fish, so the stock of small pelagic fish in the Lampung Bay Area can be used sustainably.

scholarly journals Trends of white grouper landings in the Northeastern Mediterranean: reliability and potential use for monitoring

2020 ◽  
Vol 21 (1) ◽  
pp. 183
Author(s):  
SINAN MAVRUK
Keyword(s):  
Time Series ◽  
Age Groups ◽  
Monitoring Program ◽  
Bottom Trawl ◽  
Data Sets ◽  
Trawl Survey ◽  
Catch Per Unit Effort ◽  
Multiple Sources ◽  
Statistical Institute ◽  
The Status

As a consequence of national fishery statistics showing a sharp decline in the landings of white groupers (WG), Epinephelus aeneus (Geoffroy Saint-Hilaire, 1817) after 2010, the decision to ban any further fishing of the species was implemented by the Turkish management authority in 2016. Stakeholders have since strongly objected to this decision claiming that the trends of landing statistics are unreliable. Here, this assertion is questioned using multiple sources of data. The catch per unit effort (CPUE) from the fishery independent bottom trawl survey (2004-2018) officially reported landing statistics (2002-2017) and the microdata set of landings (2012-2016) gathered by the Turkish Statistical Institute (TUIK). Based on the results of this study, there was a clear parallelism amongst the data sets. Landing records and the CPUE time series revealed unimodal non-linear patterns along the time (p<0.001). Landings increased until 2010 and decreased thereon after, whereas CPUE values started to decrease after 2009. In segmented time series, there were no statistically significant differences between the direction and magnitude of slopes of landings and fishery independent data. Cross-correlations between landings and CPUE were statistically significant with one and two-year lag distances. This was because the earlier age groups were sampled with coastal bottom trawl operations. Combined with further efforts, this finding may help to develop a monitoring program for the status of white grouper populations in the northeastern Mediterranean and contribute to a better management strategy.

scholarly journals RESPONSIBLE FISHERIES MANAGEMENT OF MINI PURSE SEINE IN THE LAMPUNG BAY AREA

2017 ◽  
Vol 8 (2) ◽  
pp. 713
Author(s):  
Yulia Estmirar Tanjov ◽  
Roza Yusfiandayani ◽  
. Mustaruddin
Keyword(s):  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Purse Seine ◽  
Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Small Pelagic Fish ◽  
Bay Area ◽  
Fisheries Resources ◽  
The Status

<p><em>Lempasing is a Coastal Fishing Port (CFP) which located in Bandar Lampung. It is one of the centers of fisheries activities in the city. One of the fishing gear which operated by most of fishermen in Lempasing is mini purse seine. Mini purse seine fishing activities in the Lampung Bay Area and Lempasing CFP is not in accordance with the conditions of the surrounding waters area. The research was conducted in the Lampung Bay Area and Lempasing CFP, Lampung. This study aims to: 1) determine the status of fisheries resources utilization, 2)</em><em> to describe the dominant fish caught by mini purse seine. </em><em> Analysis methods were used in this study namely: 1) Fishing Power Index (FPI), Catch Per Unit Effort (CPUE), and Maximum Sustainable Yield (MSY) to determine the status of fisheries resource utilization. The dominant small pelagic fishes caught were scad fish <span style="text-decoration: underline;">Selaroides</span> </em>sp<em>., mackerel fish <span style="text-decoration: underline;">Rastrelliger</span> </em>sp<em>., longnose trevally fish <span style="text-decoration: underline;">Carangoides</span> <span style="text-decoration: underline;">chrysophrys</span>. The result showed that Fox model was the best fits models with estimated maximum sustainable yield of 15.5 ton and fishing effort of 992 trip/year for mini purse seine. The longnose trevally fish in lampung bay area in do not exceeded the optimal catch fish condition can be used to sustainably. In these condition is necessary to wisely manage and setting the catches to not exceed the allowable catch of the small pelagic fish, so the stock of small pelagic fish in the Lampung Bay Area can be used sustainably.</em></p>

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.

Distribution of population-based indicators across multiple taxa to assess the status of Gulf of Alaska and Bering Sea groundfish communities

2005 ◽  
Vol 62 (3) ◽  
pp. 344-352 ◽  
Author(s):  
Franz J. Mueter ◽  
Bernard A. Megrey
Keyword(s):  
Bering Sea ◽  
Gulf Of Alaska ◽  
Population Based ◽  
Fishing Effort ◽  
Frequency Of Occurrence ◽  
Catch Per Unit Effort ◽  
Eastern Bering Sea ◽  
Trawl Fishing ◽  
The Status ◽  
Commercial Species

Abstract Ecosystem-based approaches to fisheries management require researchers and managers to take into account effects of fishing on other components of the ecosystem, including non-commercial species. Currently, stock assessments in the Northeast Pacific are limited to the most important commercial species, little being known about the status of non-commercial species. Nevertheless, standardized bottom-trawl surveys conducted in the eastern Bering Sea (EBS) and Gulf of Alaska (GoA), although primarily designed to assess commercial species, provide valuable information on the abundance, distribution, and mean weight of numerous taxa. Using a novel statistical approach and survey data for the years 1993–2003, we examined trends in catch per unit effort (cpue), frequency of occurrence, and mean weight of individuals for each taxon. Time trends were computed as the slope of a linear regression of each indicator on year, and were summarized separately for the eastern and western GoA and for the EBS. Within each system, trends were further compared between commercial and non-commercial taxa. Simulations were used to obtain reference distributions for the expected distribution of slopes across many dependent populations. Observed distributions of trends were compared with simulated distributions, suggesting that more taxa than expected showed a decreasing trend in cpue in the EBS, but not in the GoA. These trends likely resulted from low groundfish productivity in the EBS during the 1990s. At the same time, the frequency of occurrence of significantly more taxa than expected increased in the EBS and, to a lesser extent, in the western GoA. Increases in frequency of occurrence were much more common among non-commercial, invertebrate taxa, and may be a response to reductions in trawl fishing effort during the 1990s.

scholarly journals Estimating stock status from relative abundance and resilience

2019 ◽  
Vol 77 (2) ◽  
pp. 527-538 ◽  
Author(s):  
Rainer Froese ◽  
Henning Winker ◽  
Gianpaolo Coro ◽  
Nazli Demirel ◽  
Athanassios C Tsikliras ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Simulated Data ◽  
Catch Per Unit Effort ◽  
Relative Population ◽  
Stock Size ◽  
Stock Status ◽  
Catch Data ◽  
Stock Assessments ◽  
Main Input ◽  
True Values

Abstract The Law of the Sea and regional and national laws and agreements require exploited populations or stocks to be managed so that they can produce maximum sustainable yields. However, exploitation level and stock status are unknown for most stocks because the data required for full stock assessments are missing. This study presents a new method [abundance maximum sustainable yields (AMSY)] that estimates relative population size when no catch data are available using time series of catch-per-unit-effort or other relative abundance indices as the main input. AMSY predictions for relative stock size were not significantly different from the “true” values when compared with simulated data. Also, they were not significantly different from relative stock size estimated by data-rich models in 88% of the comparisons within 140 real stocks. Application of AMSY to 38 data-poor stocks showed the suitability of the method and led to the first assessments for 23 species. Given the lack of catch data as input, AMSY estimates of exploitation come with wide margins of uncertainty, which may not be suitable for management. However, AMSY seems to be well suited for estimating productivity as well as relative stock size and may, therefore, aid in the management of data-poor stocks.

Correction of Relative Fish Abundance Estimates from Catch Data for Variable Fishing Intensity during Lake Surveys

1989 ◽  
Vol 46 (6) ◽  
pp. 1022-1025 ◽  
Author(s):  
P. M. Ryan ◽  
J. J. Kerekes
Keyword(s):  
Brook Trout ◽  
Unit Area ◽  
Fishing Effort ◽  
Fish Abundance ◽  
Lake Area ◽  
Catch Per Unit Effort ◽  
Fixed Amount ◽  
Catch Data ◽  
Abundance Estimates ◽  
Lake Size

Six small Newfoundland lakes were fished with gillnets over a 3–6 yr period in a manner typical of standard lake surveys where surveyors have a fixed amount of gear available, but lake size varies. Catch and effort data for brook trout (Salvelinus fontinalis) were examined for the purpose of selecting an appropriate measure of the relative abundance of trout. Fishing effort was not a function of lake area but fishing intensity or fishing effort per unit area varied inversely with lake area. Brook trout yield (kilograms per hectare) was positively related to fishing intensity Catch per unit effort (kilograms) of brook trout was inversely related to fishing intensity. Methods are suggested to correct for the bias in catch data resulting from variable fishing intensity during lake surveys and improve the recognition of differences in relative fish abundance.

Are Age-Structured Models Appropriate for Catch-Effort Data?

1985 ◽  
Vol 42 (6) ◽  
pp. 1066-1072 ◽  
Author(s):  
Donald Ludwig ◽  
Carl J. Walters
Keyword(s):  
Simulated Data ◽  
Fishing Effort ◽  
Production Model ◽  
Model Structure ◽  
Catch Per Unit Effort ◽  
Unit Effort ◽  
Production Models ◽  
Stock Assessments ◽  
Age Structured ◽  
Age Structured Model

Simulated data have been used to evaluate the performance of schemes for estimating optimum fishing effort using a simple stock-production model and R. B. Deriso's age-structured model Even when the data are generated using Deriso's model, the simpler production model generally gives as good or better estimates for the optimal effort. The only exception to this result is when data are provided with unrealistically large contrasts in effort and catch per unit effort over time. The implication of these findings is that simple production models should often be used in stock assessments based on catch/effort data, even when more realistic and structurally correct models are available to the analyst; the best choice depends on how much contrast has occurred in the historical effort and catch per unit effort data, rather than on prior knowledge about which model structure is biologically more realistic.

scholarly journals BILLFISH CATCHES FROM OCEANIC RECREATIONAL FISHING IN THE ROYAL CHARLOTTE BANK, BAHIA, BRAZIL

2021 ◽  
Vol 46 (4) ◽  
Author(s):  
Camila PRIMITIVO ◽  
Alexandre SCHIAVETTI ◽  
Kátia Meirelles Felizola FREIRE
Keyword(s):  
Recreational Fishing ◽  
Catch Per Unit Effort ◽  
Istiophorus Platypterus ◽  
Makaira Nigricans ◽  
Unit Effort ◽  
Fishing Sector ◽  
Southern Bahia ◽  
Kajikia Albida

The aim of this study was to analyze the oceanic recreational fishing in the Royal Charlotte Bank, state of Bahia, Brazil. Only data from an oceanic recreational fishing operator based in the municipality of Canavieiras, southern Bahia, were used, from 2012 to 2017. Overall, 103 fish specimens were caught and released, during this period, belonging to the following species: Makaira nigricans, Kajikia albida, and Istiophorus platypterus. Fishery operations occurred from October to March, with the highest catch in number in December (56.3%). The largest annual catch was recorded in 2013, with 39 individuals. The catch per unit effort ranged from 1.0 to 1.4 fishes per trip, with the highest value in December. Even though data presented here are partial, they can help to establish a strategic scenario for the fishing sector in Bahia, along with data from other fishing sectors (artisanal, industrial, subsistence and scientific).

scholarly journals Sampling the stream landscape: improving the applicability of an ecoregion-level capture probability model for stream fishes

2018 ◽  
Vol 75 (10) ◽  
pp. 1614-1625 ◽  
Author(s):  
Robert Mollenhauer ◽  
Joshua B. Mouser ◽  
Shannon K. Brewer
Keyword(s):  
Spatial Scales ◽  
Probability Model ◽  
Water Clarity ◽  
Capture Probability ◽  
Data Sets ◽  
Stream Fishes ◽  
Catch Per Unit Effort ◽  
Catch Data ◽  
Wide Range ◽  
Conductivity Water

Temporal and spatial variability in streams result in heterogeneous gear capture probability (i.e., the proportion of available individuals identified) that confounds interpretation of data used to monitor fish abundance. We modeled tow-barge electrofishing capture probability at multiple spatial scales for nine Ozark Highland stream fishes. In addition to fish size, we identified seven reach-scale environmental characteristics associated with variable capture probability: stream discharge, water depth, conductivity, water clarity, emergent vegetation, wetted width–depth ratio, and proportion of riffle habitat. The magnitude of the relationship between capture probability and both discharge and depth varied among stream fishes. We also identified lithological characteristics among stream segments as a coarse-scale source of variable capture probability. The resulting capture probability model can be used to adjust catch data and derive reach-scale absolute abundance estimates across a wide range of sampling conditions with similar effort as used in more traditional fisheries surveys (i.e., catch per unit effort). Adjusting catch data based on variable capture probability improves the comparability of data sets, thus promoting both well-informed conservation and management decisions and advances in stream-fish ecology.

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