Catch Per Unit Effort Values Research Articles

Catch Composition and Catch Per Unit Effort of Small-scale Fisheries on the Coasts of the Bodrum Region (Güllük Bay, South-eastern Aegean Sea)

This study presents the species composition of fish caught using gill/trammel nets in the Bodrum and surrounding areas on the coasts of the southern Aegean Sea, along with the fish catch per unit effort (CPUE) values by fishing area and seasonality. Five types of set nets were examined: gillnets for the bogue (Boops boops) fishing, trammel nets for the common sole (Solea solea) fishing, bottom trammel nets, bottom gillnets, and trammel nets for the red mullet (Mullus barbatus) fishing. Among these, gillnets used for bogue fishing are primarily deployed near fish cages. The study revealed that the highest average CPUE values of gill nets were 50.3±8.3 kg.1000 m-1 in spring and 64.5±24.9 kg.1000 m-1 around the sea cages, attributed to the increased presence of bogue, particularly during the spring season.

Spatial characterisation and drivers of catch and effort in highly specialised recreational pelagic fisheries

Large pelagic finfish are highly mobile, distributed across broad geographical scales, and often targeted by both commercial and recreational sectors. Fishing effort in these fisheries is variable due to seasonal patterns in fish behaviour and accessibility of fishing locations. Similarly, fisher behaviour and access are likely to differ within the recreational sector, between private boat-based fishing and charter (or for hire) fishing. Here, we compare spatio-temporal patterns in catch per unit effort (CPUE), effort (boat days) and catch (total catch per fishing party) for private boat-based and charter fishing, and identify environmental variables that may influence those patterns, for two pelagic species (the tropical narrow-barred Spanish mackerel and temperate Samson fish) in Western Australia. Spatial and temporal patterns of CPUE were investigated using geostatistical indices, such as the global and local index of collocation which compares the spatial distribution of CPUE locations across years and CPUE values at common locations respectively, and the centre of gravity which calculates the mean fishing location weighted by CPUE, along with the influence of environmental variables (including rainfall and sea surface temperature) on catch using generalised additive models (GAMs). The global index of collocation showed consistency in spatial distribution of CPUE and effort between private boat-based and charter fishing for both species. In contrast, the local index of collocation showed differences in the ranges of CPUE and effort within common locations. Private boat-based fishing often occurred close to the coast and adjacent to population centres, while charter fishing occurred further offshore. Spatial shifts over time were more prominent for Spanish mackerel with an overall northerly shift. For private boat-based fishing, higher catches of Spanish mackerel were associated with higher rainfall, along with an increase in ambient air temperature. For charter fishing, higher catches of Spanish mackerel occurred with ambient air temperatures of around 30 degrees Celsius and a decrease in rainfall, where high catches of Samson fish were associated with a decrease in sea surface temperatures and austral winter months. This study highlights changes in the distributions of pelagic species over time and the potential to incorporate spatio-temporal monitoring of recreational harvest into fisheries management.

The influences of temporal-spatial parameters on CPUE of the Atlantic bluefin tuna purse seine fishery in eastern Mediterranean

Abstract In this study, we applied generalized additive model to investigate the influence of spatial temporal variables and vessel length on catch per unit-effort (CPUE) of Atlantic bluefin tuna (ABFT) purse seine fishery using catch and effort data from commercial logbooks and field surveys from 1992 to 2006. The vessel lengths of sampled purse seines ranged from 20 to 64 m. The number of ABFT caught within each operation varied between 1 and 2000. A total of 386 CPUE values for ABFT were calculated 0.05 and 60 t ⋅ (haul day)–1 with mean CPUE of 5.51 ± 0.54 t ⋅ (haul day)–1. Although the sea surface temperature had little influence on the CPUE, the effect of time and spatial variables, vessel length and salinity was found as significant. In conclusion, the spatial dynamics of ABFT should be considered if the impact of fisheries on the ecosystem is to be reduced.

Investigating Relationships Between Catch Per Unit Effort (CPUE) and Some Angler Characteristics in the Turkish Inland Recreational Fisheries: A Case Study from Uluabat Lake

In this study it is aimed that determining effect of some social and demographic properties on Catch Per Unit Effort (CPUE) in Uluabat Lake anglers. A total of 375 interview applied with angler from April 2015 to May 2016 monthly period. Mean CPUE values of each angler was estimated as 1.36 fish/hr (0.08-5.67). Generalized additive models (GAMs) was used for evaluating the data set. Variables used in model were age of angler (X1), experience of angler (X2), annual total fishing day (X3), total value of fishing equipment (X4), monthly total income of anglers (X5), household number of anglers (X6) and CPUE of anglers (Y). Effect of all variables on the CPUE were founded not significant (p>0.05), except “Annual total fishing day” (p>0.05). The variables such as monthly total income of anglers, experience of angler, total value of angling equipment and annual total fishing day positively affected CPUE.

Spatio-temporal patterns of the multi-day fishing in the Indian Ocean off Sri Lanka, and their importance for fisheries monitoring, control and surveillance

In the present study, an attempt was made to investigate temporal and spatial patterns of multi-day fishing in the Indian Ocean off Sri Lanka to elucidate how such patterns related to fishing methods of multi-day fishing vessels targeting different pelagic fish species. In the analysis, 269,564 fishing operations from 37,349 fishing trips of multi-day fishing vessels during 2019 and 2020 were used. Based on the standardized fishing effort of the three major fishing methods (i.e., longlining, drift gillnetting and ring netting), species-wise catch per unit effort (CPUE) was determined for each fishing operation.The CPUE values of the three fishing methods were grouped for fishing locations in three major basins of the Indian Ocean, and according to three monsoonal seasons having varying influences of cyclones. Accordingly, 269,564 fishing operations were summarized into 77 datasets during the study period. The mean CPUE values (kg per fishing operation) were 257.3 for longlining, 163.3 for drift gillnetting and 1642.7 for ring netting. The patterns of the data matrix were investigated using the self-organizing map routine of the Artificial Neural Network. Accordingly, based on the occurrence of target species, data were classified into six clusters from which spatio-temporal patterns of fishing operations could be visualized. Ring netting was predominantly concentrated in the equatorial region and to a lesser extent in the Bay of Bengal region, with a temporal occurrence during all three seasons. Longline fishing was also predominant in the equatorial Indian Ocean region with the majority registered in the non-cyclone period. Most drift gillnet fishing operations were concentrated in the equatorial region and the Arabian Sea region, especially during the northern Indian Ocean cyclone period. These results would provide important pieces of information for the management of pelagic fish species through monitoring, control and surveillance (MCS) of the fishery.

Analisis Hasil Tangkapan Udang Brown (Metapenaeus ensis) di Pelabuhan Perikanan Kuala Pembuang

This study aims to determine the results of Catch Per Unit Effort (CPUE), Maximum Sustainable Yield (MSY) and the utilization rate of brown shrimp (Metapenaeus ensis) at the Kuala Pemburan Fishing Port for the last 5 years (2017-2021). The basic method used in this study is a quantitative descriptive method derived from primary and secondary data. Data collection techniques were interviews and primary data collection in the form of shrimp production data at the Kuala Pemburan Fishing Port. Data analysis methods are CPUE, MSY and utilization rate analysis. The results of the study show that the CPUE value has fluctuated from 2017-2021. The highest CPUE value was in 2020 which was 37.76 kg/trip and the lowest was in 2017 which was 8.36 kg/trip. The high and low CPUE values ​​occurred because during this period there was an increase and decrease in both the use of fishing gear and fishing trips. For the yield value (MSY) the optimum fishing effort is 2,940 trips per year and the maximum sustainable catch value is 63,954 kg per year. If viewed based on the sustainable maximum catch value, the number of catches produced in 2020 and 2021 has exceeded the maximum catch limit (Cmsy), but the fishing effort has not exceeded the optimum fishing effort (Emsy). Meanwhile, the yield value of the utilization rate of brown shrimp resources in the last five years indicates that the utilization rate has increased drastically, especially in 2020 and 2021

Standardized catch per unit effort and size compositions of Atlantic bonito, Sarda sarda (Bloch, 1793), harvested by artisanal fisheries in the Senegalese Exclusive Economic Zone (SEEZ)

Atlantic bonito, Sarda sarda (Bloch, 1793), is a valuable small tuna species to coastal countries and local communities. This species is heavily exploited by artisanal fisheries in the Senegalese Exclusive Economic Zone (SEEZ). The common gears used in artisanal fisheries for catching Atlantic bonito are gillnets, purse seines, longlines, and sleeping nets. Although catches of this species have increased in recent years, little is known about the Atlantic bonito catch per unit effort (CPUE) and size selectivity in theregion. As this information is relevant for many stock assessments, available catch, effort and size data from Atlantic bonito harvested over 15 years (2004–2018) with different gears were used in the present study to calculate the nominal and standardized CPUE, size-frequency distribution and length at retentions (50 % and 95 % selectivity) of the species. To eliminate the effects of temporal, spatial, and environmental factors, the Atlantic bonito CPUE was standardized using generalized linear and additive models. The retention length at 50 % and 95 % for each year and gear was calculated from the cumulative length frequency distribution as a proxy for selectivity. Optimal model standardization CPUE results showed a significant trend for gillnets, ranging from 4.6 kg/trip in 2005–92.65 kg/trip in 2018, while sleeping nets showed lower CPUE values, ranging from 2.12 kg/trip in 2004 up to 0.83 kg/trip in 2018. This study showed that the year, month, and fishing Area variables were the main factors affecting the nominal CPUE for all scenarios evaluated in this study. Catch data, CPUE and selectivity results have shown that gillnets are the most selective and efficient among the four main gears used to catch Atlantic bonito in the SEEZ.

Climate variability and small-scale fisheries of the Albuquerque Cays Island, insular Colombian Caribbean

The relationship between climate variability and the small-scale fishery (SSF) of the Albuquerque Cays was studied from 2004 to 2018. The environmental variables analyzed were: sea surface temperature (SST), wind magnitude, and chlorophyll (Chl-α). The fishery is multi-species; 410 individuals were identified, belonging to 4 orders, 15 families, and 62 species, of which 38.7% are reef, 35.5% demersal, and 25.8% pelagic. The most dominant species were Caranx latus, Elagatis bipinnulata, Coryphaena hippurus, Lutjanus vivanus, Ocyurus chrysurus, Thunnus atlanticus, Sphyraena barracuda, Canthidermis sufflamen, Etelis oculatus, Acanthocybium solandri, Lutjanus jocu, Balistes vetula, Lutjanus buccanella, followed by Rhomboplites aurorubens and Mycteroperca bonaci. The pelagic species that contribute the most in biomass and commercial importance are S. barracuda, A. solandri, T. atlanticus, and E. bipinnulata, the most important due to their high market value. A significant correlation was found among SST, Chl-α, wind magnitude, and catch per unit effort (CPUE) anomalies. The highest CPUE values occurred in January, March, June and September were associated with the passage of cold fronts and hurricanes, giving way to new fishing opportunities and conservation of some resources.

Estimation of CPUE and CPUA of pufferfish (Tetraodontidae) caught by the Bottom Trawl Fishery in the eastern Mediterranean Coasts

Two indicators of pufferfish communities, catch per unit effort (CPUE) and catch per unit area (CPUA), were used with surveys of bottom trawl fishery to elucidate the level of the catch of each pufferfish species in the Mediterranean coasts of Turkey, comprising the Iskenderun Bay, Mersin Bay, and Antalya Bay. The surveys were conducted seasonally in 2019. The average rate of CPUE for Lagocephalus sceleratus, L. suezensis, L. spadiceus, and Torquigener flavimaculosus were 2.2, 0.8, 0.5, and 0.2 kg km-2, respectively that the highest CPUE values were in winter (8.0 kg km-2) for L. sceleratus and also lowest was in winter (0.08 kg km-2) for L. spadiceus. The highest and lowest CPUE values were at the depth of 20-50 m (2.7 kg km-2) for L. sceleratus and 50-80 m (0.08 kg km-2) for T. flavimaculosus, respectively. The highest CPUE values (3.5 kg km-2) were found at the sandy bottom for L. sceleratus, and the lowest one (0.01 kg km-2) was at the hardy-ground for T. flavimaculosus. The average annual CPUA of pufferfish species at the Iskenderun, Mersin, and Antalya bays was estimated as 15.6, 28.4, and 6.81 kg, respectively, with a mean value of 17.3 kg/day/boat. In multiple correspondence analysis, L. sceleratus showed a great contribution to CPUE and CPUA data. However, T. flavimaculosus revealed contribution, especially in catch numbers which were positively affected by precipitation. L. spadiceus, L. suezensis, and T. flavimaculosus were positively affected by depth, temperature, month, season, and bottom structure.

Mapping and Assessing Commercial Fisheries Services in the Lithuanian Part of the Curonian Lagoon

The spatial distribution of biomass of main commercial fish species was mapped to estimate the supply of a provisioning fishery service in the Curonian lagoon. Catch per unit effort (CPUE) was used as a proxy to estimate the efficiency of commercial fishing and, subsequently, the potential biomass of fishes. The relationship between distinctive characteristics of the fishing areas and corresponding commercial catches and CPUE was analyzed using multivariate analysis. The total catch values and CPUE used in the analyses were derived from the official commercial fishery records. RDE analysis was used to assess the variation of both catch and CPUE of commercial fish species, while the percentages of bottom sediment type coverage, average depth, annual salinity, and water residence time in each of the fishing squares were used as explanatory variables. This distance e-based redundancy analysis allowed for the use of non-Euclidean dissimilarity indices. Fisheries data spatial distribution map indicated the lack of coherence between the spatial patterns of commercial catches and CPUE distribution in the northern part of the lagoon. Highest CPUE values were estimated in the central-eastern part of the lagoon as compared to the western part of the lagoon where CPUE values were substantially lower. Both total catch and CPUE appeared not to be related to the type of bottom habitats statistically while being spatially correlated in-between. However, the impact of salinity and water residence time calculated using the 3D hydraulic circulation model on the distribution of both CPUE and commercial catches was statistically significant.

Spatial and Temporal Characteristics of Demersal Assemblages in Sığacık Bay, Central Aegean Sea, Turkey

This study aimed to determine the spatial and temporal variation of species diversity and CPUE in trawl fisheries in the Central Aegean Sea (Sığacık Bay). The study also aimed to evaluate changes in some biometric parameters (mean and frequency of length) depending on the season and depth for three important commercial species (Parapenaeus longirostris, Nephrops norvegicus and Illex coindetii). Monthly trawl samplings were carried out in three depth strata (0-200; 201-400 and 401-600 m) between May 2008 - April 2009. A total of 111 species were identified including 74 Osteichthyes, 13 Chondrichthyes, 18 Cephalopods and 6 Crustaceans. The highest species diversity and catch per unit effort (CPUE) values were obtained at 201-400 m strata. Among these, Osteichthyes had the highest frequency and CPUE values in all strata and seasons. Summer was the season with the highest CPUE in all groups followed by a decrease until winter due to openning of trawl fisheries in the Autumn. The mean carapace length of P. longirostris, the target species in Sığacık Bay trawl fisheries, increased with depth and this species was more abundant at the 201-400 m strata.

Fluctuations in distribution and relative abundance of Japanese Spanish mackerel, Scomberomorus niphonius, in the Yellow Sea, East China Sea and Sea of Japan

To evaluate the habitat and abundance of Japanese Spanish mackerel, we analyzed catch per unit effort (CPUE) of large and mid-sized Japanese purse-seine vessels in the Yellow Sea, East China Sea and Sea of Japan using a generalized additive model and generalized linear model. An area of high CPUE was observed in the Yellow and East China seas from 1994 to 1997, but disappeared after 1998. The high-CPUE area firstly developed in the Yellow Sea from October to December, and moved to the southern Yellow Sea, East China Sea and coastal Japan from January to March. Based on the generalized additive model, Japanese Spanish mackerel appeared to prefer regions of low temperature at 10 m depth. The lowest CPUE was observed in 1996, and increased by 2000. Annual CPUE values declined from 2000 to 2003, increased subsequently (with some fluctuations) and remained largely stable after 2010. Our results comprise the first stock assessment report of Japanese Spanish mackerel based on the Japanese large and mid-sized purse seine fishery in the Yellow Sea, East China Sea and Sea of Japan. Further cooperative assessment with China and Korea is needed for accurate stock assessment and management of this species.

Ege Denizi dip paragat balıkçılığında iğne ve yem tipinin birim çabada av miktarına etkisi

This study aimed to determine the impact of hook and bait type on the catch composition and catch per unit effort. Effects of hook and bait types on catch composition, catch per unit effort (CPUE), length and weight distributions in demersal longline fishery were determined by experimental surveys on demersal longline sets in the Aegean Sea. A total of 12 samplings corresponding to 4800 hook fishing effort were performed between April 2014 and September 2014. Two bait types; sardine (Sardina pilchardus) and grooved razor shell (Solen marginatus) and two hook types; J-hook and C-hook were tested. CPUE values were calculated for each species and assessed between different hook-bait combinations. A total of 623 individuals were captured belonging to 3 families and 9 species. It was found that more than 60% of total catch was captured by grooved razor shell and more than 50% of the total catch was caught with J type hook. J hook was found to be close to significant (p=0.06) and grooved razor shell was found significant (p=0.02) for CPUE. The effect of bait type was found to be more significant than that of hook type for CPUE and length distribution. Hook-bait combination differed according to species and C hook baited with sardine was determined to be the best combination for Sparus aurata as the most targeted fish in the study area. Discard ratio was calculated to be 34% in terms of weight and 42.5% in terms of total number of individuals for pooled data. The condition value (K) of the species ranged from 1.05 to 1.68 and differed according to bait type. Most of the high commercial value species caught with any hook-bait combination experimented within this study are larger than minimum fishing length according to minimum landing size regulations of Turkish fishery and maturity studies.

Comparación de índices de abundancia de polaca (Micromesistius australis) a partir de dos fuentes de información mediante la aplicación de Modelos Lineales Mixtos.

En este trabajo se realizó la estandarización de la captura por unidad de esfuerzo (CPUE) de polaca (Micromesistius australis) accesible a la flota surimera que operó en el océano Atlántico Sudoccidental durante el período 1993-2018. Se aplicaron Modelos Lineales Mixtos (MLM), a partir de la información de la estadística pesquera (MLMEST) y la colectada por los observadores a bordo (MLMOBS) de dichos buques con el objetivo de comparar entre sí los modelos realizados a partir de ambas fuentes de información y el modelo utilizado hasta la actualidad para la estimación de índices de abundancia de polaca. La aplicación de los MLM mejoró el ajuste con respecto al modelo utilizado hasta la actualidad, sin variar abruptamente la tendencia estimada, lo cual permitiría predecir con mayor exactitud los valores medios de CPUE estandarizados a lo largo de los años. El MLMOBS mostró un mejor ajuste y una mayor variabilidad explicada que el MLMEST. A fin de obtener estimaciones más certeras y, de esta forma poder calibrar adecuadamente los modelos de evaluación de la especie, se recomienda utilizar ambas fuentes de información, teniendo en cuenta el mayor o menor grado de representatividad de los datos.

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

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.

Yenişakran (Çandarlı Körfezi, Ege Denizi) kıyı balıkçılığının mevsimsel av kompozisyonu ve birim çaba başına düşen av miktarları

This study presents the catch records of a coastal fisherman during daily fishing trip between 2017 and 2018 in Yenişakran, Çandarlı Bay (Aegean Sea). The trammel net and longline were used at depths of 5-25 m on a sandy bottom and the sea meadows during the year. A total of 39 species were identified from the both trammel netting and the longlining. Mean catch per unit effort (CPUE) values (8.7±0.1 kg/1000 m net and 12.9±0.8 kg/1000 hooks) shown that longlining was more efficient fishing gear than the trammel netting. In terms of mean CPUE values, there is significantly difference between trammel netting and longlining (p<0.05).

Catch distribution and size structure of Nile tilapia (Oreochromis niloticus) in Lake Tana, Ethiopia: implications for fisheries management

Nile tilapia (Oreochromis niloticus) is the most important species for consumption and economic purposes in Lake Tana, yet, tilapia stocks have declined drastically over the past decades because of anthropogenic impacts. Thus, effective conservation management is required urgently. The aim of this study was to investigate the spatio-temporal distribution and size structure of O. niloticus populations in Lake Tana in order to evaluation conditions to promote sustainable exploitation. Data were collected monthly at three sites on the lake from April 2016 to March 2017. The size at first maturity was computed using logistic regression. The catch per unit effort (CPUE) of O. niloticus in Lake Tana has sharply declined from 75 kg trip−1 in 2001 to 24 kg trip−1 in 2016/2017. The mean CPUE values between sites and seasons were significantly different. The size at first maturity for O. niloticus was 21 cm in 2016/2017. Of the catches taken, more than 24% of those were motorised and reed boat fisheries and 46% of the chase-and-trap fishery catches were below the size at first maturity in 2016/2017. Additionally, large size specimens were rarely recorded. Widening the mesh size of the gillnets would give a chance for immature fish to spawn at least once. Considering the fish size distribution and social context of the fishers, limiting mesh size could be a more feasible management option than a closed season.

Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the 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. For Panulirus penicillatus, CPUE was higher at night than during the day, and for Panulirus gracilis it 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.

Fishing pressure impacts the abundance gradient of European lobsters across the borders of a newly established marine protected area.

Marine protected areas (MPAs) are considered viable fisheries management tools due to their potential benefits of adult spillover and recruitment subsidy to nearby fisheries. However, before–after control–impact studies that explore the biological and fishery effects of MPAs to surrounding fisheries are scarce. We present results from a fine-scale spatial gradient study conducted before and after the implementation of a 5 km2 lobster MPA in southern Norway. A significant nonlinear response in lobster abundance, estimated as catch-per-unit-effort (CPUE) from experimental fishing, was detected within 2 years of protection. After 4 years, CPUE values inside the MPA had increased by a magnitude of 2.6 compared to before-protection values. CPUE showed a significant nonlinear decline from the centre of the MPA, with a depression immediately outside the border and a plateau in fished areas. Overall fishing pressure almost doubled over the course of the study. The highest increase in fishing pressure (by a magnitude of 3) was recorded within 1 km of the MPA border, providing a plausible cause for the depression in CPUE. Taken together, these results demonstrate the need to regulate fishing pressure in surrounding areas when MPAs are implemented as fishery management tools.

Monitoring of weekly catch per unit effort (CPUE) and some biological features of bluefish (Pomatomus saltatrix Linnaeus, 1766) captured from southern Black Sea coasts of Turkey

In this study, changing of catch per unit effort (CPUE) and length composition of bluefish (Pomatomus saltatrix Linnaeus, 1766) caught in southern Black Sea was monitored during the period of 8 weeks in October and November 2012. A total of 2255 kg bluefishes were captured by pelagic trawl at the end of the 32 hauls. The length-weight relationships of bluefish were established as W=0.0037L3.3067 (positive allometric growth). The catch per unit effort (CPUE) and mean length were fixed as 14.43 kgh-1 and 17.5±0.03 cm, respectively. Differences between CPUE values of each weeks were found statistically significant (P<0.05). The highest and lowest mean total lengths of bluefish were determined 18.9±0.08 cm (October) and 16.2±0.10 cm (November) respectively. It is determined that changing in size composition of the caught fishes is depending on time. Also, it can be expressed that fishing period affects catch per unit effort in bluefish fisheries.