Average Catch Per Unit Effort 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.

Analysis of Floating lift net catches Based on Catch Per Unit Effort in Kolono Bay

Kolono Bay waters are one of the waters in South Konawe Regency which has a large potential for fishery resources. One of the leading commodities in the waters of Kolono Bay is anchovy. Fishing activities in the waters of Kolono Bay still use the traditional fishing gear. The purpose of this study was to determine the number of catches based on catch per unit effort (CPUE) using a floating lift net. This research was carried out for three months from January - March 2019 in the waters of Kolono Bay, South Konawe Regency, Southeast Sulawesi Province. The collection location consisted of 10 observations which were determined based on the existence of floating charts scattered in the areas of Lambangi Village and Puupi Village. Stations are set to represent the existence of charts in Kolono Bay. Time series data of catches, and the position of fishing areas are obtained through activities in the field with the help of GPS. The catches obtained were analyzed descriptively and presented in the form of tables and graphs. The catches obtained from each research sample were combined to analyze the average number of catches per station and the average number of catches per month then the catch was calculated for CPUE per station. The CPUE value is obtained from the comparison of catches with the number of trip charts. The results showed at station 5 the highest catches with an average CPUE value of 24.33 kg per hauling per month of catching close to the coast. Therefore, in the context of efficiency and optimization of results, it is recommended to place and operate charts around coastal waters.

Distribution Patterns and Factors Influencing Relative Abundance of the Alligator Snapping Turtle (Macrochelys temminckii) in Mississippi

Macrochelys temminckii (Alligator Snapping Turtle) was recently proposed as a threatened species under the US Endangered Species Act due to current and projected future declining populations range wide. Despite a presumed statewide distribution in Mississippi, the Alligator Snapping Turtle had been documented in only 32 of 82 counties between 1857 and 2012, thus leaving a substantial gap in our knowledge of this species' distribution. Therefore, we collected credible records from museums, literature, and the general public, as well as directly assessed the current distribution and relative abundance of the Alligator Snapping Turtle in all major river systems (i.e., Pascagoula, Pearl, Tombigbee, and Mississippi river drainages) in Mississippi. From 2017 to 2021, we systematically trapped 77 sites across the state totaling 839 captures of 787 individual Alligator Snapping Turtles over the course of 4750 trap nights. State-wide catch per unit effort (CPUE) averaged 0.177, with the Big Black River (0.348) and Tombigbee River (0.028) drainages having the highest and lowest average CPUE, respectively. In Mississippi, CPUE was positively correlated with greater surrounding wetland area and river size, and negatively correlated with terrain ruggedness. This survey, along with the collaboration of other biologists and the public, verified an additional 189 locality records in 56 counties, with Alligator Snapping Turtle presence reconfirmed at 29 of 30 historical localities. Currently, it appears that there have been no local extirpations of the species in Mississippi, and state-wide CPUE was higher than those of the surrounding states.

Anticipating fluctuations of bigeye tuna in the Pacific Ocean from three‐dimensional ocean biogeochemistry

Abstract Subseasonal to decadal ocean forecasting can make significant contributions to achieving effective management of living marine resources in a changing ocean. Most applications rely on indirect proxies, however, often measured at the ocean surface and lacking a direct mechanistic link to the dynamics of marine populations. Here, we take advantage of three‐dimensional, dynamical reconstructions and forecasts of ocean biogeochemistry based on a global Earth system model to hindcast and assess the capacity to anticipate fluctuations in the dynamics of bigeye tuna (Thunnus obesus Lowe) in the Pacific Ocean during the last six decades. We reconstructed spatial patterns in catch per unit effort (CPUE) through the combination of physiological indices capturing both habitat preferences and physiological tolerance limits in bigeye tuna. Our analyses revealed a sequence of four distinct regimes characterized by changes in the zonal distribution and average CPUE of bigeye tuna in the Pacific Ocean. Habitat models accounting for basin‐wide fluctuations in the thermal structure and oxygen concentration throughout the water column captured interannual fluctuations in CPUE and regime switches that models based solely on surface information were unable to reproduce. Decade‐long forecast experiments further suggested that forecasts of three‐dimensional biogeochemical information might enable anticipation of fluctuations in bigeye tuna several years ahead. Synthesis and applications. Together, our results reveal the impact of variability of biogeochemical conditions in the ocean interior on the dynamics of bigeye tuna on the Pacific Ocean, raising concerns about the future impact of ocean warming and deoxygenation. The results also lend support to incorporating subsurface biogeochemical information into ecological forecasts to implement efficient dynamic management strategies and promote the sustainable use of marine living resources.

Evaluation of the influence of spatial treatments on catch-per-unit-effort standardization: A fishery application and simulation study of Pacific saury in the Northwestern Pacific Ocean

Fishery-dependent catch-per-unit-effort (CPUE) data often exhibit spatial heterogeneity over space and time, which means that the spatial treatment in statistical models used to standardize CPUE is critically important. We evaluated several spatial treatments to standardize CPUE data using Generalized Linear Mixed Models (GLMMs). Results include a real-world application and a simulation based on the Taiwanese stick-held dip net fishery for Pacific saury in the Northwestern Pacific Ocean. We compared the performance of three spatially stratified approaches in GLMMs, (i) Ad hoc; (ii) Binary (binary recursive area partitioning based on model selection criteria); and (iii) Spatial clustering (partitioning of grids into discrete strata based on the spatial proximity and average CPUE in each grid), to a spatio-temporal GLMM (VAST). An influence analysis was constructed to quantify discrepancies between unstandardized and standardized indices that assisted in identifying the annual influence of explanatory variables in GLMMs. We developed a simulation to corroborate the results from the case study and evaluated the four spatial treatments using data generated from two contrasted, random and preferential, sampling scenarios. Results from the real-world application indicated that VAST was statistically superior to the other approaches, based on conditional deviance explained, conditional Akaike Information Criterion, and five-fold cross-validations. The influence analysis indicated that the interaction of year and spatial effect or spatio-temporal variable had a major influence on the standardized CPUE. Both simulation scenarios showed that VAST performed the best, with the lowest model error (measured by root mean square error) and bias, for estimating relative abundance indices. Although the spatial clustering approach created a flexible shape for the area strata, the simulation results under preferential samplings showed that clustering with a stronger emphasis placed on average CPUE could lead to bias in estimated abundance indices. However, spatial clustering that balanced average CPUE with spatial proximity could be a reasonable alternative if it is not possible to apply a spatio-temporal approach. The importance of conducting influence analysis and the greater performance of a spatio-temporal approach are highlighted.

Assessing the Distribution and Sustainable Exploitation of Lophius litulon in Marine Areas Off Shandong, China

In recent years, the proportion and economic value of Lophius litulon (family Lophiidae) in the coastal fishery off Shandong Province, China has increased. In this study, we mapped the distribution of L. litulon abundance [catch per unit effort (CPUE)] and applied a generalized additive model (GAM) to explore the relationship between CPUE and environmental factors. Two data-limited methods (the BSM related to the CMSY method and the AMSY method) were used to evaluate the stock status and relevant fishery reference points of L. litulon. The results showed that the L. litulon stock was concentrated in the central Yellow Sea, at 34.0°–37.0° N and 121.0°–124.0° E, and the highest average CPUE of L. litulon in this area occurred in winter. The three most significant environmental factors affecting species abundance were bottom temperature, bottom salinity, and depth. L. litulon was most abundant when bottom temperature ranged from 5.8 to 10.6°C, depth was > 18 m, and bottom salinity varied from 31.0 to 33.2‰. The BSM and AMSY models indicated that the L. litulon stock was unhealthy and had been overfished in recent years, as its biomass remained below the level that can support maximum sustainable yield. The relative exploitation ratios were also high. These results provide the basic data for improving sustainability of the exploitation of L. litulon in the Yellow and Bohai Seas.

Application of Surplus Production Model to the Yellowfin Tuna Thunnus albacares in the northern and western parts of Aceh waters

Yellowfin tuna Thunnus albacares is one of pelagic fish that has high potential and economic value in Banda Aceh. Utilization of this resource in Banda Aceh is using purse seine units, with the number of purse seines continuously increasing. Therefore, management needs to be done so that optimal productivity can be maintained. This study discusses the estimation of catch and effort at maximum sustainable yield (MSY) of yellowfin tuna based on catch per unit effort (CPUE) and purse seine production in Banda Aceh during 2013-2018. Mathematical analysis was carried out using the equilibrium approach with the Schaefer model. The highest catch of yellowfin tuna reached 191 tons (July) and the average CPUE for yellowfin tuna was 0.796 tons/trip with CMSY of 2,482 tons/year and EMSY of 2,765 trips/year. From 2015 to 2018, the trend of biomass continued to decline and overfishing occurred during this period.

Population characteristics and exploitation of yellowfin tuna (Thunnus albacares Bonnaterre, 1788) in the coastal waters of Kenya

Yellowfin tuna, Thunnus albacares (Bonnaterre, 1788) is a highly migratory and important commercial fishery species. Data on length-frequency, growth parameters and mortality rates of yellowfin tuna in the coastal waters of Kenya is limited. We assessed Catch Per Unit Effort (CPUE), size distribution, growth parameters and mortality rates based on length-frequency and catch data collected from August 2015 to December 2016 at five fish landing sites along the Kenyan coast. The sample comprised of 1281 individuals of yellowfin tuna weighing 12,671 kg. Highest CPUE was recorded in October 2015 (10.8 kg·Fisher-1Trip-1) and lowest CPUE, 2.6 kg·Fisher-1Trip-1 in December 2016. Yellowfin tuna was more abundant in the South-East Monsoon (SEM), from May to October, with an average CPUE of 7.3 kg Fisher-1Trip-1 compared to North East Monsoon (NEM), from November to April, with a CPUE of 7.0 kg Fisher-1Trip-1. Spatial variation of CPUE was evident. Old Town recorded the highest CPUE of 54.2 kgTrip-1, while Mnarani the lowest of 19.4 kgTrip-1. At least 91 % of the fish sampled were < 100 cm FL and hence not yet mature. The asymptotic Length (L∞) was found to be 195 cm FL, the Von Bertalanffy growth constant (K) 0.43 year-1, t0 - 0.82 and the Growth Performance Index (f) 4.21. The total mortality coefficient (Z) was 2.59 year-1 , Natural Mortality (M) 0.59 year-1, Fishing Mortality (F) 2.00 year-1 and Exploitation Rate (E) 0.77 year-1. Results show that mortality and exploitation rates were above the optimal, indicating high fishing pressure on coastal yellowfin tuna. The information generated by this study provides some further insights on the scientific knowledge of the coastal yellowfin tuna to inform policy for sustainable management and development of this fishery in Kenya and the entire South West Indian Ocean (SWIO) region.

Effects of Multiple Karenia brevis Red Tide Blooms on a Common Bottlenose Dolphin (Tursiops truncatus) Prey Fish Assemblage: Patterns of Resistance and Resilience in Sarasota Bay, Florida

Red tide blooms caused by the toxic dinoflagellate Karenia brevis are natural disturbance events that occur regularly along Florida’s west coast, often resulting in massive fish kills and marine mammal, seabird, and sea turtle mortalities. Limited prior work on the ecological effects of red tides suggests they play an important role in structuring ecosystem dynamics and regulating communities, however specific effects on prey populations and potential alterations to predator-prey interactions are unknown. We surveyed the prey fish assemblage of a top marine predator, the common bottlenose dolphin (Tursiops truncatus), in shallow seagrass habitat in Sarasota Bay, Florida, during 2004–2019, collecting data on prey density, species composition, K. brevis cell densities, and environmental variables. Across eight distinct red tide bloom events, resistance, resilience, and the ecological effects on the prey assemblage varied depending on bloom intensity, season, and frequency. Prey assemblage structure showed significant and distinct short-term shifts during blooms independent of the normal seasonal shifts in prey structure seen during non-bloom conditions. Canonical correspondence analysis indicated a strong influence of K. brevis density on assemblage structure. Blooms occurring primarily in the summer were associated with less initial prey resistance and higher than average annual catch per unit effort (CPUE) 1–3 years following bloom cessation, with bloom frequency prolonging the time needed to reach higher than average annual CPUE. Regardless of season, recovery to pre-bloom prey abundances occurred within 1 year. Sample-based rarefaction and extrapolation indicated significant differences in prey diversity among summer bloom events. This study is a first step in identifying differences in resistance, resilience, and the ecological effects of multiple red tide bloom events of various temporal scales and intensity on a dolphin prey assemblage. Improved understanding of the influence of red tides on estuarine structural dynamics and function can better inform management, and potentially guide mitigation efforts post-bloom.

A decade of surf-zone linefish monitoring in the Dwesa-Cwebe Marine Protected Area, with a preliminary assessment of the effects of rezoning and resource use

An 11-year assessment of surf-zone linefish (marine fish captured on hook and line) was carried out in the Dwesa-Cwebe Marine Protected Area (MPA) in the Eastern Cape, South Africa, by research fishing to determine species and size composition, movement and relative abundance using catch per unit effort (CPUE). Comparisons were made between the Cwebe and Dwesa sections of the MPA on either side of the Mbhashe Estuary, as well as between two partially protected areas (PPAs) and two no-take zones in the Dwesa section, which came into effect in January 2016. A total of 7 241 fish representing 43 species were recorded, where 39.5% of the species are endemic, 29.5% are considered threatened by the IUCN, and 27.3% are either overexploited, collapsed or in decline. Of 3 963 tagged fish, 128 (3.2%) recaptures were recorded, of which most (62%) exhibited no movement. Localised differences in species diversity, size frequency and CPUE were detected between the Dwesa and Cwebe sections, and lower average length and CPUE of some species were recorded in the Dwesa PPAs compared with in the Dwesa no-take zones. These differences were more prominent in slow-growing, long-lived species with small home ranges, indicating the negative impacts of fishing pressure on vulnerable species found in this MPA and a reduction in benefits that would otherwise be associated with no-take zonation. These findings highlight the need to revisit the rezoning of the MPA with regard to the size of the no-take zones and emphasise the need for effective law enforcement to ensure adherence to existing regulations.

Application of Schaefer model on mackerels fishery in Aceh waters, Indonesia

The mackerels were grouped into pelagic fish associated with oceanic habitat. Its exploitation in Aceh waters is quite intensive but not yet information related to its stock status. This information is needed in taking action on fisheries management with a quota approach.This study aims to assess of monthly production of mackerels tuna and maximum sustainable yield. This study deal with the estimation of catch and effort at maximum sustainable yield (MSY) of mackerels based on catch per unit effort (CPUE) and production of purse seine fishery in Banda Aceh during 2013–2018. Analysis was carried out using an equilibrium approach with the Schaefer model. The result showed that the average CPUE of purse seine for mackerels is 0,556 tonnes/trip. Since 2015 to 2018, the trend of biomass continued to decline and the over-fishing applied in this period. The catch at MSY of mackerels was 1506 tonnes/year and the effort at MSY was 2517 trips/year.

KOMPOSISI HASIL TANGKAPAN DAN LAJU TANGKAP (CPUE) USAHA PENANGKAPAN PURSE SEINE DI PELABUHAN PERIKANAN NUSANTARA (PPN) PEKALONGAN, JAWA TENGAH

Pekalongan fishing port is a fishing base for purse seiners of small pelagic fish in Central Java. Range of fishing fleets Gross Tonnage is 69 to 125 GT. Purse seine was dominant fishing gear with total percentage 84% from the total fishing gear at Pekalongan fishing port in 2014. The main target of purse seine is shoaling pelagic fish. The objectives of this research were to analyze the catch composition and Catch Per Unit Effort (CPUE) of purse seiners at Pekalongan Fishing Port. The method of this research used survey method. Data analysis with quantitative descriptive method. Analysis conducted on the catch composition and Catch Per Unit Effort of purse seiners . Data to analyze the catch composition was secondary data of purse seiners catches volume in 2016 from January until December. And to calculate the CPUE used secondary data of fishing trips and total production of purse seiners from 2008 to 2016. Variations of dominant type of captured i.e. Shortfin scad, Indian scad, Bali Lemuru, and Indian mackerel. Every month there was different of species dominance caught by the gear ranged from 7 to 11 species. The percentage of each species was Shortfin scad ( Decapterus macrosoma ) caught dominantly in January, October, November and December. Indian scad ( Decapterus russelli ) reached the highest percentage in June, July, August and September. Bali Lemuru ( Sardinella lemuru ) mostly caught in February, April and May. While Indian mackerel ( Rastrelliger kanagurta ) caught with highest percentage in March (40%). Location of fishing ground was in Indonesia Fisheries Mangement Area with code 712 and 713. The annual average CPUE of purse seine in Pekalongan Fishing Port was 18,712 kg or 18.7 metric tonnes per trip for each fleet. This result shows that the productivity of purse seiners was quite low compared with the size of fishing fleet Gross Tonnage 69 up to 125 tons.

Use of different approach in finding catch effort relationship in hook and line fishery in Kombuthurai village of Thoothukudi district of Tamil Nadu

Kombuthurai has been described as a fishing village in Thoothukudi district, Tamil Nadu which has gained immense importance by practicing sustainable fishing practices. In Kombuthurai village during 2009-2013, catch per unit effort (CPUE) has varied from 0.20 tonnes to the maximum of 0.25 tonnes during this period. It is interesting to know that despite the range of effort varying from 1598hrs to 1720hrs, the catch remained in the range of 347.4 tonnes to a maximum of 430.8tonnes. The influence of various variables (latitude, longitude, distance, depth, seasons, years and fishing gear type) on CPUE was studied by General Linear Model (GLM) and Generalized Linear Model (GLMs). Normal distribution with identity link function and a gamma distribution with log link function were used in GLMs. The variables that were found to be significant in both of the models and distributions are year and season. GLM model was good fit with R2 ranging from 67.60% to a high of 91.7%.The low and high abundance of CPUE were categorized taking the below and above average CPUE. A binary logistic regression model was used between the CPUE abundance and with above mentioned independent variables. The binary logistic regression model explained 75.4% (Nagelkerke R2) of the variance in high CPUE abundance and correctly classified 88% of cases. The independent variable such as latitude, longitude, depth, and distance added significantly to the model, but the year, season and hooks did not add significantly to the model.

Abundance and catchability estimates of the Atlantic blue crab Callinectes sapidus based on mark-recapture data from the northern Yucatan Peninsula

A short-term Jolly–Seber mark-recapture model experiment is described. This experiment was aimed at estimating the rate of catch per unit effort (CPUE) and the catchability coefficient (q) of the Atlantic blue crab (Callinectes sapidus) in the fishing port of Sisal, Yucatan, Mexico. To estimate the local population size, 52 traps were deployed along four transects located in a coastal capture area of 3600 m−2. The CPUE and q were compared between the daily mark-recapture Jolly–Seber experiment and the bi-monthly (carried out every 2 months) samplings. The average abundance was estimated at 3475 individuals. All three suggested scenarios, applied to estimate densities, gave similar estimates, i.e. 0.0386, 0.0350, 0.0365 crabs m−2 for the first (Previously Cited Attraction Radius), second (CPUE per transect) and third (Catchability-Density Relationship), respectively. Based on the latter scenario, densities ranged from 27,900 (annual average) to 36,500 (Spring) crabs km−2. The average CPUE of the daily mark-recapture experiment was estimated at 1.96 crabs trap−1, whereas the average bi-monthly CPUE was estimated at 1.13 crabs trap−1. The q (per trap) was estimated at 0.0186 for the daily mark-recapture experiment and at 0.0247 for the bi-monthly sampling. Both catchability and CPUE increased in individuals whose size ranged between 110 and 170 mm CW. However, no significant difference (ANCOVAs) was found between the daily and bi-monthly samplings neither in CPUE nor in catchability. The use of both mark-recapture data and the Jolly–Seber model proved to be a fast and reliable method for estimating the abundance and catchability of Atlantic blue crab.

Three decades of longlining in Bimini, Bahamas, reveals long-term trends in lemon shark Negaprion brevirostris (Carcharhinidae) catch per unit effort.

In Bimini, Bahamas, the consistent employment of longlines, beginning in 1982, provided a rare opportunity to explore population trends for large resident sharks. This study assessed three shallow water longline survey periods at this location; 1982-1989, 1992-2002 and 2003-2014, with the aim of determining trends in annual catch per unit effort (CPUE) for an IUCN listed near-threatened species, the lemon shark Negaprion brevirostris. A general additive model (GAM) was used to analyse the non-linear annual CPUE values over the entire 32-year research period. The GAM displayed high variability of annual CPUE, with a peak value of 0·026 N. brevirostris per hook day (hooks day(-1) ) in 2000. The temporal pattern of CPUE indicated an abundance trend with a complete cycle, from trough to trough, occurring over a period of approximately 18 years. The 1982-1989 survey period saw the highest proportion of mature individuals (19·8%) and the smallest average pre-caudal length (LPC ; 124·8 cm). The 1992-2002 survey period had the highest average annual CPUE (0·018 hooks day(-1) ), while the 2003-2014 research period saw largest average LPC size (134·8 cm) and the lowest average CPUE values (0·009 hooks day(-1) ) of the entire research period. The long-term trend identified in this study provides a baseline for future assessment.

Think outside the grids: An objective approach to define spatial strata for catch and effort analysis

A method is developed to objectively stratify a study area for standardizing catch per unit effort (CPUE) data for use in a generalized linear modeling framework. The method involves two steps: (1) subdividing the study area into small grids and applying a boosted regression tree method based on the full model to reconstruct a rough population pattern among grids and (2) applying a k-medoids algorithm to partition the grids into discrete strata based on the trend and magnitude of expected CPUE in each grid (time series clustering) or the spatial proximity and average CPUE in each grid (spatial clustering). The main advantage of this method compared to other area stratification approaches is that the shape of the resulting strata best matches the population structure as inferred from CPUE. This approach reduced bias in indices of abundance compared to ad-hoc methods. The variant of the area stratification method based on time series clustering performed best. However, this approach often performed as poorly as ad-hoc methods when there was a unidirectional shift in fishing locations over time because strata did not necessarily capture the shifts in fishing grounds over time. However, when the strata were selected to capture the shift in fishing grounds, both arbitrary and cluster-based method produced an index of abundance that was close to unbiased. Finally, the study showed that goodness of fit criteria (AICc or BIC) can be used to select the optimal number of strata for CPUE standardization, but this does not guarantee improved accuracy of the derived index of abundance compared to a pre-specified number of strata. The importance of conducting sensitivity analysis and the use of an ensemble approach is highlighted.

Spatio-temporal dynamics in the location of the fishing grounds and catch per unit effort (CPUE) for Chilean jack mackerel (Trachurus murphyi Nichols, 1920) from Chinese trawl fleets on the high seas of the Southeast Pacific Ocean, 2001-2010

The decadal spatio-temporal distribution of the fishing effort and catch per unit effort (CPUE) for Chilean jack mackerel, Trachurus murphyi, stock are poorly understood. Data from the Chinese jack mackerel fleet was used to describe the location of the fishing effort and the relationship between standardized CPUE and sea surface temperatures (SST) during the period 2001–2010. A significant change in the spatio-temporal distribution of fishing effort and standardized CPUE was observed for jack mackerel during the study period. From January to March, the average CPUE was generally <15 tonnes (t) per net, except for 2007–2009. CPUE increased significantly during the autumn-winter (April to August), then gradually decreased in the spring and early summer (September to December). Average standardized CPUE in 2001–2005 was 23.3 t per net, but decreased to 19.7 t per net in 2006–2010. The change in the gravity center location of CPUE between months was similar during the primary fishing period (autumn to winter) in 2001–2006. After 2006, the pattern began to differ in July–October, which resulted in fishers spending more time to search for aggregations. A seasonal change was observed in the range of SSTs associated with high CPUE. Generally, the optimal SST range was from 13.0–15.0°C in autumn, 12.0–14.0°C in winter, 13–16°C in spring, and 15–19°C before 2006. However, a 1–2°C decrease in the optimal range in recent years was associated with a shift in the fishing grounds location to the southern area. In 2009, the optimal SST range was lower than in all other years. Taken together, the results suggest that a more thorough understanding of the seasonal or decadal relationship between SST and location of the fishing grounds is critical to improving the efficiency of the fishery and its management.

Catch Composition of the bottom trawl fishery along the coasts of Karataş-Adana (Northeastern Mediterranean Sea)

The catch composition of the bottom trawl fishery along the coasts of Karatas was evaluated in the 2002-2003 fishing season. A total of 110 species were registered, the fishes showed the highest diversity (90 species) followed by 15 crustaceans species and 5 species of cephalopods. The highest catch per unit effort (CPUE) value (66.8 kg h -1 ) was recorded in September when the fishing season was opened and decreased to the lowest value in March (12.5 kg h -1 ). The average CPUE was 26.3 ± 18.9 kg h -1 . The result showed that catch of fish decrease with increasing depth. The highest fish catch (47.42%) was found in 0-20 m depth range. 35.58 percent of the catch was between 20-50 m, and 17.00% between 50-100 m depth. Lessepsian fish comprise 18.90% of all fish in terms of the number of species and 26.66% of the total fish catch.

The FAD fishery in the Gulf of Thailand: time for management measures

Fish aggregating devices (FADs) used in the Gulf of Thailand are made of bamboo poles, twisted wire and coconut leaves, fastened to a concrete block. Purse seines with 2.5 cm mesh size are used to surround the fish, using fishing boats ranging from 18 to 26 m in overall length. Fishing grounds are located in the central Gulf of Thailand at a depth of 25–60 m. Catch per unit effort (CPUE), species composition and size of economically important species were analyzed by collecting data from fishing boats using FADs at nine main fishing ports along the Gulf of Thailand between January and December 2007. The results show that the average CPUE was 3351 kg day-1 , which was composed of 88% pelagic fishes, 5% demersal fishes, 4% trash fishes and 2% squids and cuttlefishes. The major pelagic species were Indian mackerel (Rastrelliger kanagurta ), Indian scad (Decapterus russelli ) and bigeye scad (Selar crumenophthalmus ), which made up 25%, 24% and 8% of the total catch, respectively, while neritic tunas (kawakawa; Euthynnus affinis , frigate tuna; Auxis thazard thazard and longtail tuna; Thunnus tonggol ) made up 8% of the total catch. The mean length of ten economically important species was smaller than their size at first maturity, while two species were above their size at first maturity. The results indicated that juvenile fish were mostly being caught by FAD fishery, and this may lead to depletion in fisheries resources and economic loss. Although there is a set of measures to control the use of purse seines, effective management of the FAD capacity is also urgently needed.

Is natural bait type a stochastic process for size and condition of fishes in the recreational fishery of Ιzmir Bay?

Determining bait type might be one of the most important factors that influence the amount and size of the fish catch in marine recreational fishery. To this end, the relationships between two types of natural bait and catch per unit effort (CPUE), yield per unit effort (YPUE), fish size and condition (K=W/TL3) were evaluated in recreational fishery İzmir Bay (Middle Eastern Aegean Sea, Turkey). The most abundant angling species in Turkish coasts; annular sea bream (Diplodus annularis), blotched picarel (Spicara flexuosa), two banded sea bream (Diplodus vulgaris) and bogue (Boops boops) were collected by anglers between September 2006 – February 2007 with using baits; onyx (Solen vagina), and sardine (Sardina pilchardus). The average CPUE and YPUE of hooks baited with onyx were significantly higher than the bait sardine. Eventhough the averages of specimens caught with bait sardine were bigger than onyx except for bogue but, total length-frequency distributions were revealed some differences only for annular sea bream and blotched picarel between two baits. High conditioned individuals of bogue were caught with bait sardine and the rest of the other species with onyx.