Shark Catch Research Articles

Shark longline fishery of Papua New Guinea: size and species composition and spatial variation of the catches

This study provides the first detailed investigation of the catches of the shark longline fishery in Papua New Guinea. Fisheries observers collected data on shark catches from a total of 318 longline sets between May and June 2014, before its closure in July 2014. In all, 14694 sharks were recorded with a total estimated biomass of 439 tonnes (Mg). Eighteen species of sharks were recorded in the observer data, with the most dominant species being Carcharhinus falciformis, which constituted more than 90% of the total catches by both weight and number of individuals. The level of observer misidentification was low (<10%), which reflected the use of region-specific identification guides by well-trained fisheries observers. The most diverse catches were in the Solomon Sea area, whereas catches in most other areas, particularly the Bismarck Sea areas, were less diverse and more strongly dominated by C. falciformis. Size and sex ratios varied by species, highlighting the importance of obtaining species-level information from the fishery being investigated. Any consideration by fisheries managers to reopen this fishery needs to consider the effect this will have on the species targeted and the livelihoods of coastal fishers who also rely on the same resources.

Life-history traits inform population trends when assessing the conservation status of a declining tiger shark population

The assessment of the conservation status of wide ranging species depends on estimates of the magnitude of their population trends. The accuracy of trend estimates will depend on where and how many locations within a species' range are sampled. We ask how the spatial extent of sampling interacts with non-linear patterns in long-term trends to affect estimates of decline in standardised catch of tiger sharks (Galeocerdo cuvier) on the east coast of Australia. We apply a Bayesian trend model that uses prior information on life-history traits to estimate trends where we use data from all regions versus spatial subsets of the data. As more regions were included in the model the trend estimates converged toward an overall decline of 71% over three generations. Trends estimated from data only from northern regions or southern regions underestimated and overestimated the regional decline, respectively. When a subset of regions was modelled, rather than the full data-set, the prior informed by life-history traits performed well, as did a weakly informed prior that allowed for high variation. The rate of decline in tiger sharks is consistent with a listing East Coast Australia tiger sharks as endangered under local legislation. Monitoring programs that aim to estimate population trends should attempt to cover the extremes and mid-points of a population's range. Life-history information can be used to inform priors for population variation and may give more accurate estimates of trends that can be justified in debates about the status of threatened species, particularly when sampling is limited.

Length–weight relationships of three species of pelagic sharks from southeastern Arabian Sea

Length–weightrelationships (LWRs) of three species of pelagic sharks belonging to the family Carcharhinidae viz., the silky shark Carcharhinus falciformis and the graceful shark C. amblyrhynchoides and Alopidae viz, the pelagic thresher Alopias pelagicus, were estimated based on 525 samples collected from the longline and gillnet fishery of southeastern Arabian Sea from January 2016 to November 2018. Two major fish landing centres of Kerala, southwest coast of India were selected for sampling; Cochin (Lat. 09∘56′327′′N, Long. 76∘15′764′′E) and Munambam (Lat. 10∘10′965′′N, Long. 76∘10′258′′E). The estimated allometric coefficient b value ranged from 2.687 (A. pelagicus, N = 122) to 3.11 (C. falciformis, N = 295). Coefficient of determination scores ranged from 0.901 (A. pelagicus) to 0.984 (C. amblyrhynchoides, N = 108), indicating robustness of the samples analysed. Maximum total length presented for C. amblyrhynchoides in this study was a new record. The study reports first estimates of length–weight relationships for three important species of pelagic sharks which contribute to most of the shark catches in the region, and the generated parameters will be useful for the assessment of stocks and sustainable management of pelagic sharks in southeastern Arabian Sea.

Official catch data underrepresent shark and ray taxa caught in Mediterranean and Black Sea fisheries

One in four fishes of the subclass Elasmobranchii (sharks and rays) is estimated to be threatened with extinction, according to the IUCN Red List. Their primary threat is overfishing, but data deficiency makes stock assessment difficult. Over 50% of shark and ray species are listed as Data Deficient, in part because the taxonomic resolution of existing catch statistics is too low to identify species-level trends of abundance. Less than 25% of the shark catch reported to the FAO is identified below the genus level; the other 75% is lumped into categories such as “sharks”, “rays”, or “elasmobranchs nei”, (not elsewhere included). This study evaluates the taxonomic resolution of domestic elasmobranch landings in the Mediterranean and Black Seas, where over half of shark and ray species are threatened with extinction, but data deficiency and ambiguity consistently limit conservation action. A Taxonomic Resolution Index (TRI) was calculated for the landings of 24 countries over 65 years (1950–2014) to evaluate the quality of catch reporting over time. The TRI revealed that less than a quarter of commercial elasmobranch taxa are represented in Mediterranean and Black Seas landings data, and reporting quality has hardly improved. Conservation and management policy exists for effective fisheries data collection in the Mediterranean and Black Seas, but lacks implementation.

Species composition and catch of sharks, rays and skates in Ba Ria - Vung Tau and Binh Thuan provinces of Vietnam

Research on 2,626 individuals of sharks, rays and skates in total of 123 fishing boats were sampled during 2015 to 2016 in Ba Ria - Vung Tau and Binh Thuan provinces. The results identified 77 species of sharks, rays and skates belong to 22 families and 10 orders in Ba Ria - Vung Tau and Binh Thuan provinces. Of these, 57 species were recorded in Ba Ria - Vung Tau and 48 species in Binh Thuan. The families were found in the highest number of species such as Carcharhinidae family with 9 species, Dasyatidae family with 19 species and Rajidae family with 5 species. The total catch of sharks, rays and skates was 23,599 tons in Ba Ria - Vung Tau and was 24,355 tons in Binh Thuan. Sharks, rays and skates ratio made up from 0.2% to 0.5% in total catch landing from landing sites. Total length of sharks ranges from 21.0 cm to 366.0 cm, disc length of rays fluctuates from 11.0 cm to 248.0 cm and skates have a range from 0.7 cm to 152.0 cm in disc length.

Pola Pertumbuhan dan Faktor Kondisi Hiu Merak Bulu Carcharhinus brevipinna di Perairan Selatan Nusa Tenggara

<strong>Growth Pattern and Condition Factor of Spinner Shark Carcharhinus brevipinna in Southern Nusa Tenggara Waters.</strong> The spinner sharks are one of shark commodities that are utilized optimally from the southern of Nusa Tenggara waters, however, the scientific information is still limited. This study aimed to assess the growth pattern and condition factors of the spinner shark, <em>Carcharhinus brevipinna</em> in southern Nusa Tenggara waters. The research was conducted from January to December 2016 using direct recording of the catch data. Information on length, weight and sex determinations were collected by the enumerator. The data was analysed descriptively with the shark condition was determined based on the relative condition factor obtaining from the length-weight relationship. The results showed that growth patterns of the spinner shark, both males and females, were allometrically negative. The relative condition factors of the catch of male sharks were ranged from 0.206 – 2.225 and females from 0.237 – 3.361. The condition factors of spinner sharks were not different between sexes and time of fishing, but they were different in length classes.

Effects of inconsistent reporting, regulation changes and market demand on abundance indices of sharks caught by pelagic longliners off southern Africa.

The assumption of a proportional relationship between catch-per-unit-effort (CPUE) and the abundance of sharks caught by pelagic longliners is tenuous when based on fisher logbooks that report only retained specimens. Nevertheless, commercial logbooks and landings statistics are often the only data available for stock status assessments. Logbook data collected from local and foreign pelagic longline vessels operating in four areas off southern Africa between 2000 and 2015 were used to construct standardized CPUE indices for blue sharks Prionace glauca and shortfin makos Isurus oxyrinchus. Generalized linear mixed models were used to explore the effects of year, month, vessel, fleet and presence of an observer on blue shark and shortfin mako variability. Landing statistics and auxiliary information on the history of the fishery, regulation changes, and market factors were superimposed on the CPUE indices, to test hypotheses that they would influence CPUE trends. Indices in the West and Southwest (Atlantic) areas were elevated for both species, compared to the South and East (Indian Ocean). The scale of year-on-year CPUE increments, up to an order of magnitude for blue sharks, reflected occasional targeting and retention, interspersed with periods where blue sharks were not caught, or discarded and not reported. Increments were smaller for higher value shortfin makos, suggesting that indices were less affected by unreported discarding. CPUE indices and landings of both shark species have increased in recent years, suggesting increased importance as target species. Analysis of logbook data resulted in unreliable indicators of shark abundance, but when trends were interpreted in conjunction with landings data, disaggregated by area and month, and with hindsight of market demand and regulation changes, anomalies could be explained.

Increasing Abundance of Silky Sharks in the Eastern Indian Ocean: Good News or a Reason to be Cautious?

The silky shark (Carcharhinus falciformis) is the most common shark landed in Indonesian waters, including in the Indian Ocean. However, even though they are frequently caught, there is a lack of information on the population and abundance of silky sharks in the Indian Ocean. Cilacap and Tanjung Luar are two of Indonesia’s shark fishery hotspots, both located on the edge of the Indian Ocean, which is a part of the Indonesian Fisheries Management Area (FMA) 573. The fishers from both places usually have fishing grounds in that particular fisheries management area. This research aims to update the abundance, and to investigate the factors, which influence catches of silky shark in the FMA 573 based on monthly enumeration during 2015–2016. This study found that standardized catch-per-unit-effort (CPUE) or abundance indices of silky shark in the Indonesian FMA 573 increased from 2015 to 2016. We suggested that fish immigration and decreasing fishing pressure may affect the fish abundance. Fisheries management is required to regulate the fishing pressure, such as controlling the number of boats/licenses and the number of trips or fishing gear, as well as initializing spatial and temporal fishing closure.

Rainfall and sea surface temperature: key drivers for occurrence of bull shark, Carcharhinus leucas, in beach areas

Climate and weather-based drivers of shark movement are poorly known, yet vital for determining measures for effective conservation of shark populations and the management of shark-human interactions at different time scales. The bull shark, Carcharhinus leucas, an IUCN ‘Near-threatened’ species, is globally distributed in subtropical to tropical regions and is implicated in many attacks on humans because of its euryhaline habitat-use. However, drivers determining rapid transitions of this species among habitats along the freshwater-estuarine-marine continuum are yet to be fully understood. To identify triggers for movement by this species into beach areas we used conditional (binomial and gamma) generalised linear modelling (CGLM) of historical bull shark catches from the Queensland Shark Control Program (QSCP) collected from 1996 to 2007 across 1783 km of the Queensland coastline, Australia. We then compared catches before and after key weather events (such as floods) between 2006 and 2014 and used passive long-term acoustic telemetry to monitor movements of bull sharks into beach areas to test the model predictions. The CGLM showed that bull shark catch (occurrence) in beach areas is driven by rainfall and further influenced by sea surface temperature. Our model suggests that ≥100 mm total rainfall in the catchment associated with each beach area is significantly correlated with increased bull shark catch 1–8 days after the rainfall, a relationship also confirmed by the movements of acoustic tagged sharks between estuarine and beach areas. These trends provide the first predictive relationship for identifying increased risk of bull shark-human interactions in beach areas. They also suggest that the activity patterns of bull sharks are correlated with rainfall and this makes them particularly susceptible to localised, short-term changes in weather and long-term climate change.

Improving reliability of species identification and logbook catch reporting by commercial fishers in an Australian demersal shark longline fishery

AbstractLarge adult carcharhinid and sphyrnid sharks have been targeted in coastal waters off New South Wales, eastern Australia, by commercial fishers using demersal longlines since 2005. Inaccurate fisher reporting of the composition of catches led in 2008 to a range of complementary management measures to help improve reliability, including a redesigned catch logbook, species identification guide and at‐sea education via an observer programme. This study provides results from assessments of the effectiveness of those measures. A questionnaire yielded overwhelmingly positive feedback from fishers regarding the usefulness of the species identification guide. Comparison of observer‐recorded data and corresponding fisher‐reported logbook data via weighted linear mixed‐effects modelling found that since 2008, misreporting of catches has varied considerably among species and, for some species, among fishers. With some species commonly under‐reported and others frequently over‐reported, it is apparent that certain species were likely mistaken for other morphologically similar species. Such systematic error inherently undermines stock assessments of these vulnerable species. Management strategies designed to include education and extension will ensure greater reliability of fisher reporting of shark catches in the future.

Electro shield system applications on set gill net as efforts to preserve shark resources

Sharks are kind of ETP biota (Endangered, Threatened, and Protected), and are generally caught as by catch during fishing operations. In addition, sharks are one of the biota that plays a role in the life cycle in coastal waters. The Electro Shield System (ESS) was a device with an electromagnetic wave source that the shark can detect and make it afraid. ESS can be applied to set gill net operation to prevent the shark from getting caught. The objective of the study was to analyze the ESS on shark catches during set gill net operations. The research method was experimental fishing, conducted in March-May 2017 in Bangka Belitung Islands, Indonesia. Design the study by comparing shark catches during set gill net operation between those without using ESS (control) and using ESS with frequency 55 Hz. The shark catch by using Electro Shield System was 5.26% lower than control (7.80%). T-student analysis (sign 0.05) indicates that there was a significant difference between the set gill net without ESS and using the ESS against shark biota as bycatch. This indicates that the application of ESS in set gill net can reduce the capture of shark as by catch.

Delineation and mapping of coastal shark habitat within a shallow lagoonal estuary.

Estuaries function as important nursery and foraging habitats for many coastal species, including highly migratory sharks. Pamlico Sound, North Carolina, is one of the largest estuaries in the continental United States and provides a variety of potential habitats for sharks. In order to identify and spatially delineate shark habitats within Pamlico Sound, shark catch and environmental data were analyzed from the 2007–2014 North Carolina Division of Marine Fisheries (NCDMF) gillnet and longline surveys conducted within the estuary. Principal species were identified and environmental data recorded at survey sites (depth, temperature, salinity, dissolved oxygen, submerged aquatic vegetation (SAV) distance, and inlet distance) were interpolated across Pamlico Sound to create seasonal environmental grids with a 90-m2 cell size. Boosted Regression Tree (BRT) analysis was used to identify the most important environmental factors and ranges associated with presence of each principal species, and the resulting models were used to predict shark capture probability based on the environmental values within the grid cells. The Atlantic Sharpnose Shark (Rhizoprionodon terraenovae), Blacktip Shark (Carcharhinus limbatus), Bull Shark (Carcharhinus leucas), Sandbar Shark (Carcharhinus plumbeus), Smooth Dogfish (Mustelus canis), and Spiny Dogfish (Squalus acanthias) were the principal species in Pamlico Sound. Most species were associated with proximity to the inlet and/or high salinity, and warm temperatures, but the Bull Shark preferred greater inlet distances and the Spiny Dogfish preferred lower temperatures than the other species. Extensive Smooth Dogfish habitat overlap with seagrass beds suggests that seagrass may be a critical part of nursery habitat for this species. Spatial delineation of shark habitat within the estuary will allow for better protection of essential habitat and assessment of potential interactions with other species.

Analysis of the supply chain and conservation status of sharks (Elasmobranchii: Superorder Selachimorpha) based on fisher knowledge.

Increasing fishing effort has caused declines in shark populations worldwide. Understanding biological and ecological characteristics of sharks is essential to effectively implement management measures, but to fully understand drivers of fishing pressure social factors must be considered through multidisciplinary and integrated approaches. The present study aimed to use fisher and trader knowledge to describe the shark catch and product supply chain in Northeastern Brazil, and evaluate perceptions regarding the regional conservation status of shark species. Non-systematic observations and structured individual interviews were conducted with experienced fishers and traders. The demand and economic value of shark fins has reportedly decreased over the last 10 years while the shark meat trade has increased slightly, including a small increase in the average price per kilogram of meat. Several threatened shark species were reportedly often captured off shore and traded at local markets. This reported and observed harvest breaches current Brazilian environmental laws. Fishing communities are aware of population declines of several shark species, but rarely take action to avoid capture of sharks. The continuing capture of sharks is mainly due to a lack of knowledge of environmental laws, lack of enforcement by responsible authorities, and difficulties encountered by fishers in finding alternative income streams. National and regional conservation measures are immediately required to reduce overfishing on shark populations in Northeastern Brazil. Social and economic improvements for poor fishing communities must also be implemented to achieve sustainable fisheries.

Oceanographic Factors in Fishing Ground Location of Anchovy at Teluk Cenderawasih National Park, West Papua : Are These Factors Have an Effect of Whale Sharks Appearance Frequencies?

The appearance frequencies of whale sharks in Teluk Cenderawasih National Park (TCNP) is unique because they appear throughout the year and are not related to any seasons. WWF Indonesia's monitoring results from 2011 untill now showed the appearance of whale sharks is closely related to the presence of fisherman liftnet and anchovies. This study focuses on oceanographic factors in fishing ground areas such as chlorophyll-a and satellite imagery data including chlorophyll-a, Sea surface Temperature (SST) over the last four years resulting in AQUA MODIS level 2 recording with 1km resolution in 2013-2016. The catch of anchovies and chlorophyll-a values showed a fairly good correlation during the west monsoon, 0.305, in addition the relationship between the anchovies with SST has a good correlation value starting in the transition period 1 towards the east monsoon. Based on these data, oceanographic factor conditions in TCNP provide a good opportunity for anchovies that live in warm waters to grow and reproduce. This also influences the appearance of whale sharks closely related to the presence of the anchovies where a positive correlation value is found between the catch of anchovies and whale sharks during the west monsoon and east monsoon in sequence 0,912 and 0.819. Chlorophyll-a and SST have a significant effect on fish catch of anchovies and the appearance frequencies of whale sharks even it were not in all seasons.

Behavioural responses of draughtboard sharks (Cephaloscyllium laticeps) to rare earth magnets: Implications for shark bycatch management within the Tasmanian southern rock lobster fishery

Catches of draughtboard shark (Cephaloscyllium laticeps) in the Tasmanian Southern Rock Lobster Fishery are considered an economic and potentially ecological issue. Consequently, there is interest in developing strategies to mitigate and minimise shark bycatch within this fishery. This field study examined the behavioural responses of draughtboard sharks to neodymium-iron-boron (Nd2Fe14B) rare earth magnetic rods attached to baited video apparatus. Two magnetic treatments and one control were used in 12 × 1.5 h observational trials conducted in inshore waters of Tasmania, Australia. Results demonstrate that draughtboard sharks: (1) showed substantial individual variation in behaviours both between and within treatments, with no patterns of individual responses observed over time to both magnetic treatments or the control, (2) showed significant differences in initial interactions between the magnetic treatments and the control, and (3) attempted to take bait at the control significantly more often than at the 2-magnet treatment. These findings demonstrate the individualistic and highly variable response behaviours of draughtboard sharks to rare earth magnets. Understanding such behaviours may facilitate the development of effective deterrent strategies in this fishery and improve management of shark-fishery interactions globally.

The shark by-catch of tuna longline fisheries in Southern Indian Ocean of Java, Indonesia

In relation to the achievement of the target SDG’s No. 14, the sustainable shark fisheries management need to implement. As a part of the tuna fisheries by-catch, a high number of shark resources have been caught in the Indian Ocean waters. One of the main vessels of tuna catchers in the Southern Indian Ocean of Java is the tuna longline from Cilacap. This paper aims to analyze the shark by-catch of tuna longline in the Indian Ocean in the south Java that landed in Cilacap. The research data was obtained from daily recording activities of fishing vessel loading activities by Cilacap Ocean Fisheries Port staff during the period of 2013-2017. The analysis was done through data tabulation, graphical approaches, and data trend analysis through the availability of time series data. The data analyzed include fleet development, fishing ground, catch composition and CPUE value. The results of the analysis show that there are about eight species of sharks that are by-catch of tuna longline from Cilacap. The highest shark by-catch occurred in April with CPUE averaging 9 kg/day/vessel. The blue shark (Prionace glauca) is the dominant shark catch which reaches 66% of the total sharks catch.

CATCH AND RELATIVE ABUNDANCE OF SOME SHARKS LANDING IN TANJUNG IN LUAR, LOMBOK

Tanjung Luar is the center of shark fisheries in Indonesia because it has more shark catches than any other fish landing places in Indonesia. The aims of this study were to present the catch characteristics and the relative abundance of some sharks landing in Tanjung Luar, Lombok. Data were obtained through the interview with enumerators and from their daily monitoring record on the shark landing at Tanjung Luar, East Lombok during eleven months period from January to November 2015. Data statistics were calculated descriptively and presented as a percentage of relative abundance. The result shows the shark caught in 2015 has fluctuated monthly with the peak of catch occurred on September 2015. Total shark caught were about 237.5 tonnes and average landing per day was 1.4 tonnes. Species composition of overall catch comprised of 28 species which belong to 11 families. Among those species, Silky shark/ Carcharhinus falciformis (42.06%), Blue shark/ Prionace glauca (10.45%) and Blacktip shark/ Carcharhinus limbatus (10.31%) were predominant as indicated having relative abundance more than 10%.

Habitat features influence catch rates of near-shore bull shark (Carcharhinus leucas) in the Queensland Shark Control Program, Australia 1996–2012

Understanding shark habitat use is vital for informing better ecological management of coastal areas and shark populations. The Queensland Shark Control Program (QSCP) operates over ∼1800 km of Queensland coastline. Between 1996 and 2012, catch, total length and sex were recorded from most of the 1992 bull shark (Carcharhinus leucas) caught on drum lines and gill-nets as part of the QSCP (sex and length was not successfully recorded for all individuals). Gear was set at multiple sites within ten locations. Analysis of monthly catch data resulted in a zero-inflated dataset for the 17 years of records. Five models were trialled for suitability of standardising the bull shark catch per unit effort (CPUE) using available habitat and environmental data. Three separate models for presence-absence and presence-only were run and outputs combined using a delta-lognormal framework for generalized linear and generalized additive models. The delta-lognormal generalized linear model approach resulted in best fit to explain patterns in CPUE. Greater CPUE occurred on drum lines, and greater numbers of bull sharks were caught on both gear types in summer months, with tropical sites, and sites with greater adjacent wetland habitats catching consistently more bull sharks compared to sub-tropical sites. The CPUE data did not support a hypothesis of population decline indicative of coastal overfishing. However, the total length of sharks declined slightly through time for those caught in the tropics; subtropical catches were dominated by females and a large proportion of all bull sharks caught were smaller than the size-at-maturity reported for this species. These factors suggest that growth and sex overfishing of Queensland bull shark populations may be occurring but are not yet detectable in the available data. The data highlight available coastal wetlands, river size, length of coastline and distance to the 50 m depth contour are important for consideration in future whole of lifecycle bull shark management. As concerns for shark populations grow, there is an increasing requirement to collate available data from control programs, fisheries, ecological and research datasets to identify sustainable management options and enable informed stock assessments of bull shark and other threatened shark species.

Reconstructing Western Australian white shark (Carcharodon carcharias) catches based on interviews with fishers

The assessment of fisheries-related effects on protected species, such as white sharks (Carcharodon carcharias), is often hampered by a lack of historical catch information. In the present study, historical catch estimates derived from interviews with fishers operating in the Western Australian Temperate Demersal Gill-net and Demersal Longline Fisheries were matched with fishing effort data reported in statutory fishing returns. Catch estimates obtained from interviewed fishers were extrapolated to account for total catch in two different ways, resulting in mean (95% confidence intervals) estimates of 1232 (476–2245) and 1039 (505–2096) white sharks caught between 1988 and 2012. These estimates were then used to reconstruct catches over a 59-year period, from the start of commercial gillnetting in the mid-1950s. The reconstructed catch trend reflected the history of gill-net fishing effort, peaking in the late 1980s at a level approximately fourfold greater than the estimated catch of ~30 sharks year–1 in 2014. More than one-third of fishers interviewed expressed doubts about the accuracy of self-reported white shark catch data, a requirement of current legislation. Given the benefits of reporting data from protected species bycatch, efforts to accurately record this information should be continued and improved.

Persepsi Nelayan Terhadap Status Konservasi Hiu dan Pengaruhnya Terhadap Penangkapan Hiu: Studi Kasus di Kabupaten Badung, Provinsi Bali

Shark is one of top predator that can define and control marine food chain. Shark breeding process is relatively slow and increase of catching activity has even given worse impact to shark population. Several endangered shark species has already protected the catch activity was banned. Some of them, such as Alopias superciliosus are found in Benoa and Kedonganan harbour. This condition happened because of not enough information and knowledge transfer to the local community about the protected species and catching regulation. Based on that information,the research about fishermen perception on shark conservation status and its correlation with the shark catch is important to be conducted. Data was collected using quisioner through interview approach. All the respondent is men with the age ranged from 16-67 years old, and 98% of respondent is labor. About 55% of the respondent graduated from elementary school. The result showed that the fisherman perception of shark conservation status categorized as good, while shark catch that is related with conservation in Badung district is categorized very good. The correlation of fisherman perception to shark conservation status with shark catching effort is negative, and significant to the shark catching effort (?=0,05) in Badung district. It means that if the fisherman perception to the shark conservation status in Badung district increased, so that the catch effort will be decrease.