Illegal Fisheries Research Articles

Development of Sustainable Minapolitan Area in Tamako District, Kepulauan Sangihe Regency


 
 
 The aim of this study is to address the challenges facing the Dagho Beach Fishing Port Area in North Sulawesi, which plays a pivotal role in the region's fisheries sector but suffers from inefficiencies in development systems, markets, distribution, and infrastructure. This dependence on natural resources has eroded community independence, exacerbated by issues such as illegal fisheries transactions, price disparities, and the absence of processing industries. Additionally, limited accessibility for exports and regulatory hurdles impede the area's potential, with only a small fraction of the population engaged in fishing activities. To tackle these issues, the study employs a comprehensive four-stage analysis approach. Firstly, Descriptive Analysis delineates the economic, political, social, and environmental characteristics of the area. Secondly, Analytical Hierarchy Processes (AHP) identify the most influential indicators for focused development efforts. Thirdly, a combination of Scalogram and Weighted Sum methods determines suitable minapolitan zones. Finally, Descriptive Direction offers development guidelines based on previous analyses. The research yields actionable directions, including the establishment of a modern market, enhancing fishery product marketing through the "Marketing Mix" and Free Trade Agreement (FTA) implementation. It advocates for technology-based processing units and integrated infrastructure, alongside policy development to support the fisheries industry and promote sustainable practices. The study emphasizes the importance of infrastructure development, economic collaboration, and community empowerment initiatives to foster local fishery development, cultivation, and business capital.
 
 

Use of bird-borne radar to examine shearwater interactions with legal and illegal fisheries.

Seabirds interact with fishing vessels to consume fishing discards and baits, sometimes resulting in incidental capture (bycatch) and the death of the bird, which has clear conservation implications. To understand seabird-fishery interactions at large spatiotemporal scales, researchers are increasing their use of simultaneous seabird and fishing vessel tracking. However, vessel tracking data can contain gaps due to technical problems, illicit manipulation, or lack of adoption of tracking monitoring systems. These gaps might lead to underestimating the fishing effort and bycatch rates and jeopardize the effectiveness of marine conservation. We deployed bird-borne radar detector tags capable of recording radar signals from vessels. We placed tags on 88 shearwaters (Calonectris diomedea, Calonectris borealis, and Calonectris edwardsii) that forage in the northwestern Mediterranean Sea and the Canary Current Large Marine Ecosystem. We modeled vessel radar detections registered by the tags in relation to gridded automatic identification system (AIS) vessel tracking data to examine the spatiotemporal dynamics of seabird-vessel interactions and identify unreported fishing activity areas. Our models showed a moderate fit (area under the curve >0.7) to vessel tracking data, indicating a strong association of shearwaters to fishing vessels in major fishing grounds. Although in high-marine-traffic regions, radar detections were also driven by nonfishing vessels. The tags registered the presence of potential unregulated and unreported fishing vessels in West African waters, where merchant shipping is unusual but fishing activity is intense. Overall, bird-borne radar detectors showed areas and periods when the association of seabirds with legal and illegal fishing vessels was high. Bird-borne radar detectors could improve the focus of conservation efforts.

First inventory of Ants (Hymenoptera: Formicidae) with detection of potential invasive species in National Park of Ehotilés islands, Côte d’Ivoire

Estuarine and wetland ecosystems are becoming increasingly altered by the concentration of human population near the coastline. A major threat to biodiversity related to this human footprint is the introduction of invasive alien species, particularly in isolated ecosystems like islands where biological invasion is often harmful. The National Park of Ehotilés Islands is an archipelago of 6 islands and a RAMSAR site subjected to disturbances activities like agriculture, illegal fisheries, and tourism. These factors often act as an accelerator for the introduction of invasive species. However, there is a lack of research conducted on insects, specifically ants on these islands. This study aimed to inventory the present ant fauna and estimate the vulnerability to tramp and potential invasive ant species. Ants were collected using Winkler, pitfall, and funnel traps on five islands. In total, 76 ant species were recorded. These species are distributed into 20 genera and five subfamilies: Dolichoderinae (5 species), Formicinae (11 species), Myrmicinae (49 species), Ponerinae (11 species) and Proceratiinae (1 species). We also detected two tramp and potentially invasive species: the ghost ant Tapinoma melanocephalum and the big-headed ant Pheidole megacephala. Ant communities are dominated by six species, namely Odontomachus troglodytes, Oecophylla longinoda, Nylanderia lepida, Pheidole sp.2, Monomorium invidium, and the invasive ghost ant Tapinoma melanocephalum. This work is the first to inventory ants on the Islands of Ehotilés National Park and may serve as a basis for conservation decisions as it demonstrates that this park is not spared from the introduction of invasive ant species.

Gauging the threat: exposure and attraction of sooty albatrosses and white-chinned petrels to fisheries activities in the Southern Indian Ocean

Abstract Bycatch risk assessments typically rely on spatial overlaps between seabirds and fishing vessels but should also consider seabirds’ position in the attraction spectrum. Investigating seabird-fishery interactions in relation to habitat use is vital for species-specific risk assessments. To address this, we studied interactions between sooty albatrosses (SA) and white-chinned petrels (WCP) with fisheries. GPS data from 20 SA and 18 WCP individuals from Marion Island were analysed alongside Automatic Identification System-derived boat locations over two breeding seasons. We calculated encounter and attraction rates and correlated them with marine habitat characteristics. SA interactions occurred in deeper, warmer waters compared to their foraging habitat when vessels were absent, with 20% of individuals encountering and only 5% being attracted to boats. In contrast, WCP interactions occurred in shallow, warm South African shelf waters, consistent with their typical foraging habitats, with 72% encountering and 56% attracted to boats. These results highlight the need for continued reinforcement of mitigation measures for WCP. Despite the low attraction rates for SA, ongoing vigilance is required due to their smaller population size, which heightens the potential impact of illegal fisheries. The comparison of species along an attraction spectrum contributes to refining risk assessments and informs species-specific conservation strategies.

Stakeholder consensus suggests strategies to promote sustainability in an artisanal fishery with high rates of poaching and marine mammal bycatch

Abstract Illegal fishing for high value species in artisanal fisheries drives incidental catch and declines of marine mammals and other large vertebrates of conservation importance around the world. Engaging with stakeholders is essential to understand which strategies will be effective in motivating the development of more sustainable practices, and disengagement from illegal fisheries. Here we present the results of a Q study carried out in autumn 2018 with 50 stakeholders from the Caspian Sea coast of Dagestan (Russian Federation), including fishers illegally targeting sturgeon (Acipenseridae) and Caspian seals Pusa caspica, traders and fisheries managers. We assess viewpoints on biodiversity governance; illegal, unreported and unregulated (IUU) fishing; illegal wildlife trade (IWT) and conservation. Three distinct viewpoint groups emerged from a factor analysis, which we designated as ‘Nostalgists’, ‘Optimists’ and ‘Pessimists’. Nostalgists were concerned with decline in environmental quality, and emphasised a need for increased centralised involvement of authorities reminiscent of the old Soviet system. Optimists expressed support for a well‐regulated legal fisheries sector, while Pessimists were very aware of the negative impact of illegal fisheries and IWT, but felt they could not be controlled. Among all groups we found a strong desire for alternative livelihoods (ALs), improved sustainability and agreement on the potential effectiveness of marine protected areas (MPAs) and increased regulation, even if some stakeholders felt they were not achievable goals. We used our results to inform three workshops in which Dagestani fishers and fishery experts discussed potential conservation interventions, and the barriers to their implementation. Six action types were identified including enhanced law enforcement, increased regulation, protected areas, alternative livelihoods, reducing demand for sturgeon and seal products and the need for further research to guide policy development. This consensus suggests that communities are willing to reduce participation in illegal fishing given appropriate support. The socioeconomic factors driving illegal fisheries and bycatch for Caspian seals parallel those for other endangered marine mammals such as Vaquita Phocoena sinus and suggest that Q studies could be applied in other artisanal fisheries with high rates of marine mammal bycatch to help identify policy interventions supported by involved communities. Read the free Plain Language Summary for this article on the Journal blog.

Derelict gear from an illegal fishery: Lessons from gear retrieval efforts in the Upper Gulf of California

The Gulf of California illegal fishery for totoaba (a CITES Appendix I-listed fish species since 1977) has led to socio-ecological degradation. Particularly, this fishery is well known for incidentally catching the critically endangered vaquita. However, its impacts on the larger ecosystem are understudied. For decades local experts and non-governmental organizations had reported large amounts of in-use and derelict fishing gear used for totoaba in the Upper Gulf of California (UGoC), but the issued remained unstudied. Six of the co-authors participated directly in gear retrieval efforts and their experience is recorded here. We also performed a literature review to collect a) information on the history, dimension, root causes and impacts of gear discarding practices, and b) lessons drawn from the inter-institutional gear recovery effort performed between 2016 and 2020. For this last objective, we used the Inter-Institutional Gap Framework (IIG). By mapping all institutions involved and their relationships, the IIG allows to identify coordination gaps among multi-level institutions. We found that the gear recovery allowed to bridge historical gaps between formal and informal institutions in the UGoC. The results of the gear recovery effort (9.3 tons of intercepted nets within a section of the UGoC) also helped illustrate the large scope of the problem, which seems to be caused by local oceanographic conditions and the fishers’ need to avoid enforcement. Our study provides a first estimation of the size of this problem and adds to a body of literature on the relationship between illegal fisheries and gear discarding.

Deep Learning-Based Automatic Detection of Ships: An Experimental Study Using Satellite Images.

The remote sensing surveillance of maritime areas represents an essential task for both security and environmental reasons. Recently, learning strategies belonging to the field of machine learning (ML) have become a niche of interest for the community of remote sensing. Specifically, a major challenge is the automatic classification of ships from satellite imagery, which is needed for traffic surveillance systems, the protection of illegal fisheries, control systems of oil discharge, and the monitoring of sea pollution. Deep learning (DL) is a branch of ML that has emerged in the last few years as a result of advancements in digital technology and data availability. DL has shown capacity and efficacy in tackling difficult learning tasks that were previously intractable. Specifically, DL methods, such as convolutional neural networks (CNNs), have been reported to be efficient in image detection and recognition applications. In this paper, we focused on the development of an automatic ship detection (ASD) approach by using DL methods for assessing the Airbus ship dataset (composed of about 40 K satellite images). The paper explores and analyzes the distinct variations of the YOLO algorithm for the detection of ships from satellite images. A comparison of different versions of YOLO algorithms for ship detection, such as YOLOv3, YOLOv4, and YOLOv5, is presented, after training them on a personal computer with a large dataset of satellite images of the Airbus Ship Challenge and Shipsnet. The differences between the algorithms could be observed on the personal computer. We have confirmed that these algorithms can be used for effective ship detection from satellite images. The conclusion drawn from the conducted research is that the YOLOv5 object detection algorithm outperforms the other versions of the YOLO algorithm, i.e., YOLOv4 and YOLOv3 in terms accuracy of 99% for YOLOv5 compared to 98% and 97% respectively for YOLOv4 and YOLOv3.

Fisheries assessment of the Albanian lagoon fisheries

Abstract The present study uses fisher knowledge to outline the basic socio-economic framework of Albanian lagoon fisheries based on on-the-spot interviews conducted with fishers operating in the most important Albanian lagoons. The results indicated that Albanian lagoon fisheries were family-based, with spatial differences observed in vessels from the northern lagoon that were older, larger in size, with more powerful engines, and involved more persons in comparison with corresponding vessels from the southern lagoon. The results also indicated that lagoon fisheries were in decline, ageing fishers, and encountering problems with illegal fishery and invasive species. Most of the fishers were aware that protected areas existed in Albanian waters, whereas severe contradictions among fishers existed about the need to establish new Marine Protected Areas (MPAs). An aggravating factor that threatened the viability of the lagoon fisheries and coastal ecosystems was high incidental catches of the Blue crab, Callinectes sapidus. These issues revealed the increased marginalization of the Albanian lagoon fisheries that might be able to be generalized beyond this case study to other Mediterranean lagoons. The present work also highlighted the need to establish a decent stratified statistical survey to monitor the highly complex nature of lagoon fisheries.

The effectiveness of Indonesia’s fisheries policy to reduce illegal fishing

The sea has economic potential such as marine tourism, energy, maritime industry, marine transportation, marine building and services, and fisheries. Indonesia has fishery resources with high biodiversity and easily accessible (renewable resources). Indonesia’s fishery production reached approximately 12.6 million tonnes, of which marine catch accounted for about 6.71 million tonnes, inland capture for 0.51 million tonnes and the rest is in aquacultures. In addition, Indonesia is facing the problem of illegal fishing by foreign fishing vessels from Thailand, Vietnam, China, Malaysia, Japan, Taiwan and Cambodia. Foreign fishing vessels conducting illegal fishing are not only found in the EEZ, but also in territorial and archipelagic waters. Based on the findings of this study, the illegal fishing policy has a positive impact by reducing illegal fishing activities in the short term and increasing fisheries stocks. However, negative impacts were also found, the national fisheries business has decreased by number, especially local fishermen business, so that fishermen are unable to optimize their capture fisheries activities. Some local fishermen benefit economically from illegal fishing, this is what causes illegal fishing activities to continue. The policies that have been implemented have not been optimal in ensuring that fishermen are more prosperous. A sovereign state not only owns the territory and defends it from foreign disturbances, but must realize the welfare of its people, including fishermen. The purpose of this research is to see the effectiveness of fisheries policies in Indonesia to tackle illegal fisheries and improve fishermen’s welfare. This research uses regulation analysis and Actor Network Theory to analyze the effectiveness of fishery policies

On-Board Ship Detection for Medium Resolution Optical Sensors.

In recent years there has been an increased interest in ocean surveillance. The activity includes control and monitoring of illegal fisheries, manmade ocean pollution and illegal sea traffic surveillance, etc. The key problem is how to identify ships and ship-like objects accurately and in a timely manner. In this context, currently, many solutions have been proposed based on high resolution optical and radar remote sensing systems. Most often, these systems suffer from two major limitations viz., limited swath, thereby requiring multiple satellites to cover the region of interest and huge volumes of data being transmitted to ground, even though effective per-pixel information content is minimal. Another limitation is that the existing systems are either simulated on ground or built using the non-space qualified/Commercial Of-The-Shelf (COTS) components. This paper proposes an efficient on-board ship detection system/package connected with medium resolution wide swath optical camera. The methodology adopted has three major components, viz., onboard data processing for improving the radiometric fidelity, followed by a ship detection using modified Constant False Alarm Rate algorithm (CFAR) and a false alarm suppression module to mask false identifications. Finally, the package outputs only the locations of the ships, which is transmitted to the ground. The proposed system reduces the effective volume of data to be transmitted and processed on ground and also significantly cuts down the turnaround time for achieving the end objective. The system is built on radiation hardened Field Programmable Gate Array (FPGA) devices to meet the various engineering constraints such as real-time performance, limited onboard power, radiation hardness, handling of multiple custom interfaces etc. The system is tested with one of the medium resolution Multispectral Visual and Near Infra-Red (MX-VNIR) sensor having a spatial resolution of around 50 m and swath of around 500 Kms, which would be flown with one of the upcoming satellites. The systems performance is also verified on ground with Indian Remote Sensing (IRS) Satellite’s Resourcesat’s Advanced Wide Field Sensor (AWiFS) data and the results are found to be quite encouraging as well as meeting the mission objectives.

조선후기 압록강 하안의 신도(薪島) 범월과 신도진(薪島鎭)의 설치

The Shindo island of Joseon was located on the Abrok-gang riverline which faced Chinese dynasties, first Ming and later Qing. Fishery was good in the area and there was also ample land that could be cultivated. So the Chinese people would frequently cross the border to come here, and engage in illegal activities. The Joseon government recognized Shindo as part of its territory, but was unable to actually move some Joseon people there and establish administrative control over the island. As a result, the island became a hotbed for illegal fishery and trades, and an island frequently violated by the Chinese via illegal trespassing.<BR> In order to put an end to all these illegal activities continuing on the Shindo island, the Joseon government decided to initiate a Suto(搜討) search and investigation. Such investigation seems to have begun around the latter half of 17th century when the Qing government’s ban on the sea was lifted, and was to be conducted ‘three times a month(月三搜討).’ Yet such plan was not successfully implemented, and the Joseon government finally decided in 1808–with the Qing’s approval- to establish a Naval headquarters (“Jin”) on Shindo, which was located near one of the farthest positions of the northern part of the Korean peninsula.<BR> The “Shindo-jin” office was a reestablishment of the Yongcheon area’s Migot-jin office, which had originally been maintained as an on-land facility. An administrative office was built on Shindo, and people were ordered to live there. The office itself was established not to defend the area from external enemies, but to monitor and minimize all the illegal trespassing and smuggling, so not a lot of soldiers were required. Unlike other naval facilities, only around a hundred soldiers were stationed at Shindo-jin.<BR> Meanwhile, the functions of the original Migot-jin also needed to be maintained. So the Joseon government had the Shindo Cheomsa official to man Shindo from March to September, and then regulate the Migot-jin area from October to February. In other words, the Shindo Cheomsa had to regulate the late Migot-jin on land and the new Shindo-jin on an island, and as a result the Shindo-jin in the 19th century had to be operated with two centers: one on the island(Dojin, 島鎭) and one on the land(Yukjin, 陸鎭). Shindo-jin served as an important checkpoint on the farthest North region of the West sea throughout the 19th century, and in the early 20th century actually enabled Joseon to have an upper hand in a series of territorial disputes with China over areas such as Hwangchopyeong and Shindo.

Illegal fisheries, environmental crime, and the conservation of marine resources.

The illegal harvest of marine species within exclusive economic zones can have a strong impact on the function of local ecosystems and livelihoods of coastal communities. The complexity of these problems is often overlooked in the development of solutions, leading to ineffective and sometimes harmful social and environmental outcomes. One-dimensional, oversimplified perspectives can lead to conservation prescriptions that exacerbate social stressors. This is particularly critical in the case of international illegal trade of endangered, high-value species, which generate a value chain in which artisanal fishers are the first operational and often the weakest link of an intricate web. We examined 2 illegal fisheries, totoaba (Totoaba macdonaldi) and sea cucumber (Isostichopusbadionotus and Holothuriafloridana), in Mexico. Although these are 2 separate and independent fisheries, important ecological (resource condition, fishery impacts at the ecosystem level) and social (governance, markets) similarities improve understanding of their complexity. Our findings are relevant globally and show the need for interdisciplinary decision-making groups, community engagement, and the development of demand reduction measures.

MODELING OF FISH SEIZURES AFTER THE IMPLEMENTATION OF THE CLOSED FISHING SEASON LAW IN THE AMAZON BASIN

The organization of fisheries in the Amazon region is an important theme, since the current management model is based mainly on the closed fishing season policy. This strategy suspends the catching of specific fish stocks and provides subsidies to professional fishers. Thus, the present study analyzed, through mathematical modeling, the behavioral interfaces of illegal fisheries that occurred between 1992 to 2017 in the Amazon basin, considering the hydrological seasonality and the effect of the presence or absence of the Closed Fishing Season law (CFSL). The data were tabulated and used for the construction of two illegal fishing scenarios. The first showed negative impacts with the absence of the CFSL, indicated by the high number of seizures of illegal catches that occurred during the period in which river water level is rising and showed continued growth over time. However, the second scenario showed apprehension apexes occurring at the beginning of the high-water level and at beginning of the low water level, with a continuous decrease in the seizures of illegal catches due to the new law. Thus, the ecosystem model constructed is a promising instrument for testing hypotheses and for formulating and monitoring management scenarios for fisheries in the region.

Illegal Fisheries; from Responsibility of the Coastal States and Flag State to the Regional Fisheries Management Organization’s Monitoring

Illegal Fisheries; from Responsibility of the Coastal States and Flag State to the Regional Fisheries Management Organization’s Monitoring

Space Remote Sensing and Detecting Systems of Oceangoing Ships

This paper introduces the implementation of space remote sensing and detecting systems of oceangoing ships as an alternative to the Radio – Automatic Identification System (R-AIS), Satellite – Automatic Identification System (S-AIS), Long Range Identification and Tracking (LRIT), and other current vessel tracking systems. In this paper will be not included a new project known as a Global Ship Tracking (GST) as an autonomous and discrete satellite network designed by the Space Science Centre (SSC) for research and postgraduate studies in Satellite Communication, Navigation and Surveillance (CNS) at Durban University of Technology (DUT). The ship detection from satellite remote sensing imagery system is a crucial application for maritime safety and security, which includes among others ship tracking, detecting and traffic surveillance, oil spill detection service, and discharge control, sea pollution monitoring, sea ice monitoring service, and protection against illegal fisheries activities. The establishment of a modern sea surface and ships monitoring system needs enhancement of the Satellite Synthetic Aperture Radar (SSAR) that is here discussed as a modern observation infrastructure integrated with Ships Surveillance and Detecting via SSAR TerraSAR-X Spacecraft, Ships Surveillance and Detecting via SSAR Radarsat Spacecraft and Vessels Detecting System (VDS) via SSAR.

The Intersection Between Illegal Fishing, Crimes at Sea, and Social Well-Being

Illegal, unregulated, and unreported (IUU) fishing is a major contributor to global overfishing, threatening food security, maritime livelihoods, and fisheries sustainability. An emerging narrative in the literature posits that IUU fishing is associated with additional organised criminal activities, such as drug trafficking, human trafficking, slavery, and arms smuggling. We explored this narrative through a systematic literature review to identify the empirical evidence of association between illegal fisheries activities and organised crimes. Here we show that there is minimal evidence of organised crimes being linked to IUU fishing. Due to the covert nature of both organised crime and IUU fishing, we supplemented the literature review with analysis of media reports on illegal fishing from 2015-2019. We reviewed more than 330 individual media reports from 21 countries. From this database, less than 2% reported crimes associated with illegal fishing. The predominant associated crime mentioned were violations of worker’s rights, forced labour and/or modern slavery. We resolve the contradiction between the common narrative that fisheries and other crimes are linked by presenting three distinct business models for maritime criminal activities. These models offer an explanation to why certain crimes such as forced labour are associated with illegal fishing, while other crimes such as trafficking or smuggling are less likely to be linked to fishing activities. By disentangling these crimes from one another we can better focus on solutions to reduce illegal behaviour on the sea, protect those vulnerable to fisheries exploitation, and enhance livelihoods and social well-being.

Moving within and beyond illegal crustacean fishery: why do Indonesian fishermen not comply with the crustacean catch ban rule?

Illegal wild capture fisheries undermine crustacean (e.g., crabs, lobsters, and swimming crabs) stock and their habitats. In a search for a new approach to the fisheries issues, this paper aims to explain why the illegal fishing for crustacean species still exists in Indonesia. It focuses on analyzing a set of practices in crustacean production and consumption. Banyuwangi (Indonesia) was the case study area of the conducted fieldwork. The method applied semi-structured interviews and participant observation. The design of research enabled the researcher to study daily fishing, purchasing, and processing. These practices determined the exploitation of crustacean species in the sea. This paper shows that the current fishing, purchasing, and processing of crabs, swimming crabs, and lobsters played a vital role in constructing the habit of illegal fishing. When the catch prohibition rules heavily focused on the wild capture fisheries in the sea, the local intermediaries and processors innovated their purchasing and processing to obtain crustacean species incessantly. Such an innovation was in response to the crustacean scarcity problems. (1) In swimming crab mini-plants, processors diversified their processed swimming crab products. The crab product diversification allowed them to process swimming crabs in all sizes. (2) The local intermediaries gave fishermen binding loans. Fishermen paid back the loans by supplying the crustacean species to the loan givers. (3) The existence of processing and purchasing stimulated fishermen to harvest every last crustacean species. Even though such crustacean fishing was illegal, it contributed to the livelihoods of fishermen, local intermediaries, and processors. This paper makes a research contribution to the use of social practice theory in fisheries issues. It gives a novel research approach to the habit of illegal fishing problems.

Illegal, Unreported, and Unregulated Fisheries: The Northwest Atlantic Fisheries Organization Experience

Illegal, Unreported, and Unregulated Fisheries: The Northwest Atlantic Fisheries Organization Experience

Preparing the French military to a warming world: climatization through riskification

This article studies the process of climatization of the French military initiated with the 21st Conference of the Parties in 2015 through an analysis of the discourses produced by military actors on climate change. I will argue that there are two ways in which the climatization of the military discourse operates. First, it leads to a reframing of existing security narratives such as migrations or armed conflicts through a climatic lens, which creates a sense of urgency and intensity. Second, the climatization of the military discourse is mediated by a riskification of climate change, through the adoption of a risk-based approach to prevent its security implications. It creates a sense of uncertainty and leads to the climatization of a growing number of security issues such as terrorism or illegal fisheries. Both processes contribute to legitimize military solutions in global climate governance and expand the scope of intervention of the armed forces.

First concurrent assessment of elemental- and organic-contaminant loads in skin biopsies of whale sharks from Djibouti

The Gulf of Tadjoura (Djibouti) is an important site where the whale shark (Rhincodon typus Smith, 1828) aggregates seasonally. Because of the proximity to the port of Djibouti that is located along one of the busiest shipping areas in the world, whale sharks are potentially exposed to relatively high levels of trace elements and organochlorines. To assess their contamination status, concentrations of 15 trace elements, DDTs and PCBs were concurrently assessed for the first time in skin biopsies of 20 whale sharks. Additionally, 12 zooplankton samples were collected and analyzed for trace elements content. Concentration of As, Cu, Zn and Se were higher than in previous studies on this species. Whale shark samples exceeded the maximum allowable limits for foodstuffs for Cr, Pb Se, Cd and Zn. Results from this study suggests that Cr, Ni and Mo may biomagnify in this species. With regard to PCBs, the predominant congener were Tetra-CB, accounting for 41% of total PCBs and Penta-CB for 23%, while for DDTs, the predominant metabolite was DDE contributing for 51% of total compounds. The maximum residue limit for DDTs and for the ind-PCBs in fish set by U.S. EPA and by the EU regulation, respectively, was exceeded in 62% of whale sharks. Moreover, the p,p′DDE/ΣDDT ratios were higher than the critical value of 0.6, indicating possible recent inputs of technical DDTs in the area. This study suggests some concerns for the contamination status of whale sharks in Djibouti and, since major threats for this species include bycatch and illegal fisheries, highlights some level of risk from the exposure to elemental- and organic-contaminant via shark consumption.