Illegal Trawling Research Articles

Türk Balıkçı Gemileri Tarafından İşlenen Yasa Dışı, Kayıt Dışı, Kural Dışı (YKK) Trol İhlallerinin Değerlendirilmesi

This study analyses a highly damaging and prevalent fishing practice of trawl infringements, which is one of the crucial components of IUU fishing in Turkish waters. The raw data gathered from the Turkish Coast Guard Command (TURCG), covered 2012 – 2014 period. Data covered a total of 1040 trawl infringements, with considerable differences in trawling violations among the seas surrounding Türkiye; the Black Sea, the Sea of Marmara, the Aegean Sea, and the Mediterranean Sea. With respect to trawling infringements, the Sea of Marmara (37%) and Istanbul Strait (15%) were the hot points. The most common infringement type was trawling in a closed area (43%) and when combined with the rate of infringements on trawling during the closed season (10%), these violations accounted for 53% of spatio-temporal infringements. Regarding illegal trawling by vessel type, trawl vessels had a 44% share and non-trawlers had a share of 56%, of which included infringements by other type of fishing vessels (46%) and non-fishing vessels (10%). It was also found that infringement by vessels smaller than 12 meters in length had a share of 46%. These vessels (known as "şebeke" in Turkish), trawl illegally using small types of nets and gears in coastal waters without giving any obvious indication of fishing activity. The results of this study will be useful to policy-makers, practitioners and scientists to successfully combat trawling infringements by providing information on distribution, intensity and methods of trawl violations.

Effect of Artificial Reefs on the Alimentary Strategies of Two Mediterranean Sea Teleosts

In this study, we aimed to investigate the presence of an alteration in the feeding ecology of fish after the deployment of anti-trawling reefs at the Punta Tramontana site (Sardinia, Italy). To achieve this aim, we examined prey in the stomach contents of two target species of fish: Diplodus annularis and Mullus surmuletus. The samples were obtained from fishing activities carried out over one year from June 2017 to October 2018 at two impact sites, selected by the presence of artificial reefs, and two control sites. The results showed that installing these artificial devices increased the food spectrum availability of the target species and induced two different ecological feeding behaviors, probably derived from their different ecologies. D. annularis changed its alimentary strategy from generalist at control sites to specialist at impact sites, focusing its diet on the crustacean Gnathia maxillaris. Mullus surmuletus was not affected by the presence of the barriers, which constitute an additional site where the fish feed during their foraging activities. In conclusion, these anti-trawling reefs, in addition to the purpose for which they are designed (in this case, avoiding illegal trawling), did not produce any negative environmental impact on surrounding marine biota.

Marine habitat mapping to support the use of conservation and anti-trawl structures in Kep Province, Cambodia

Abstract The marine habitats within the Kep Archipelago, Cambodia, support species of conservation importance and commercial value. Despite the area being designated a Marine Fisheries Management Area (equivalent to a Marine Protected Area locally), illegal trawling has continued to damage vulnerable habitats within the region. To augment the protection of the designated area, Conservation and Anti Trawl Structures (CATS) have been deployed locally. These structures can snare the nets of illegal trawlers and provide a hard substratum for coral colonization. A sidescan sonar survey and ground truthing campaign was used to precisely locate the 40 CATS deployed and produce maps of the important benthic habitats in the area. Due to the challenging coastal environment and minimal available infrastructure, this study used small, rechargeable or low-power (12 V), and low-cost habitat mapping equipment to map the approximate extent of several benthic habitats of conservation interest. The area and type of habitat protected by CATS has been estimated by combining the marine habitat map with the precise locations of the deployed CATS. It is hoped that this information will help inform local management decisions, such as optimizing the placement of future CATS.

Initial recovery of demersal fish communities in coastal waters of Hong Kong, South China, following a trawl ban

Fisheries resources in Hong Kong have been overexploited since the 1970s due to intensive bottom trawling and other fishing activities that have depleted stocks and destroyed marine habitat. To rehabilitate depleted fisheries resources, a permanent ban on trawling in Hong Kong territorial waters came into force on December 31, 2012. In order to determine whether the trawl facilitated recovery of fish communities, trawl surveys were conducted at two sites in each of the eastern, southern and western (estuarine) coastal waters of Hong Kong before and three years after the trawl ban. A total of 315 species and 86 families of fishes in nine feeding groups were encountered during the surveys. Mean trophic level of the fish community, abundance and biomass of total fishes and of predatory fishes increased in eastern and western waters after the ban, but no changes or declines in these metrics were observed in southern waters. Although initial recovery in fish community were observed in eastern and western waters, anthropogenic disturbances might hinder the recovery process, including a large-scale reclamation for construction of coastal infrastructures in the west, illegal trawling, and expansion of non-trawling fishing efforts in the southern and eastern waters. Longer term monitoring is needed to evaluate the effects of the trawl ban, and determine whether recovery in the southern waters will continue to be constrained by the anthropogenic disturbances.Graphic abstract

Does a Trawl Ban Benefit Commercially Important Decapoda and Stomatopoda in Hong Kong?

Crustaceans were among the most valuable fishery resources in Hong Kong. However, the unrestricted and intensive use of different fishing gears, especially bottom trawling, has led to the depletion of commercially important crustaceans in Hong Kong since the 1980s. This study investigated whether commercial crustaceans recovered after the implementation of a permanent Hong Kong-wide trawl ban that began on December 31, 2012. Standardized field surveys were conducted using a commercial shrimp trawler at two sites in eastern and western waters of Hong Kong before (2004) and after the trawl ban (2013–2014 and 2015–2016) and two sites in southern waters after the trawl ban. Diversity, mean size, abundance, biomass and level of disturbance of commercial crustaceans from the three periods were investigated. The eastern waters exhibited an increased diversity of crustacean assemblages in Inner Tolo, and a higher abundance and biomass of crabs were detected in Outer Tolo after the trawl ban. Reduced disturbance, higher diversity in crustacean assemblages and greater abundance and biomass of predatory crabs were observed after the trawl ban in the outer estuary of western waters, and increased abundance and biomass of shrimp were detected in the inner estuary of western waters. No temporal or negative changes were detected in the southeast and southern waters of Lamma Island. The various responses of crustacean assemblages in Hong Kong waters revealed the critical role of complex interactions among multiple stresses, such as ongoing reclamation works, illegal trawling activities and increased fishing efforts using other (legal) fishing methods.

Turning the tide on bottom trawling

Trawling is universally recognized as one of the most destructive fishing methods, causing irreversible damage through scraping large tracts of bottom habitats. These habitats then suffer from declines in ecosystem functions and services, and collapses in populations of trawled species. The plethora of studies on the unsustainable impacts of commercial trawling is widely acknowledged by the scientific community, but few findings have been translated to actual policy. High profile attempts to curb deep-sea trawling have failed in the recent past, e.g. proposed moratoriums on deep-sea bottom trawling at the United Nations General Assembly in 2006 and within the European Union in 2013. In light of the global inertia to sanction trawling, countries in the Asia-Pacific are making significant headway. Within one week in November 2014, two giants in marine capture fisheries announced expansions in national trawling regulations. From 2016, Malaysia will extend their trawling ban from 8 nautical miles (nm) to 15 nm from the shore, requiring trawl fishers to convert to alternative fishing gear (http://www.nst.com.my/node/48495). Indonesia effected an immediate moratorium on licences for large fishing trawlers (>30 GT), with plans to end fuel subsidies and renew efforts to tackle illegal fishing (http://www.antaranews.com/en/news/ 96371/indonesian-new-minister-vows-to-crack -down-upon-illegal-fishing). More recently, the moratorium was extended to a national ban on large trawlers starting in September 2015 (http:// www.medanbisnisdaily.com/news/read/2015/02/14/ 146904/kapal-besar-dilarang-pakai-trawl). Although trawling was largely banned throughout Indonesia in 1980 (Bailey, 1997), this ban faced enforcement difficulties and a lack of political will. By the 2000s, trawling was again permitted in certain areas and illegal trawling was rampant (REBYC-II CTI, 2010). Continued trawling at the current rate is untenable, and is presumably the impetus for renewed efforts to regulate this fishery. These measures in Malaysia and Indonesia, the complete ban on trawling in the territorial waters of Hong Kong (2012) and Palau (2006), and the announcement in December 2014 to permanently ban super trawlers in Australian waters (http://www.theguardian.com/environment/2014/ dec/24/supertrawlers-to-be-banned-permanently -from-australian-waters), represent a significant advancement towards fisheries sustainability and marine conservation in the region. Asia-Pacific nations account for half of all global marine capture fishery production, with Indonesia ranking 5th (5.1%) and Malaysia 16th (1.5%) in global

Protecting Coastal Habitats and Enhancing Fisheries Resources Using Big Size Artifi cial Reefs in the East Coast of Peninsular Malaysia

Artifi cial reefs (ARs) program in the east coast of Peninsular Malaysia commenced in 1979 with the objective to promote and establish fi sh sanctuaries, enhance coastal fi sheries resources and deter the encroachment of prohibited inshore areas by trawlers. The program initially started off with the utilization of discarded materials such as tyres and derelict wooden boats. However, in 2006, the Department of Fisheries Malaysia (DoFM) made a major policy change in terms of choice and design of construction material by opting for large and robust reinforced concrete ARs. The newly designed ARs took into consideration the biotic and abiotic factors such as the fi sh behavior, targeted species, physical oceanography and marine engineering cogitations. The ARs were built according to the British Standard 8110. By the end of 2010, a total of 15 newly designed ARs weighing between 5-42 metric tons/ module and measuring between 1.6-3.85m (length, width and height) were produced and nine of them were deployed in the East Coast of Peninsular Malaysia. Those ARs have by now developed into new habitats not only for fi sh, but also for other marine fl ora and fauna. At least 76 commercial and 33 coral fi sh species were recorded near or within the AR structures. The ARs are also functioning effectively as hindrance to illegal trawling. This paper reports on the progress of the research and development (R&D) of the big size ARs program implemented in the East Coast of Peninsular Malaysia within the 2006-2012 period. (Keywords: big size artifi cial reefs, Malaysia)

The Political Economy of Somali Piracy

There are two main arguments, one political and one economic, that can be used to explain the rise of Somali piracy. The first is that Somalia's political vacuum following the 1991 collapse of the government created an enabling environment for illicit activities. The second is that entrepreneurial Somali pirates have created a business model that successfully exploits the incentives driving international maritime trade. The reason the Somali piracy boom did not materialize until 2005 is that local Somalis did not realize the potential of piracy and were not desperate enough until economic conditions deteriorated sufficiently as a result of of illegal trawling and toxic dumping by foreign ships and damage caused by the Indian Ocean Tsunami. The last few years' decline in the number of attacks by Somali pirates is primarily due to the coordinated efforts of navies that police the Gulf of Aden. While these efforts have increased the risk of being caught, and hence the costs of engaging in piracy, they do not address the root causes of piracy in Somalia. Until effective political authority and improved economic opportunities permanently alter the cost-benefit calculations of Somali pirates, the underlying incentives driving Somali piracy will remain unchanged, necessitating extensive and indefinite naval operations.

Has The Sea Changed? Qualitative Analyses on the Views of Fishermen in the east coast zone of Peninsular

Problem statement: Pressure from the uncontrolled human activities had caused damages to our environment. The sea, as one of the environment components has also suffered from these activities. Fishermen, whom depend on the sea for their income and sources of protein, can be one of the groups who are suffering the most. This study intends to discover the perception of this group on the current situation of the sea, their perception on the quantity and the quality of the sea fauna, their perception on the possible factors that contribute to these changes and impacts of these changes on their socio-economic activities. Approach: This was a qualitative study whereby four in-depth interviews were conducted with the fishermen of the east coast zone of Peninsular Malaysia whom their main fishing area was on South China Sea. The data then were transcribed verbatim and analyzed. Results: Data gained had proven that the fishermen agreed that the current situation on the South China Sea was not anymore similar to their early day as a fisherman. The weather nowadays was ifficult to be predicted as there are changes in the trend of sea current, waves and temperature. They also agreed that the quality and quantity of the flora and fauna in their catching areas were lesser compared to the past. There are number of possibilities that can contribute to these changes which were illegal bottom trawling, foreign fishermen intrusion, climate change and fishing pressure. All of these according to them were affecting their socio-economic activities. Conclusion/Recommendation: Based on the data gained, it is recommended that more monitoring programs can be conducted to reduced illegal bottom trawling activities; Program such as Rakan Cop which is introduced by Royal Police of Malaysia can be practiced among the concern agencies and fishermen. A number of programs to increase awareness among the fishermen on the danger of illegal bottom trawling activities, threats of the climate change and the importance for them to save usage of energy (eg: Fuel) can also be conducted. Some effective actions taken by other countries to overcome their fishing pressure might also have the potential to be practiced in Malaysia.

Illegal trawling and induced invasive algal spread as collaborative factors in a Posidonia oceanica meadow degradation

Posidonia oceanica, a key seagrass species of the Mediterranean Sea, shows clear signs of regression throughout the Mediterranean and illegal trawling is recognized as one of the main causes. We examined the condition of a P. oceanica meadow in Alykes Bay (Zakynthos Island, western Greece), a typical Mediterranean littoral area where illegal trawling is common practice, in respect to the total area affected, and in terms of possible ecological substitution. A side scan sonar (SSS) survey of the seafloor provided an image of the condition of the meadow and biological sampling evaluated the ecological status in affected meadow areas. SSS images revealed that trawling has a serious effect on the meadow, with 11% of the vegetated area being abraded, and the affected areas were also found to be fully colonized by the invasive alga Caulerpa racemosa. Moreover, unusually high densities of the polychaete Sabella pavonina were detected in the affected areas among C. racemosa fronds. Recolonization by P. oceanica of the affected meadow areas that have been colonized by C. racemosa seems improbable considering the allelopathic interactions between the species, with the alga displaying phytotoxic properties through caulerpenyne production and deterioration of the sediment quality.

Identifying drivers for fishing pressure. A multidisciplinary study of trawl and sea snail fisheries in Samsun, Black Sea coast of Turkey

This study aims to investigate and model driving forces that lead to increased fishing pressure and an altered state of the environment in the coastal areas near Samsun on the Turkish Black Sea coast. We have applied a modified DPSIR model to structure our investigation and analysis and have investigated the drivers that generate fishing pressure in the Samsun fisheries. The overall health of the ecosystem is declining, and there is a consistent trend of deterioration in the condition of the three major species targeted by the trawl fisheries. Although introduced invasive species have brought significant changes to the Black Sea, it is clear that the state of the environment is significantly and negatively affected by the pressure exerted by fisheries. Fishing pressure has to a certain extent been redirected to pelagic trawling as bottom trawling has become less profitable and a rise in catch capacity has levelled off. This reduction is, however, offset by an increase in illegal trawling and dredging by a very rapidly growing sector of multi-purpose small boats, resulting in a considerable increase in the overall accumulated engine power of fishing boats in Samsun during 2000–2005. Fisheries in Samsun, in particular sea snail fisheries, have constituted a frontier of sorts open to the poorer populations of Samsun during the last 20 years, and, thereby, constitute one of the major drivers for fishing pressure. We identify eight drivers of importance for the period 2000–2005. Although the authorities can impact all or most of those drivers, most of them are beyond the scope of conventional ‘fisheries management’.

<strong>The polychaete community of the Fregene artificial reef (Tyrrhenian Sea, Italy): a 20-year study (1981–2001)</strong>

The artificial reef of Fregene, Italy, was built in 1981 as a multipurpose structure with the intent of protecting the coastal environment from illegal trawling and also improving fishery production. It is located at 10–14 m depth on a sandy-silty seabed in the Tyrrhenian Sea, 5 nmi north of the outlet of the Tevere River (Latium, Italy) and 1.5 nmi offshore the town of Fregene (Latium, Italy). The development of the polychaete community on the reef was studied from May 1981 to December 2001 in order to examine long-term community dynamics and verify to what extent changes in polychaete assemblage could depict the development of the benthic assemblage. At each sampling time, two standard surfaces of 400 cm2 were scraped from the vertical walls of the same block. Temporal changes in the development of the polychaete community were detected by univariate (S, N, ExpH', 1/Simpson, J') and multivariate (CLUSTER, nMDS) analysis of the faunal data. Functional structure of the community was also analyzed. Changes in the community structure were shown by an overall increasing trend in the total number of species and individuals. The 20-year development of the polychaete community was divided into five different phases representing different benthic assemblages on the reef: the first two periods correspond to settlement of pioneer species (1981–82); the third is a phase characterized by Mytilus galloprovincialis dominance and regression (1983–85); the fourth is a phase of mud accumulation between dead balanids, with the presence of laminar bryozoans (1991–92), and the last corresponds to a phase dominated by bryozoan bioconstruction (2001). The increased complexity in the benthic assemblage and substratum on the reef is also shown by an increased differentiation and distribution of polychaete functional groups. Increasing environmental heterogeneity on the reef is the basic factor that affected biodiversity by generating new niches that could be occupied by additional species with different ecology. The similarity of the benthic assemblage observed on the reef in 2001 with natural bioconstructions suggest that after two decades the ecological succession has lead to a settlement at a steady-state of equilibrium with the surrounding environment.

Changes in the composition and structure of a molluscan assemblage due to eelgrass loss in southern Spain (Alboran Sea)

The composition and structure of a molluscan assemblage was studied in a deep subtidal eelgrass bed located in southern Spain before and after the eelgrass decline experienced during 2005 and 2006 due to illegal trawling by fishermen. Sampling was undertaken in summer 2004 (with eelgrass) and summer 2007 (without eelgrass) in an extensive eelgrass bed located in Cañuelo Bay (12–14 m depth) and in the same area once the eelgrass bed disappeared. Eelgrass was completely absent in those samples of summer 2007 and an increase of the organic content and mud was registered in the sediment between 2004 and 2007. The density and the richness of molluscan species decreased significantly in summer 2007, especially for epifaunal gastropods associated with the leaf and sediment stratum. Some species disappeared completely in summer 2007 such as the dominant periphyton grazersJujubinus striatusandRissoaspp., the egg feederMitrella minorand the seagrass feederSmaragdia viridisas well as the infaunal bivalveSolemya togata. Other species increased their densities such as the carnivoresCylichna crosseiorC. cylindraceaas well as the bivalveNucula nitidosa. Some dominant infaunal species, such asChamelea gallina, Spisula subtruncataorTellina fabuladid not significantly change their densities. The composition and structure of the assemblages in summer 2004 and summer 2007 was significantly different according to the Bray–Curtis similarity index using qualitative and quantitative data and considering the entire assemblage (epifaunal and infaunal species) or only the infaunal species. The registered changes in the molluscan assemblage may have produced cascade effects in higher trophic levels because molluscs generally represent an important food source for some decapods and fish. Urgent conservation measures are needed for protecting the remaining fragmented eelgrass beds of southern Spain from further illegal fisheries activities and other types of human impacts (e.g. sand extraction and coastal infrastructures), because they support the most diverse faunistic communities for eelgrass beds in Europe due to their bathymetry and geographical location.

A comparison of demersal communities in an area closed to trawling with those in adjacent areas open to trawling: A study in the Great Barrier Reef Marine Park, Australia

The faunal composition of an extensive area (10,000 km 2) closed to trawling in the Great Barrier Reef Marine Park, Australia was compared with that in two adjacent areas open to fishing. Sampling was undertaken over 2 years using a dredge and a prawn trawl. For analysis, we split the study area into a northern and a southern section, and compared adjacent pairs of zones open and closed to trawling, after adjusting for a strong cross-shelf longitudinal gradient using sediment and depth data. The median coefficient of variation for the ratio of biomass in adjacent pairs of open and closed zones was around 15% for both sampling devices. However, the difference between open and closed pairs of zones was not consistent either within species or across species. Instead, these differences were consistent with the moderate difference between the northern and southern halves of the study area. Three reasons are proposed for the lack of measurable difference that could be attributed to trawling. Firstly, the level of trawling in the open area has been relatively low and, because of targeting of concentrations of prawns, it has been unevenly distributed leaving extensive areas unfished. This suggests that trawling has not had a major impact on the demersal fauna of the region. Secondly, illegal trawling in the closed area could also have confounded the results of the study, though logbook records suggest the level of this fishing was low and its extent restricted. Thirdly, the complexity of the region as shown by a north–south difference in fauna of the closed area might obscure any effects of fishing. We also suggest that areas with high habitat diversity ranging from complex structured seabed to relatively clear open muddy or sandy plains do not lend themselves to open versus closed studies because of the differential effect of fishing on the various habitats.

Recovery of deep Posidonia oceanica meadows degraded by trawling

The recovery capacity of meadows of the Mediterranean seagrass Posidonia oceanica (L.) Delile in an area affected by illegal trawling were assessed after protection by anti-trawling reefs. The differences in vegetative growth between two impacted and two undisturbed localities were tested using growth, shoot balance, aborted branches, and leaf and rhizome production of both plagiotropic and orthotropic rhizomes. The organic matter in sediments, silt clay fraction and light intensity incident on the bottom were also measured in order to evaluate the physical conditions. Environmental and plant variables were measured in three sites placed inside each locality. The vegetative growth was positive in both impacted and control meadows but growth rates were lower in impacted than in control meadows. Average growth, production and shoot balance were greater in plagiotropic rhizomes from undisturbed localities (40.7±1.75 vs. 28.4±1.34 mm/year, 1133±0.06 vs. 708±0.04 mg DW/shoot/year, 1.36±0.08 vs. 0.96±0.06 shoots/year, respectively). Significantly greater values were also found in undisturbed localities for orthotropic rhizomes in terms of shoot balance and rhizome production (0.07±0.01 vs. 0.01±0.003 shoots/shoot/year and 155 vs. 124 mg DW/shoot/year, respectively). Of the physical parameters measured, only light intensity differed significantly between impacted and undisturbed localities. This parameter was 15.5% to 67.6% lower in impacted localities than in undisturbed localities, and this is the factor that causes the retardation of vegetative growth. The results show that recovery of P. oceanica meadows is possible after eliminating the cause of the impact. However, the very low rates of vegetative growth may prolong the time to total recuperation to almost 100 years. Therefore, effective management of P. oceanica meadows should aim to prevent meadow loss.

A marine biological underwater depuration system (MUDS) to process waste waters

An underwater device, able to favour the sea auto-cleaning capacities, is herein described. This system, called MUDS (marine underwater depuration system), consists of a percolating filter and is placed at sea over an urban sewage outflow of a submarine pipeline. Due to the density difference, the water effluent flows through the percolating filter: this favours the mixing and a prompt recycling of organic matter, activating a marine trophic web. Rich microbenthic communities develop on the MUDS, both interstitially, inside the filter, and on the structure. The community mainly consists of ciliates, nematods, harpacticoid copepods and polychaetes, all of which being organisms that increase the depuration efficiency by consumption of organic matter. This structure acts also as a deterrent for the illegal trawling activity in the area, and attracts large numbers of several finfish species, thus working as a fish aggregating device (FAD). It is possible to utilise this underwater device for medium littoral towns with strong differences in effluent discharges during the year, where the use of land-built effluent treatment plants is too expensive.

Artificial reefs in Turkey

Artificial reef deployment in Turkish waters and results from monitoring studies are described. The first known project with 10 old trolley-bus bodies was in 1989, and presently there are six ongoing projects in which reinforced concrete modules of five different designs are being used. The main aims are: (1) to protect fish-spawning and nursery areas from illegal trawling; (2) to create new sites for recreational fishing and diving; (3) to protect small-scale artisanal fisheries from damage caused by illegal trawling; and (4) to conduct scientific experiments. Most projects are supported by local municipalities and fishery cooperations. Following a meeting of the experts and foundations involved, a “Project Guide for Artificial Reef Applications” has been produced recently which formulates the requirements that must be met by all new artificial reef projects along Turkish coasts. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.

Kuwait's Post Gulf-War Shrimp Fishery and Stock Status from 1991/92 Through 1995/96

Comparisons of catch and effort data from 5 seasons by dhow and industrial fleets showed annual landings to vary around the long-term average of 2100 tons. No direct long-term effects of the Gulf War were identified, but indirect effects have caused substantial changes in Kuwait's shrimp fishery. The effort expenditure in 1993/94 reached an all-time high of 17,615 industrial boat-days, more than the sum total of the last three seasons' effort (16,400 industrial boat-days) prior to the War. With a fixed number of industrial vessels, dhow boats have been responsible for the increased effort. Low total landings and catch rates since the Gulf War reflect low stock abundance and high effort. Penaeus semisulcatus, Kuwait's most important shrimp species, dominated shrimp landings for all 5 seasons, but its importance to the total landings declined to a historical low during the 1995/96 season accounting for only 50% of the dhow landings and presumably the industrial boat landings. The primary factors for this decrease appear to be increasing fishing pressure during the shrimp season as well as illegal trawling during closed season and altered discharge rates of the Shatt Al-Arab. Growth performance indices for P. semisulcatus, Metapenaeus affinis, and Parapenaeopsis stylifera during the 1995/96 season compared closely with those of the 1988/89, 1989/90, 1991/92, and 1992/93 seasons when shrimp populations experienced high densities, decreased water temperatures resulting from the oil-fire smoke, or overfishing and other environmental conditions. Fishing mortality of all species for 1995/96 exceeded the natural mortality, a clear indication of overexploitation. Results of bio-economic analysis show that 4000 industrial boat-days would maximize economic returns, while 8000 industrial boat-days would maximize the sustainable yield. Both the values are higher than estimates prior to the War. With both reversible (overfishing) and irreversible (altered Shatt Al-Arab discharge influences operating), prudent management of trawling effort will become increasingly important if Kuwait is to maintain its position as a shrimp exporter.

Fishing effort in the far northern section cross shelf closure area of the Great Barrier Reef Marine Park: the effectiveness of area-closures

A meta-analysis of available information on the intensity and distribution of illegal prawn (shrimp) trawling is reported from a 10 000 square kilometre cross shelf area-closure in the tropical Great Barrier Reef Marine Park. Northern and southern borders of the closure were subject to edge effects as trawlers over-ran their hauls, legally started in the adjacent open zones. There was considerable illegal trawling inshore along a north–south navigation channel running through the area-closure. The middle and outer regions of the closure were originally denied to trawlers because of «rough ground» but this is probably no longer the case since the general adoption of advanced navigation aids (GPS). The area least likely to have been heavily trawled is the central mid-shelf section of the closure in a region of uncharted shoal reefs. Many trawlers fish in the accessible sections of the closure on a casual or incidental basis but approximately 47 boats do so on a consistent basis. An estimated yearly total of 3260 days illegal trawling occurs, giving an approximate estimate of 69 days illegal trawling per regular offender. The implications of this level of non-compliance are the probable invalidation of the original objectives of conservation and maintenance of a pristine reference area in all but the central section of the closure. Management of marine world heritage areas requires the acknowledgement that the harvesting of fish, prawns and other living resources may be an established use of the Marine Park but it also requires a combination of education plus the adoption of effective monitoring technology, such as satellite vessel monitoring systems, to stop or at least reduce unauthorized fishing.