Showing papers on "Fishing published in 2003"

Benefits beyond boundaries: the fishery effects of marine reserves

Abstract: Marine reserves are areas of the sea where fishing is not allowed. They provide refuges where populations of exploited species can recover and habitats modified by fishing can regenerate. In some places, closed areas have been used for fisheries management for centuries [1] and, until recently, natural refugia also existed, inaccessible through depth, distance or adverse conditions. Developments in technology have left few areas of fishing interest beyond our reach. Recently, the idea of marine reserves as fisheries management tools has re-emerged with developing interest in ecosystembased management, and observations of incidental fisheries benefits from reserves established for conservation. In light of new evidence, we argue that, by integrating large-scale networks of marine reserves into fishery management, we could reverse global fishery declines and provide urgently needed protection for

The National Recreational and Indigenous Fishing Survey

Abstract: A national survey of recreational and indigenous fishing was conducted in Australia during 2000-01 The survey was a joint initiative of Commonwealth and State governments Grants from the Natural Heritage Trust, Fisheries Research and Development Corporation, State and Territory fisheries agencies supported the project The national survey was a multifaceted project designed to provide a range of information about non-commercial fishing in Australia The project comprised three independent surveys, the National Recreational Fishing Survey, the Indigenous Fishing Survey of Northern Australia and the Overseas Visitor Fishing Survey Different methodologies and analytical approaches were required for each of these surveys, reflecting their varying characteristics

State of the World’s Fisheries

Abstract: ▪ Abstract The total world catch from marine and freshwater wild stocks has peaked and may be slightly declining. There appear to be few significant resources to be developed, and the majority of the world's fish stocks are intensively exploited. Many marine ecosystems have been profoundly changed by fishing and other human activities. Although most of the world's major fisheries continue to produce substantial sustainable yield, a number have been severely overfished, and many more stocks appear to be heading toward depletion. The world's fisheries continue to be heavily subsidized, which encourages overfishing and provides society with a small fraction of the potential economic benefits. In most of the world's fisheries there is a “race for fish” in which boats compete to catch the fish before a quota is achieved or the fish are caught by someone else. The race for fish leads to economic inefficiency, poor quality product, and pressure to extract every fish for short-term gain. A number of countries hav...

Effects of habitat, wave exposure, and marine protected area status on coral reef fish assemblages in the Hawaiian archipelago

Abstract: The relationships between fish assemblages, their associated habitat, and degree of protection from fishing were evaluated over a broad spatial scale throughout the main Hawaiian islands. Most fish assemblage characteristics showed positive responses to protection whether it was physical (e.g. habitat complexity), biological (e.g. coral cover growth forms), or human-induced (e.g. marine reserves). Fish biomass was lowest in areas of direct wave exposure and highest in areas partially sheltered from swells. Higher values for fish species richness, number of individuals, biomass, and diversity were observed in locations with higher substrate complexity. Areas completely protected from fishing had distinct fish assemblages with higher standing stock and diversity than areas where fishing was permitted or areas that were partially protected from fishing. Locations influenced by customary stewardship harbored fish biomass that was equal to or greater than that of no-take protected areas. Marine protected areas in the main Hawaiian islands with high habitat complexity, moderate wave disturbance, a high percentage of branching and/or lobate coral coupled with legal protection from fishing pressure had higher values for most fish assemblage characteristics.

Protection of exploited fish in temperate regions: high density and biomass of snapper Pagrus auratus (Sparidae) in northern New Zealand marine reserves

Abstract: Summary 1. The use of marine reserves as tools either for conservation or fisheries management requires rigorous empirical evidence for the recovery of exploited species within them. 2. The relative density and size structure of snapper Pagrus auratus (Sparidae), an intensively exploited reef fish species, were measured, using baited underwater video, inside and outside three northern New Zealand marine reserves (Leigh Marine Reserve, Hahei Marine Reserve and Tawharanui Marine Park) every 6 months from October 1997 to April 1999. 3. Log-linear modelling showed that relative total density and egg production of snapper were higher in all three reserves than in fished areas. Snapper that were larger than the minimum legal size were estimated to be 14 times denser in protected areas than in fished areas, and the relative egg production was estimated to be 18 times higher. In the Leigh reserve, legal-size snapper were larger than legal-size snapper in fished areas. 4. At the Leigh reserve, snapper density consistently peaked at the reserve centre and declined towards either boundary, which suggests that snapper became increasingly vulnerable to fishing towards the reserve boundaries. 5. Inshore snapper density was significantly higher in autumn than in spring, supporting previous suggestions that snapper make regular onshore‐offshore seasonal migrations that might be related to spawning. We suggest that the observed recovery of snapper populations within reserves is attributable to immigration of individuals from fished areas that take up residency within reserves, rather than juvenile recruitment. 6. Synthesis and applications. This study demonstrates the effectiveness of marine reserves for protecting an exploited species previously thought to be too mobile to respond to area-based protection. Although it is difficult to envisage significant enhancement of fished areas via adult emigration, it is likely that the reserves contribute significantly to local gamete production. In addition, the protection of fish populations within reserves might slow reductions in genetic diversity caused by size-selective mortality brought about by exploitation.

Impact on indigenous species biodiversity caused by the globalisation of alien recreational freshwater fisheries

Abstract: One of the most insidious threats to fish conservation around the world is deliberate or accidental introduction of fish species. The impact of alien invasive sport fish is for the most part unpredictable in time and space, with the introduction of relatively few species having resulted in many extirpations of indigenous fish species worldwide. More nations need to quantify biodiversity loss caused by alien sport fishes. The spread of alien invasive fishes does not respect political boundaries. Therefore total global costs to aquatic biodiversity and ecosystem functioning resulting from these introductions need to be assessed. The global invasive species database of the Global Invasive Species Programme, highlights eight fish species among the one hundred ‘World’s Worst Invasive Alien Species’. Three of these fish species (two trout and one bass species) were introduced solely for sport. Historically the social value of recreational fishing was usually more important than conserving biodiversity. Globalisation of alien fish species for sport is best illustrated by rainbow trout — now in 82 countries, and still spreading, along with the associated expensive angling gear, magazines and accommodation infrastructure. Such sport species have become part of the global consumer society. The nature and extent of the globalisation phenomenon is addressed with regard to how introduction of alien fish for recreational angling has impacted on biodiversity; trophic cascades at a local level and the unassessed total cumulative global trophic cascades; and some of the motives that underlie promotion of this sport within the complexity of globalisation as we know it today. Alien invasive recreational fish species are now recognised as a global environmental degradation problem resulting in loss of biodiversity and therefore require a global solution. Parallel trends such as globalisation of environmental education and the internet must be encouraged to counteract the damage caused and reverse the trend. This globally concerted campaign requires utilizing environmental education forums aimed at the angling community, general public and policy makers; networking with existing alien invasive groups; legislation; better understanding of processes; development of environmental economic evaluation tools; international bio-invasion control; wider use of the precautionary approach and utilization of the present globalisation of ecological thought.

Capturing the Commons: Devising Institutions to Manage the Maine Lobster Industry

Abstract: James M. Acheson, author of Lobster Gangs of Maine (the bestselling work on the culture and economics of lobster fishing), here turns his attention to the management of the lobster industry. In this illuminating book, he shows that resource degradation is not inevitable. Indeed, the Maine lobster fishery is one of the most successful fisheries in the world. Catches have been stable since World War II, and record highs have been achieved since the 1980s. According to Acheson, these high catches are due partly to the institutions controlling lobster fishing practices.

Shifting gears: assessing collateral impacts of fishing methods in US waters

Abstract: Problems with fisheries are usually associated with overfishing; in other words, with the deployment of “too many” fishing gears. However, overfishing is not the only problem. Collateral impacts of fishing methods on incidental take (bycatch) and on habitats are also cause for concern. Assessing collateral impacts, through integrating the knowledge of a wide range of fisheries stakeholders, is an important element of ecosystem management, especially when consensual results are obtained. This can be demonstrated using the “damage schedule approach” to elicit judgments from fishers, scientists, and managers on the severity of fishing gear impacts on marine ecosystems. The consistent ranking of fishing gears obtained from various respondents can serve as a basis for formulating fisheries policies that will minimize ecosystem impacts. Such policies include a shift to less damaging gears and establishing closed areas to limit collateral impacts.

Impact of a large-scale area closure on patterns of fishing disturbance and the consequences for benthic communities

Abstract: Seasonal area closures of fisheries are primarily used to reduce fishing mortality on target species. In the absence of effort controls, fishing vessels displaced from a closed area will impact fish populations and the environment elsewhere. Based on the observed response of the North Sea beam trawl fleet to the closure of the ‘‘cod box’’ and an existing size-based model of the impacts of beam trawling, we predict the effects of seasonal area closures on benthic communities in the central North Sea. We suggest that repeated seasonal area closures would lead to a slightly more homogeneous distribution of annual trawling activity, although the distribution would remain patchy rather than random. The increased homogeneity, coupled with the displacement of trawling activity to previously unfished areas, is predicted to have slightly greater cumulative impacts on total benthic invertebrate production and lead to localized reductions in benthic biomass for several years. To ensure the effective integration of fisheries and environmental management, the wider consequences of fishery management actions should be considered a priori. Thus, when seasonal closures increase the homogeneity of overall disturbance or lead to the redistribution of trawling activity to environmentally sensitive or previously unfished areas, then effort reductions or permanent area closures should be considered as a management option. The latter would lead to a single but permanent redistribution of fishing disturbance, with lower cumulative impacts on benthic communities in the long run. 2003 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights

In a Perfect Ocean: The State Of Fisheries And Ecosystems In The North Atlantic Ocean

Abstract: In a Perfect Ocean: The State of Fisheries and Ecosystems in the North Atlantic Ocean presents the first empirical assessment of the status of ecosystems in the North Atlantic. The authors analyze 14 large marine ecosystems, providing an indisputable picture of an ocean whose food webs have been dramatically altered, resulting in a phenomenon described by the authors as "fishing down the food web." The book: - provides a snapshot of the past health of the North Atlantic and compares it to its present status - presents a rigorous scientific assessment based on the key criteria of fisheries catches, biomass, and trophic level - considers the factors that have led to the current situation - describes the policy options available for halting the decline - offers recommendations for restoring the North Atlantic An original and powerful series of maps and charts illustrate where the effects of overfishing are the most pronounced and highlight interactions among the various factors contributing to the overall decline of the North Atlantic's ecosystems. This is the first in a series of assessments by the world's leading marine scientists, entitled In a Perfect Ocean. The State of Fisheries and Ecosystems in the North Atlantic Ocean is a landmark study and will be essential reading for policymakers at all levels concerned with fisheries management, as well for scientists, researchers, and activists concerned with marine issues or fishing and the fisheries industry.

Life Cycle Assessment of Frozen Cod Fillets Including Fishery-Specific Environmental Impacts

Abstract: The purpose of the present study was to perform an environmental assessment for the entire life cycle of a seafood product and to include fishery-specific types of environmental impact in inventory and assessment. Environmental data for a frozen block of cod fillets was collected and used for a Life Cycle Assessment, including the fishery-specific environmental aspects seafloor use and biological extraction of target, by-catch and discard species. The fishery takes place in the Baltic Sea where cod is mainly fished by benthic trawls and gillnets. The functional unit was a consumer package of frozen cod fillets (400 g) reaching the household. Data was gathered from fishermen, fishery statistics, databases, companies and literature. Fishery-specific issues like the impact on stocks of the target and by-catch species, seafloor impact and discarding were quantified in relation to the functional unit and qualitative impact assessment of these aspects was included. Findings include the fact that all environmental impact categories assessed (Global Warming Potential, Eutrophication Potential, Acidification Potential, Photochemical Ozone Creation Potential and Aquatic Ecotoxiciy) are dominated by the fishery. Around 700 m2 of seafloor are swept by trawls and around 50 g of under-sized cod and other marine species are discarded per functional unit. The phases contributing most to total environmental impact following fishery were transports and preparation in the household. The process industry and municipal sewage treatment cause considerable amounts of eutrophying emissions. Conclusions are that there are considerable options for improvement of the environmental performance of the seafood production chain. In the fishery, the most important environmental measure is to fish sustainably managed stocks. Speed optimisation, increased use of less energy-intensive fishing gear and improved engine and fuel technology are technical measures that would considerably decrease resource use and environmental impact caused by fishery. Due to the importance of fishery for the overall results, the most important environmental improvement option after landing is to maintain high quality and minimise product losses. The need for good baseline data concerning resource use and marine environmental impact of fisheries in order to perform environmental assessment of seafood products was demonstrated. LCA was shown to be a valuable tool for such assessments, which in the future could be used to improve the environmental performance of the seafood production chain or in the development of criteria of eco-label-ling of seafood products originating in capture fisheries.

Status of Exploited Marine Fishery Resources of India

Abstract: The marine fisheries sector in India has witnessed a phenomenal growth during the last five decades both quantitatively and qualitatively. The subsistence fisheries during the early 50’s produced about 0.5 million tonnes annually. Currently, the total production is about 2.7 million tonnes. This increase is the result of improvements in the harvesting methods, increase in the fishing effort and extension of fishing into relatively deeper regions. The increased effort over time and space is the consequence of ever-increasing demand for marine food both from external and internal markets. This phenomenal growth also brought in imbalances in the exploitation across the regions and among the resources. Besides, with production levels for most of the commercially important resources showing signs of approaching saturation levels, inter sectoral conflicts increased due to competition to exploit the common resource. Fleet size and operations underwent quantitative and qualitative change. Traditional boats are being increasingly motorised and the mechanised sector operating with trawlers and gillnetters are resorting to multi-day fishing, thus contributing to increased fishing pressure. The situation thus calls for an appraisal of the status of the resources on a regional and all India basis, taking into consideration the scientific database developed over a period of about half a century to enable formulate suitable strategies of exploitation and management.

Estimating enhancement of fish production by offshore artificial reefs: uncertainty exhibited by divergent scenarios

Abstract: Whether artificial reefs installed in estuarine/marine waters function to produce more fish (enhancement) or simply to attract existing fish (attraction) is still under debate. Despite little resolution over this issue, artificial reefs are often considered for use as compensatory mitigation for damaged marine resources. We estimate the quantitative enhancement of fish production under 4 plausible scenarios: attraction, enhancement, enhancement with fishing, and attraction with fishing. Our intent is not to resolve the attraction-enhancement debate, but to quantify the uncertainty associ- ated with using artificial reefs as compensatory mitigation. Pertinent parameters for production calcu- lations (fish density by size class, length-frequency distributions, diets, behaviors, age-specific growth and mortality rates) were obtained from syntheses of findings from artificial reef studies conducted in coastal waters of the southeastern USA and from species life-history profiles. Year-round reef inhabitants were separated into 2 groups: those whose recruitment appears to be limited by available reef habitat (only 2 taxa) and those not augmented in recruitment but potentially enhanced in realized production by provision of refuges and reef-associated prey (15 taxa). Estimates of enhanced produc- tion in this latter group were discounted by an index of reef exclusivity in diet to give production credit in proportion to consumption of reef-associated prey. Estimates of annual production enhancement per 10 m 2 of artificial reef ranged from 0 kg under the attraction scenario to 6.45 kg wet weight under the assumption of enhancement plus protection from fishing. Application of fishing reduced the enhance- ment estimate by 32% to 4.44 kg 10 m -2 yr -1 . A 4th scenario of attraction with fishing may yield a net decline in production of a similar magnitude. In contrast to many natural structural habitats (seagrass meadows, oyster reefs, salt marshes, mangroves) that have dramatically decreased over past decades and are clearly important nursery grounds, evidence is weak that habitat provided by artificial reefs on the shallow continental shelf of the southeastern USA is currently limiting to fish production. Until con- vincing empirical evidence appears, high scientific uncertainty limits confidence in using artificial reefs as compensatory mitigation. Furthermore, even if augmented production were achieved, managing fishing impacts would be critical to achieving the expected production benefit.

Active Management of Walleye Fisheries in Alberta: Dilemmas of Managing Recovering Fisheries

Abstract: Managers of the recreational fishery for walleyes Sander vitreus (formerly Stizostedion vitreum) in Alberta, Canada, face an unusual combination of very low productivity (related to the northern climate) and high fishing pressure. Passive management of the large recreational fishery and active management of the smaller commercial fishery failed to prevent declines and collapses of walleye stocks. During the 1990s, extensive consultations with the public resulted in the development of an active recreational fishery management system using set points to classify stocks. Catch and release and large, highly restrictive length limits were used to regulate the harvest. These restrictions on the recreational harvest resulted in a dramatic increase in the catch rates of growth-overfished stocks. Paradoxically, this recovery has created dilemmas and controversies in both the recreational and commercial fisheries. Anglers are now dissatisfied with the low harvest rates and absence of large fish attending t...

A Broad‐Scale Approach to Management of Ontario's Recreational Fisheries

Abstract: Sustainable exploitation of Ontario's aquatic resources calls for a new management approach. This vast resource includes more than 250,000 lakes and offers angling opportunities for many popular species (e.g., walleye Sander vitreus (formerly Stizostedion vitreum), lake trout Salvelinus namaycush, brook trout S. fontinalis, northern pike Esox lucius, smallmouth bass Micropterus dolomieu, largemouth bass M. salmoides, and muskellunge E. masquinongy). In pioneer days, the “apparently inexhaustible abundance of resources” fostered an open-access policy promoting the recreational use of these resources for the benefit of the economy. After World War II, there was a rapid increase in angling effort and by the 1970s many lakes were being overexploited. Clearly, an unrestricted, open-access policy was no longer appropriate. The result has been a rapid proliferation of fishing regulations as exceptions to divisionwide regulations that were created to protect lakes where problems were detected. The growin...

Current issues with fish and fisheries: editor's overview and introduction

Abstract: Summary. 1. By any measure, fishes are among the world's most important natural resources. Annual exploitation from wild populations exceeds 90 million tonnes, and fish supply over 15% of global protein needs as part of total annual trade exceeding $US 55 billion. Additionally, with over 25 000 known species, the biodiversity and ecological roles of fishes are being increasingly recognised in aquatic conservation, ecosystem management, restoration and aquatic environmental regulation. 2. At the same time, substantial management problems now affect the production, exploitable stocks, global diversity, trophic structure, habitat quality and local composition of fish communities. 3. In marine systems, key issues include the direct effects of exploitation on fish, habitats and other organisms, while habitat or water quality problems arise also from the atmospheric, terrestrial and coastal environments to which marine systems are linked. In freshwaters, flow regulation and obstruction by dams, fragmentation, catchment management, pollution, habitat alterations, exotic fish introductions and nursery-reared fish are widespread issues. 4. Management responses to the problems of fish and fisheries include aquatic reserves in both marine and freshwater habitats, and their effectiveness is now being evaluated. Policies on marine exploitation increasingly emphasise fishes as integral components of aquatic ecosystems rather than individually exploitable stocks, but the rationalisation of fishing pressures presents many challenges. In Europe, North America and elsewhere, policies on freshwaters encourage habitat protection, integrated watershed management and restoration, but pressures on water resources will cause continued change. All these management approaches require development and evaluation, and will benefit from a perspective of ecological understanding with ecologists fully involved. 5. Synthesis and applications. Although making a small contribution to the Journal of Applied Ecology in the past, leading work on aquatic problems and fish-related themes appear increasingly in this and other mainstream ecology journals. As this special profile of five papers shows, significant contributions arise on diverse issues that here include the benefit of aquatic reserves, river restoration for fish, the accumulation of contaminants, interactions with predators, and the fitness of salmonids from nurseries. This overview outlines the current context in which papers on the applied ecology of fish and fisheries are emerging, and it identifies scope for further contributions.

Assessment of Alternative Harvest Regulations for Sustaining Recreational Fisheries: Model Development and Application to Bull Trout

Abstract: Regulations designed to protect recreational fisheries from overexploitation can fail. Regulations such as size and bag limits restrict harvest by individual anglers but not angler effort and therefore not total harvest. Even when individual harvest limits are set to zero (i.e., catch and release), a combination of hooking mortality and noncompliance may lead to fishing mortality rates that are not sustainable if angling effort is sufficiently high. These assertions were tested and quantified by using simulation experiments on a size- and age-structured model developed for a fishery on an adfluvial bull trout population. The functions and rates describing the biology and fishery were derived from a variety of sources, including published and unpublished information on bull trout and, where such sources were unavailable, from other salmonid species. The model predicts that a 40-cm minimum size limit for harvest would maintain viable populations at an annual effort up to 4 angler-hours · ha−1 · yea...

Development of wild Atlantic salmon stocks in the rivers of the northern Baltic Sea in response to management measures

Abstract: Since 1980, the abundance of wild Atlantic salmon has been monitored by means of catch records, adult counts, electrofishing and smolt trapping in six rivers flowing into the northern Baltic Sea. River abundance (spawners, parr and smolts) was compared with implemented large-scale and river-specific management measures and with natural factors potentially affecting abundance. Since the 1980s, the wild stocks have recovered in a synchronous cyclical pattern. The recovery occurred mainly in two jumps, first a sudden increase dating back to around 1990 and a second sharp rise in the late 1990s. River abundance of young salmon commonly rose about 10-fold and approached the previously estimated production capacity in some of the rivers. This positive development may be explained by a decline in fishing pressure together with covarying natural factors influencing survival and growth. The offshore fishery started to decline at the time of the first increase, while the reduction in the total allowable catches together with seasonal restrictions on the coastal fishery strengthened the second increase. Improved natural conditions seem to have increased both survival and escapement during the first rise. Spawners producing the second rise were the offspring of the spawners of the first rise. The outbreak of the M74 mortality syndrome among alevins reduced the abundance of several year-classes that hatched during the first half of the 1990s. In most rivers, the fraction of older and female fish in the spawning run has increased over the period, thereby increasing the reproductive capacity of the populations. No distinct effects of variations in river-specific management regimes were observed. Instead, the results emphasize the role of fisheries management in the open sea as well as in coastal waters, and also of non-human factors in controlling overall abundance of wild salmon in northern Baltic rivers.

A model for fishery resource with reserve area

Abstract: In this paper, we propose and analyse a mathematical model to study the dynamics of a fishery resource system in an aquatic environment that consists of two zones: a free fishing zone and a reserve zone where fishing is strictly prohibited. Biological and bionomic equilibria of the system are obtained, and criteria for local stability, instability and global stability of the system are derived. It is shown that even if fishery is exploited continuously in the unreserved zone, fish populations can be maintained at an appropriate equilibrium level in the habitat. An optimal harvesting policy is also discussed using the Pantryagin's Maximum Principle.

Mangrove shoreline fishes of Biscayne Bay, Florida

Abstract: Biscayne Bay is a shallow subtropical lagoon on Florida's southeastern coast that is bordered to the west by the mainland and to the east by barrier islands and keys. Fish assemblages inhabiting two types of mangrove-lined shoreline that encompass the Bay were examined using a visual 'belt-transect' census method over four consecutive seasons. Several significant differences were evident between shoreline habitats in terms of fish species composition, taxonomic richness and taxon-specific densities; seasonal changes and fish size-structure differences were few. The mangrove shorelines along the mainland (ML) consistently harbored less fish taxa than those on the leeward side of the islands and keys (LK), but harbored higher densities of several euryhaline forms (i.e., killifishes and livebearers). Densities of fishes that are typically associated with coral reef habitats (i.e., snappers and grunts) tended to be higher within LK vs ML mangrove shorelines, but there were exceptions (e.g., great barracuda, Sphyraena barracuda). For five fish species, length-frequency distributions were compared between the Bay's mangrove shorelines and nearby coral reef habitats. These data comparisons lent partial support to an ontogenetic 'mangrove-to-reef' migration model for only two of the five species examined. Results suggest that these shoreline habitats play varying ontogenetic and trophic roles, depending on location, season and fish species Biscayne Bay's mangrove shoreline fish assemblages appear to reflect: (1) proximity of the mangroves that they occupy to offshore reef habitats; (2) salinity regime along the shoreline; and (3) water depths within the mangrove forest interior. The fish assemblage information collected here may serve as a 'baseline' in future assessments of fishing impacts or the effects of other anthropogenic changes to Biscayne Bay and its watershed.

Use of Pop-up Satellite Archival Tags to Demonstrate Survival of Blue Marlin (Makaira nigricans) Released from Pelagic Longline Gear

Abstract: Blue marlin (Makaira nigricans) sup(MSY) and that current harvests are port commercial and recreational more than twice the replacement yield, fisheries throughout the tropical and further contributing to the decline of subtropical waters of the Atlantic the stock (ICCAT, 2001). A reduction in Ocean. The species is taken in directed fishing mortality of approximately 60% recreational and artisanal fisheries is needed simply to halt the decline in in several areas and constitutes an stock abundance (Goodyear, 2000). incidental catch of the widespread One means of reducing fishing mor­ commercial pelagic longline fishery. tality on blue marlin, without severely Although blue marlin comprise only a impacting catches of target species of small fraction of the catch of the pelathe pelagic longline fishery, is to release gic longline fishery that targets tunas those blue marlin that are alive at the and swordfish, this fishery accounts time longline gear is retrieved (hauled for the majority of fishing mortality back). Jackson and Farber (1998) reon Atlantic blue marlin (ICCAT, 1997; ported that 48% of blue marlin caught 2001). in the Venezuelan longline fishery are Atlantic blue marlin were last asalive at the time of haulback. Data from sessed in 2000 by the Standing Committhe U.S. observer program between tee for Research and Statistics (SCRS) 1992 and 1996 indicate that 66% of of the International Commission for the blue marlin were released alive from Conservation of Atlantic Tunas (ICthe domestic longline fishery (Lee and CAT). The assessment indicated that Brown, 1998) and U.S. National Marine the total biomass of Atlantic blue marFisheries Service (NMFS) data and lin is only about 40% of that necessary mandatory pelagic longline logbook to produce maximum sustainable yield submissions between 1987 and 1991 indicate that 59.8% of blue marlin are released alive from commercial pelagic longline gear (Cramer, 1998). ICCAT has been encouraging the release of live blue marlin for several years, and in 2000 the Commission mandated that all live blue marlin and white marlin be released from com­ mercial longline and purse seine ves­ sels. However, for such a management measure to significantly reduce fishing mortality, released animals must have a reasonably high postrelease survival rate. Little information exists about postrelease survival of blue marlin, espe­ cially of animals taken on pelagic longline gear. In general, recovery rates of billfish tagged with conventional (streamer) tags have been quite low (<2%; Jones and Prince, 1998; Ortiz et al., 1998). This observation is consis­ tent with high postrelease mortality, although low recovery rates could also result from tag shedding and a lack of reporting recovered tags (Bayley and Prince, 1994; Jones and Prince, 1998). Results of acoustic tracking studies of blue marlin captured on recreational gear suggest that postrelease survival over periods of a few hours to a few days is relatively high, although mortalities have been noted (reviewed in Pepperell and Davis, 1999). More recently, popup satellite archival tags (PSATs) have been used to study postrelease survival of blue marlin taken in a recreational fishery. Graves et al. (2002) attached nine PSATs to blue marlin caught on recreational gear off Bermuda. Eight of the tags detached from the animals and reported as expected after five days; net displacement and direction, tag incli­ nation, and temperature data for all eight individuals were consistent with postrelease survival for five days. In this note, we present the results of a study evaluating the postrelease survival of blue marlin from pelagic longline fishing gear in the western North Atlantic. We include analyses of the movement and behavior of these animals for tagging periods of both five days and thirty days.

The importance of habitat quality for marine reserve fishery linkages

Abstract: We model marine reserve – fishery linkages to evaluate the potential contribution of habitat-quality improvements inside a marine reserve to fish productivity and fishery catches. Data from Mombasa...