Reproduction and growth of Aphanopus carbo and A. intermedius (Teleostei: Trichiuridae) in the northeastern Atlantic

Commercial fishery landings of the black scabbardfish, Aphanopus carbo, from the Madeira mid‐water drifting longline fleet (northeastern Atlantic) were studied for 2 years within a Portuguese government programme for fishing management. The process noted that 20% of the total catch corresponded to the intermediate scabbardfish, Aphanopus intermedius. Length‐frequency distribution, and age, growth and reproduction of both species were analysed and compared. The results revealed significant differences in age and growth in influencing the length‐frequency distributions. Intermediate scabbardfish attained the largest size (148 cm TL) and age (15 years). However, the two species had similar reproductive strategies. According to data published on A. carbo in this region, it is thought to be very likely that previous studies unintentionally mixed both species together in their analyses.     

An historical overview of the Republic of Ireland's lobster (Homarus gammarus Linnaeus) fishery,with reference to European and North American (Homarus americanus Milne Edwards) lobster landings

Historical developments of the Republic of Ireland's Homarus gammarus fishery are reviewed and compared in the context of landings in Europe and the North American H. americanus fishery. H. gammarus fishing has provided essential income for over a century to many Irish coastal communities. There have been significant fluctuations (greater than 460%) in recorded landings over this time and the relative importance of H. gammarus fishing has changed with the establishment of ancillary crustacean fisheries. In 1994, H. gammarus landings reached an all-time high of 714 tonnes, with a landed value of IR £6.3 million; in 1999 landings were 597 tonnes valued at IR £6.15 million. Current Republic of Ireland lobster fishery regulations are: (a) minimum carapace length of 85 mm, (b) ban on landing lobsters that have been `V-notched' or have a mutilated tail fan, and (c) prohibition of capturing lobsters by SCUBA diving. Chronological details on recent legislation, regulations and landings relating to Ireland's lobster fishery sector are reviewed. In the last 40 years landings of H. gammarus in the Republic of Ireland exhibit signs of an overexploited stock characterised by a reduction in catch per unit effort and there has been a general decline of total landings for H. gammarus throughout Europe. This contrasts with North America, where many regulations govern the H. americanus fishery and landings appear to be in a healthier state.     

Comparing Trawl and Creel Fishing for Norway Lobster (Nephrops norvegicus): Biological and Economic Considerations

This study compares the fishing activity and landings of the trawl and creel fisheries for Norway lobster (Nephrops norvegicus (L.)) off the Portuguese coast, and evaluates the financial viability of two vessels typical of each fleet. Crustacean trawlers are part of an industrial fleet that, besides Nephrops, targets deep water shrimps. Creels are used by a multi-gear, multi-target artisanal fleet, fishing only in areas unavailable to trawlers and, when catching Nephrops, set specifically to target this species. Trawlers have in recent years contributed with 85% of the landings in weight, but only 74% in value (2005-2009 average). Despite smaller landings, the Nephrops creel fishery provides individuals of larger size and in better condition, thereby obtaining higher unit prices. Economic viability was also higher for the creel vessel, with trawling being only viable if major costs (such as labor and fuel) are covered by the revenue from other target species (e.g., the rose shrimp). At present, Nephrops populations on the South and SW coast are subject to intense fishing and to a recovery plan. The possibility of reallocation of some of the fishing effort directed at Nephrops from trawlers to creels is discussed in terms of the conservation of the resource and economic return.     

Gargoor trap fishery in Kuwait,catch rate and species composition

Kuwait's fisheries include shrimp trawlers, gill nets, intertidal stake nets, and demersal fish traps, known locally as gargoor. The gargoor fishery used to be the nation's most important in terms of value and landings volume, but declines in catch rates have reduced its ranking. This paper describes the status of the gargoor artisanal fishery. The main landings place was sampled for catch and effort, and fish length‐frequency data from May 2003 to December 2005. The catch rate, monthly average number of boats operating, and the number of gargoor cleared were estimated for dhow boats fishing in Kuwait's waters and international waters, and speed boats operating in Kuwait waters only. Over the duration of the study period, the speedboat catch rates were higher than those of dhow boats, i.e., 3.7 kg/trap‐pull vs. 2.6 and 2.5 kg/trap‐pull for dhows fishing in Kuwait's territorial waters and international waters, respectively. The grouper, Epinephelus coicodes, was the main species captured, contributing 19.3% and 17.8% to the dhow catch in Kuwait waters and international waters, respectively. The catch rates by dhow boats declined from an average of 4.7 kg/trap‐pull in 2003 to 2.7 kg/trap‐pull in 2005 representing a 41% decrease. If this decreasing catch rate trend continues, then fishing effort should be reduced to allow stock recovery. It is recommended that the number of gargoor fished in Kuwaiti waters should be limited and that several no‐fishing zones be established to ensure the minimum spawning stock biomass and preserve biodiversity for all fisheries.     

VMS-based fishing effort and population demographics for the European squid (Loligo vulgaris) off the Portuguese coast

This study presents a 1-year synopsis of the trawl fishery for the European squid Loligo vulgaris in Portuguese waters, integrating length-structured landings with corresponding geo-referenced fishing activities. From vessel monitoring system (VMS) data, landings and biological sampling, a “status-report” was obtained for 2003. Fishing pressure was found to be most intense in inshore areas of the northwest and the south coasts. Population size structure, classified into three categories, was not uniform throughout the fishing areas. Larger squid are found offshore in the northwest (International Council for the Exploration of the Sea—ICES rectangle 10E0) and in the south (rectangles 2E1 and 3E1), whereas all inshore western coast rectangles showed larger proportions of small squid relative to the southern rectangles. The analysis carried out in this study provides an insight into the possible impact of the fishing intensity pattern on the population structure in various zones. The results demonstrate the benefits of combining geo-referenced fisheries information with landings and size data, to produce explicit spatio-temporal information that can contribute to integrated planning and management for the sustainable exploitation of this resource.     

Box-Jenkins analysis for shark landings in Costa Rica

Sharks are highly vulnerable to intense and prolonged fishery extraction. This article analyzes the data on shark landings from the artisan fishing fleet on Costa Rica's Pacific coast between 1988 and 1997. The data come from an invoicing system administered by the Costa Rican Fisheries Institute (Instituto Costarricense de la Pesca y Acuacultura, INCOPESCA). Pacific coast shark fishing during the period under study represented approximately 20% of the total national fisheries volume. According to data from the invoicing system, the Northern Pacific region was the most productive, reporting 58% of the shark catch nationwide. Within this region, shark fishing in Papagayo Gulf represented 91% and 53% of the landings by fishery region and nationwide, respectively. The mid-sized and advanced (length of boat > 10 meters) artisan fishing fleets reported 96% of the shark catches in the zone. The study of shark fisheries in the Papagayo Gulf zone is crucial for an understanding of fishery dynamics for this resource at the national level. A monthly chronological series was constructed with the landings in the Papagayo Gulf zone, and a Univariate Box-Jenkins (UBJ) Model was estimated for first-order moving averages MA(1) with a seasonal component of the Yt = lamda(t-1) + gammaS12 + a(t) type.     

The relevance of size parameters as indicators of fishery exploitation in two West African reservoirs

Fish communities living within the artificial reservoirs of Manantali and Selingue in Mali are compared after the monitoring of small-scale fishery landings over 13 months (May 2002–June 2003). The fishing pressure constitutes the main difference of these two similar reservoirs. The effects of fishing on the structure of the fish communities are analyzed by using fish size spectra and derived indicators. In Selingue Reservoir, the fishing gears mostly target smaller species (mean length of 165 mm) than in Manantali Reservoir (mean length of 210 mm). Unlike in Selingue, the size structure does not change between seasons in Manantali. In Selingue, fishing practices that target the fish recruitment of the year constitute a structuring factor of the fish sizes observed in the catches. In spite of similar values of the slopes of the global fish communities’ size spectra between the two reservoirs, they clearly display an intense exploitation at Selingue. Then, size-based spectra indicators represent a potential tool for assessing the impact of fishing on fish communities in small-scale fisheries.     

Combining Telephone Surveys and Fishing Catches Self-Report: The French Sea Bass Recreational Fishery Assessment

Fisheries statistics are known to be underestimated, since they are mainly based on information about commercial fisheries. However, various types of fishing activities exist and evaluating them is necessary for implementing effective management plans. This paper assesses the characteristics and catches of the French European sea bass recreational fishery along the Atlantic coasts, through the combination of large-scale telephone surveys and fishing diaries study. Our results demonstrated that half of the total catches (mainly small fish) were released at sea and that the mean length of a kept sea bass was 46.6 cm. We highlighted different patterns of fishing methods and type of gear used. Catches from boats were greater than from the shore, both in abundance and biomass, considering mean values per fishing trip as well as CPUE. Spearfishers caught the highest biomass of sea bass per fishing trip, but the fishing rod with lure was the most effective type of gear in terms of CPUE. Longlines had the highest CPUE value in abundance but not in biomass: they caught numerous but small sea bass. Handlines were less effective, catching few sea bass in both abundance and biomass. We estimated that the annual total recreational sea bass catches was 3,173 tonnes of which 2,345 tonnes were kept. Since the annual commercial catches landings were evaluated at 5,160 tonnes, recreational landings represent 30% of the total fishing catches on the Atlantic coasts of France. Using fishers'' self-reports was a valuable way to obtain new information on data-poor fisheries. Our results underline the importance of evaluating recreational fishing as a part of the total amount of fisheries catches. More studies are critically needed to assess overall fish resources caught in order to develop effective fishery management tools.     

Reproductive biology of Zearaja chilensis (Chondrichthyes: Rajidae) in the south-east Pacific Ocean

Between 2000 and 2002, three artisanal landing sites were sampled in southern Chile, with data on population structure and reproductive development collected from 5477 yellownose skates Zearaja chilensis. Total length (L(T) ) ranged from 33 to 158 cm for females and 34 to 155 cm for males. No sexual dimorphism was evident in disc size (length or width) or in L(T)-mass relationships. The smallest mature female was 95 cm L(T) and the size at which 50% were mature (L(T50) ) was 109 cm. Males matured between 80 and 90 cm L(T) with a L(T50) of 88 cm. Although the largest Z. chilensis captured by the artisanal fishery was 155 cm L(T) , 89% of landings comprised relatively small, immature fish. This situation may compromise the stock integrity if intrinsic vulnerability and probable long-life span of Z. chilensis are considered. Consequences for the survival of the species and possible signs of a fishery collapse must be reviewed by management authorities by consideration of both artisanal and industrial landings in Chile.     

The Ecuadorian Artisanal Fishery for Large Pelagics: Species Composition and Spatio-Temporal Dynamics

The artisanal fisheries of Ecuador operate within one of the most dynamic and productive marine ecosystems of the world. This study investigates the catch composition of the Ecuadorian artisanal fishery for large pelagic fishes, including aspects of its spatio-temporal dynamics. The analyses of this study are based on the most extensive dataset available to date for this fishery: a total of 106,963 trip-landing inspection records collected at its five principal ports during 2008 ‒ 2012. Ecuadorian artisanal fisheries remove a substantial amount of biomass from the upper trophic-level predatory fish community of the eastern tropical Pacific Ocean. It is estimated that at least 135 thousand metric tons (mt) (about 15.5 million fish) were landed in the five principal ports during the study period. The great novelty of Ecuadorian artisanal fisheries is the “oceanic-artisanal” fleet component, which consists of mother-ship (nodriza) boats with their towed fiber-glass skiffs (fibras) operating with pelagic longlines. This fleet has fully expanded into oceanic waters as far offshore as 100°W, west of the Galapagos Archipelago. It is estimated that nodriza operations produce as much as 80% of the total catches of the artisanal fishery. The remainder is produced by independent fibras operating in inshore waters with pelagic longlines and/or surface gillnets. A multivariate regression tree analysis was used to investigate spatio-environmental effects on the nodriza fleet (n = 6,821 trips). The catch species composition of the nodriza fleet is strongly influenced by the northwesterly circulation of the Humboldt Current along the coast of Peru and its associated cold waters masses. The target species and longline gear-type used by nodrizas change seasonally with the incursion of cool waters (< 25°C) from the south and offshore. During this season, dolphinfish (Coryphaena hippurus) dominates the catches. However, in warmer waters, the fishery changes to tuna-billfish-shark longline gear and the catch composition becomes much more diverse.     

Historical and contemporary evidence of a mutton snapper (<Emphasis Type="Italic">Lutjanus analis</Emphasis> Cuvier, 1828) spawning aggregation fishery in decline

Scientific information on reef fish spawning aggregation fisheries is sparse in light of numerous regional declines and extirpations from overexploitation. Fisher interviews of the small-scale commercial mutton snapper (Lutjanus analis) spawning aggregation fishery at Gladden Spit, Belize, suggests a historic decadal decline. The reported trend is supported by analysis of inter-seasonal catch and effort and yield (2000–2002) that reveals a 59% decline in catch per unit effort (CPUE) and a 22% decrease in mean landings per boat. Declining population-level trends are also supported by a significant decrease in inter-annual median lengths of mutton snappers (2000–2006). These findings demonstrate the need for additional life history information that includes length-associated age and details on growth to provide clearer support of the effects on, and responses by, populations following fishing. In view of the historical changes to mutton snapper CPUE and landings at Gladden Spit and the fishery-associated declines in fish spawning aggregations observed globally, a precautionary approach to spawning aggregation management is warranted that provides full protection from fishing to enhance population persistence. The findings also highlight the need for substantially greater enforcement and long-term fisheries monitoring under a comprehensive regional management strategy.     

INTERACTIONS BETWEEN CETACEANS AND THE TUNA FISHERY IN THE AZORES

We studied the operational and ecological interactions between cetaceans and the tuna-fishery in the Azores, based on reports of observers placed on board tuna fishing vessels from 1998 to 2000. Data were collected during 617 fishing trips (representing 43% of total fishing trips) and 6,554 fishing events. Cetaceans were present during <10% of the observed fishing events, with common dolphins ( Delphinus delphis ) accounting for 78% of the occurrences. The presence of cetaceans during fishing varied both spatially and temporally, depending on the distribution of fishing effort and on the pattern of occurrence of each cetacean species in the region. Overall, cetaceans interfered in 5% of the fishing events. This interference resulted in a higher proportion of events with no catches. In the three years, 49 dolphins were caught in the fishing lines but were released alive, although it is impossible to determine if they survived the interaction. Annual estimates of incidental capture of cetaceans by all the tuna fleet were calculated based on total tuna landings. An estimated 55 dolphins were captured in 1999, 38 in 1998, and 16 in 2000. Overall, our results suggest a low level of interaction between cetaceans and this fishery.     

The Social Aspects of Fishing Effort

While economic literature inspired by the “tragedy of the commons” has emphasised people’s tendency to increase fishing effort beyond desirable levels, sociologists and anthropologists who have studied the social aspects of fishing have often emphasised the capacity of these factors to restrict fishing effort. The article addresses the influence of social norms and communication on fishing effort in an empirical study of the Atlantic blue whiting fishery. The data were generated at a time when this fishery had yet to see efficient quota regulations, and had been subject to a rapid growth in fishing effort, making it the largest fishery in the Atlantic. The article argues that social norms and communication patterns in the fishing fleet create a synergic effect of co-operation and competition on fishing effort. The article questions the view that social norms and communication necessarily represent a solution to the tragedy of the commons.

Deep-water fisheries along the British Isles continental slopes: status,ecosystem effects and future perspectives

In this paper, we revisit the state of deep-water fisheries to the west of the British Isles and aim to provide an overview on the key drivers behind community changes along continental margins. The deep-water fisheries to the west of the British Isles that extend from the shelf-slope break down to the lower slope and along banks and seamounts of the Rockall Basin, mainly target blue ling Molva dypterygia, roundnose grenadier Coryphaenoides rupestris, orange roughy Hoplostethus atlanticus, with by-catches of black scabbardfish Aphanopus carbo and tusk Brosme brosme. These fishing grounds experienced a long period of exhaustive exploitation until the early 2000s, but subsequently the implementation of management strategies has helped to relieve excessive fishing pressure. It is widely accepted that a better understanding of the long-term implications of disturbance is needed to understand patterns in deep-water communities and what sustainable use and exploitation of resources might look like in this context.     

Competition between the krill fishery and penguins in the South Shetland Islands

Among the South Shetland Islands, the potential competition for krill (Euphausia superba) between the Japanese fishery and krill-eating breeding penguins was assessed. A low level of competition was apparent due to several factors. Spatial overlap between the main fishing and foraging areas was insignificant. Firstly, the large colonies of the dominant penguin (chinstrap penguins,Pygoscelis antarctica) occurred where sea ice disappears early in spring, and not necessarily where krill are abundant in summer, i.e. the area of krill fishery. Secondly, overlap between trawling depth and foraging dive depth of penguins was marginal, with the latter depth being shallower. Moreover, overlap in the size-frequency of krill caught by trawlers and those captured by penguins was not complete; the penguins took larger krill on average. Finally, the present small fishery is unlikely to impact upon local krill biomass in the region. Krill biomass was estimated to be 250–1500 × 10³ tonnes within the preferred fishing areas during summer. The present catch rate by the fishery (≤13 × 10³ tonnes/half-month period) is smaller by an order of magnitude, and the fishing area does not include the main foraging areas of breeding penguins.     

More than One Bag for the World Fishery Crisis and Keys for Co-management Successes in Selected Artisanal Latin American Shellfisheries

Global concerns about the depletion of marine stocks have been widely documented in industrial fisheries. However, small-scale artisanal fisheries constitute a second component for the world fishery crisis, normally ignored or erroneously lumped into the industrial component. In this paper we first present a brief comparison between industrial and artisanal fisheries, highlighting the differences between them and the differential feasibility for implementing management options. We propose that industrial and artisanal fishery problems have to be treated separately and thus cannot be lumped into a single “fishing bag”. Among artisanal fisheries, we focus on coastal benthic shellfisheries, highlighting that their sedentary or sessile nature make them amenable to implement spatially-explicit management tools such as rotation of areas and territorial user rights (TURFs). Then, using long-term catch trends and selected examples, we demonstrate the power and validity of co-management for some Latin American shellfisheries, notably in Chile and Mexico, and stress the need to institutionalize the existent fishery knowledge. Several idiosyncratic properties of co-management in our Latin American examples have been useful to sustain the resources over time, including: (a) allocations of TURFs, (b) Community Fishery Quotas, which may be sub-allocated to families, (c) community-based and family-oriented sociological and organizational context of co-management, which may drive short and long-term market forces.     

Modeling responses of coupled social–ecological systems of the Gulf of California to anthropogenic and natural perturbations

Key elements of the rapidly expanding field of ecosystem-based management include: (a) understanding connections among social and ecological systems and (b) developing analytical approaches to inform the necessary trade-offs among ecosystem services and human activities in coastal and marine areas. To address these needs, we investigate the impacts of multiple economic sectors on the marine ecosystem and dependent human community in the Gulf of California with an ecological-economic model. We focus on the spotted rose snapper (Lutjanus guttatus), an economically important species targeted concurrently by the nearshore artisanal fleet, the sportfishing fleet, and by the industrial shrimp fleet as bycatch. Economic returns to the local community are driven by the artisanal fishery catch and the number of tourists who engage in the sportsfishery, and these variables are in turn impacted by fish abundance. We find that the coexistence of the two sectors (and production of both seafood and tourism services) creates stability in key elements of the coupled systems. When the coupled systems are perturbed by changes in exploitation and climate variability, the artisanal fishery responds more rapidly and to a greater degree than the sportsfishery to shifts in the fish population. Our results suggest that vital components of coupled systems may well respond differently to climate variability or other perturbations, and that management strategies should be developed with this in mind. Models like ours can facilitate the development and testing of hypotheses about the form and strength of interactions between ecosystems, services, and the human communities that rely on them. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. H. M. Leslie and M. Schlüter contributed equally to this paper.     

Length–weight relationships of six elasmobranch species captured at the artisanal fishery of Margarita Island,Venezuela

This study reports the length – weight relationship (LWR) for five batoid and one shark species, all frequently captured by the artisanal commercial fishery on Margarita Island (10º44’ – 11º10’N and 63º46’ – 64º13’W), Venezuela. In 2013, elasmobranchs captured by the artisanal fleet (using bottom gillnets 200–400 m in length with 5–8 inch mesh size) were identified, sized, weighed and sexed. The value of a ranged from 0.0006 to 0.0351, meanwhile the b value ranged from 2.84 (for pooled Myliobatis freminvillei) to 3.39 (male Mustelus higmani), with r² ranging from 0.920 to 0.991. Differences in LWR due to sex were observed for three elasmobranch species. This study offers LWRs separate for males and females, also for species for which LWRs already exist and thus new knowledge is gained through the estimate presented here.     

Length–weight relationships and biological data on guayana pike‐conger Cynoponticus savanna (Bancroft, 1831)

This study presents the first references available for Cynoponticus savanna length–weight relationships (LWR) as well as other biological information, based on its unique population in the South Atlantic Ocean, specifically, Todos os Santos Bay, on the Brazilian central coast. A total of 464 individuals were obtained from artisanal fishing landings between July 2012 and June 2013. Total lengths ranged from 14.5 to 139.6 cm. The length‐weight relationship was BW = 0.716 TL^3.31. Length at first maturity (L_m) was 48.9 cm. Reproduction began gradually in May, reaching a peak around December, with most individuals completing reproduction by January. The gonadosomatic index (GSI) was highest in January (GSI = 0.21) and lowest in March (GSI = 0.024). The male index (GSI = 0.073) was lower than in females (GSI = 0.10) (P < 0.01). This study presents the first population data for C. savanna, which is under threat due to overfishing and habitat loss.     

Importance of discards of a beam trawl fishery as input of organic matter into nursery areas within the Tagus estuary

The brown-shrimp beam trawl fishery carried out within the Tagus estuary produces discards due to the little commercial interest of most of the species caught. Between 1994 and 1996, monthly samples were collected in the two major fishing areas within the Tagus estuary, using a beam trawl, in order to estimate the amount of fish and crustaceans caught per unit of effort. The fishing effort of the commercial fleet was determined based on surveys of professional fishermen. Mortality estimates of discards were also evaluated experimentally. The main fish and crustacean species discarded after capture were Crangon crangon (Linnaeus, 1758), Liza ramada (Risso, 1826), Carcinus maenas (Linnaues, 1758) and Pomatoschistus minutus (Pallas, 1770). The estimated total amount of fishery discards in the upper part of the Tagus estuary is approximately 1500 tonnes per year, which represents ca. 90% of the captures. The mortality rate of the fishes and crustaceans discarded varied according to species and season, with the highest rates during Summer months. Considering nitrogen and carbon content of the main discarded species, an input of particulate organic matter of more than 140 tonnes of carbon and 35 tonnes of nitrogen per year were estimated for these estuarine areas.