Artisanal Fisheries Research Articles

Marine carbonate mining in the Southwestern Atlantic: current status, potential impacts, and conservation actions

Marine carbonate sediments have economic value because of their high concentration of calcium minerals and important trace elements. However, increasing mining interest in these stocks is threatening unique ecosystems, such as rhodolith beds, which provide many ecosystem goods and services. We review the potential of the unexplored Brazilian deposits and the rising conflicts with other blue economic sectors and biodiversity hotspots. The tropical Southwestern Atlantic Ocean, particularly the Brazilian Exclusive Economic Zone, has the largest deposit of marine limestone worldwide, which is very attractive to the global industry, with reserves measured at more than 1355,157,240 tons of CaCO3 and it is especially useful as a supply for agriculture and animal nutrition. This large mining potential raises concerns regarding licenses and potential impacts, especially considering the biological and socio-economic importance of extensive rhodolith beds, which may conflict with mining. Additionally, future dredging activities will take place in vulnerable ecosystems without adequate marine spatial planning (MSP). Currently, there is no long-term scientific information on the available carbonate stocks, stock recoverability, risks to connectivity with other ecosystems (e.g., coral reefs), and the reduced provision of ecosystem services which may affect activities such as artisanal fisheries. In this context, encouraging carbonate mining without science-based information and MSP accelerates the unsustainable exploitation of this important ecosystem. This activity will contribute to the degradation of tropical marine biodiversity and threaten the food security of traditional and vulnerable human communities, which is in opposition to the Sustainable Development Goals and reaching the 2030 United Nations Agenda.

Gill Monogeneans of African Tetra, Brycinus kingsleyae (Günther, 1896), From the Nyong River: Biotope, Distribution and Site Selection

Monogenea is a taxon containing flatworms that are primarily parasites of the skin and gills of fish. The African tetra, Brycinus kingsleyae (Günther, 1896), is a commercial fish species in artisanal fisheries in Southern Cameroon. Although the gill monogeneans of this fish species have been described, no ecological research has been carried out on this component community. The present study was conducted in the Nyong River to provide the first data about some factors that influence the structure of its infracommunities. In dry seasons, 70 fish specimens consisting of 27 males and 43 females of fork length between 9.5 and 14.1 cm were sampled.The analysis of their gill filament number indicated that the gill system of B. kingsleyae is heterogeneous because this factor varies with the length of the fish and depends on the gill arch. The studied guild consisted only of core species: Annulotrema combesi Birgi, 1988, Annulotrema maillardi Birgi, 1988, Annulotrema nyongensis Birgi, 1988, Annulotrema bouixi Birgi, 1988, and Characidotrema regia Birgi, 1988. The number of gill filaments and the parasitic load increased with the fish length, indicating that larger hosts provide a greater diversity of niches for parasites. Monogenean species exhibit various occupation patterns of gill arches, sectors, zones and gender differences in parasitological indices. This study reveals that the host length and sex, filament number, gill arch, sector and zone are largely responsible for structuring the studied component community.

Economic Improvement of Artisanal Fishing by Studying the Survival of Discarded Plectorhinchus mediterraneus.

Europe calls for the end to fisheries discards, which means bringing all caught fish (subject to minimum sizes or quotas) to land. This decision is beneficial to the ecosystem, since it forces the selectivity of the fishing gears to improve. However, artisanal fishermen find themselves in a vulnerable situation where their subsistence depends on catches with small profit margins. An exemption to this landing obligation exists, as it is also ruled that those animals whose survival is scientifically guaranteed may be returned to the sea. Here we study the survival of Plectorhinchus mediterraneus captured by hookline and gillnet, as well as their physiological recovery. Survival exceeds 93% in both cases. The physiological assessment of primary (cortisol) and secondary (energy mobilization, acid-base and hydromineral balance, and immune system) stress responses indicates that surviving animals are able to recover after fishing. Thus, we propose the optimal size of capture of this species to achieve greater economic benefit. For this, we rely on the prices according to size in recent years, as well as on the growth curves of the species. In this way, by releasing fish of less than 1 kg, the current benefits could be multiplied between 2.3 and 9.6 times. This pilot study lays the groundwork for regulating artisanal fisheries through scientific data related to survival of discards along with information on the sale prices.

Hatchery tanks induce intense reduction in microbiota diversity associated with gills and guts of two endemic species of the São Francisco River.

The São Francisco River (SFR), one of the main Brazilian rivers, has suffered cumulative anthropogenic impacts, leading to ever-decreasing fish stocks and environmental, economic, and social consequences. Rhinelepis aspera and Prochilodus argenteus are medium-sized, bottom-feeding, and rheophilic fishes from the SFR that suffer from these actions. Both species are targeted for spawning and restocking operations due to their relevance in artisanal fisheries, commercial activities, and conservation concerns. Using high-throughput sequencing of the 16S rRNA gene, we characterized the microbiome present in the gills and guts of these species recruited from an impacted SFR region and hatchery tanks (HT). Our results showed that bacterial diversity from the gill and gut at the genera level in both fish species from HT is 87% smaller than in species from the SFR. Furthermore, only 15 and 29% of bacterial genera are shared between gills and guts in R. aspera and P. argenteus from SFR, respectively, showing an intimate relationship between functional differences in organs. In both species from SFR, pathogenic, xenobiont-degrading, and cyanotoxin-producer bacterial genera were found, indicating the critical pollution scenario in which the river finds itself. This study allowed us to conclude that the conditions imposed on fish in the HT act as important modulators of microbial diversity in the analyzed tissues. It also raises questions regarding the effects of these conditions on hatchery spawn fish and their suitability for restocking activities, aggravated by the narrow genetic diversity associated with such freshwater systems.

Heavy metal contamination in European conger (Conger conger, Linnaeus 1758) along the coastline of Morocco

BackgroundIn Morocco, fish is an important protein source especially, even not exclusively, for coastal communities and marketed fresh all along the coastline. One of the main targets of coastal artisanal fisheries is the European conger (Conger conger, Linnaeus 1758), a widely distributed benthic predatory species of a maximum weight of up to 50 kg. However, information on heavy metal contamination of conger is scarce. Therefore, concentrations of mercury, lead and cadmium were analysed in 108 European conger specimens from nine locations along the along the Atlantic and Mediterranean coasts of Morocco to describe the spatial distribution of heavy metal contamination.ResultsThe average heavy metal concentration in all conger samples under investigation was 246.90 ± 216.83 µg mercury/kg wet mass, 74.14 ± 87.02 µg lead/kg wet mass and 255.12 ± 287.15 µg cadmium/kg wet mass respectively. Mercury and cadmium showed a clear site-specific bioaccumulation in European conger but lead does not. Hence, the effect of fish length bias on contamination was corrected through a generalized linear model (GLM) prior to any spatial comparison.ConclusionsDifferent regional hotspots for the three analysed metals are identified and local sources are discussed. Mercury levels in big specimens of European conger exceeded the European threshold level for human consumption at some of the locations under investigation.

Nutrient capture and sustainable yield maximized by a gear modification in artisanal fishing traps

Coral reef artisanal fisheries are an important source of nutrition and economic wellbeing for coastal communities, but their management is subject to conflicts and tradeoffs between short-term food security benefits and long-term ecological function. One potential tradeoff is between nutrient capture and fish yields, where targeting small, nutrient-dense species may be more valuable for food security than maximizing fish yields, which is more closely aligned with supporting biodiversity and ecological function. We explored these potential tradeoffs by comparing two similar gears: traditional African basket traps and traps modified with an escape gap. Traps without escape gaps captured a higher frequency of fish with body sizes below their estimated lengths at maximum sustainable yield than gated traps. Estimates of nutrient yields for six micronutrients among the 208 captured species indicated high hump-shaped relationships for gated traps and low and linear positive relationships for traditional traps. Maximum nutrients in gated traps frequently corresponded to body sizes at maximum sustainable yield. Daily capture rates of nutrients were above daily needs more often in gated than traditional traps, but calcium values were low in both trap designs. Gated traps were more likely to capture species with unique and potentially important functional traits, including browsing herbivores, which could have negative effects on ecological functions and reef recovery. However, gated traps also catch fewer immature fish and fewer predators. Our results indicate that nutrient yields can be maximized while using a gear that captures larger and more sustainable body sizes in coral reef artisanal fisheries. Preferential targeting of nutrient-dense fishes is only one of many metrics for evaluating a nutrition-centered management strategy and may only be a management target in specific contexts.

Nijerya'da geleneksel balıkçılık yapan çiftçilerin refah düzeyleri: Etkili faktörler ve sorunlar

Aims: Despite the contribution of artisanal fishery to the fishery sector, there is a dearth of information on the welfare of artisanal fish farmers. Therefore, this study investigated the welfare of artisanal fish farmers in Nigeria.Methods and Results: The study used primary data collected from 330 artisanal fish farmers, which were analysed with descriptive statistics, Foster-Greer-Thorbecke index and multiple regression. The results indicated that the artisanal fish farmers had poor access to credit facilities, standard medical facilities, quality and nutritious food, quality education for their children, shelter, drinkable water and environmental security. While the highest share (52.42%) of farmers' expenditures was allocated to food expenditures, only 15.02% was allocated to basic non-food items such as children's education, shelter, clothing and health. Analysis of the relative poverty indices of the farmers showed that the poverty incidence, depth and severity were 0.633, 0.165 and 0.062, respectively. Their welfare was significantly influenced by gender, age, income from artisanal fish farming, income from other sources, access to credit, household size, farming experience and assets. The major constraints to the welfare of the farmers were inadequate credit facilities and a lack of government support.Conclusions: The artisanal fishing households had a low standard of living, poor welfare and high poverty incidence. This study, therefore, advocates institutional support by relevant agencies to improve the welfare of this group of farmers. This could be in form of the provision of modern fishing equipment, adequate and necessary information, modern health care centres, free standard schools and loans at little or no interest rate.Significance and Impact of the Study: This study contributes to the body of knowledge by using the expenditure approach to measure artisanal fishing households’ welfare and the results will serve as a reference point for policymakers to improve the artisanal fish farmers’ and rural households’ welfare.

Recent rise in exploitation of Tanzanian octopuses: a policy and management challenge

The artisanal octopus fishery is important for the coastal communities in Tanzania. In this work the octopi landing data from the United Nations Food and Agriculture Organization (FAO), Ministry of Livestock and Fishery Development (MLFD) and trade statistics from Comtrade of the United Nations were analysed. The FAO dataset show that from 1980 to 2017 annual octopus landings stayed below 2000 tons until 2018 when the catch increased to 2864 tons, and doubled to 5,687 tons in 2019. FAO datasets show large catches in 1995, 2003 and 2019, with 2019 recording the largest catch. For both Comtrade and MLFD export statistics, approximately 5,818 and 2,254 tons of octopus were exported globally from 2018 to 2020 with an equivalent value of approximately 13 and 19 million US$ respectively. Portugal was the largest importer of Tanzanian octopi, followed by Turkey, Italy, Spain, Netherlands, Israel, France and Panama. The current management interventions relating to octopi are presented, including the challenges needed to be addressed for sustainability of the octopi fishery. Voluntary octopi closures indicated some signs of success, but an in-depth assessment of the associated effects is required. The study recommends a need for verification mechanisms to ensure consistency of FAO and MLFD statistics, stock assessments, in-situ research on recruitment patterns of octopi, as well as innovation and research in designing sustainable fishing gear to support development of policies for sustainability.

Courtship and Reproduction of the Whitetip Reef Shark Triaenodon obesus (Carcharhiniformes: Carcharhinidae) in an Ex Situ Environment, with a Description of the Late Embryonic Developmental Stage.

Elasmobranchs represent a group of species under considerable anthropic pressure because of the scale of industrial and artisanal fisheries and the loss of essential areas for nursery and feeding, which are causing substantial population losses around the world. Reproduction in an ex situ environment enables a healthy population to be built and maintained in networks of public aquariums, increasing our knowledge of elasmobranch reproductive biology and offering the opportunity for reintroductions in areas where native populations have been removed. The study reports two successful pregnancies of the whitetip reef shark Triaenodon obesus, considered a vulnerable species by the International Union for the Conservation of Nature. Copulation and gestation data are provided, including ultrasound recordings of the late stage of embryo development. Ultrasonography was performed with the GE Logiq and convex transducer and revealed a fetus with defined fins and organogenesis, with definition of eyes, gills, liver, a heart with individualized chambers, partially defined kidneys, and a well-defined spiral intestine. A cartilaginous skeleton forming a posterior acoustic shadow was detailed, as well as a moving fetus with a biparietal diameter of 6.47 cm and a heart rate of 62 Beats Per Minute on spectral Doppler. This is the first successful reproduction of T. obesus in an aquarium in Brazil.

Local Ecological Knowledge, Catch Characteristics, and Evidence of Elasmobranch Depletions in Western Ghana Artisanal Fisheries

Local Ecological Knowledge, Catch Characteristics, and Evidence of Elasmobranch Depletions in Western Ghana Artisanal Fisheries

Local Ecological Knowledge, Catch Characteristics, and Evidence of Elasmobranch Depletions in Western Ghana Artisanal Fisheries

Local Ecological Knowledge, Catch Characteristics, and Evidence of Elasmobranch Depletions in Western Ghana Artisanal Fisheries

Arabian/Persian Gulf artisanal fisheries: magnitude, threats, and opportunities

Arabian/Persian Gulf artisanal fisheries: magnitude, threats, and opportunities

Sewage contamination assessment in an urbanized tropical estuary in Northeast Brazil using elemental, isotopic and molecular proxies

The Capibaribe Estuarine System (CES) is a tropical estuary located within a densely populated metropolitan region in the Brazilian Northeast, providing multiple ecosystem services including artisanal fisheries, tourism, and navigation. A significant load of domestic and industrial effluents is causing visible environmental degradation that needs to be characterized. This study evaluated the degree of contamination by domestic sewage and the relative contribution of organic carbon (OC) sources in sediments, measuring carbon-to-nitrogen atomic (C/N)a ratios, δ13C of OC, and linear alkylbenzene concentrations (LAB). The SIAR mixing model indicated that estuarine phytoplankton and sewage contribute 73% and 22% to OC, respectively, based on sedimentary (C/N)a ratios that varied from 8.5 to 13, and δ13C ranging from −25.21 to −21.63‰. This suggests that eutrophication of CES is triggered by sewage inflow. The CES was moderately contaminated by LAB, and the highest concentrations observed in the inner portion, from 287 to 1349 ng g−1 dry weight, suggests the retention of sewage. The mixing isotopic model indicated a significant dilution process of sewage-derived OC by estuarine phytoplankton. The lowest LAB in the lower estuary (317–320 ng g−1 dw) probably resulted from marine dilution. Principal component analysis demonstrated that mud regulates sedimentary OC content, and that the sewage plume regulates sedimentary LAB. High degradation of LAB isomers probably reflects the net heterotrophic condition of this system, also suggesting these compounds are introduced into CES partially degraded. Our results pointed out that degraded OM is a result of chronic and long-term sewage input. Considering the implications of sewage pollution to environmental and public health, there is an urgent need of better policies to improve domestic effluent treatment capacity, reducing contamination of estuarine environments.

How far can Tunas and Sardinellas derived from artisanal fishing be exported for retail trade from Côte D’Ivoire, West Africa?

In West Africa, marine artisanal fisheries´ usefulness lies in their capability to support people´s increasing demand for fish, as fish-consumption is generally viewed as the first and foremost way to provide a large amount of animal proteins to consumers. Here, information about the marine artisanal fishery located at Sassandra, southwestern Côte d’Ivoire, are provided, talking about the processing, marketing and distribution of two small pelagic species that are targeted by that fishery. The study was carried out as field work activities in February-March and August-September 2021, using a questionnaire to which people working for the benefit of the fishery willingly submitted themselves. The results shed light on marketing and the route to be followed by the fishery products when these are to leave Sassandra for retail trade. Women participation in post-harvesting tasks is also singled out as a way to acknowledge the significant role they play in artisanal fisheries. The study calls on decision Makers to equip attention to equip women with modern ovens as a way to tackle problems facing women in their efforts to process the fish.

Pirogues to Paradise?

Pirogues to Paradise?

Maximilian Viatori and Héctor Bombiella, Coastal Lives: Nature, Capital, and the Struggle for Artisanal Fisheries in Peru (Tucson, AZ: University of Arizona Press, 2019), pp. 228, $50.00 hb.

Maximilian Viatori and Héctor Bombiella, Coastal Lives: Nature, Capital, and the Struggle for Artisanal Fisheries in Peru (Tucson, AZ: University of Arizona Press, 2019), pp. 228, $50.00 hb. - Volume 54 Issue 4

Professionalizing Community-Based Coastal Resource Management (CRM) Services

Philippine artisanal fisheries have historically been self-regulating, although concerns regarding sustainability have led to significant countrywide and international focus on national improvements in Coastal Resource Management (CRM). The process to professionalize CRM skills in the Philippines is outlined herein as a reflexive or solution-focused approach to mitigate fisherfolk poverty, enhance skills available to local government, manage the national heritage of marine resource extraction, and emerging food-security challenges of the growing population. Ongoing progressions are put in context with several decades of programmatic work through the lens of Ecohealth Action Research that has led to specific foundational outcomes. Emphasis is placed upon overcoming the historical disconnect between fisherfolk and government regarding; CRM program implementation, inclusive, participatory designs, and methodologies that lead to enhanced community-based skills and capacity. Collaborative approaches to developing adaptive co-management that include fisherfolk are directly linked to a government stakeholder analysis and roles under the Local Government Code (RA 7160). The projected Green Jobs are subsequently considered within the international Sustainable Development Goals.

Two Morphotypes with Genetic Divergence, Different Ploidy, and Habitat Preference in an Exploited Corbicula Population in China

The genus Corbicula is well known as one of the most invasive bivalves globally, and is morphologically variable and taxonomically complicated. Continuous effort has been made to establish the correspondence between morphological forms and genetic lineages of Corbicula, mostly across invasive populations, but far less for the native populations, especially for exploited ones that support important Corbicula fishery. This research studied a Corbicula population that supported the largest artisanal and commercial Corbicula fishery in China, in terms of the morphotypes composition, ploidy, mt COI sequence, phylogenetic relationship, and habitat preferences. Two morphotypes with 9.5% mt COI genetic divergence, that is, the “distantly-placed-ridges morphotype”-morph D, and the “closely-situated-ridges morphotype”-morph C were identified. Morph D individuals contained diploids and triploids, and were closely related to the invasive lineage. They were found in higher proportions in lotic habitats with lower transparency and chlorophyll α. Morph C were all diploids and sister to C. fluminalis and C. japonica. They had higher proportions in lentic habitats. Thus, fishery management of Corbicula should consider multiple compositions of the Corbicula resource. Further research that confirms the population parameters difference of the two morphotypes and surveys in other water systems should be conducted. Moreover, the two morphotypes were sympatric representatives of the invasive and noninvasive Corbicula lineages, comparisons between them and with their congener invasion populations suggested that preference of flowing water and polyploidy might contribute to the invasive success of some Corbicula lineages in addition to androgenesis.

Feeding guilds among batoids in the northwest coast of the Baja California Sur, Mexico

AbstractResearch on the feeding habits of batoids provides information of intra and interspecific interactions of this taxon in marine ecosystems. We analyzed 832 stomachs of nine ray species collected from the artisanal fishery on the Northwest coast of Baja California Sur (NBCS). We identified 79 prey items assembled in five trophic groups (crustaceans, fish, mollusks, polychaetes, and sipunculidae). Results indicated that the red crabPleuroncodes planipeswas the most important prey in the diet of the seven batoid species. A low dietary similarity of the rays was observed, which evidenced different feeding strategies. In this regard, we identified four well‐separated trophic guilds. Each guild was characterized by the consumption of specific prey: (1)Hypanus dipterurusandNarcine entemedorthat fed mostly on polychaetes; (2)Rostroraja veleziandGymnura marmoratafed mostly on fishes (Clupeidae and Batrachoididae); (3)Hypanus longus,Myliobatis californica, andPlatyrhinoidis triseriatafed on crustaceans (Munnidae) and Sipunculus worms; and (4)Pseudobatos productusandZapteryx exasperatafed on crustaceans (Portunidae) and fishes (Synodontidae and Batrachoididae). We concluded that batoids off the NBCS show prey sharing between the different species.

Endoparasites and diet of the “bigeye grenadier” Macrourus holotrachys Günther, 1878 from the deep sea in the Southeastern Pacific Ocean

A total of 106 specimens of the big eye grenadier, Macrourus holotrachys, were obtained from 2015 to 2019 as bycatch from the artisanal fishery for Patagonian toothfish (Dissostichus eleginoides) at depths between 1000 and 2200 m in Northern Chile (app. 22°S 70°W). All individuals were examined for their endoparasite fauna and diets. A total of twenty-five parasite taxa (e.g. fifteen Digenea, six Nematoda, three Cestoda, and one Acanthocephala) were found.Twenty taxa were found as adults, four species were found in the larval stage, and one species was found in both the larval and adult stages. Hysterothylacium sp. (Nematoda); Trypanorhyncha gen. sp. (Cestoda); and Monorchiinae gen. sp. (Digenea) were the predominant species, which had a prevalence of 64.2%, 42.5% and 31.1%, respectively. The diet of M. holotrachys included thirteen item-prey, Decapoda and Ophiuridae showed the highest frequency of occurrence (66.3% and 43.3% respectively). A multivariate canonical correspondence analysis (CCA) showed that the association between endoparasites and diet of M. holotrachys explained 45.1% of the total variance. The detected parasite community consisted of parasites linked to benthic, benthopelagic and pelagic environments. This suggests the role of M. holotrachys as a predator of communities close to the seabed but also within the water column, performing vertical and horizontal migrations in the South Eastern Pacific Ocean.