CATALOGUE OF AQUATIC MITES FROM THE MINHO RIVER (NW IBERIAN PENINSULA)

Acari are a subclass of chelicerate arthropods that includes mites and ticks. The present study focuses on the taxonomic diversity of aquatic mites in the Portuguese territory of the Minho Region. Our aim was to compile all available information and thus generate a list of species linking them to the site where they were recorded. Aquatic species were all those that live exclusively in the marine environment, deep sea, intertidal, freshwater, brackish water or in transitional environments with the terrestrial environment if their lifestyle is associated with the aquatic environment. Since the first records of Portuguese endemic mites by Lunblad in the 1950s several authors have contributed to accurately catalogue, record, and redescribe this vast group in Portugal and Minho consecutively. In our review in this work, we used the Global Biodiversity Information Facility (GBIF) to obtain previous occurrences supplemented by an extensive literature review and the book collection Süßwasserfauna von Mitteleuropa, among others. Additionally, we resorted to active sampling and by-catch sampling in the Portuguese section of the Rio Minho catchment area. The collected organisms represent 12 new records for the Minho River and among them 10 are new records for Portugal, which were deposited in the Natural History Museum of the Iberian Peninsula - NatMIP (“Museu de História Natural da Península Ibérica”), Vila Nova de Cerveira, Portugal.

CARACTERIZAÇÃO DA PESCA COM REDE SERREIRA NO MUNICÍPIO DE RAPOSA-MA = CHARACTERIZATION OF FISHING WITH DRIFT GILLNET IN THE MUNICIPALITY OF RAPOSA-MA

Com o propósito de estimar a produção do peixe serra (Scomberomorus brasiliensis) e de sua fauna acompanhante, foram acompanhados desembarques de uma embarcação componente da frota serreira que atua ao longo do litoral maranhense e está sediada no município de Raposa. O controle nos desembarques caracterizou a composição e abundância dos pescados no período de janeiro de 2009 a dezembro de 2010, totalizando 17 desembarques. Um total de 27 espécies pertencentes a 16 famílias e 8 ordens, foram registradas nos desembarques. Em relação ao peso, a família Scombridae superou as demais, representando 50,02% da biomassa, seguida da Sciaenidae (21,60%) e Carangidae (11,13%). As 6 principais espécies desembarcadas, respondem por 81% do total desembarcado, destacando-se Scomberomorus brasiliensis, Cynoscion microlepidotus e Sarda sarda. Das espécies capturadas, 74,07% foram classificadas como acidentais, as espécies acessórias não ultrapassaram 14,81%, enquanto as constantes foram representadas em menos de 11,11% dos desembarques. O rendimento médio estimado das pescarias na região foi de 361 Kg/hora.AbstractTo estimate the production of Spanish mackerel (Scomberomorus brasiliensis) and its by-catch were accompanied by a landing craft fleet serreira component that acts along the coast of Maranhão and is based in the Raposa. The control landings characterized the composition and abundance of fish in the period January 2009 to December 2010, a total of 17 landings. A total of 27 species belonging to 16 families and eight orders were recorded in the landings. A total of 27 species belonging to 16 families and 8 orders were recorded in the landings. Regarding weight, the family Scombridae surpassed the others, representing 50.02% of the biomass, then the Sciaenidae (21.60%) andCarangidae (11.13%). Six species account for approximately 81% of total landings, most abundant being Scomberomorus brasiliensis, Cynoscion microlepidotus and Sarda sarda. Of the species caught, 74.07% were classified as accidental, the species accessory did not exceed 14.81%, while the constants were represented in less than 11.11% of the landings. The estimated average yield of the fisheries in the region was 361 kg / hour.

Wanted not, wasted not: Searching for non-target taxa in environmental DNA metabarcoding by-catch

Metabarcoding of environmental DNA is based on primers that are specific to the target taxa (e.g. bacteria, zooplankton, fishes). However, due to the nature of the commonly used protocols, regardless of the chosen primers, several sequences of non-target species will inevitably be generated, but are usually discarded in commonly used bioinformatics pipelines. These non-target sequences might contain important biological information about the presence of other species in the studied habitats and its potential for ecological studies is still poorly understood. Here, we analyzed the presence of mammal and bird species in aquatic environmental samples that were originally amplified targeting teleost fish species. After all cleaning and checking steps, we kept 21 amplicon sequence variants (ASVs) belonging to mammals and ten to birds. Most ASVs were taxonomic assigned to farm/domestic animals, such as cats, cows, and ducks. Yet, we were able to identify a native semi-aquatic mammal, the capybara, in the samples. Four native bird species and a non-native potentially invasive bird (Corvus sp.) were also detected. Although the data derived from these samples for mammals and birds are of limited use for diversity analyses, our results demonstrate the potential of aquatic samples to characterize non-aquatic birds and highlight the presence of a potentially invasive species that had not been recorded before in the region.

Assessment of Postharvest Losses Due to Catching Undersized Fishery Commodities and Size-Dependent Pricing in the Philippines

The continuing decline in catch rates instigates various fishing adjustments to keep up with the demands of a growing population. Fishery resources are being caught before they can attain their optimum harvestable size. Undersized catch elicits lower economic value; thus, considered as losses in postharvest fisheries. The present study focused on generating actual data on the volume of undersized catches in selected landing sites in the Philippines. It aims to quantify the magnitude of postharvest and financial losses incurred from catching fishery commodities below their marketable sizes. The estimated loss at 0.97% and 4.02% for capture and aquaculture commodities, respectively, was equivalent to PHP 15,235,290 financial loss. Estimation of losses by commodity showed that squid recorded the highest at 20.14%, followed by tilapia (9.61%), blue swimming crab (4.48%), shrimp (2.75%), small pelagics (1.98%), mussel (1.46%), oceanic tuna (0.91%), by-catch (0.79%), milkfish (0.09%), and oyster (0.02%). Excessive catching of undersized BSC and squid in Western Visayas may lead to overexploitation of resources and may adversely affect subsequent recruitment in the long run. The study's results indicate that catching undersized species could lead to substantial postharvest losses and subsequent loss of potential revenue to the industry players. Allowing the stocks to attain their maximum biomass level will minimize postharvest losses; thus, maximizing utilization of resources and benefits derived from the sector. Unrestrained catching of undersized fishery commodities undermines resource sustainability, economic potential, and food security. The strengthening of regulatory frameworks is, therefore, necessary to address both economic and ecological impacts.

Spesifikasi dan Identifikasi Hasil Tangkapan Garok Rajungan di Pelabuhan Perikanan Pantai (PPP) Bondet Kabupaten Cirebon, Jawa Barat

Crayfish (Portunus pelagicus) is the leading export commodity of Indonesian fishermen. The increasing demand for exports and high selling prices have made fishermen at the Bondet Beach Fishing Port, Cirebon Regency, use garok crabs to maximize their catch. The purpose of this study was to identify tool specifications, catch yields, selectivity and productivity of garok crab fishing gear operated at the Bondet Coastal Fishery Port, Cirebon Regency, West Java. The research was carried out in April – June 2021. The method used was a case study method with quantitative descriptive analysis to determine the specifications of the tools and catches taken by interviewing fishermen. The results showed that the crab claws were included in the dredge gear category. Its components consist of body mouth, garok, frame, nets, and ropes of various sizes. The main catch of garok crab in Cirebon Regency consists of small crab (Portunus pelagicus), and by-catch in the form of shellfish, shrimp, cuttlefish, and demersal fish, with a total of 14 species. This tool is classified as non-selective because of the small size of the bag mesh construction (30 mm) so that this tool catches many species with large and small size fish caught. The average catch obtained from 5 trips was 23.8 kg, with the lowest catch on the 2nd trip, which was 19.7 kg and the highest on the 5th trip, which was 31.3 kg, while the average sweep area was 0.0040 km2 with an average productivity of 3.97 kg/hour and the highest catch rate value was obtained on the 5th trip, which was 5.21 kg/hour, while the lowest catch rate was found on the second trip, which was 3.28 kg/hour.

A viability analysis of sustainable by-catch fisheries under direct conservation measures

<p>Sustainability in fisheries is a complex concept and one that has attracted a rich history of research over time. The basic concerns of sustainability are how to reconcile ecological, economic and social requirements within the perspectives of intra- and inter-generational equity. Therefore, maintaining these requirements simultaneously is critical to achieving a perennial system and avoiding so-called “crisis” situations. It is contended that viability theory, which is a relatively new area of mathematics, rigorously captures the essence of sustainability. Using viability theory, this thesis develops two viability models based on different direct conservation measures (i.e. input and output controls) to examine the feasibility conditions under which a regulator can achieve sustainability in a fishery characterised by a “by-catch process”, whereby one species is targeted and another species is incidentally caught as by-catch. The first model considers a by-catch fishery where fishing input is controlled by a regulator. The second model considers two interrelated fisheries managed using a dual quantity-price system, which is based on New Zealand’s Quota Management System (QMS). For each model, the set of constraints representing the “good health” of the system are characterised using managerial priorities identified in the literature. Then, the viability kernel, which is the largest set of initial states for which there are controls that result in inter-temporal trajectories satisfying all the constraints, is approximated numerically. This is achieved by employing VIKAASA, which is a computer application capable of generating kernel approximations. The viability kernel provides the regulator with meaningful reference values and indicators for desirable or undesirable states of the fishery, which serve as important inputs into policy decisions. This study also shows the potential for viability theory to provide policy makers with a better insight of how to integrate ecosystem considerations into the QMS.</p>

A viability analysis of sustainable by-catch fisheries under direct conservation measures

<p>Sustainability in fisheries is a complex concept and one that has attracted a rich history of research over time. The basic concerns of sustainability are how to reconcile ecological, economic and social requirements within the perspectives of intra- and inter-generational equity. Therefore, maintaining these requirements simultaneously is critical to achieving a perennial system and avoiding so-called “crisis” situations. It is contended that viability theory, which is a relatively new area of mathematics, rigorously captures the essence of sustainability. Using viability theory, this thesis develops two viability models based on different direct conservation measures (i.e. input and output controls) to examine the feasibility conditions under which a regulator can achieve sustainability in a fishery characterised by a “by-catch process”, whereby one species is targeted and another species is incidentally caught as by-catch. The first model considers a by-catch fishery where fishing input is controlled by a regulator. The second model considers two interrelated fisheries managed using a dual quantity-price system, which is based on New Zealand’s Quota Management System (QMS). For each model, the set of constraints representing the “good health” of the system are characterised using managerial priorities identified in the literature. Then, the viability kernel, which is the largest set of initial states for which there are controls that result in inter-temporal trajectories satisfying all the constraints, is approximated numerically. This is achieved by employing VIKAASA, which is a computer application capable of generating kernel approximations. The viability kernel provides the regulator with meaningful reference values and indicators for desirable or undesirable states of the fishery, which serve as important inputs into policy decisions. This study also shows the potential for viability theory to provide policy makers with a better insight of how to integrate ecosystem considerations into the QMS.</p>