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- Effects of reallocating fishing effort from trawling to creels in a Norway lobster fisheryPublication . Eichert, Moritz; Campos, Aida; Fonseca, Paulo; Lopes, Pedro; Marques, Lino; Castro, MargaridaThe consequences of reallocating fishing effort from trawling to creels in an area off the West coast of Portugal for the operation of the trawl fleet, as well as on the population dynamics and the global catch value for a high valued species, the Norway lobster (Nephrops norvegicus) are evaluated. The results suggest that only small portions of the area of interest are used by the trawl fleet, opening the possibility for a trawl ban without major disruption of the trawling activity. Economic benefits are expected, since predictions two scenarios tested, heavy and moderate exploitation, indicate no loss of catch value with much lower operational costs. Social benefits to local communities can also be expected since a much lower investment is needed for creel fishing, making this fishery attractive to small local companies already operating in the region. The proposed ban is consistent with the ecosystem approach to fisheries management and the Common Fisheries Policy (CFP) where the transition towards more responsible fishing practices is encouraged.
- Preliminary results on the use of semi-floating shrimp traps for the striped soldier shrimp, Plesionika edwardsii (Crustacea: Decapoda: Pandalidae), off the Algarve coast (southern Portugal)Publication . Eichert, Moritz; Campos, Aida; Fonseca, Paulo; Henriques, Victor; Castro, MargaridaThe present study provides an account of an experimental survey aiming at the evaluation of the catchability of the striped soldier shrimp, Plesionika edwardsii, using semi-floating shrimp traps off the Algarve coast (southern Portugal). Currently, this species is not targeted by the crustacean bottom trawl fleet, and preliminary results on product value suggest that this may become an economically viable new fishery. Preliminary results suggest that this fishery could contribute to the diversification of fixed gears of low environmental impact targeting deep-water crustaceans, in agreement with the objectives of both the Marine Strategy Framework Directive and the reformed Common Fisheries Policy. However, potential spatial conflicts with trawling. the unknown size of the resource and a necessary precautionary approach may limit the number of licences that can be granted.
- By-catch species susceptibilities and potential for survival in Algarve (southern Portugal) deep-water crustacean trawl fisheryPublication . Adão, Ana Catarina; Breen, Michael; Eichert, Moritz; Borges, Teresa C.Bottom trawling for crustaceans in Portuguese coastal waters is an important fishery in terms of revenue, despite its negative impacts on deep-sea ecosystems. This fishery catches large amounts of unwanted species that were discarded for various reasons before the introduction of the Landing Obligation, which banned the discarding of regulated species. However, where it can be demonstrated that a species has an acceptably high likelihood of survival, exemptions to this ban may be granted. In this study, time-to-mortality was used to estimate immediate mortality rates and identify important biological characteristics determining the susceptibility of 14 by-catch species. most with commercial interest (Conger conger, Galeus melastomus, Helicolenus dactylopterus, Lepidorhombus boscii, Lophius budegassa, Lophius piscatorius, Merluccius merluccius. Micromesistius poutassou, Mullus surmuletus, Phycis blennoides. Scyliorhinus canicula, Trigla lyra. Trachurus trachurus and Trachurus piciuratus). Species with potential to survive after the discarding process were identified and a short-term survival assessment of conger eel (Conger conger) was performed. The results suggest that species with scales, gas bladder and high metabolic rates have higher post-discard mortality. Size was a critical factor determining survival in some species, with smaller individuals dying faster. The short-term survival rate of conger eel was determined to be 84% (95% Cl: 75.5 to 93.3%). The methodology and results from this study can help identify species that may survive the discarding process and factors influencing their survival.
- Technical and economic viability of traps in the portuguese fishery of deepwater rose shrimp (Parapenaeus longirostris)Publication . Eichert, Moritz; Castro, MargaridaThe Marine Strategic Framework Directive and the Reformed Common Fisheries Policy are following the ambitious objective to stop the loss of biodiversity and to make fisheries more sustainable. In most cases several fishing practices for one species exist, while in the exploitation of deepwater rose shrimp (Parapenaeus longirostris) and other nektobenthic crustacean, exploitation is exclusively reserved to the demersal trawling fleet. Because of the environmental impact of demersal trawling especially in deep waters and bycatch proportions exceeding ethical and ecological limits alternative fishing practices are needed urgently. In the Azores, Canary Islands and Cape Verde shrimp fisheries developed using semi-floating traps, the present work provides information about the feasibility of using such traps in a commonly trawling dominated fishery of the deepwater rose shrimp. However the low abundance of the specie made experimental conditions unfavorable. More frequent the golden shrimp (Plesionika martia), a scavenging specie was caught. A broad range of baits was tested, including fluorescent light and proceeded baits such as sardine paste (chum) with promising outcomes for future research in this field.