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- Identifying métiers using landings profiles: an octopus-driven multi-gear coastal fleetPublication . Szynaka, Monika; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Campos, AidaThe multi-gear coastal vessels in the Algarve (South Portugal) own licenses for various fishing gears. However, it is generally uncertain what gears they use, which is problematic as each individual gear is responsible for unique impacts on the resources and the environment. In this study, landing profiles identified for the multi-gear coastal fleet (2012–2016) were used as support in defining potential métiers using k-mean clustering analysis (CLARA) along with information from past studies on métiers. The results showed that more than 50% of the vessels were engaged in the octopus fishery year-round, using traps, while a small percentage (~13%) were entirely dedicated to clam dredging. In general, gillnets (21%) were used to target monkfish, hake and bastard soles, while trammel nets (6%) were used to target cuttlefish, with some vessels alternating the fishing gears (either seasonally or annually) according to target species. The method for the initial characterization of this fleet’s métiers and its efficiency with limited data is discussed, as well as the utility of this segmentation in support of management advice.
- Improving fisheries management through spatio-temporal analysis of catches, discards, fishing effort and selectivity, across different métiersPublication . Szynaka, Monika; Karim, Erzini; Gonçalves, Jorge; Campos, AidaI would first like to thank my advisers, especially Dr. Karim Erzini for helping me with the project change during the first of the PhD and for overall support since the beginning of my master’s project. I deeply admire your passion for fisheries research and the number of hours you have spent reviewing my writing. Thank you to Dr. Aida Campos for giving me an opportunity to expand my horizons in fisheries when I joined the TecPescas project and for support in and outside the PhD. Thank you to Dr. Jorge Gonçalves for the local support during the PhD, especially for helping me learn how to take care of the financial side of science. Finally, a thank you to Dr. Svein Løkkeborg in Norway for the original opportunity to collaborate with him prior to my change in the project and for the support during writing my first review. Thank you to all the fishers I worked with, and we interviewed for giving me the data that I needed to complete this PhD. A special thanks to the captain and crew of Mar Vivo, for a very wild experience on the sea and delicious fresh lunches. And to the captain and crew of Bartolomeu who worked with us on the trammel net project as I thoroughly enjoyed the dinners that I received from them and due to all of them being extremely friendly. A thank you to all my colleagues who worked with me at various periods of the PhD. Without your support I could not have finished my work. Thank you to Mariana Fernandes, Ana Marçalo and especially Pedro Monteiro for helping me grow as a researcher from the master’s until now. Thank you to all the people of Fisheries, Biodiversity and Conservation lab for all the help, for creating a general environment of friendliness and for making time to chat. Thank you so much to all my friends and to my husband that have also been there for me throughout the PhD. From getting coffees in the morning, to lunches in the afternoon, to those who were there from the beginning and to those I met later in the PhD program, as well as those who I’ve known from 6 to 15 years and have supported my dreams in science. Thank you to my parents who have supported my journey in science since I decided I was going to do a PhD in marine biology when I was only 13 years old. Thank you for the sacrifices you both made and for being role models in what hard and efficient work can mean, as well as taking pride in your work. Thank you to my sister who has been my cheerleader through the past years and especially during my periods of struggle, I am extremely thankful to have a sibling who cares so much to see me succeed. Thank you to my grandma for getting on skype almost every weekend and to my grandpa for making me laugh. (PL: Dziękuję mojej babci za to, że prawie w każdy weekend wchodziła na skype i słuchała mnie i mojemu dziadkowi za rozśmieszenie mnie.) Fishers in the Southern Portuguese multi-gear coastal fleet own licenses for a variety of fishing gears including static nets, longlines, and traps, and dredges. Information on the fishing gear being actively used is scarce and most vessels are not required to report geographic location, making the impact of the local environment difficult to evaluate. The first and main objective of this thesis was to identify métiers in the multi-gear coastal fisheries operating in the Portuguese south coast, including the type of gear being used to target specific species or assemblages in certain areas during a specific time of year in a three-step process. The first step was a review to understand the definition of fisheries métiers using static longlines due to their well-defined target species, little environmental impacts, and various characteristics that can be modified for improved fishing. This was followed by a cluster analysis on landing profiles for the fleet (2012-2016), followed by the second and third step in which validations using questionnaires and onboard observations, respectively. The main finding was the application of a low-cost analysis to identify métiers within a multi-gear fleet with limited data, and specific to this fleet, an increasing number of vessels active within the octopus (Octopus vulgaris) trap métier. The second objective was to assess a proposed raised trammel net (by insertion of a section referred to as “aranha”) to reduce by-catch and habitat impacts in the cuttlefish (Sepia officinalis) trammel net fishery. The results were promising as the modified net caught significantly less habitat forming organisms and similar target species’ amounts as the standard net. The results presented in this thesis can contribute to the management of this multi-gear fleet by presenting the necessary information to make decisions, especially for métiers with high number of vessels, and effort in highlighting the necessity for gear modifications in areas where the habitat is impacted.
- Fishers, let us talk: validating métiers in a multi-gear coastal fishing fleetPublication . Szynaka, Monika; Fernandes, Mariana; Anjos, Mariana; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Campos, AidaIn the multi-gear coastal fleet in the Algarve (South Portugal), fishers own licenses for various fishing gears. However, they generally do not use all these licenses, and therefore, it is difficult to estimate the impacts this fleet has on the local environment. In this study, two types of questionnaires were used directed to the local fishers from the multi-gear fleet during interviews carried out between November 2019 and July 2021 with the objective to validate the métiers proposed for this fleet in a previous study using multivariate analysis on past landing profiles. A total of 10 out of the 11 proposed métiers were validated, including four métiers with gillnets, three with dredges, two with trammel nets, and one with traps. Additional métiers were identified not found in the previous study. The results obtained with the two types of questionnaires are presented, and their usefulness in validating the gear used and the seasonality of fishing activities are discussed, as well as their contribution to a clearer distinction between target species and commercial by-catch.
- Reducing invertebrate by-catch in a coastal fishery using a raised monofilament trammel netPublication . Monika Jadwiga Szynaka; Pedro Monteiro; Karim Erzini; Jorge M.S. Gonçalves; Aida Campos; Szynaka, Monika Jadwiga; Monteiro, Pedro; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Campos, AidaTrammel nets are one of the least selective fishing gears and are known to catch a variety of species, many of which are discarded, including important invertebrates that are considered habitat-forming species. Although there are few studies focusing on this type of by-catch, these habitat-forming species include corals and sponges that are vulnerable to disturbances from fishing activities using bottom contact gear. Experimental fishing was conducted off the port of Portimao (southern Portugal) from November 2021 to April 2022 using standard and modified trammel nets rigged to be lifted off the bottom with the objective of reducing invertebrate by-catch and impacts on the bottom habitat. The modified lifted net caught 36% less by-catch of invertebrates in numbers than the standard net, with no significant decrease of biomass and value of target species. The results obtained with the two net types are discussed, as well as the necessity for good video recording equipment that can improve sampling accuracy, and the usefulness of interviewing the fishers on net performance after experimental fishing was conducted.