Spiny lobster fishery on the southwest coast of Portugal: conciliating fisheries and conservation

Dissertação de mest., Aquacultura e Pescas (Pescas), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011

The effect of conservation measures on the spatial and temporal variation of rocky fish assemblages in the Arrábida Marine Park

Marine protected areas (MPAs) have been widely proposed for conservation purposes and as a tool for fisheries management. The Arrábida Marine Park is the first MPA in continental Portugal having a management plan, fully implemented since 2009. The main objective of this study was to evaluate the effect of protection measures on rocky reef fish assemblages and target invertebrates through before-after and control-effect (no-take vs. fished areas) underwater visual surveys and analysis of landings trends. Second, we used surveys before, during and after implementation of the management plan to understand fishers‟ preferences for fishing grounds and adaptation to the new rules, and evaluated the reserve effect through analysis of both ecological responses and fishing effort density. Third, we identified the main oceanographic drivers influencing the structure of reef fish assemblages and predicted the community structure for the last 50 years, in light of climatic change. Overall results suggest positive responses in biomass but not yet in numbers of some commercial species, with no effects on non-target species. The reserve effect is reinforced by the increase in landings of commercial species, despite increased fishing effort density in some areas, especially with octopus traps. Fishing grounds are mainly chosen based on the distribution of target species and associated habitats, but distance to port, weather conditions and safety also influence fishers‟ choices. Moreover, different fisheries respond differently to the protection measures, and within each fishery, individual fishers show distinct strategies, with some operating in a broader area whereas others keep preferred territories. Our results also show that wind stress and temperature are the main oceanographic drivers for rocky reef fish assemblages, with tropicalization of assemblages and polewards movements of species over the last 50 years consistent with temperature trends. We believe this study provides significant lessons for marine conservation and management of coastal systems.

Recreational shore fishing in southern Portugal: biological and socio-economic aspects and perspectives for management

Although overfishing is a concern for many fish stocks, it was for a long time only associated with commercial fishing exploitation, with less or no attention being given to the recreational fisheries. Recent research has shown however that the impact of recreational fishing on particular species can be considerable, and that the recreational harvest needs to be taken into account if fisheries are to be accurately assessed and effectively managed. In Portugal, the first recreational fishing regulations were only recently implemented. However, mirroring other European countries, regulations lacked scientific support, and specific knowledge of the activity was limited to a few studies with limited coverage. This thesis aimed to characterize the biological and socioeconomic aspects of the recreational shore angling activity in southern Portugal, to investigate whether the regulations in place were adequate and effective, and to provide recommendations for improved management and conservation of the inshore fisheries resources. A combined aerial-roving survey was conducted to gather data on fishing effort, catch, fishing trips and socioeconomic aspects (including anglers’ perceptions of regulations) of the recreational angling activity. The analysis of anglers’ catches suggested that compliance with daily bag limits was high, with less than 0.5% of creels exceeding the 10 kg angler-1 day-1 bag limit. Overall, 11.5% of the retained fishes were undersized, but non-compliance with minimum size limits was found to be high for some species (e.g. seabass, 73% undersized). In terms of the impact of recreational shore angling, the total estimated catches corresponded to less than 1% of the commercial landings for the same period (shared species). However, shore angling catches for white sea bream (Diplodus sargus) were found to be considerable, corresponding to 65% of the commercial landings (39.4% of total catch). In terms of anglers’ perceptions about the recreational fishing regulations in Portugal, the present study has shown that the majority of anglers accepted the existence of some kind of SRF regulations, but in general there was a partial or total disagreement with the recreational fishing restrictions recently put in place. Most anglers perceived themselves as not being involved in the decision-making process and claimed that some restrictions lacked a meaningful rationale (e.g. prohibition of fishing from piers/jetties). Fishers’ awareness with regard to specific aspects of the restrictions (such as the rationale for minimum size limits) was found to be very limited. During the same period, catches from sport fishing competitions were examined to test for differences with the recreational activity in terms of catches, and evaluate long term trends in catch and mean size of fish. Catches of the sport fishing competitions were found to be different from those observed for recreational fishing, being dominated by different species (e.g. garfish, mullets), and suggesting different fishing strategies of the the two types of anglers. High percentages of undersized fish were observed to be captured (and retained) during the competitions (in particular seabass, with 100% undersized), probably as a result of a single allowable minimum size (AMS) of 15 cm for all species in use in competitions. Lastly, catch and release fishing experiments were carried out to assess post-release mortality of three recreationally important species: two banded sea bream Diplodus vulgaris; black sea bream Spondyliosoma cantharus; and gilthead sea bream Sparus aurata. Post-release mortalities were found to be low (0-12%). The main predictor of mortality for Sparus aurata was anatomical hooking location, with 63% of the fishes that died being deeply hooked. The results support the release of fish, either from mandatory (e.g. minimum landing sizes) or voluntary practices. In summary, this thesis has demonstrated that the impact of recreational fishing for particular species is significant and needs to be taken into account for more effective management and stock assessment purposes. It has also highlighted several management issues that should be addressed in order to promote more adequate regulations in the future and prevent noncompliance issues. A periodic monitoring of the recreational fishing activity including all fishing modes (i.e. spear fishing, boat, and shore angling) would also be beneficial to ensure a timely knowledge on the global recreational fishing activity and support future management actions.

Dinâmica das pescas e gestão participativa do polvo vulgar (Octopus vulgaris) capturado pela frota de covos e alcatruzes no sul de Portugal

Tese de Doutoramento, Ciências do Mar, da Terra e do Ambiente, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

From a traditionally open access fishery to modern restrictions: Portuguese anglers' perceptions about newly implemented recreational fishing regulations

Saltwater recreational fishing (SRF) in Portugal was for a long time an open-access activity, without restrictions of any kind. Restrictions to control the recreational harvest were first implemented in 2006 and were highly criticized by the angler community, for being highly restrictive and lacking scientific support. The present study aimed to obtain socio-economic data on the recreational shore anglers and gauge their perceptions about recreational fishing regulations and the newly implemented restrictions in Portugal. Roving creel surveys were conducted along the south and south-west coasts of Portugal, during pre and post regulation periods (2006-2007). A total of 1298 valid face-to-face interviews were conducted. Logit models were fitted to identify which characteristics influence anglers' perceptions about recreational fishing regulations. The majority of the interviewed anglers was aware and agreed with the existence of recreational fishing regulations. However, most were against the recreational fishing regulations currently in place. The logit models estimates revealed that Portuguese anglers with a higher level of formal education and income are more likely to agree with the existence of recreational fishing regulations. In contrast, anglers who perceive that more limitations and a better enforcement of commercial fishing would improve fishing in the area are less likely to agree with the existence of SRF regulations. The findings from this study will contribute to inform decision-makers about anglers' potential behaviour towards the new and future regulations. Although the existence of fishing regulations is a good starting point for effective management, the lack of acceptance and detailed knowledge of the regulations in place by fishers may result in lack of compliance, and ultimately hinder the success of recreational fishing regulations in Portugal. (C) 2013 Elsevier Ltd. All rights reserved.

Using a modified Nordmore grid for by-catch reduction in the Portuguese crustacean-trawl fishery

By-catch and discards are a common problem to all fisheries. Recent studies of the Portuguese crustacean-trawl fishery show that discards average 70% of the total catch. This situation poses a threat not only to the management of target and commercial fish by-catch species stocks, but also in terms of the ecosystem impact of the discarded species whose survival is generally low. Previous attempts to address this problem by using oblique separator mesh panels associated with square-mesh windows, or square-mesh windows alone, provided encouraging results, but these are unlikely to have commercial applicability at present. Therefore, we tested the efficiency of a modified Nordmore grid in excluding some of the most captured non-commercial by-catch species, such as the blue whiting, Micromesistius poutassou, and the boarfish, Capros aper, evaluating simultaneously the losses of the crustacean target species (rose shrimp, Parapenaeus longirostris, Norway lobster, Nephrops norvegicus and red shrimp, Aristeus antennatus) and commercially valuable fish by-catch. A total of 41 valid hauls were carried out during 2001, and 15 in 2002 on board the R/V "Noruega". Results from both years varied considerably, with higher by-catch exclusion rates, in weight, registered in the second survey (73-74 and 48-63% for blue whiting and boarfish, respectively). The corresponding percentage reduction for target species was 8-15% for the Norway lobster, 4-9% for rose shrimp and 7-10% for red shrimp. The level of exclusion of the non-commercial by-catch is encouraging, although short-term loss of Norway lobster, where the escapees comprised larger individuals, raises some concern with regards to fishers' acceptance of mandatory use of grids. (C) 2004 Elsevier B.V. All rights reserved.

Assessment of catches, landings and fishing effort as useful tools for MPA management

Marine protected areas (MPAs) have been widely recognized as a tool to achieve both fisheries management and conservation goals. Simultaneously achieving these multiple goals is difficult due to conflicts between conservation (often long-term) and economic (often short-term) objectives. MPA implementation often includes additional control measures on fisheries (e.g. vessel size restrictions, gear exclusion, catch controls) that in the short-term may have impacts on local fishers' communities. Thus, monitoring fisheries catches before, during and after MPA implementation is essential to document changes in fisheries activities and to evaluate the impact of MPAs in fishers' communities. Remarkably, in contrast with standard fisheries-independent biological surveys, these data are rarely measured at appropriate spatial scales following MPA implementation. Here, the effects of MPA implementation on local fisheries are assessed in a temperate MPA (Arrabida Marine Park, Portugal), using fisheries monitoring methods combining spatial distribution of fishing effort, on-board observations and official landings statistics at scales appropriate to the Marine Park. Fisheries spatial distribution, fishing effort, on-board data collection and official landings registered for the same vessels over time were analysed between 2004 and 2010. The applicability and reliability of using landings statistics alone was tested (i.e. when no sampling data are available) and we conclude that landings data alone only allow the identification of general patterns. The combination of landings information (which is known to be unreliable in many coastal communities) with other methods, provides an effective tool to evaluate fisheries dynamics in response to MPA implementation. As resources for monitoring socio-ecological responses to MPAs are frequently scarce, the use of landings data calibrated with fisheries information (from vessels, gear distribution and on-board data) is a valuable tool applicable to many worldwide coastal small-scale fisheries. (C) 2015 Elsevier B.V. All rights reserved.