[eng] The social relevance of recreational fisheries and their impact on the exploited resourcesand on the ecosystems have been widely recognized. However, the impact of recreationsfishing is still rarely accounted for when assessing the population dynamics of targetedspecies.The European squidLoligo vulgarisis a paradigmatic case-study. In the BalearicIslands (NW Mediterranean), this species is targeted by both the commercial and therecreational fishing sectors. The commercial squid fishery is relatively well knownbut the effect of the recreational sector on the population dynamics ofL. vulgarisiscurrently unknown although potentially relevant. The assessment and managementof recreational fisheries is particularly challenging due to the difficulties in estimatingboth, catches and fishing effort. Accordingly, the main objective of this Ph.D. Thesisis to estimate the recreational squid harvest . To face this challenge requires a socio-ecological approach, by which the ecological characteristics of the squid, the socialcharacteristics of the angler and the interactions between them have been tackled.The first section of the Ph.D. Thesis provides new insights linking some features ofthe squid life-history with the recreational fishing effort patterns. First, it is demon-strated that during the cold season (winter-spring) squid expand their spawning areato inshore waters, probably searching for the environmental conditions that maximizespawning success (e.g., sea temperature). This pattern is in accordance with the hy-pothesis that squid undergoes inshore spawning migrations. Accordingly, recreationalfishers (anglers) exploit squid when they approach to the coast for spawning. Second,squid moves more actively at nighttime than during the day. This pattern was revealedusing acoustic tracking telemetry and it is in accordance with the hypothesis of “feedingat night and spawning during the day”. Accordingly, anglers exploit squid at sunset(using line jigging), when squid has already shift to the feeding state and lures are stillvisible.Once solved the life-history patterns ofL. vulgaris, the next step involved the understanding of the fishery dynamics. All boats fishing squid were recorded (on-boatcensuses) in order to disentangle the drivers of angler’s site (and day) choices. Both,catch-related (expected harvest) and non-catch related variables (e.g., sea conditionand distance to the nearest homeport) play a relevant role. This Ph.D. Thesis providesfine-scale (1 km2day1) estimates of the recreational fishing effort.Harvest not only depends on effort but on catch. To assess the effect of the environ-ment on squid catchability, a set of experimental fishing sessions were performed. Thecombination of variables such as low windspeed, low atmospheric pressure and daysclose to the new moon maximized catch rates, although the main variable involvedin catch fluctuations was sea temperature. Catches are higher during the cold season,which is again in accordance with the hypothesis that squid undergoes inshore spawningmigrations. Moreover, the 30 minutes period around sunset is the more efficient thanany other 30 minutes period before or after sunset for capturing squid. This secondpattern is again in accordance with the “feeding at night and spawning during the day”hypothesis.During the above-mentioned experimental fishing sessions, a potential indirect effectof jigging was detected: some squid escape by losing one or both tentacles. The possibleindirect effect of tentacle loss was tested through tank experiments. The results showedthat loosing tentacles significantly decreased the predation efficiency, which in turn mayaffect long-term survival and fitness. We suggest that such a (possible) ghost fishingshould be considered.Finally, this Ph.D. Thesis proposes a new framework for estimating harvest byintegrating the above-mentioned information. This framework combines model-basedestimates of effort (varying in space and time) with model-based estimates of catchesper unit effort (varying in time and on the angler type). In order to account for theangler heterogeneity, anglers were classified into three types according with the answersto a short interview. The questionnaire was designed for revealing angler’s skill andexperience. By including heterogeneity of anglers, the estimated harvest gained inprecision. The recreational squid harvest in Palma Bay was estimated in 20.5 tonnesduring 2010. This means that recreational harvest represents 34% of the total squidlandings by the entire commercial fleet of Mallorca Island during the same year (59.5tonnes). Although to explicitly model the population dynamics of squid is outside thescope of this Ph.D. Thesis, this is the first empirical data quantifying the importanceof the recreational fishing ofL. vulgaris. The knowledge provided certainly shouldconstitute a baseline for a long-term monitoring program, and it demonstrates thatstock assessment should incorporate the role of the recreational fishery.

Sistema socio-ecològic, Pesca recreativa, Loligo vulgaris, Migracions reproductores, Heterogeneïtat del pescador, Esforç pesquer, Captures totals

Sistema socio-ecológico, Pesca recreativa, Loligo vulgaris, Migraciones reproductoras, Heterogeneidad del pescador, Esfuerzo pesquero, Capturas totales

Socio-ecological system, recreational fishery, Loligo vulgaris, Spawning migrations, angler heterogeneity, Fishing effort, Total harvest