The sociology and habits of recreational anglers on the Island of Majorca (western Mediterranean) were evaluated using telephone and on-site surveys, as well as fishing logbooks and recreational fishing competitions. The recreational fishery is one of the island's main leisure activities, 5.14% of the population (37 265 people) participating. Enthusiasts tend to be mainly middle class (most anglers own boats moored at marinas), middle-aged males (90% male, mean age 46 ± 2 years). The most popular fishing method is from a boat (62.9%), followed by fishing from shore (32.4%), and spearfishing (3.6%). The mean time spent fishing is 3.86 ± 0.03 h d−1, and more than one type of gear (mean 1.27 ± 0.21) is used simultaneously by a single angler. The frequency of fishing is 4–6 times per month, mainly on holidays and weekends, increasing in summer. The activity has a sizeable impact on the coastal fauna, with diverse catches of at least 1209.25 t year−1 (about 615 000 fishing outings year−1). Thus, the amount of carbon extracted annually is at least 137.34 kg C km−2 year−1, and the recreational fishery removes about 31% of production at trophic level 4. Although these are gross estimates and more detailed study of the effect on trophic level and local production is needed, the values do highlight the pressure the recreational fishery exerts on coastal fish communities. Assuming that this level of exploitation is common to north-shore Mediterranean countries, there may be cause for concern about sustainable exploitation in the recreational fishery, and the effectiveness of current protection measures is discussed. Despite the limitations of the study, recreational fisheries clearly should be taken into account when considering measures for fisheries management. Moreover, fishing has considerable social import, and the benefits must be taken into account when investments to protect exploited resources are being contemplated.

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6I5N and 6°C were determlned for plants invertebrdtes and f~s h e s collected from 3 s~t e s on the southern coast of the Mediterranean Island of Mallorca Spdln The sites were separated by distances of 1250 to 3750 m The mean Si5N of plants was 1 1 to 4 1 " W , , benthic Invertebrates 5 9 to 6 g':%) planktonic Invertebrates 5 5 to 5 8% and fishes 8 4 to 13 8%" 6"N became ennched with increasing trophic level The mean 6I3C of plants was -11 4 to -16 3'Xo benthlc invertebrates -14 8 to -16 8'X, planktonlc Invertebrates -19 3 to -19 8 O W b and fishes -16 1 to -19 2"y) There were s~g n~f i c a n t d~f f e iences in the lsotopic c o m p o s~t~o n of ~ndividual specles w~t h i n the plant invertebrate 01 flsh groupings at each slte and there were s~g n~f i c a n t d~fferences in the ~s o t o p~c composit~on of the same specles at dlfferent sites Depleted ' < C was assoc~ated w~t h b e n t h~c food chalns and enrlched ''C w~t h planktonlc chalns The data suggest that b e n t h~c food chalns are Important to the rocky reef assoclated f~s h e s studled as might be expected In a nutrlent poor system where planktonlc product~on IS relatively low Hoivever, the vanance In 6I1C composltlon between sltes was such that the r e l a t~v e s~g n~f l c a n c e of the 2 pdthways could not be determlned I5N measurements indicated that some of the flsh species studled had adopted d~fferent feedlng strategies at d~fferent sites and, as a result ~n d l v~d u a l s of the same species could sometimes be a s s~g n e d to different t r o p h~c groups at different sltes The data suggest that these f~s h e s e x h i b~t plast~clty in t h e~r feedlng strateg~es and this may p r o v~d e them wlth greater adaptlve flexibll~ty to respond to s~t e -s p e c~f~c changes In food avallabllity Moreover the data p r o v~d e emplrlcal support for current theones of food web dynamlcs w h~c h suggest that trophlc levels a r e dynamlc rather than flxed and that multlchannel omnivory IS an Important feature of food webs KEY WORDS Stable lsotopes T r o p h~c interact~ons Variablllty Mediterranean Reefs Feeding strategy

3 faunally-distinct depth zones: 200 to 800 m (upper slope), 800 to 1425 m (middle slope) and 1425 to 1800 m (lower slope). Differences in δ 15 N and δ 13 C between October 1996 and May 1998 were observed only in the crustaceans Aristeus antennatus and Nematocarcinus exilis. There were few differences among depths in δ 15 N or δ 13 C of benthic fishes or crustaceans: the shrimps A. antennatus and Acanthephyra eximia showed higher δ 15 N values at greater depth, and δ 13 C values of the fishes Alepocephalus rostratus (Alepocephalidae) and Coelorhynchus coelorhynchus (Macrouridae) also tended to increase with increasing depth. Differences in plankton and suprabenthos were also observed among zones (at depth, greater δ 15 N values of gelatinous plankton, calanoid copepods and peracarids were recorded, along with smaller δ 13 C values of gelatinous plankton and peracarids). These are attributed to a microbially-mediated increase in δ 15 N and a reduction in δ 13 C of the particulate material remaining after preferential utilization of labile organic matter in the stable and relatively high (13°C) temperature of the Mediterranean water column. Strong positive correlations between δ 15 N and δ 13 C data for plankton, fishes and crustaceans indicated a single primary source material for these communities, which is attributed to marine snow.

A total of 13 026 fishes belonging to 82 species and 43 famllies were collected in a continuous transect between depths of 200 and 1800 m south of the Baleanc Islands (Algerian basin, western Mediterranean). The analysis of 32 bottom trawls showed the existence of 4 groups associated with the upper slope (groups 1 and 2, from 200 to 400 and 400 to 800 m, respectivelv), middle slope (group 3, from 800 to 1400 m) and lower slope (group 4, below a depth of 1400 m) Thc differcnces in the mean values of the ecological parameters species richness, abundance, biomass and mean fish weight were also indicative of distinctive characteristics between these fish assemblages. Species richness decreased significantly with depth. The highest values of diversity corresponded to the samples from group 2. Biomass did not show any specific trend throughout the whole bathymetric range. Mean fish weight show 2 different trends along the continental slope: a bigger-deeper phenomenon at the upper 1000 to 1200 m depth. and a smaller-deeper phenomenon below this depth. Our results are compared with those obtained in the north Atlantic basin and in the western Mediterranean (Balearic basin), and the main factol-s affecting these deep-sea fish assemblages are discussed.