Interaction between small pelagic purse seine fishery and its top predators case study in the eastern Adriatic Sea - Zorica, Barbara; Čikeš Keč, Vanja; Zanki, Kristijan; Grubišić, Leon; Šegvić Bubić, Tanja (2018)
Due to very good collaboration with one commercial purse seiner, using “Srdelara” and operating in fishing zone G, preliminary data concerning the interaction between small pelagic purse seine fishery and its predators were obtained. According to the notes taken by experience observer on-board in period from year 2013 to 2016, seems that tunas, dolphins and swordfish were the faithful companions of purse seiner fisherman with abundance of 68.6%, 22.0% and 9.4%, respectively. Although they were present all year round, their monthly pattern of appearance indicated that less tunas were recorded in May-June, more dolphins were noted from July to October while swordfish were mostly abundant in winter (January-March). Within the investigated period, slightly increasing trend of tuna and dolphins’ appearance was recorded, although statistically not significant. Analysing possible correlation between purse seine catches and predator’s abundances, revealed that appearance of tuna had negative impact on the catches (dispersion of schools), while realised catches in presence of dolphins were quite good so it seems that they tend to round up small pelagic fish schools.
Zahvaljujući vrlo dobroj suradnji s ribarskim sektorom, točnije jednom komercijalnom plivaricom koja koristi plivaricu “Srdelaru” u ribolovnoj zoni G, su prikupljeni preliminarni podaci vezani uz interakciju ovog tipa ribolova i njegovih predatora. U razdoblju od 2013. do 2016. godine, prema podacima prikupljenim od strane iskusnog promatrača na palubi ove komercijalne plivarice, je utvrđeno da su tune, dupini i igluni najvjerniji pratioci ovog tipa ribolova te da je njihova abundancija redom bila 68,6%, 22,0% i 9,4%. Premda je uočeno da su navedeni grabežljivci prisutni tijekom cijele godine ipak je njihova pojavnost kolebala od mjeseca do mjeseca – najmanje tuna je zabilježeno u razdoblju od svibnja do lipnja, nešto više dupina je uočeno od srpnja do listopada, dok su igluni bili najbrojniji od siječnja do ožujka. Tijekom istraživanog razdoblja je utvrđeno blago povećanje broja tuna i dupina premda to povećanje nije bilo statistički značajno. Korelirajući ulove ostvarene istraživanom komercijalnom plivaricom i broja uočenih grabežljivaca, čini se da će u slučaju pojave tune ostvareni ulov biti manji s obzirom da ona rasprši ciljanu plovu sitne plave ribe, dok će relatvno dobar ulov ista plivarica ostvariti u prisutnosti dupina koji će uočenu plovu još više zbiti.
Bibliografija: 15 jed.
Summary ; Sažetak.
Keywords: Ribarstvo -- Ribe -- Grabežljivci -- Srdela -- Brgljun -- Tuna -- Dupin; Jadransko more