Population Characteristics of the European Lobster, Homarus gammarus in the Adriatic Sea: Implications for Sustainable Fisheries Management

Abstract

The European lobster, Homarus gammarus, was sampled from September 2016 to August 2017, using pots and gillnets in the Eastern Adriatic Sea. Official landings were also analyzed (2008–2020). The majority of landings were from the Northern Adriatic and showed an increase of 18.5% over the study period. Results revealed an extremely low catch rate that fluctuated significantly by season. Dominance by specimens in the size classes of 90–110 mm carapace length (CL) was observed. Experimental design revealed spatial heterogeneity, with larger individuals caught further from the coast (>3 nm) and undersized specimens caught near the coast (<3 nm). With increasing CL and total length (TL), an increase in weight was higher in males than females. TL and abdomen width (AW) increased linearly with CL and were more pronounced in females. At 80 mm CL, females started to develop secondary sex characteristics with wider AW than males. The results suggest that the modern legal framework is appropriate for lobster fisheries and a longer fishing season is not advisable, despite a positive catch trend in the northern part of the sea. Additional efforts are desirable to reduce fishing pressure in the coastal part. The morphometric relationships could reveal population characteristics required as inputs in stock assessment analysis for effective management.

Catch per Unit Effort of Decapod Species, C. pagurus and H. gammarus, from a Voluntary Marine Reserve

“…It has been suggested that soak time does not linearly affect the end catch [20], which is apparent in Figures 4-6. Other studies suggest that the number of C. pagurus landings positively correlates with soak time [36] but also declines with increasing soak time [39]. In the Northern Taiwan Strait, soak times of <48 h saw a greater catch of target crustacean species, whereas soak times of >48 h saw a greater haul of bycatch [40].…”

“…CPUE of H. gammarus also showed a negative correlation with sea surface temperature in this study, but [23] found that temperature had no significant effect on the number of individuals caught. In the Mediterranean Sea, warmer waters (May-August) were associated with higher CPUE for H. gammarus [39]. Soak time ranged from 1 to 7 days, with the optimal soak times differing depending on which target species was being caught.…”

“…The same study showed that all but one individual remained in depths shallower than 30 m for longer and shorter periods of activity [46]. The CPUE of H. gammarus was influenced by depths below 30 m (Figure 5) which would suggest a similar trend to [53], but also the limited activity in this species is likely to be associated with site fidelity which is common with this species [57], with activity commonly associated with feeding and territorial behaviour [58] within a few (~3.8 km) kilometres from their shelter [39]. Within a 20 m distance of a deployed creel, H. gammarus can remain in this vicinity for up to 17 h, and their presence can reduce the catch of both C. pagurus and N. puber [2,9].…”

Impacts of Sea Bottom Temperature on CPUE of European Lobster Homarus gammarus (Linnaeus, 1758; Decapoda, Nephropidae) in the Eastern Adriatic Sea

“…Therefore, high temperatures in shallow coastal waters during summer in the Mediterranean could play a major role in juvenile survival and the recruitment success (Pere et al, 2019). Moreover, a recent study in the northern Adriatic reported a high number of pre-adult lobster (Pavicǐćet al, 2021).…”