Fishing strategy choices of purse seines in the Mediterranean: implications for management

Abstract

An observer's sampling scheme, that employed fisheries scientists onboard fleet vessels was used to examine temporal fishing tactics and strategies affecting catches of the purse seine fishery in the Mediterranean. The month, water depth and the fishers' behavior were found to have an effect on total and Trachurus spp. retained catches, with fishers' behavior explaining the largest percentage of the data variation. The distance of the fishing ground from port and the market price modulated both the retained catches and the fishing location choice. Results confirmed that fishers while in a specific fishing ground developed strategies that would allow them to retain, and thus land, the best possible combination of landings ¥ market value. The current findings also revealed that, when constrained by physical and economic conditions, fishers preferred to minimise risk rather than maximize landings. The observed major switches in fishing strategy were attributed to fishers' risk attitude response towards higher profitability. As the Mediterranean fishery system is mainly based on control effort and technical measures regimes, the current findings are discussed in the light of the need to consider additional information to management plans and decisions.

Fish predation in the proximity of purse seine fishing lights: The case of Atherina boyeri (Actinopterygii: Atheriniformes: Atherinidae) in a Greek Lake

“…Purse seining with light is among the most important fishing practices in the Mediterranean Sea being able to harvest large quantities of shoaling fish such as sardinella, sardine, anchovy, mugilids, horse mackerel, sand smelt, etc. (Papaconstantinou and Farrugio 2000, El-Haweet 2001, Tsitsika and Maravelias 2008. The typical purse seine practice involves anchoring lamp rafts with their lights turned on for some time in order to attract a fish school.…”

Economic efficiency analysis and fleet capacity assessment in Mediterranean fisheries

“…Observations made by fisheries scientists onboard confirmed that in the Mediterranean purse-seine fishery, the retained catches were modulated by both market price and distance from port (Tsitsika and Maravelias, 2006;Tsitsika et al, 2007). Furthermore fishers adapted their fishing operations in that way so as to return to port as early as possible and sell their catches at the best price they could ("profit maximisers", Tsitsika and Maravelias, 2008). It is more than likely that the performance of the models could be improved with the inclusion of additional information, not readily available, such as stock size, recruitment fluctuations, fishing ground, skipper age/education, crew etc.…”

“…As largest vessels have higher levels of engine power are able to steam in different fishing grounds and thus conduct more fishing operations than the smaller vessels in a given trip (Guyader and Daurès, 2005;Tsitsika and Maravelias, 2008). In a typical Mediterranean purse-seine fishery vessels operate exclusively during night hours i.e., from 20:00 to 05:00.…”

“…This fishery is heavily affected by weather conditions. Strong winds and currents prevailing after September impede the setting of the nets and thus increase fish species' escapement during fishing activity (Tsitsika and Maravelias, 2006;Tsitsika and Maravelias, 2008). Since fishers are known to be profit maximizers, weather conditions force them to adapt their individual decision-making process and many times prefer not to conduct any fishing activity (Tsitsika and Maravelias, 2008).…”

“…In such a fishery the choice of the total revenue or the total weight could alter the output measures. In the Eastern Mediterranean a recent study revealed that the purse-seine fishers have developed strategies to maximize their overall fishing trip profit instead of targeting a specific species fishery (Tsitsika and Maravelias, 2008). High revenue could result from a low catch of high values species, large catch of low value species (e.g.…”