Observations on board of Portuguese purse seine fleets: activity pattern, catch, landing composition and fishing yields between 2009 and 2013
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1
The Portuguese Sea and Atmosphere Institute, I. P. - IPMA Matosinhos, Departament of the sea and marine resources, Portugal
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2
The Portuguese Sea and Atmosphere Institute - IPMA Algés, Department of the Sea and Marine Resources, Portugal
In Portugal, the purse seine fishery is one of the most important fisheries, accounting for about 40% by weight of landings on the Portugal mainland. The fishery targets several small and medium pelagic species, being sardine (Sardina pilcharus) and chub mackerel (Scomber colias) the main landings. Sardine landings peaked in 2008, decreased 20% until 2011 and dropped sharply since 2012 to below the annual catch limit. Chub mackerel as the second most important species, their landings increased continuously from 2009, and the total landed in this fishery fluctuated until today. This work aims to study the Portuguese purse seine fleet activity and catch composition for 2009 to 2013 using data from daily landings and on board observations at the mainland fishing ports. The study area was divided into three areas, North (Caminha to Figueira da Foz), Centre (from Peniche to Sines) and South (Portimão to Olhão). Data on purse-seine fishing activities and catches were collected by observers onboard commercial vessels (length-overall>16m) operating along the Portuguese coast between 2009 and 2013. Most trips (108 in 179) were carried out within the framework of the European Commission Data Collection Regulation (Programa Nacional de Amostragem Biológica/EU-Data Collection Framework) and data were collected using a standard protocol (Feijó et al. 2012). Since 2010, additional data were obtained within SAFESEA and Life+MARPRO projects (http://marprolife.org/) in Peniche, Olhão and Portimão. During the study period, an average of 149 purse-seiners made around 12 000 trips per year (Silva et al., 2015).We observed 179 trips and 229 sets in Portuguese purse seine fleet, so the observation effort represents 1.49% of daily landings. The capture observed was around 21 tons (North= 7,8 tons, Centre = 5,7 tons, South = 7,1 tons), and landings were around 18,5 tons (North= 6,9 tons, Centre = 4,4 tons, South = 6,6 tons). Although, chub-mackerel was the dominant capture, but not all its capture was landed. Over the period, sardine captures and landings decreased until 2013. By area, sardine captures decreased during the period. In the centre have been observed more landings of sardine, specially in 2013. The decline of sardine landed in the centre and south ports has been compensated by increasing capture and landings chub mackerel. The discards by "slipping" were more frequent in the North, mainly because of the implementation of daily limit quotas. Slipping is the deliberate release of the catch when the skipper finds reasons not to transfer part or the total catch, such as daily quotas, minimum sizes or mixture with not commercial species) In the Southwest, “slipping” usually resulted from mixture with non-commercial species that would decrease the landing price. That’s the main reason that capture is different of purse-seine landings.
Keywords:
Purse seine fishery,
catches,
landings,
Slipping,
Sardine
Conference:
XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016.
Presentation Type:
Oral Presentation
Topic:
4. FISHERIES, AQUACULTURE AND BIOTECHNOLOGY
Citation:
Feijó
D and
Silva
A
(2016). Observations on board of Portuguese purse seine fleets: activity pattern, catch, landing composition and fishing yields between 2009 and 2013.
Front. Mar. Sci.
Conference Abstract:
XIX Iberian Symposium on Marine Biology Studies.
doi: 10.3389/conf.FMARS.2016.05.00071
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Received:
30 Apr 2016;
Published Online:
02 Sep 2016.
*
Correspondence:
Ms. Diana Feijó, The Portuguese Sea and Atmosphere Institute, I. P. - IPMA Matosinhos, Departament of the sea and marine resources, Matosinhos, 4450-208, Portugal, dfeijo@ipma.pt