The present study intends to update a previous study (EC MED92/011) in order to (i) assess the effect of an eight-year trawl ban on the demersal resources (over trawlable and non-trawlable bottoms) in the Gulf of Castellammare, and (ii) investigate how these resources are now being exploited by the small-scale fishery, as well as the extent of any social or economic gain arising as a result of the trawl ban. The study is made of two parts: A) biological section, and B) socio-economic section. A - Biological section Four seasonal trawl surveys were carried out from June 1998 to March 1999 on the continental shelf. The stratum that yielded the highest CPUE was stratum A (10-50 m: 61248 gr/haul), followed by str. B (51-100 m: 47914 gr/haul) and str. C (101-200 m: 26356 gr/haul). Considering the seasons, CPUEs were 34663 gr/haul in spring, 52234 in summer, 53079 in autumn and 27578 in winter. Mullus barbatus was the most abundant species overall. Highly commercial species were the dominant category in almost all the seasons and strata, with a peak in str. A in summer. Twelve trammel-gillnet surveys were carried out on a monthly basis in shallow waters on sandy bottoms (SB), rocky bottoms (RB) and an artificial reef area (ARA), from June 1998 to May 1999. The area that yielded the highest CPUE was SB (4000 gr/trip), followed by RB (3646 gr/trip) and ARA (3322 gr/trip). Considering the seasons, CPUEs were 2709 gr/trip in spring, 3569 in summer, 3168 in autumn and 4006 in winter. The most abundant species overall was Boops boops. Moderately commercial species dominated the trammel-gillnet catches; highly commercial species reached a peak in abundance in RB in summer. The CPUEs of the total catch in the trawl surveys was larger in 1998-99 than in 1993-94, especially in str. A. Considering the single strata and seasons, CPUEs were larger in 1993-94 only in winter (str. B, C and total area) and in spring (stratum B). The CPUEs of the following target species (mean over the total area) decreased in 1998-99: M. barbatus (which increased in str. A), Lithognathus mormyrus, Sepia officinalis, Eledone moschata. The proportion of highly- and non-commercial species decreased in 1998-99, while that of moderately commercial species increased. The CPUEs of the trammel-gillnet surveys were larger in 1998-99 than in 1993-94, especially in SB. Considering the single areas and seasons, there was a decrease in 1998-99 in spring (in ARA and RB). The CPUEs of following species decreased in 1998-99: Octopus vulgaris in RB, Scorpaena porcus in RB, S. officinalis in ARA and RB. The proportion of highly commercial species decreased in 1998-99, while that of moderately commercial species increased. A landings survey of the small-scale fishery catches was carried out on a fortnightly basis from July 1998 to June 1999. The highest catches of the set net fishery were made in winter and spring, the lowest in summer. Fishermen in Castellammare and Balestrate obtained the largest CPUEs. Considering the Balestrate FAD fishery, dolphin fish (which is the target species) was the most abundant fish, followed by amberjack and juvenile bluefin tuna. B - Socio-economic section In 1998-99 there were 147 fishing vessels registered to fish in the Gulf of Castellammare. Of these, 96 were registered artisanal fishing boats. The main gear used by fishermen was a set net (trammel or gillnet). The economic assessment of the small-scale fishery required primary data, which were collected through a landings survey, a fishing characteristics survey and a motivations survey. The assessment of the financial performance of artisanal fishermen also data on fish price and capital costs were collected. Net financial profit (boat income) of trammel netters in 1998-99 averaged 8.7 million lira (= 4493 Euro). Just fewer than 7% of operators incurred losses, while some 13% earned profits in excess of 25 million lira (= 12911 Euro). The fishery has the potential to be economically sustainable, since the capital necessary for its long-term continuation would be expected to earn a competitive return. Biological data based on experimental trawl surveys and trammel net surveys showed a large increase in demersal stocks since the ban was imposed. However, over the period species composition has changed, with most of the biomass increase being for varieties classed as only 'moderately commercial'. This may therefore have attenuated the financial gains for artisanal fishermen. Recreational fishing was identified as the single most important problem facing professional artisanal fishermen. As far as the ban is concerned, most fishermen felt that fishing was "better" or "much better" since the ban, 14% "worse" or "much worse". This contrasts with their view of prospects, where 24% believed fishing would be "better" or "much better" while 55% stated it would be "worse" or "much worse". Despite their apparent pessimism, the overwhelming majority (86%) signalled their intention of carrying on fishing in the Gulf in the future.
Trawling ban in the Gulf of Castellammare: effects on the small scale fishery economics and on the abundance of fish
PIPITONE C;BADALAMENTI F;D'ANNA G;
2000
Abstract
The present study intends to update a previous study (EC MED92/011) in order to (i) assess the effect of an eight-year trawl ban on the demersal resources (over trawlable and non-trawlable bottoms) in the Gulf of Castellammare, and (ii) investigate how these resources are now being exploited by the small-scale fishery, as well as the extent of any social or economic gain arising as a result of the trawl ban. The study is made of two parts: A) biological section, and B) socio-economic section. A - Biological section Four seasonal trawl surveys were carried out from June 1998 to March 1999 on the continental shelf. The stratum that yielded the highest CPUE was stratum A (10-50 m: 61248 gr/haul), followed by str. B (51-100 m: 47914 gr/haul) and str. C (101-200 m: 26356 gr/haul). Considering the seasons, CPUEs were 34663 gr/haul in spring, 52234 in summer, 53079 in autumn and 27578 in winter. Mullus barbatus was the most abundant species overall. Highly commercial species were the dominant category in almost all the seasons and strata, with a peak in str. A in summer. Twelve trammel-gillnet surveys were carried out on a monthly basis in shallow waters on sandy bottoms (SB), rocky bottoms (RB) and an artificial reef area (ARA), from June 1998 to May 1999. The area that yielded the highest CPUE was SB (4000 gr/trip), followed by RB (3646 gr/trip) and ARA (3322 gr/trip). Considering the seasons, CPUEs were 2709 gr/trip in spring, 3569 in summer, 3168 in autumn and 4006 in winter. The most abundant species overall was Boops boops. Moderately commercial species dominated the trammel-gillnet catches; highly commercial species reached a peak in abundance in RB in summer. The CPUEs of the total catch in the trawl surveys was larger in 1998-99 than in 1993-94, especially in str. A. Considering the single strata and seasons, CPUEs were larger in 1993-94 only in winter (str. B, C and total area) and in spring (stratum B). The CPUEs of the following target species (mean over the total area) decreased in 1998-99: M. barbatus (which increased in str. A), Lithognathus mormyrus, Sepia officinalis, Eledone moschata. The proportion of highly- and non-commercial species decreased in 1998-99, while that of moderately commercial species increased. The CPUEs of the trammel-gillnet surveys were larger in 1998-99 than in 1993-94, especially in SB. Considering the single areas and seasons, there was a decrease in 1998-99 in spring (in ARA and RB). The CPUEs of following species decreased in 1998-99: Octopus vulgaris in RB, Scorpaena porcus in RB, S. officinalis in ARA and RB. The proportion of highly commercial species decreased in 1998-99, while that of moderately commercial species increased. A landings survey of the small-scale fishery catches was carried out on a fortnightly basis from July 1998 to June 1999. The highest catches of the set net fishery were made in winter and spring, the lowest in summer. Fishermen in Castellammare and Balestrate obtained the largest CPUEs. Considering the Balestrate FAD fishery, dolphin fish (which is the target species) was the most abundant fish, followed by amberjack and juvenile bluefin tuna. B - Socio-economic section In 1998-99 there were 147 fishing vessels registered to fish in the Gulf of Castellammare. Of these, 96 were registered artisanal fishing boats. The main gear used by fishermen was a set net (trammel or gillnet). The economic assessment of the small-scale fishery required primary data, which were collected through a landings survey, a fishing characteristics survey and a motivations survey. The assessment of the financial performance of artisanal fishermen also data on fish price and capital costs were collected. Net financial profit (boat income) of trammel netters in 1998-99 averaged 8.7 million lira (= 4493 Euro). Just fewer than 7% of operators incurred losses, while some 13% earned profits in excess of 25 million lira (= 12911 Euro). The fishery has the potential to be economically sustainable, since the capital necessary for its long-term continuation would be expected to earn a competitive return. Biological data based on experimental trawl surveys and trammel net surveys showed a large increase in demersal stocks since the ban was imposed. However, over the period species composition has changed, with most of the biomass increase being for varieties classed as only 'moderately commercial'. This may therefore have attenuated the financial gains for artisanal fishermen. Recreational fishing was identified as the single most important problem facing professional artisanal fishermen. As far as the ban is concerned, most fishermen felt that fishing was "better" or "much better" since the ban, 14% "worse" or "much worse". This contrasts with their view of prospects, where 24% believed fishing would be "better" or "much better" while 55% stated it would be "worse" or "much worse". Despite their apparent pessimism, the overwhelming majority (86%) signalled their intention of carrying on fishing in the Gulf in the future.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
