A Pesca de Emalhe e de Espinhel de Superfície na Região Sudeste-Sul do Brasil

Publisher: Série Documentos Revizee, ISBN: 85-98729-14-0


Drifters operated from Itajaí-Navegantes (Santa Catarina State) and Ubatuba (São
Paulo State),between 1993 and 1997 years.Panel mesh size ranged from 12 to 40 cm
(opposite knots, streched) and net length from 1.130 m to 7.560 m.Hammerheads
(mainly Sphyrna lewini, Griffith & Smith, 1834) were the target species , due to its
highly valuable fins in the international market. They represented 77,8% and
28,5% of the total driftnet landings in Itajaí-Navegantes and Ubatuba respectively.
In 1995, the high fishing effort applied by drifters from Itajaí and Navegantes
(72 .216 km of net length estimated), plus the patchy distribution of the adult
hammerheads during the reproductive season, led to a steep yield decline the
following years.

The monofilament longline fishery, based in Itajaí and Navegantes (Santa
Catarina State, Brazil) was described, focusing on sharks and finning. Between
2000 and 2002 years, sharks represented more than 50% of the total longline
landings in Santa Catarina State, being the carcasses for domestic market and fins
exported to Asia. Steel wires used at the gangions are the main responsible for the
high shark rate capture. The blue shark (Prionace glauca), is the most important
species. A seasonal pattern was presented for blue sharks, hammerheads,
billfish, albacores and swordfish catches. Longline survival was high for sharks
(more than 50%) and most of them are sacrificed aboard. Higher hammerhead
catches used to happen in the second quarter of the year.

The hammerheads catch dynamics (Sphyrna lewini and Sphyrna zygaena)
was studied through covariance analysis (ANCOVA) on longline data for the fleet
based in Itajaí and Navegantes (Santa Catarina State, Brasil). Catch and effort
observations (n � 596) were used for the period 1996-2001.Year, season, and area
effects were tested in the model, being the natural logarithm of the fishing effort
(hook number) the covariable. The adjusted means by the model showed higher
hammerhead catches during winter (related to Sphyrna zygaena), spring and
summer (related to Sphyrna lewini).There was a low variation in the hammerhead
catches between 1996 and 2001 years. An area over the continental slope,
between 200 and 3.000 m depth and limited by 30° – 35° S latitudes, yielded the
best catches. The logarithmic relationship between catch (Kg) and effort (hook
number) is linear and positive.

    • "There are also two isolated reports of the lesser Guinean devil ray (Mobula rochebrunei (Vaillant, 1979)) from southern Brazil that needs confirmation (Barletta et al. 1989 and Charvet 1995 cited in Valenti and Kyne 2009), as this species is considered to be endemic to the central and south-eastern Atlantic Ocean (Couturier et al. 2012). Although there are no reports of fisheries targeting mobulids in south-western Atlantic waters, they are still captured as by-catch by longline and gill-net fisheries (Amorim et al. 1998; Kotas et al. 2005; Domingo et al. 2008). However, given the difficulties with their identification and the fact that they are never retained on board because of their low commercial value, catch statistics provide very little information about mobulids at the species level. "
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    ABSTRACT: This paper presents the first by-catch assessment focussed on mobulid rays in pelagic longline fisheries based on on-board scientific observer data (1998–2013) over the south-western Atlantic. Mobulid diversity, as well as their catch distribution and disposition, were investigated. Mobulid by-catch frequency was low, but by-catch probability increased at lower bottom depths (i.e. continental shelf and slope), higher fishing effort and during the warm period (summer–autumn). Photographic and video records allowed the identification of two devil ray species, the spinetail devil ray (Mobula japanica) and the bentfin devil ray (Mobula thurstoni), but the number of species interacting with longliners in the region could also be greater. Southernmost captures of both species (36°S) exceed previous reported records by almost 12°, therefore greatly expanding their known distribution ranges towards southern waters in the south-western Atlantic. Mobulids were never retained on board, and most of them were released alive. However, hooks were often not removed from their bodies and on several occasions fishermen caused injuries while trying to cut the branch line, so some uncertainty remains regarding their post-capture mortality. More specific studies that assess these particular aspects are needed to better understand the potential effect of longline fisheries on mobulid populations.
    No preview · Article · Mar 2015 · Marine and Freshwater Research
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    ABSTRACT: Fisheries are recognised as a major threat to sea turtles worldwide. Oceanic driftnets are considered the main cause of the steep decline in Pacific Ocean populations of the leatherback sea turtle Dermochelys coriacea. The world’s largest leatherback population nests in West Africa and migrates across the Atlantic Ocean to feed off the South American coast. There, the turtles encounter a range of fisheries, including the Brazilian driftnet fishery targeting hammerhead sharks. From 2002 to 2008, 351 sea turtles were incidentally caught in 41 fishing trips and 371 sets. Leatherbacks accounted for 77.3% of the take (n = 252 turtles, capture rate = 0.1405 turtles/km of net), followed by loggerheads Caretta caretta (47 individuals, capture rate = 0.0262 turtles/km of net), green turtles Chelonia mydas (27 individuals, capture rate = 0.0151 turtles/km of net) and unidentified hard-shelled turtles (25 individual, capture rate = 0.0139 turtles/km of net) that fell off the net during hauling. Immediate mortality (i.e., turtles that were dead upon reaching the vessel, excluding post-release mortality) was similar among the species and accounted for 22.2 to 29.4% of turtles hauled onboard. The annual catch by this fishery ranged from 1,212 to 6,160 leatherback turtles, as estimated based on bootstrap procedures under different fishing effort scenarios in the 1990s. The present inertia in law and enforcement regarding gillnet regulations in Brazil could result in the reestablishment of the driftnet fishery, driving rates of leatherback mortality to levels similar to those observed in previous decades. This development could potentially lead to the collapse of the South Atlantic leatherback population, mirroring the decline of the species in the Pacific. In light of these potential impacts and similar threats to other pelagic mega fauna, we recommend banning this type of fishery in the region.
    Full-text · Article · Apr 2012 · Biodiversity and Conservation
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    Full-text · Article · Apr 2015 · Marine Mammal Science