Flávia Lucena Frédou

High Value and Long Life—Double Jeopardy for Tunas and Billfishes

The first standardized, global assessment of these fishes, using Red List criteria, reveals threatened species needing protection. There is growing concern that in spite of the healthy status of several epipelagic (living near the surface) fish stocks (1), some scombrid (tunas, bonitos, mackerels, and Spanish mackerels) and billfish (swordfish and marlins) species are heavily overfished and that there is a lack of resolve to protect against overexploitation driven by high prices (2–5). Many populations are exploited by multinational fisheries whose regulation, from a political perspective, is exceedingly difficult. Thus, assessment and management is complicated and sometimes ineffective (4). Regional Fisheries Management Organizations (RFMOs) were created to manage and conserve scombrids and billfishes because of their transnational distributions and widespread economic importance (6). However, species-specific catch data for many scombrids and billfishes are not collected or are aggregated with other species. Even for the larger tunas, for which relatively rich data exist, population assessments and data are complex (1) and are difficult to combine across RFMOs, which prompts a need for alternative means of assessment.

A better way forward for Brazil's fisheries.

In December 2014, the Brazilian Minister of the Environment released the new national red lists enumerating 2113 plants and 1173 animals threatened with extinction ([ 1 ][1]). Of the 475 aquatic species on the list, 83 are commercially exploited by fisheries, mainly as by-catch. The industrial

Sharks caught by the Brazilian tuna longline fleet: an overview

AbstractLarge pelagic sharks are distributed throughout all of the oceans and are caught as bycatch in pelagic longline fisheries worldwide. In the southern Atlantic Ocean, more than a dozen shark species are caught by the Brazilian tuna longline fleet. This study compiles information of the main shark species caught by the Brazilian tuna longline fishery in the southwestern and equatorial Atlantic Ocean. Catch and effort data of 14,860 longline sets from the Brazilian chartered tuna longline fleet, between 2004 and 2010, were analyzed. The blue shark Prionace glauca was the main shark species captured by this fishery. Shark catches showed contrasting trends during the study period: the silky (Carcharhinus falciformis) and the oceanic whitetip (C. longimanus) sharks catch increased up to 2008 and then declined, while mako sharks (Isurus spp.) showed an opposite trend. Effort for the Brazilian longline fishery had a higher concentration from 10°N to 30°S and from 20°W to 40°W. High values of catch per unit effort of southwestern and equatorial Atlantic Ocean sharks were heterogeneously distributed and, although elasmobranchs were caught over most of the longline fishing range, only blue sharks were caught in all areas. In the southern Atlantic Ocean, high fishing effort zones overlap significantly with some nursery areas, especially for the oceanic whitetip shark, indicating that these areas are at a direct risk from the industrial longline fishery.

POPULATION DYNAMICS OF THE PINK SHRIMP FARFANTEPENAEUS SUBTILIS (PÉREZ-FARFANTE, 1967) IN NORTHEASTERN BRAZIL

This study provides information on the population structure, growth, mortality, maximum recruitment yield, and longevity for pink shrimp Farfantepenaeus subtilis (Perez-Farfante, 1967) on the coast of Pernambuco state, northeastern Brazil. A total of 1246 specimens (545 males and 701 females) were monthly collected from August 2011 to July 2012. Mean total length of females was higher (11.42 ± 1.61 cm) than males (10.5 ± 1.62 cm) and dominated in the largest length classes. Estimation of von Bertalanffy growth parameters for total length resulted in L∞ of 19.74 cm and k of 1.06 year −1 for males, while females’ L∞ was 21.64 cm and k was 1.10 year −1 . Mortality of females was higher than males resulting higher value in the exploitation rates. The exploitation rate for maximum recruitment yield was similar between males and females with a value of 0.67, which was above the exploitation rates (0.50-0.64).

Reproductive cycle of seabob shrimp Xiphopenaeus kroyeri (Crustacea, Penaeidea) from the northeast coast of Brazil

Abstract The reproductive cycle of Xiphopenaeus kroyeri north-eastern Brazil was described to contribute to the sustainable management of this stock in the region. Specimens were collected monthly from August 2011 to July 2012 using a local vessel of the artisanal fleet. A total of 1201 individuals were analyzed (673 females and 528 males) with a mean carapace length (CL) of 1.88 ± 0.16 cm and total length (TL) of 9.00 ± 1.22 cm. The lowest CL and TL of mature females were 1.33 and 6.5 cm, respectively, and all females above 2.44 cm (CL) and 11.5 cm (TL) were mature. Ovarian maturation was classified into four stages: I (immature), II (maturing), III (mature) and IV (spawned). Individuals of all maturational stages were present throughout the year. Considering the macro and microscopic analysis, it was suggested that this species in north-eastern Brazil has a continuous reproductive cycle, with two seasonal peaks, November/December and February (austral spring and summer). A positive correlation between the percentage of mature females and temperature was observed, and a higher percentage was reported in the warmer months of the year. This suggests that the reproductive peaks can be triggered by water temperature variation throughout the year.

Fish bycatch of the laulao catfish Brachyplatystoma vaillantii (Valenciennes, 1840) trawl fishery in the Amazon Estuary

Este estudo objetivou analisar a composicao e variacao sazonal da ictiofauna acompanhante da pesca de arrasto de Brachyplatystoma vaillantii no estuario amazonico, em 2009, atraves do monitoramento de viagens de 48 embarcacoes. A ictiofauna acompanhante representou 29% das capturas, totalizando 22.228 individuos e 52 taxons pertencentes a 22 familias, sendo estas as principais: Ariidae, Pimelodidae e Sciaenidae. Brachyplatystoma rousseauxii, Plagioscion squamosissimus e Sciades herzbergii representaram juntas 69% da captura e foram consideradas constantes. Embora o maior percentual de captura tenha ocorrido no periodo chuvoso, as diferencas sazonais nao foram significativas. Analises de ordenacao (MDS) e de similaridade (ANOSIM) mostraram que a composicao da captura entre os periodos e semelhante; entretanto, maiores capturas de B. rousseauxii e P. squamosissimus foram observadas no periodo chuvoso, enquanto S. herzbergii foi dominante no periodo seco. As guildas migrantes marinhas e especies estuarinas apresentaram maior riqueza, enquanto as migrantes dulcicolas predominaram em percentual de individuos. Considerando as guildas alimentares, as zoobentivoras apresentaram a maior riqueza, enquanto as piscivoras predominaram em abundância relativa. Os resultados indicam que a pressao pesqueira atua sensivelmente sobre os individuos de pequeno (20-30 cm) e medio (30-50 cm) porte, embora a captura de P. squamosissimus seja composta predominantemente por adultos. A captura de B. rousseauxii e B. vaillantii, entretanto, foi composta predominantemente por juvenis.

A new multifrequency acoustic method for the discrimination of biotic components in pelagic ecosystems: Application in a high diversity tropical ecosystem off Northeast Brazil

Underwater acoustics have an unrealized potential for multicomponent ecosystem characterization. A variety of methods (e.g., backscattering differences, clustering, Gaussian model) are currently used for multifrequency classification. In this study we propose and implement a new method based on the distribution of scatters on multifrequency spatial planes. Our approach is based on both the sum and the difference of backscattered energy of up to five bi-frequency pairs. This method was developed using four frequencies (38, 70, 120 and 200 kHz) data collected in the frame of the ABRAÇOS (Acoustics along the BRAzilian COaSt) project, around Archipelago of Fernando de Noronha and Atoll das Rocas; an area characterized by low productivity but high biodiversity. By applying the method we could discriminated six groups: Fish like, two types of High Resonant at 38 kHz associated to gelatinous, Fluid Like associated to crustacean macrozooplankton, High Resonant at 70 kHz associated to pelagic algae, and a group of Unclassified echoes. The algorithm was validated using in situ sampling performed by mesopelagic trawl and zooplankton nets. Results are coherent in terms of distribution pattern of each group allows for a 3D representation of organisms distribution around the oceanic islands. Among other, we reveal the importance of gelatinous are the dominant group in the vicinity of the islands where they form a dense layer above the thermocline. These results open new perspectives to improve knowledge on the patterns of distribution and the interaction of a variety of functional groups in tropical and other systems.