Kátia Cristina de Araújo Silva

Reproductive potential and stock recruitment of the Caribbean and Brazilian metapopulations of the spiny lobster, Panulirus argus (Latreille, 1804)

The spiny lobster Panulirus argus (Latreille, 1804) is the most important commercial fishing resource in the western central Atlantic and Brazil. Field studies covering the waters off southwestern Cuba and northern Brazil have improved our understanding of the variations in the reproductive potential (number of eggs), stock recruitment and reproductive efficiency of spiny lobsters according to location, depth and size class. Using the spawner-recruitment model, the reproductive potential index was correlated with the index of subsequent recruitment based on field sampling. Spiny lobster habitats in deeper waters need special attention in order to protect the species from overfishing of the recruitment. Considering the longevity and absence of reproductive senility in spiny lobsters, management strategies should ideally include the creation of spawner sanctuaries (marine protected areas) capable of restoring and maintaining the biomass of the spawning stock and the establishment of a maximum catch size of 135 mm (CL) for both sexes along the entire Brazilian coast. Based on our findings, we propose to establish spiny lobster sanctuaries (50-100 m) on the continental shelf off northern Brazil, from Amapa (5°25′N 51°0′W) to the western reaches of the coast of Para (1°11′N 46°27′W, 0°42′N 46°45′W), covering a total surface area of 64 230 km2.

Assessment of wild spiny lobster stocks on the Brazilian continental shelf

The red spiny lobster Panulirus argus (Latreille, 1804) and the green spiny lobster Panulirus laevicauda (Latreille, 1817) are the most abundant and commercially valuable lobster species on the Brazilian continental shelf. Though sold on the domestic market, the painted spiny lobster (Panulirus echinatus Smith, 1869) and the slipper lobster (Scyllaridae) are of little economic importance and have been the object of very little research. Brazilian spiny lobster fisheries have been in decline for many years due to growth overfishing, including the capture of undersized specimens (>50%). Furthermore, fishing berried females and older lobsters from deeper waters (≥50 m), compromising the reproductive potential of the species and increasing the risk of low recruitment and fishing collapse. The setting of quotas on catches is in itself insufficient to protect Brazilian lobster stocks. Management efforts should instead focus on the enforcement of control measures in order to increase lobster stocks. In this study we make several recommendations: (i) lobster traps should be furnished with escape gaps for undersized lobsters, (ii) the use of undersized lobsters (decoys) in traps should be avoided, (iii) gillnets (“cacoeira”) and artificial shelters (“marambaia”) should be eliminated, (iv) an optimal minimum legal size should be established (80 mm CL for all spiny lobster species and 85 mm CL for slipper lobsters), (v) a maximum legal size should be established (135 mm CL for P. argus and 100 mm CL for P. laevicauda of both sexes), (vi) the capture of berried females should be prohibited, (vii) a closed season should be instituted to protect ovigerous females and ensure recruitment, (viii) establishment of marine reserves or a total closed season to protect the juveniles in nursery areas, (ix) a monitoring program collecting catch and effort data should be implemented to help assess lobster stocks adequately, and, (x) stratified random sampling must be implemented.

Large-scale oceanic circulation and larval recruitment of the spiny lobster Panulirus argus (Latreille, 1804)

The most important populations of the spiny lobster (Panulirus argus (Latreille, 1804)) in the Atlantic are found in the Caribbean and along the Brazilian coast. Field studies covering the waters off the Cuban archipelago and Brazil have improved our understanding of the importance of oceanic circulation to larval recruitment. South of Cuba, puerulus settlement is intensive in October and November when the coastal reefs (83°W) are impacted by a cyclone-anticyclone pair, suggesting this area is the main source of retention and supply of surviving larvae, thus of self-recruitment. On the continental shelf of Brazil, puerulus settlement takes place throughout the year, but two annual peaks have been identified: one in March-April and one in July-September, when retroflection eddies of the North Brazil Current are more intense and feed into the eastward-flowing North Equatorial Countercurrent. Conceivably, Brazilian spiny lobster larvae are trapped in this oceanic system, leading to self-recruitment. On the continental shelf of Brazil the larval period lasts 6-7 months, depending on the season and spawning date. In the Caribbean the period is reported to be 6-8 months. Information on the relative abundance of early-stage spiny lobster larvae makes it possible to predict patterns of recruitment of pueruli and juveniles and the timing of their life cycle. However, further research on seasonal variations in local currents, current retroflection and ring formation is needed to clarify important aspects of larval transport, puerulus settlement and recruitment.

Structure and diversity of the lobster community on the Amazon continental shelf

The present study analyses the diversity and community structure of the lobsters captured using bottom trawl shrimp nets at depths of 41 to 626 m during fishery prospection cruises conducted between 1996 and 1998. The study area encompasses the coasts of the Brazilian states of Amapa and Para, which were divided into two sectors, to the north and to south of Cape North. The 44 lobster specimens identified belonged to nine species: Acanthacaris caeca (A. Milne-Edwards, 1881), Nephropsis aculeata Smith, 1881, Nephropsis rosea Bate, 1888, Palinustus truncatus A. Milne-Edwards, 1880, Panulirus argus (Latreille, 1804), Parribacus antarcticus (Lund, 1793), Polycheles typhlops Heller, 1862, Scyllarides delfosi Holthuis, 1960 and Stereomastis sculpta (Smith, 1880). The specimens were captured preferentially on muddy sand substrates in the northern sector and gravelly and muddy sand in the southern sector. All species were more common in the northern sector during the dry season (June-November), and in the southern sector in the rainy season (December-May).

Spatial distribution of southern brown shrimp (Farfantepenaeus subtilis) on the Amazon continental shelf: a fishery, marine geology and GIS integrated approach

The spatial distribution of the southern brown shrimp Farfantepenaeus subtilis (Perez-Farfante, 1967) was studied based on industrial fishing fleet activities and is associated with geological and oceanographic characteristics of the benthonic environments on the Amazon continental shelf. Using a geographical information system (GIS) this paper sought to calculate the relative abundance of brown shrimp based on catch per unit effort (CPUE) and compare it with bathymetry, type of sedimentary structure, sedimentation rate and bottom salinity. As a result, we have concluded that the relative abundance (in terms of CPUE) is not uniformly distributed in space. Spatial analysis indicates that commercial trawling efforts were made in the (foreset) region of the subaqueous Amazon delta at depths of 40 to 60 m. In this region, prawn are responsible for the bioturbation of the sediments and the creation of a sedimentary structure called mottled mud. In the foreset region, sedimentation rates progressively increased up to 10 cm.yr-1; re-suspension was reduced and bottom salinity was high (~ 36). It appears that all of these factors define a stable muddy area with intense bioturbation. This notable biological activity is to be explained by the occurrence of a high F. subtilis abundance that appears to originate in a microbial loop. We concluded that by combining fishery information with environmental data from a GIS, it was possible to identify abundance distribution patterns for southern brown shrimp and other economically important fishery resources and to understand how they change on a large spatial-scale.

Impact of lobster size on catches and prediction of commercial spiny lobster landings in Brazil

On the Brazilian continental shelf, red spiny lobsters, Panulirus argus (Latreille, 1804) constitute a separate population with two distinct stocks, one in shallow waters ( 135 mm CL) from deeper waters increases the risk of low recruitment and fishing collapse. The observed change in fishing patterns appears to be the consequence of increased fishing mortality (F) among pre-recruits. This is possibly the main cause of the large fluctuations observed in landings, although other factors, such as the interplay between environmental conditions and recruitment abundance, may have to be considered. Our results show that increasing the minimum legal size of red lobsters is likely to improve total landings in the long term, provided appropriate and tightly enforced control measures are designed and implemented.

Seletividade do matapi nas capturas de Macrobrachium amazonicum no baixo Rio Tocantins, Amazônia, Brasil

The study aimed to determine the selectivity of matapi used in catching Amazon-shrimp, Macrobrachium amazonicum (Heller, 1862), the lower Tocantins River. The fishing was carried out during the rainy season and the dry season of 2013 in three sampling points. Thirty matapis were used for every collection point, with spacing between battens 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 mm, all with babassu baits. The Kruskal-Wallis test was used to compare mean total length and weight and condition factor of the specimens with 5% error; the weight/length ratios were analyzed by bilateral t test with α=5%; and the selectivity for the curves of selection. The results demonstrated that males are bigger and females are heavier. The weight/length relationship were positively correlated, differed between the sexes (t = - 4.59; p <0.0001), whereas males and females exhibited negative allometric growth. The condition factor was higher in the rainy season. The matapi with spacing of 5 mm of splices is the most suitable for fishing, taking into account the capture of 50% of the adult population and the captured volume.

Avaliação do desembarque de Hemiodus unimaculatus (Bloch, 1794) na área de influência da Usina Hidrelétrica de Tucuruí, Pará, Brasil / Landing assessment of Hemiodus unimaculatus (Bloch, 1794) in the área of the Tucurui Dam, Pará, Brazil

A pesca na area de influencia do reservatorio da Usina Hidreletrica de Tucurui e a principal atividade economica, o que gera alimento, emprego e renda para pescadores da regiao. Neste cenario, a jatuarana-escama-grossa, Hemiodus unimaculatus (Bloch, 1794) se destaca como uma das principais especies desembarcadas. Foram analisadas series temporais de dados de desembarque (do periodo de 2000 a 2008) de jatuarana-escama-grossa. A especie e capturada nas tres subareas de influencia da UHE Tucurui durante o ano todo, sendo a montante responsavel pela maior producao desembarcada. Picos de producao foram verificados nos meses de maio, junho e outubro, na subarea a montante, de maio a agosto no reservatorio e em janeiro e de maio a junho, na subarea a jusante. O principal porto de desembarque de jatuarana-escama-grossa esta localizado no municipio de Itupiranga, que fica a montante da UHE Tucurui. Considerando que a tendencia da producao anual desembarcada esta aumentando continuamente na subarea a montante, e reforcada a necessidade de implementar infraestrutura local, visando essa pescaria e trabalhar regras de ordenamento da pescaria na area.

Diversity and structure of the stomatopod (Crustacea) community on the Amazon continental shelf

The present study aimed to characterize the biodiversity of the Stomatopoda species found off the coast of the northern Brazilian states of Amapa and Para, within the regions Exclusive Economic Zone. Two distinct sectors were surveyed, to the north and to the south of Cape Norte. The specimens were collected during fishery surveys carried out between 1996 and 1998 by the Revizee Program, using bottom shrimp trawl nets. The specimens were identified at the Crustaceans Laboratory of the Center for Research and Management of Fishery Resources of the Northern Coast and the Carcinology Laboratory of the Federal Rural University of Pernambuco. The 189 identified specimens represented Lysiosquilla scabricauda (Lamarck, 1818) (n = 2), Parasquilla meridionalis Manning, 1916 (n = 1), Squilla empusa Say, 1818 (n = 6), and Squilla lijdingi Holthuis, 1959 (n = 180). Only three species were collected in each of the survey sectors, with L. scabricauda and S. lijdingi being captured in both sectors. Squilla lijdingi was dominant in both sectors, whereas the other species were considered to be rare. Squilla lijdingi was very frequent in the northern sector, although the other stomatopods were infrequent. In the southern sector, L. scabricauda was sporadic, S. empusa was frequent, and S. lijdingi was very frequent. A significant difference was observed in the number of specimens captured in both sectors. The Shannon index was 0.6144 bits.ind-1 for the northern sector and 0.2708 bits.ind-1 for the southern one, whereas equitability was 0.3876 in the North and 0.1708 in the South. The stomatopods were collected at depths between 32 and 109 m, and were captured primarily on gravelly bottoms in the northern sector, and on muddy substrates in the southern sector. Stomatopods were more abundant in the northern sector during the dry season from June to November, whereas they were more common in the South during rainy season, from December to May.

Report of Scyllarus chacei Holthuis, 1960 (Decapoda, Scyllaridae) in Amapá State continental shelf of Brazil

The lobster Scyllarus chacei Holthuis, 1960, a species of the family Scyllaridae Latreille, subfamily Scyllarinae Latreille, is reported for the first time from the continental shelf of Amapa State, Brazil. The female specimen was collected on September 31, 2010, at 72 m depth in the shrimp fishing zone of Amapa State (03°53′N 50°19′W), on a muddy bottom. The present record extends the geographic range known for this species in Brazil to the North.